WO2021068043A1

WO2021068043A1 - A method of applying a two-component coating material on a surface using a portable hand held spray gun

Info

Publication number: WO2021068043A1
Application number: PCT/AU2020/051096
Authority: WO
Inventors: Travis BAENSCH
Original assignee: Woodside Energy Technologies Pty Ltd
Priority date: 2019-10-11
Filing date: 2020-10-12
Publication date: 2021-04-15

Abstract

A method (100) of applying a two-component coating material on a surface includes separately decreasing the viscosity of each component of the two-component coating material from that at ambient temperature and pressure. This may be achieved by separately heating the components. The heated components are mixing to form a discrete batch of the two-component coating material is supplied in a container adapted for connection to a hand held portable spray gun that is untethered or otherwise connected to an apparatus used for heating of each component. The spray gun is then operated within the pot life of the coating material to spray the batch of the two-component coating material on the surface.

Description

A Method of Applying a Two-Component Coating Material on a Surface Using a

Portable Hand Held Spray Gun

Technical Field

A method of applying a two-component coating material on a surface is disclosed. The method involves applying the coating material by use of a hand held portable spray gun.

Background Art

Two-component coating materials, such as two-component epoxy resin coating materials, may be applied on a surface by brush or by spray depending on various factors such as: the material properties of the coating material; and, the result sought to be achieved. Due to the relatively high viscosity of these materials they are applied either by brush for small areas or by complex expensive big scale spray equipment including plural spray system for larger surface areas. The cost of these system may be in the range of AU$100,000 - AU$150,000.

A plural spray system often includes a feed system for feeding the components from individual tanks to a proportionating unit. The proportionating unit meters these the components to a mixer at a designated ratio. The mixer is carefully designed and operated to minimise the likelihood of foaming. Heaters may also be used in as part of the plural spray system. These may include individual heaters for tanks holding the components or in-line heaters. A circulation system moves separate components of the coating material from the containers, through the proportioning unit and a hose bundle to a connected hands sprayer.

There appears to be a need in the market for a unique way of applying a two or plural component coating which provides better surface finish than a brush but does not require the complex expensive and physically large spray systems which also have limited mobility.

Summary of the Disclosure

In a first aspect there is disclosed a method of applying a two-component coating material on a surface, the method comprising: separately decreasing the viscosity of each component of the two-component coating material from that at ambient temperature and pressure; mixing the viscosity decreased components to form the two-component coating material; supplying a batch of the formed two-component coating material to a hand held portable spraying device untethered to an apparatus used for decreasing the viscosity of each component; and operating the spraying device to spray the batch of the two-component coating material on the surface.

In one embodiment separately decreasing the viscosity of each component comprises separately heating each component of the two-component coating material to a predetermined temperature.

In a second aspect there is disclosed a method of applying a two-component coating material on a surface, the method comprising: separately heating each component of the two-component coating material to a predetermined temperature; mixing the heated components to form the two-component coating material; supplying a batch of the two-component coating material to a hand held portable spraying device untethered to an apparatus used for heating of each component; and operating the spraying device to spray the batch of the two-component coating material on the surface.

In one embodiment the mixing comprises transferring respective quantities of each component into a standalone container and mixing the components in the container to form the batch of the two-component coating material.

In one embodiment the transferring comprises pouring respective quantities of each component into the container subsequent to being heated, or having its viscosity reduced.

In one embodiment supplying the batch comprises connecting the container to the spraying device.

In one embodiment the method comprises bleeding air from the container after being connected to the spraying device and before operating spraying device to spray the batch.

In one embodiment the method comprises: after spraying the batch, passing a cleaning fluid through the spraying device. In one embodiment passing the cleaning fluid through the spraying device comprises attaching a container holding a volume of cleaning fluid to the spraying device and operating the spraying device.

In one embodiment the method comprises disconnecting the container holding cleaning fluid from the spraying device and operating the spraying device to flush the cleaning fluid therefrom.

In one embodiment the method comprises: when the hand held portable spraying device includes a demountable filter in a flow path between the container and a spraying orifice of the spraying device, removing the demountable filter prior to spraying the batch.

