GB2329133A

GB2329133A - Keying vehicle bodies and vehicle body parts.

Info

Publication number: GB2329133A
Application number: GB9715753A
Authority: GB
Inventors: Stephen Alan Jones; Andrew Paul Lawton
Original assignee: REFINISH SYSTEMS
Current assignee: REFINISH SYSTEMS
Priority date: 1997-07-26
Filing date: 1997-07-26
Publication date: 1999-03-17
Also published as: GB0003995D0; WO1999005234A1; AU8455698A; GB2343188A; GB9715753D0

Abstract

A method of preparing a vehicle body part comprising applying a solid, granular abrasive powder to the surface of the body part, rubbing to obtain a key and then removing the powder. A powder composition for use in carrying out this method may comprise equal proportions of calcined alumina, pumice, and calcined china clay, and is used substantially dry.

Description

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2329133 Keying Vehicle Bodies and Vehicle Body Parts

This invention relates to a method of keying vehicle body parts and to a composition for use in carrying out this method. In particular, this invention relates to a method of keying metal or plastic body parts of landborne vehicles and to a composition for use therein, however, the method and composition have uses in relation also to waterborne and airborne vehicles. References to vehicles in this specification should be construed as references to landborne, waterborne or airborne vehicles unless the context suggests otherwise.

It is already known that vehicle bodies and vehicle body parts are keyed prior to applying one or more surface coatings such as refinish primers, base coats, lacquers and top coats. Such keying provides a surface preparation which ensures that the desired coating is suitably adhered to the surface of the vehicle body or vehicle body part. This has traditionally been carried out using abrasive papers, abrasive cloths, abrasive creams or shaped abrasive paper disks or the like (for use with orbital sanding machines).

1 2 3 4 6 7 8 9 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 2 These all have disadvantages such as that they do not provide an evenly keyed finish, they are impractical in difficult areas such as under door handles and often cause breaking through on the edges and chines of body parts to which a surface coating has been applied. The abrasive creams have the further disadvantage that they contain a relatively low percentage of abrasive component, thereby requiring considerable work to obtain the desired finish, with the associated loss of time in carrying out the task. Problems also occur wherein abrasive papers become clogged with particles of the body part or surface coating which is being keyed, hampering the operation.

According to a first aspect, the present invention provides a method of preparing a vehicle body part comprising the steps of:

(i) applying a solid, granular abrasive powder to the surface of the body part; (ii) rubbing the abrasive powder into the surface of the body part until an even key is obtained over at least a portion of the surface of the body part; and (iii) removing the abrasive powder.

Preferably the method of preparing the vehicle body part also includes the step of applying a surface coating to the keyed surface of the body part. The surface coating may be a refinish primer, a base coat, a lacquer or a top coat. Alternatively, the method may include the step of applying a polishing compound to the keyed surface of the body part and polishing the keyed surface to obtain a suitable finish.

The method may be used to provide a keyed surface upon 1 3 1 2 3 4 6 7 8 9 11 12 13 14 15 16 17 18 19 21 22 23 24 25 26 27 28 29 31 32 33 34 35 36 an uncoated body part prior to applying a surface coating. Alternatively, the method may be used to provide a keyed surface upon a body part which already has one or more surface coatings.

Preferably the abrasive powder is rubbed into the surface of the body part manually, utilising suitable applicator means. Preferably the applicator means is a damp cloth. Alternatively, the applicator means may be an electrical power tool.

Preferably the abrasive powder is removed by being wiped or blown off the surface of the body part. Alternatively, it may be removed by being washed off the surface using a suitable liquid.

According to a second aspect, the present invention provides a composition in the form of a solid, granular abrasive for preparing a vehicle body part for the application of a surface coating or for the carrying out of a finishing process, the powder comprising pumice, calcite alumina and molochite.

Preferably the pumice, calcite alumina and molochite are mixed in an equal ratio by volume of %: 113: 1/3. Alternatively, the ratio of pumice, calcite alumina and molochite may be varied by increasing the amount of molochite, keeping the ratio of pumice to calcite alumina constant.

Preferably the composition is prepared by mixing and sieving the three components, removing impurities. The particle size of the finished product is preferably no greater than 300 micrometers. A particle size in excess of 300 micrometres may be utilised where a good surface finish is not required. The particle size may 4 1 2 3 4 5 6 7 be determined by the grain size of the sieve used in the preparation of the composition.

