GB2131741A

GB2131741A - Panel repair method

Info

Publication number: GB2131741A
Application number: GB08332959A
Authority: GB
Inventors: Ronald William Jenkins
Original assignee: Individual
Current assignee: Individual
Priority date: 1982-12-10
Filing date: 1983-12-09
Publication date: 1984-06-27
Also published as: GB2131741B; GB8332959D0

Abstract

A method of repairing a damaged panel comprises cutting out the damaged area, making a keying formation on a repair element and on the edge of the panel surrounding the cutout, inserting the repair element into place and applying a hardenable filler to the keying formation to bond the repair element to the panel.

Description

SPECIFICATION Repair method and materials This invention relates to panels ahd the like, typically panels made of the material known commercially as FRP (fibre-reinforced plastics), and more particularly to such panels and the like constituting parts of transport containers.

When damage occurs to such panels it is necessary to cut away the damaged portion and create a convenient repair area, then insert a filler element, and secure the filler element in position in a secure and permanent manner and preferably with both surfaces of the repair area flush with the remainder of the panel.

The object of the present invention is to provide an improved method for the repair of panelling including FRP panelling which fulfils these requirements.

According to the present invention, a method of repairing a damaged area of a panel, e.g. an FRP panel, comprises the steps of: (i) cutting away part of the panel, to include the damaged zone, to provide therein a cut-out area of predetermined size and shape, (ii) forming along at least part of the edge of the panel material, bounding the cut-out area, a keying formation, (iii) preparing a repair element, of similar panel material, having a keying formation along at least part of the edge thereof, of such shape and dimensions as to fit within the cut-out area with a small spacing from the edge of the main panel, (iv) inserting the repair element into the cut-out area substantially in the same plane, (v) applying a hardenable filler material to the gap between the main panel and the repair element, including the keying formation of both the panel and the repair element, (vi) making the hardenable material flush with the panel and allowing it to set, or allowing the hardenable material to set and then making it flush with the panel.

The term "keying formation" is intended to convey that the formation is adapted to resist deformation by force applied in both directions normal to the plane of the panel and of the repair element. Preferably, the "keying formation" is in each case a doubly undercut formation.

In a preferred form, the doubly undercut formation is a V-shape with the point of the "V" directed towards the cut-out area (on the panel) and with the point of the "V" directed towards the panel (on the repair element).

A preferred angle of the "V" cut formation is about 450 to the plane of the bounding surfaces of the panel and of the repair element.

Certain FRP panels comprise an FRP skin and a liner of for instance a rigid plastics foam. The present invention may be applied to such a panel incorporating a liner.

Accordingly, the invention includes according to a second aspect a method of repairing a damaged area of panel comprising a skin and liner which method comprises the steps of: (i) cutting away part of the panel, to include the damaged zone, to provide therein a cut-out area of predetermined size and shape, (ii) preparing a liner repair element of similar liner material, (iii) in either order, bonding the liner repair element to the adjacent liner in the cut-away area and shaping the liner material of the panel adjacent the skin bounding the cutaway area and the adjacent edge of the liner repair element to form a trench in said liner material extending beneath the skin of the panel bounding the cutaway area as a first undercut formation, (iv) preparing a skin repair element, of similar skin material, of such shape and dimensions as to fit within the cut-out area with a small spacing from the edge of the skin of the main panel, but overlying the trench at the edge of the liner repair element whereby to define a second undercut formation between the skin repair element and liner repair element, (v) inserting the skin repair element into the cutout area substantially in the same plane as the skin of the panel, (vi) applying a hardenable filler material to the spacing between the skin of the panel and the skin of the repair element, including the undercut formations of both the panel and the repair element, and (vii) allowing the hardenable material to set.

A preferred hardenable material is that known commercially under the trade name UREFIX which is a urethane-based sealant and adhesive for which no primer is required and which is compounded to self-cure at a relatively rapid rate, e.g. about 3 hours at a minimum application temperature of 50C. UREFIX is distributed in the U.K. by Kent Industries of Billingshurst, Sussex, England.