In one embodiment each component is heated to a temperature in a temperature range between 55^eC and 70^eC inclusive.

In one embodiment the batch of the two-component coating material supplied to the spraying device has a temperature between 55^eC and 65^eC.

In one embodiment the two-component coating material has a first viscosity in a range between 5 Pas (pascal-second) and 25 Pas inclusive at a temperature of 23^eC, or any sub range within that range for example, but not limited to between 5 Pas and 23 Pas; or, between 5 Pas and 15 Pas; or between 6 Pas and 15 Pas; or between 5, or 6, or 7, or 8, or 9, or 10, or 11 , or 12, or 13 or MPas and; 16 or, 17, or 18, or 19, or 20, or 21 , or 22, or 23, or 24, or 25 Pas; at a temperature of 23^eC.

In one embodiment the two-component coating material has a first viscosity in a range between 7 Pas and 10 Pas at a temperature of 23^eC.

In one embodiment the two-component coating material, when formed by mixing the heated components, has a second viscosity that is less than the first viscosity.

In one embodiment operating the spraying device comprises spraying the batch of the two- component coating material at a pressure of up to 5000psi inclusive. In one embodiment wherein the two-component coating material has a density in a range in the order of between 1 and 2 g/cm³ at a temperature of 23°C.

In one embodiment the two-component coating material is a two-component solvent-free modified polyamine cured epoxy system.

In one embodiment the method comprises using as a first of the two-component system, a base component which includes one or more non-crystallisable epoxy resins, and using as a second of the two component system, a hardener.

In one embodiment, wherein the spraying device comprises an electrically operated motor, a pneumatically operated motor, or a hydraulically operated motor.

Brief Description of the Drawings

Notwithstanding any other forms which may fall within the scope of the disclosure as set forth in the Summary, specific embodiments will now be described, by way of example only, with reference to the accompanying drawings in which:

Figure 1 is a flow chart of a method of applying a two-component coating material on a surface in accordance with an aspect of the present invention;

Figure 2 is a flow chart of a method of applying a two-component coating material on a surface in accordance with another aspect of the present invention;

Figures 3(a) - (b) are side view photographs of a heating system used in accordance with an embodiment of the present invention;

Figure 4 is a photograph of a heating system used in accordance with another embodiment of the present invention; and

Figure 5 is a top view photograph of a container filled with a two-component coating material in accordance with an embodiment of the present invention. Detailed Description of Embodiments

Embodiments of the present disclosure seek to provide a method of spraying a two- component coating material on a surface without the need for the traditional large expensive plural type spray systems.

Figure 1 shows a flow diagram of a method 100 of applying a two-component coating material on a surface in accordance with a first aspect of the disclosed method. The method 100 comprises at step 102 separately decreasing the viscosity of each component of the two-component coating material from that at ambient temperature and pressure. At step 104, the method 100 comprises mixing the viscosity decreased components to form the two- component coating material, and at step 106 a batch of the formed two-component coating material is supplied to a spraying device. At step 108, the method 100 comprises operating the spraying device to spray the batch of the two-component coating material on the surface.

The mixing step 104 can be performed by transferring prescribed amounts of each heated component into a common container, then mixing the components for example with a mixing stick or other mechanical device. Each component may be transferred by pouring prescribed amounts into the common container. In order to maximise the pot life of the mixed components, the container may be one that is adapted for coupling to a spraying device. In this way the time between mixing the components and the commencement of spraying can be reduced by not needing to subsequently transfer the mixed component from the container to another container or cup that is specifically designed for attachment to the spraying device. For example, when the spraying device is a handheld portable spray gun having a cup or canister for holding a batch of material to be sprayed, then the separately heated components can be transferred into and mixed in that cup or canister. It should be appreciated that in this instance the mixing takes place in a standalone container that is not physically connected with a device or apparatus used for heating the components. To provide context in one example if the spraying device were the GRACO^® XForce FID heavy duty cordless airless sprayer, then the transferring of the heated components and the subsequent mixing would occur in the demountable material cup of the sprayer.