Preferably the composition contains the following compounds as a percentage of the total volume of the composition:

8 Compound % by Volume 9 A1203 52.69 S'02 40.76 11 Fe203 1.03 12 Na203 1.45 13 T'02 0.06 14 CaO 0.27 Mgo 0.13 16 K20 2.17 17 Kno 0.03 18 S03 0.07 19 H20 1.34 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 The chemical analysis of the composition may vary depending upon the volume ratio of the pumice, calcite alumina and molochite.

An embodiment of the present invention will now be described by way of example only:

The present invention provides a method of preparing a vehicle body part prior to applying a surface coating to the body part or performing a finishing process upon the body part. The method has applications both in preparing an uncoated body part for the application of one or more surface coatings and also in the application of a further surface coating or for performing a finishing process on a vehicle body part which has already had one or more surface coatings 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 applied to it. A further surface coating is typically required when a vehicle body part becomes scratched or otherwise damaged.

In the case of an uncoated body part, the surface is keyed by applying a small amount of the abrasive powder to the surface and either manually rubbing the powder across the surface area of the body part in a polishing motiont utilising a damp cloth, or by using an electrical power tool with a suitable head attachment. Typically 10-15 grammes of the powder is sufficient for preparing a body part such as a door panel in a medium sized car. Such an operation takes of the order of 45 seconds to carry out in a manual application, providing an evenly keyed surface to the body part. The abrasive powder is then removed either by being simply wiped off or by being blown off using, for example, a supply of compressed gas. The body part is now ready for a surface coating to be applied, the keying on the surface providing adhesion between the surface coating and the surface of the body part in question. This has advantages as compared to the use of abrasive papers or shaped abrasive paper disks for use with orbital sanders, as in such methods, the paper often becomes clogged with residue, particularly when keying a body part which has had one or more surface coatings applied to it.

In applying the abrasive powder to a body part which has already had a surface coating applied, the method is similar. In the case where it is required to perform extensive repair such as in applying surface coatings to a replacement body part in an existing vehicle or in repairing major damage to a body part in such a vehicle, the method enables a good, matched surface finish to be obtained.

1 2 3 4 5 6 7 8 9 10 11 12 13 14 is 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 6 The traditional method of repair includes the practice of "blending", in which, following application of primer and base coat as necessary, the top surface coatings are applied not only to the replacement body part, but also to the neighbouring body parts. The top coating is gradually faded across approximately half the width of the neighbouring parts, in an attempt to produce a colour and shade match. Following this, a transparent lacquer coating is applied to the replacement panel and the neighbouring parts which have been blended in.

The disadvantages of the traditional method are that individual scratches produced by abrasive methods show through the lacquer as black lines, and an uneven key produces a shadow effect.

The method of the present invention provides a good surface finish with an even key and no such individual scratches, and furthermore does not require the "blending" process to be carried out. In the case of an uncoated replacement body part, the surface of the body part is keyed by applying the abrasive compound over the surface until an even key is obtained. Primers and base coats are applied as necessary, with the surface being keyed in a similar fashion between each coating. one or more top surface coatings are then applied, again keying as necessary. When the final coating has been applied, the surface of the coated body part and the neighbouring parts are keyed using the abrasive powder, to obtain an evenly keyed surface. A good surface finish which matches the existing body parts is therefore obtained without the need for "blending". Finally, the method includes the step of either applying a lacquer coating to the replacement body part and the existing body parts, or 7 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 of applying a polishing compound and buffing the surface as necessary.

The method is similar in the case of repairing extensive damage to an existing body part, except that initial repair in the form of reshaping, sanding and filling may be necessary prior to applying a base coat, primer and top surface coatings.

The method further applies to repairing minor scratches to surface coatings on a body part by carrying out the steps of applying the abrasive powder, rubbing the powder into the surface until the scratch is removed and a keyed surface is obtained, removing the abrasive powder and either applying a polishing compound and polishing the surface coating using an electrical power tool with a buffing attachment, to return the surface coating to its original condition, or applying a clear lacquer coating to the keyed surface.

The method further applies to the repair of deep scratches or other such damage where the top surface colour coatings on a body part become damaged. In the case of a long deep scratch, a "blow-in" repair is carried out, wherein a small area of a body part is repainted, avoiding the need for a costly, time consuming repair job wherein one or more body parts are repainted and "blended".