In the drawing:- Fig. 1 is an elevation of part of a damaged panel to be repaired; Fig. 2 is an elevation of the panel with damaged part removed to provide a cut-out area; Fig. 3 shows the panel with a repair element inserted; Fig. 4 is a cross-section to a much enlarged scale, to show adjacent edges of the panel and repair element; Fig. 5 is a view similar to Fig. 4, after insertion of the hardenable filler material.

Fig. 6a to 6c show stages in a repair carried out according to a first embodiment in accordance with the second aspect of the invention; Fig. 6d is an enlarged view of the circled area of Figure 6c.

Fig. 7a to 7d show stages in a repair carried out according to a second embodiment of the second aspect of the invention.

The panel 1 has a damaged zone 2, e.g. a cut or split.

Referring to Figure 2, an area 3 (including the damaged zone) is cut-out of the panel.

Referring to Figure 4, a repair element 4, of the same panel material, is inserted in the cut-out area 3, leaving a gap 5 between the two.

Referring to Figure 4, the edge 6 of panel 1, and the edge 7 of repair element 4 are both cut at 450 to result in a V-formation each directed towards the other.

Referring to Figure 5, with the repair element 4 suitably supported in position by any convenient temporary retaining means (not shown), the gap 5 between the panel and the repair element is filled with hardenable filler material 8, such as UREFIX.

When the filler material has hardened, the retaining means are removed. The repair element 4 is then keyed extremely firmly in position flush with the panel 1 at both surfaces, and with the joint and repair substantially as strong as the remainder of the panel.

Such a method permits repair to be effected with a much reduced time, use of labour, and cost of material, as compared with previously known methods, and results in a repair which leaves the panel both adequately strong and of good appearance. If the filler material is not flush when hardened, it can be readily rubbed down to surface level.

Figure 6a shows damage 12 in a container panel 1 A cut-out area 13 is removed from the panel in the first stage of the repair.

Figure 6b shows in section the repair area. The panel 11 is made up of a kin 20 of FRP material bonded to a liner 21 of rigid plastics foam.

In the second stage of the repair a liner repair element 1 4a exactly filling the cut-out area 13 in the liner is inserted into place and bonded by suitable adhesive edge to edge with the surrounding liner. A "V"-shaped trench 23 is cut along the join of the liner of the panel and the liner repair element. The trench extends beneath the edge 1 6 of the panel skin, which is thereby left overhanging an undercut formation. The included angle of the "V"-shaped trench is about 450.

In Figure 6c, a skin repair element 1 4b has been inserted into the cut-out area 1 3 flush with the panel skin but spaced therefrom. The skin repair element I 4b is bonded face to face with liner repair element 1 4a by a suitable adhesive which may also coat the "V"-shaped trench.

The top margin of the skin of the panel and of the skin repair element have been cutaway to form a further trench of "V"-shape of similar shape and dimensions to that in the liner. The two "V"-shaped trenches are overlying and are connected by a gap surrounding the skin repair element.

In Figure 6c, and as seen in detail in Figure 6d, the gap has been filled with a hardenable filler material 1 8 which fills both "V"-shaped trenches and has been made flush with the skin surface.

A method as illustrated in Figure 6 is particularly applicable to containers of the "Concargo" type.

Figure 7a shows a container 31 having damage 32 and a cut-out area 33.

Figure 7b shows in section the structure of the walls of container 31. A skin 40 of metal such as "Duramin" overlies a liner 41 a of rigid plastics foam which is sandwiched between skin 40 and a lining skin 41 b of material similar to or the same as skin 40.

As shown in Figure 7b a liner repair element 34a comprising a top layer of liner 41 a to a lower layer of lining skin 41b has been prepared to be an exact fit in cut-out area 33.

The liner repair element has been bonded edge to edge with the edge of the panel bounding the cutout area 33 by a suitable adhesive.