The method 100 may have application in various industries, including, however not limited to, applications in the oil and gas industry or the marine industry for applying protective coatings to the surface of plant and equipment including pipes. In accordance with an embodiment, the two-component coating material has a viscosity in a range between about 5 and 25 Pas at a temperature of 23^eC and a density in a range in the order of between 1 and 2 g/cm³ at a temperature of 23 ^eC.

In broad terms, in one embodiment the two-component coating material comprises as a first component a base component which includes one or more non-crystallisable epoxy resins, and as a second of the two component system, a hardener. In one, but non-limiting embodiment, the two-component coating material is a two-component solvent-free modified polyamine cured epoxy system sold under the brand name Humidur® FP Brush, which has a first viscosity of 8.8± 1 Pas at a temperature of 23^eC and has a density of approximately 1.13 g/cm³ at a temperature of 23^eC. One component of the Humidur® FP Brush coating material is a base component which includes one or more non-crystallisable epoxy resins, high-tech modifying agents and elastifiers, lamellar abrasion and impact resistant fillers, and colouring pigments. The second component is a hardener containing a polyamine hardener complex. The two-component solvent-free epoxy system Humidur® FP Brush is well-known for providing protection to surfaces exposed to extreme corrosive environments.

It will however be understood that embodiments of the dislcosed method are not limited to the two-component coating material being a two-component solvent-free modified polyamine cured epoxy system, such as the Humidur® FP Brush product.

In accordance with an embodiment, to separately decrease the respective viscosity of each component of the coating material, each component of the coating material may be heated to a predetermined temperature. Figure 2 specifically illustrates a flow diagram of a method 200 of applying a two-component coating material on a surface in accordance with a second aspect, wherein at a step 202, each component of the two-component coating material is separately heated to a predetermined temperature. At step 204, the method 200 comprises mixing the heated components to form the two-component coating material, and steps 206 and 208 are essentially the same as steps 106 and 108.

In a particular embodiment, each component is heated to a temperature in a range between 55^eC and 70^eC, such as between 55^eC and 65^eC. The temperature range between 55^eC and 65^eC is chosen such that the coating material formed by mixing the heated components has a second viscosity at the temperature between 55^eC and 65^eC that is less than the first viscosity at 23^eC, and that is suitable for achieving an even spraying of the coating material on the surface using a hand held portable spray gun. The formed coating material having the second viscosity is suitable for application on the surface using a spraying device which forces the material under pressure through an orifice or nozzle having a given opening size, shape and angle, so that the formed coating material can be atomised to produce an even spray of particles or droplets. The temperature range 55^eC - 65^eC is particularly appropriate for the Humidur® FP Brush two-component solvent-free modified polyamine cured epoxy system.

It will however be appreciated that for two-component materials other than the Humidur® FP Brush product, the temperature range may not be limited to between 55^eC and 70^eC or between 55^eC and 65^eC and each component may be heated to a temperature in a temperature range between 55^eC and 70^eC inclusive.

The heating step 204 may be performed in many ways including but not limited to:

1 . placing each component in separate canisters and heating the separate canisters in a common heater;

2. placing each component in a separate canister and heating the separate canisters in separate heaters;

3. placing each component in a heating chamber of separate heaters.

Also heat transfer can be accomplished in various ways including but not limited to: a. application of microwave energy directly to the components; b. thermal conduction via heating solution (which may optionally be EX rated) which in turn may be heated by an electric power source, e.g. a heating blanket, or a further heating fluid such as glycol or heated air; c. exothermic reaction which may heat the components directly or via a heating solution.

Also, during heating the components may be stirred or otherwise agitated to promote uniform heating.

More specific example of methods and apparatus for heating the complete will now be described.

A first quantity of a first component of the two-component coating material is placed into a first container, such as a first canister, and a second quantity of the second component of the two-component coating material is placed into a second canister. The first and second canisters are each placed into a drum containing a heating solution classified as safe for use in hazardous areas, such as an EX rated heating solution. The outside wall of the drum is surrounded by a heating device in the form an electrically heated jacket coupled to a thermostat. The first and second components are thus heated through the transfer of heat from the electric blanket to the heating solution and through the canister to the respective component.