The first step of the method in such a case is to sand the scratch and the area surrounding it along a narrow strip of approximately five centimetres in width. A filler compound is applied if necessary after keying the sanded surface and subsequent base coats, primers and top surface coatings are applied as necessary, with the surface being keyed between each coating. The top 8 1 2 3 4 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 surface coatings overlap the area surrounding the scratch onto the originally coated body part, such that a matched finish can be obtained. After applying the final top surface coating, the scratched area and surrounding body part is keyed using the abrasive composition, and the finished, repaired surface is then lacquered or polished as appropriate. In this way, the finish on the repaired area is matched for colour and shade with the originally coated body part.

The method also permits a good, even key to be applied to the surface of a body part in and around difficult areas such as in door handle recesses, where it is normally difficult to apply a key using conventional methods.

Referring now to the composition of the abrasive powder, the powder includes pumice, calcite alumina and molochite, ideally in an equal ratio of %: %: 'h by volume. The percentage of molochite in this composition may be increased, however it is necessary to keep the proportions of pumice to calcite alumina equal in order to obtain the best results and ensure that the composition is non-porous, this causing problems in removing the composition from the body part. The components of the composition are sieved and impurities are removed before the components are mixed to form the composition. The composition is subsequently sieved to obtain a regulated spread of particle size and hardness, this being necessary to achieve the uniform finish of the method. To obtain a mix suitable for producing a good finish, for example, for car body parts, a sieve is used which produces a composition having particle sizes up to 300 micrometres. A larger, coarser particle size is obtained using a coarser sieve. Such a composition has 9 1 2 3 4 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 uses where it is not required to obtain such a fine surface finish.

The method has the advantage that during use, no dust is produced and furthermore, the contents of the abrasive powder are non-hazardous, nontoxic and do not produce any allergic or narcotic reactions. It is also free of ammonia, asbestos, wax products and any other volatile or organic chemical or solvent, and furthermore is not a pollutant. A chemical analysis of the composition incorporating pumice, calcite alumina and molochite in a IA: 'h: 'h by volume ratio shows that the composition contains the following compounds as a volume percentage of the total volume of the composition:

Compound A1203 S '02 Fe203 Na203 T'02 CaO Mgo K20 MnO S03 H20 % by Volume 52.69 40.76 1.03 1.45 0.06 0.27 0.13 2.17 0.03 0.07 1.34 Modifications and improvements may be made to the foregoing within the scope of the invention.

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34 36 1.

Claims

A method of preparing a vehicle body part comprising applying a solid, granular abrasive powder to the surface of said body part, rubbing said abrasive powder into the surface of said body part until an even key is obtained over at least a portion of said surface of said body part, and removing said abrasive powder.

2.

A method as claimed in Claim 1, wherein a surface coating is applied to the keyed surface of the body part.

A method as claimed in Claim 2, wherein the surface coating is a refinish primer, a base coat, a lacquer, or a top coat.

A method as claimed in any preceding claim, wherein a polishing compound is applied to the keyed surface of the body part to polish the keyed surface to obtain a suitable finish.

A method as claimed in any preceding claim, wherein the abrasive powder is rubbed into the surface of the body part manually utilising a suitable applicator means.

A method as claimed in Claim 5, wherein the applicator means is a damp cloth or an electrical power tool.

Wmethod as claimed in any preceding claim, wherein the abrasive powder is wiped, blown, or washed off the surface of the body part.

11 1 2 3 4 6 7 8 9 10 11 12 13 14 is 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 8. A composition for preparing a vehicle body part for the application of a surface coating or for the carrying out of a finishing process, said composition being in the form of a solid, granular abrasive comprising pumice, calcite alumina and Molochite.

9. A composition as claimed in Claim 8, wherein the pumice, calcite alumina and Molochite' are mixed in an eoual ratio bv volume of 1/3: 1/3: 'h.

10. A composition as claimed in Claim 9, wherein the ratio of pumice, calcite alumina and Molochite' is varied by increasing the amount of Molochite', keeping the ratio of pumice to calcite alumina constant.

A composition as claimed in any of Claims 8 to 10, wherein the composition is prepared by mixing and sieving the three components to remove impurities, and the particle size of the finished product is no greater than 300 micrometres.

12. A composition as claimed in Claim 9, wherein said composition contains the following compounds as a percentage of the total volume of said composition: A1203 - 50-60%, Si02 - 35-45%, Fe203 0.5-1.5%, Na203 - 1-2%, K20 - 1.5-2.5%.