The liner 41 a of the panel and of the liner repair insert has then been cut to form a "V"-shaped trench 43 around the join, extending beneath the skin 40 of the panel.

The top surface of the liner repair element and the trench 43 are coated with adhesive.

As shown in Figure 7c, and enlarged in Figure 7d, a skin repair element 37b is bonded to the top of the liner repair element 34a leaving a circumambient gap between the skin of the panel and the skin repair element. The gap is over- filled with hardenable filler which fills the gap and the "V" trench beneath as well as lying over the outer surface of the skin repair element 34b.

The last described method is particularly suitable for the repair of containers of the "Conair" or "Reefer" type.

It will be appreciated that the invention is not restricted to the particular details described above with reference to the drawings, but that numerous modifications and variations can be made without departing from the scope of the invention.

Claims

1. A method of repairing a damaged area of a panel comprising the steps of: (i) cutting away part of the panel, to include the damaged zone, to provide therein a cut-out area of predetermined size and shape, (ii) forming along at least part of the edge of the panel material, bounding the cut-out area, a keying formation, (iii) preparing a repair element, of similar panel material, having a keying formation along at least part of the edge thereof, of such shape and dimensions as to fit within the cut-out area with a small spacing from the edge of the main panel, (iv) inserting the repair element into the cutout area substantially in the same plane, (v) applying a hardenable filler material to the spacing between the main panel and the repair element, including the keying formation of both the panel and the repair element, and (vi) in either order, making the hardenable material flush with the panel and allowing the hardenable material to set.

2. A method as claimed in Claim 1 wherein the keying formation in each case is a doubly undercut formation.

3. A method as claimed in Claim 2 wherein the doubly undercut formation is provided by the facing edges of the panel and of the repair element each being of a "V" shape with the point of the "V" of the panel directed towards the cut-out area and the point of the "V" of the repair element directed towards the panel.

4. A method as claimed in Claim 3 wherein the included angle of the said "V" shapes is about 45".

5. A method of repairing a damaged area of panel comprising a skin and liner which method comprises the steps of: (i) cutting away part of the panel, to include the damaged zone, to provide therein a cut-out area of predetermined size and shape, (ii) preparing a liner repair element of similar liner material, (iii) in either order, bonding the liner repair element to the adjacent liner in the cut-away area and shaping the liner material of the panel adjacent the skin bounding the cutaway area and the adjacent edge of the liner repair element to form a trench in said liner material extending beneath the skin of the panel bounding the cutaway area as a first undercut formation, (iv) preparing a skin repair element, of similar skin material, of such shape and dimensions as to fit within the cut-out area with a small spacing from the edge of the skin of the main panel, but overlying the trench at the edge of the liner repair element whereby to define a second undercut formation between the skin repair element and liner repair element, (v) inserting the skin repair element into the cutout area substantially in the same plane as the skin of the panel, (vi) applying a hardenable filler material to the spacing between the skin of the panel and the skin of the repair element, including the undercut formations of both the panel and the repair element, and (vii) allowing the hardenable material to set.

6. A method as claimed in Claim 5, wherein the cut away profile of the liner repair element is a chamfer.

7. A method as claimed in Claim 5 wherein the cutaway profile of the liner repair element and the undercut formation of the liner of the panel when adjacent together form a "V" shaped groove.

8. A method as claimed in any one of Claims 5 to 7 further comprising forming a trench along the exposed join of the skin of the panel and the skin repair element which trench also in step (vi) is filled with the hardenable filler material.

9. A method as claimed in any one of Claims 5 to 8 comprising making the hardenable material, before or after setting, flush with the skin surface of the panel.

10. A method as claimed in any preceding claim wherein the hardenable material is a urethane-based adhesive.

11. A method as claimed in any one of Claims 1 to 10 wherein the at least the skin of the panel is of an FRP material.

12. A method of repairing a damaged area of a panel substantially as hereinbefore described with reference to Figures 1 to 5, 6a to 6d or 7a to 7d of the accompanying drawings.