Alternatively, it is envisaged that the first and second canisters simultaneously be placed in a drum containing a heating solution (which may or may not be EX rated) with the outside wall of the drum surrounded by a heating device in the form an electrically heated jacket coupled to a thermostat.

In accordance with the present example, the first and second components are heated to a temperature in a temperature range between 55^eC and 65^eC in order to have an optimum viscosity and allow (once the first and second components are mixed, and a batch of the formed coating material is supplied to a spraying device) even spraying of the coating material using the hand held portable spray gun.

Figures 3(a) - (b) illustrate an example of a drum 300 used to heat the first and second components (not shown). An electrically heated blanket 302 is positioned around the drum 300 and surrounds the outer wall of the drum 300. The electrically heated blanket 302 is coupled to a thermostat 304. In order for the first and second components to reach a temperature between 55^eC and 65^eC, the thermostat temperature may be set to a temperature between 65^eC and 70^eC, and heating to the required temperature of each of the first and second components in the respective canisters through the heating solution may take approximately three hours depending on the respective amounts of the components being heated and volume of the heating solution.

In another alternative embodiment, it is also envisaged that a first quantity of a first component of the two-component coating material be placed directly into a first drum such as drum 300 and heated to a temperature between 55^eC and 65^eC by means of the electrically heated blanket such as blanket 302, and that a second quantity of the second component of the two-component coating material directly be placed into a second drum such as drum 300 and heated to a temperature between 55^eC and 65^eC by means of an electrically heated blanket such as blanket 302. The first and second drums may be equipped with a stirring or agitation means for stirring/agitating the respective components during the heating process, wherein the respective components can be heated in a relatively homogeneous manner. In an alternative heating system that may also be used to separately heat the first and second components, the first and second components may each be heated using microwaves wherein the first and second components may each be placed into a respective suitable container into a microwave oven.

It is also envisaged to use a heating chamber, such as vessel 400 illustrated in Figure 4. The vessel 400 may contain a heating solution 402, such as, but not exclusively, the EX rated heating solution mentioned above, and be coupled to a heating device 404, which may for example be an electric heating device. The vessel 400 may further comprise an inside wall 408 and an outside wall 408’ with the space between the inside wall 408 and the outside wall 408’ defining a region 410 which may be filled with a heating fluid such as glycol. Each component may be held in a respective canister 406, 406’ placed in the vessel 400 and surrounded by the heating solution 402. The heating device 404 is equipped with a thermostat for heating the heating fluid in the region 410, wherein, by thermal conduction, the EX rated heating solution 402 is subsequently heated and the first and second components in the respective canisters 406, 406’are heated to a temperature in the range between 55^eC and 65^eC. It is also envisaged that the canisters 406, 406’ be placed in respective vessels of the vessel type 400 containing a heating solution (EX rated or otherwise) 402, wherein the heating of the respective components in canisters 406, 406’ occurs independently as described in relation to Figure 4.

In another alternative embodiment, a relatively high quantity of the first component may be placed inside a first large vessel, such as vessel 400, and a high quantity of the second component may be placed inside a second large vessel, also of the type of vessel 400. In this embodiment, each of the first and second components may be heated to a temperature between 55^eC and 65^eC by heat transfer from the heating fluid in region 410, the heating fluid being heated using the electric heating device 404 equipped with a thermostat. The respective large vessels containing the first and second components may further comprise a stirring or agitation means for stirring/agitating the respective components during the heating process such that the respective components can be heated in a relatively homogeneous manner. Such embodiment may be advantageous for separately heating respective high quantities of the first and second components and maintaining the heated first and second components at the required temperature between 55^eC and 65^eC so that several batches of the first and second components can be supplied to one or more spraying devices as needed. The temperature of each component can then be measured using an infrared laser thermometer and once the components are heated and have reached a temperature between 55^eC and 65^eC, a respective amount of the components, selected in accordance with the manufacturer’s product instructions, is transferred in a container wherein the components are mixed together thoroughly. At a temperature between 55^eC and 65^eC, the respective viscosities of the components of the two-component solvent-free modified polyamine cured epoxy systems including, but not limited to, that sold under the brand name Humidur® FP Brush are such that they can be relatively easily mixed with a mixing stick. When the heated components are mixed, the coating material having the second viscosity is formed, the second viscosity being less than the first viscosity at 23^eC and CSS750Pa, i.e. less than 8.8 ± 1 Pas. While the Humidur® FP Brush solvent-free modified polyamine cured epoxy system has a pot life of 25 minutes at a temperature of 23^eC, this pot life is shortened to approximately 5 minutes when heated at a temperature in the range between 55^SC and 65^eC. This reduction of the pot life of the Humidur® FP Brush coating material is in part due to the fact that this coating material is solvent-free. Further, an exothermic reaction occurs when the first and second components are heated and mixed, which contributes to a fast curing process of the coating material.

It is further to be noted that if the temperature of the mixed heated coated material is less than in the range between 55^eC and 65 ^eC, the respective viscosities of the components and further formed coating material will be affected, which may cause fingering and an uneven spray pattern when the coating material is sprayed on a surface using the spraying device.

If, however, the first and second components are overheated, and the formed two- component coating material has a temperature that exceeds a temperature of 65^eC to 70^eC, the pot life expectancy of the Humidur® FP Brush coating material will be substantially shortened.

Once mixed, a batch of the formed coating material is supplied to the hand held portable spray gun. The amount of formed coating material to be supplied to the hand held portable spray gun is typically chosen to allow for the entire amount of formed coating material to be sprayed out of the hand held portable spray gun prior to the expiration of the coating material’s pot life. For example, approximately 1 kg of Humidur® FP Brush epoxy system the pot life is approximately 5 minutes at a temperature between 55^eC and 65 ^eC. To be supplied to the hand held portable spray gun, the batch of the coating material (formed by mixing the components in a container) may be poured into a further container arranged to contain approximately 1 kg of coating material and then mounted on a hand held portable spray gun. Alternatively, the container in which the heated components are mixed to form the coating material may already be arranged to contain approximately 1 kg of formed coating material and be directly suitable for mounting on the hand held portable spray gun. Taking into account the exothermic reaction that occurs when heating and mixing the components to form the coating material, the temperature of the batch of the coating material may further be measured prior to being supplied to the hand held portable spray gun to ensure that it has a temperature between 55^eC and 65^eC.

Figure 5 shows a canister/cup 500 comprising a batch of the coating material 502, having its temperature measured using the infrared laser thermometer 504 prior to mounting the canister/cup 500 onto the hand held portable spray gun (not shown). In Figure 5, the thermometer 504 indicates that the temperature of the coating material 502 is 62.7^eC. The coating material 502 thus has the required temperature for the canister 500 to be supplied to the hand held portable spray gun and for the spraying of the coating material to be performed.

The hand held portable spray gun used for spraying the formed two-component coating material is in the form of a portable handheld airless and cordless electrical spraying gun which is not tethered to a hose bundle through which the material is pumped.

The spray gun is then operated to spray the formed two-component coating material having a temperature between 55^eC and 65^eC onto a surface of a substrate. The spray gun may be operated at a pressure suitable for spraying high viscosity solvent-free products, such as, but not limited to, the two-component solvent-free modified polyamine cured epoxy system Flumidur® FP Brush having the second viscosity at a temperature between 55^eC and 65^eC. In accordance with an embodiment, the spray gun may spray the coating material at a pressure of up to at least 3000 psi or more, for example 5000 psi.

It will however be understood that the supplied coating material may be sprayed at a pressure in any sub-range within the range between 3000psi and 5000psi depending on the coating material, the viscosity of the coating material, and the effect to be achieved when spraying on the surface if the substrate using the spraying device. For example, the supplied coating material may be sprayed at a pressure in sub-ranges between any one of: 3000, or 3100, or 3200, or 3300, or 3400, or 3500, or 3600, or 3700, or 3800, or 3900 psi and, any one of: 5000, or 4900, or 4800, or 4700, or 4600 or 4500, or 4400, or 4300, or 4200, or 4100 psi. Due to the substantially shortened pot life of a two-component solvent-free modified polyamine cured epoxy system such as, but not limited to Humidur® FP Brush, at a temperature in the range between 55^eC and 65^eC, the mixing step 204, supplying step 206 and operating step 208 should occur sequentially in a swift manner. Once the whole batch of coating material supplied to the spray gun has been sprayed, steps 202 to 208 may be repeated. It is in this situation advised to have a person mixing a further kit of heated first and second components to form the coating material in preparation for when the spray gun, operated by another person, needs to be supplied with more coating material.

The two-component solvent-free modified polyamine cured epoxy systems also have a rapid curing process. This rapid curing process, along with the exothermic reaction occurring when the first and second components are heated and mixed, will typically lead to the two- component coating material curing within the spray gun if it is not washed quickly after spraying is complete. It is consequently imperative that once spraying has been completed, the spray gun is washed without delay.

A user should thus ensure to have a cleaning material cup filled with a cleaning product appropriate for removing the coating material. For example, when the two-component solvent-free modified polyamine cured epoxy system is Flumidur® FP Brush, the cleaning product Humiclean® (which is a bio-degradable, non-toxic and non-VOC cleaning agent which is composed of: a reaction mass of dimethyl adipate and dimethyl glutarate and dimethyl succinate; and methanol) may be used. The cleaning material cup filled with the cleaning product should be suitable for mounting onto the spraying gun and ready to attach to the spray gun when spraying of the coating material is complete and it is time to wash the spray gun. The inside of the spray gun may be cleaned by spraying the cleaning product into, for example, a bucket. Another reservoir filled with the cleaning product and a brush should also be at hand to clean the outside of the gun and the spray tip. The wash out process may be repeated several times to ensure that the spraying gun remains clean internally and in good working order. The container in which the heated components were mixed to form the coating material, and/or the container in which the batch of coating material was contained may further be cleaned after use using the cleaning product or may alternatively be disposable.

One, but not the only, handheld airless spray gun well suited for an embodiment of the disclosed method is the previously mentioned GRACO® XForce FID Heavy Duty Cordless Airless Sprayer. This is a hand held spray gun having a rechargeable battery for driving an electric motor which in turn operates a pump to draw fluid from a demountable material cup that has a screw-on lid and seats a replaceable liner. The liner can be taken out or placed in the cup when the lid is removed. The lid has a one way valve to allow for the escape of air from the cup when fitted to the gun. The material is pumped from the cup, through a filter, a front shut off valve and a spray tip assembly having a spray tip that can be turned between SPRAY and UNCLOG positions. The spray gun has a manually operable pressure control knob to adjust the spraying pressure and a pressure relief valve/prime valve.

One possible sequence of steps for applying a two-component solvent-free modified polyamine cured epoxy system such as the commercially available Humidur^® FP Brush using the GRACO^® XForce FID Heavy Duty Cordless Airless Sprayer or similar sprayer is as follows with a starting set up being that the spray gun has not previously been used to spray the epoxy system:

1 . Reduce the viscosity of each of the two components of the epoxy system by heating them separately to a temperature of between 55°C-65°C.

2. Transfer respective volumes of each of the heated components into a mixing container in the prescribed epoxy resin to hardener ratios of about: 3.7:1 by weight or about 3.475:1 by volume, and thoroughly mix the components together, for example using a mixing stick.

3. Pour the mixed Humidur® FP Brush epoxy system into a liner which has been place in, or is to be placed in, the material cup and screw the lid on tightly. Squeeze as most of the air out of the material cup as possible by pressing on the liner as the cup is being attached to the gun. Once tightly fitted, bleed any remaining air out of the cup by squeezing it and allowing air to escape through the one way air valve on the top of the cup lid.

4. Prime the gun by lifting the prime valve handle located on the side of the gun. Set pressure control knob to the highest pressure setting. On the GRACO^® XForce gun this is done by turning knob to the “11 ” setting for extremely thick material. Pull trigger on the gun to allow priming of the gun to occur. This is normally accompanied by a change in the sound of the gun as the material flows into the gun body. The prime valve handle can then be pushed back to the down position.

5. The spray gun is now ready to spray the mixed epoxy resin coating. Transit to the spray site and completion of spraying the contents of the material cup needs to be accomplished with the short pot life window of the material which in this instance is about 5 minutes. Within this time: a. Move as quickly as possible to the application site. b. Optionally conduct a test the spray application first before applying to surface and ensure the product is spraying evenly through the spray fan. This may involve adjusting the pressure control knob. c. Apply the material in a swift manner.

6. Squeeze the material cup as spraying progresses to ensure all the coating is being used.

7. If more than one cup (i.e. one batch) of coating is needed for the job it is recommended to have another person mixing the next batch of heated components ready for when the applicator has exhausted the contents of the material cup connected to the gun. At this time, the exhausted cup is disconnect from the gun, and either (i) the lid is removed from the cup and the fresh batch is poured into the cup, optionally given a quick mix, and the lid reattached to the cup and the then reconnected to the gun; or (ii) the next mixed batch is pre poured into a replacement cup/liner and the lid attached, so now the applicator simply disconnects the exhausted cup and connects the replacement cup.

8. At the completion of spraying, be it a single batch or more than one batch where successive batches are sprayed substantially continuously and within the remaining pot life of the last sprayed batch, clean the gun and its components by: a. attach a material cup with a liner holding a volume of cleaning fluid to the gun. In one embodiment the volume may be in an amount to fill the cup but in another embodiment the volume may less, for example in an amount between 1/3 to 2/3 the volume of the cup; or about one half the volume of the cup. Filling the cup with the cleaning fluid to a volume of less than the full volume of the cup may assist in reducing handling and wastage of the cleaning fluid; b. place the prime/pressure relief valve in the UP position; c. set the pressure control knob to a low pressure setting, for example on the GRACO^® X Force a setting of “1 ”; d. turn the spray gun upside-down and operate the gun for several seconds (e.g. 3- 8 second, or 4-6 seconds or 5 seconds); otherwise simply operate the gun for the immediately previously mentioned time period; e. turn the spray tip to the UNCLOG position (assuming it is not already in that position), place the prime/pressure relief valve to the spray position down and operate the gun for a few seconds such as up to 3 second, or for about 1 -2 second. The cleaning material can be sprayed into a waste container; f. toggle the prime/pressure relief valve to release pressure for the gun. Conveniently this can be done when the gun has been turned back to a right- side up orientation, assuming it had been previously turned upside down; g. remove the material cup; h. toggle the prime/pressure relief valve down to the spray position and operate the gun to discharge fluid from the pump; i. toggle the prime/pressure relief valve up and operate the gun to finish flushing material from the gun.

Optionally, prior to step 1 above, the filter in the gun which is held between the spray tip assembly and the pump, can be removed. Removing the filter may be beneficial to minimise the risk of uneven/non-uniform spray pattern or gun failure whilst using a rapid cure two- component solvent-free modified polyamine cured epoxy system.

If the gun does not produce enough pressure to achieve an acceptable spray pattern, the spray tip can be removed and replaced with one having a smaller orifice size.

It will be understood that cleaning products other than the Humiclean® product are envisaged to clean the spraying gun as deemed appropriate to the type of coating material used.

Embodiments of the present method enjoy numerous benefits over known methods which rely on continuous spraying using large pumps which are permanently connected by hoses to a heating and mixing station. These include but are not limited to:

• low capital cost of the equipment needed to perform embodiments of the disclosed method in comparison to the above-mentioned prior art by at least a factor of 10;

• lower labour cost with a team of only two people being needed over a team of four to operate the prior art spray systems;

• the ability to apply the coating to difficult to reach locations for example at elevated locations where it is logistically very difficult if not impossible to locate the prior art heating, pumping and mixing equipment; for example, an operator can easily scale a ladder or operate a winch/pulley on a spraying platform while holding or carrying the self-contained fully portable, self-powered untethered spray gun;

• no need for support equipment such as gensets, laydown space and compressors;

• enables the spray on application of a coating for a relatively small area which has benefits over using a brush in terms of coating uniformity and completeness, but also can be used for large areas; and

• easier handling and manipulation of the spray gun because it is untethered by hoses to a supply of the mixed material to be applied. In the claims which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary implication, the word “comprise” or variations such as “comprises” or “comprising” is used in an inclusive sense, i.e. to specify the presence of the stated features in various embodiments of the invention.

Modifications and variations as would be apparent to a skilled addressee are determined to be within the scope of the present invention.

Claims

1 . A method of applying a two-component coating material on a surface, the method comprising: separately decreasing the viscosity of each component of the two-component coating material from that at ambient temperature and pressure; mixing the viscosity decreased components to form the two-component coating material; supplying a batch of the formed two-component coating material to a hand held portable spraying device untethered to an apparatus used for decreasing the viscosity of each component; and operating the spraying device to spray the batch of the two-component coating material on the surface.

2. The method of claim 1 , wherein separately decreasing the viscosity of each component comprises separately heating each component of the two-component coating material to a predetermined temperature.

3. A method of applying a two-component coating material on a surface, the method comprising: separately heating each component of the two-component coating material to a predetermined temperature; mixing the heated components to form the two-component coating material; supplying a batch of the two-component coating material to a hand held portable spraying device untethered to an apparatus used for heating of each component; and operating the spraying device to spray the batch of the two-component coating material on the surface.

4. The method of any one of claims 1 -3 wherein the mixing comprises transferring respective quantities of each component into a standalone container and mixing the components in the container to form the batch of the two-component coating material.

5. The method of claim 4 wherein the transferring comprises pouring respective quantities of each component into the container subsequent to being heated, or having its viscosity reduced.

6. The method of claim 4 or 5 wherein supplying the batch comprises connecting the container to the spraying device.

7. The method of claim 6 comprising bleeding air from the container after being connected to the spraying device and before operating spraying device to spray the batch.

8. The method of any one of claims 1 -7 comprising, after spraying the batch, passing a cleaning fluid through the spraying device.

9. The method of claim 8 wherein passing the cleaning fluid through the spraying device comprises attaching a container holding a volume of cleaning fluid to the spraying device and operating the spraying device.

10. The method of claim 9 comprising disconnecting the container holding cleaning fluid from the spraying device and operating the spraying device to flush the cleaning fluid therefrom.

11 . The method of any one of claims 1 -10 comprising, when the hand held portable spraying device includes a demountable filter in a flow path between the container and a spraying orifice of the spraying device, removing the demountable filter prior to spraying the batch.

12. The method of any one of claims 2-11 , wherein each component is heated to a temperature in a temperature range between 55^eC and 70^eC inclusive.

13. The method of any one of claims 2-11 , wherein the batch of the two-component coating material supplied to the spraying device has a temperature between 55^eC and 65^eC.

14. The method of any one of the preceding claims, wherein the two-component coating material has a first viscosity in a range between 5 Pas and 25 Pas inclusive at a temperature of 23^eC.

15. The method of any one of the preceding claims, wherein the two-component coating material has a first viscosity in a range between 7 Pas and 10 Pas at a temperature of 23^eC.

16. The method of any one of claims 2-15, wherein the two-component coating material, when formed by mixing the heated components, has a second viscosity that is less than the first viscosity.

17. The method of any one of claims 1 -16, wherein operating the spraying device comprises spraying the batch of the two-component coating material at a pressure of up to 5000psi inclusive.

18. The method of any one of the preceding claims, wherein the two-component coating material has a density in a range in the order of between 1 and 2 g/cm³ at a temperature of 23°C.

19. The method of any one of the preceding claims, wherein the two-component coating material is a two-component solvent-free modified polyamine cured epoxy system.

20. The method of claim 19 comprising using as a first of the two-component system, a base component which includes one or more non-crystallisable epoxy resins, and using as a second of the two component system, a hardener.