Nevs board repair - PART 1

Winter winds are fickle around here, so its a good time of year to repair broken and damaged equipment. The deck on one of Nevs wave boards had become soft and spongy between front and rear footstraps. I told him he should really fix it pronto before the damaged area spread. I had all the vacuum bagging gear and some left over resin, so all he needed to do was purchase some glass fibre matting and a small sheet of high destiny foam (like Divinycell).

Having had such great success with my previous [ board nose repair ], once again I followed the steps on the [ Board Lady's ] website for repairing a soft deck.

Peel back the EVA deck

Peel back the EVA deck

Nev used a razor to carefully lift the EVA foam layer off the deck and peel it back. Below it is the fibreglass deck which has a sandwich construction of carbon fibre, high density foam, glass fibre and finally the closed cell Polystyrene core. We used our thumbs to press around the damaged area and mark out how far it extended with a pen.

Cut out the damaged area

Cut out the damaged area

From this point on, you need to be wearing a quality dust mask and some eye protection - overalls are not a bad idea either - the glass fibres can get pretty itchy if you get them on your skin.

Next, using the router attachment on my rotary tool with the speed set to the lowest setting (6,000 RPM) and using a bur tip, I cut out the damaged area. You have to be careful not to generate too much heat - by using a low RPM and sharp tool - or the Polystyrene foam core will melt.

The core has separated from the outer layer

This revealed that the core underneath had completely separated from the outer sandwich layer. Some of the high density foam had also been compromised and turned to powder. However, a lot of it was still in good nick. We gradually worked our way out until the area of damaged outer layer was removed. However we did leave a bit of an overlap, where it was still spongy but the outer sandwich layer was intact, because we figured we could fill the void using marine foaming resin injected into the cavity. We picked all the loose material away using a bradawl. I sanded all the edges down flush with my random orbital sander on low speed using course grit paper. Finally I got stuck into it with the shop vac to clear all the dust and debris away.

Fill with foaming resin

Fill with foaming resin

The next step was to fill the voids with marine foaming resin. I purchased this at my local chandlery. I strongly recommend that you test it on piece of Polystyrene foam first just to make sure it doesn't react with Polystyrene and melt it. You need to use a either a pair of syringes or a set of scales to accurately measure both parts so they are in equal proportions. You also have to mix it thoroughly or it won't foam evenly. Working in winter helps because it doesn't react as quickly. On a hot summer day, I would recommend cooling the resins in the fridge before mixing so they react more slowly. We drilled 4mm holes all around the edge, and used another syringe to inject the resin mix into the gap between the outer sandwich layer and the core. You have to work quickly and mix a small amount at a time or it will go off before you have time to use it. Finally I poured about 1/4 of a cup into the middle and placed a sheet of plastic film over it, taped on each side with some Gaffer tape. This provides a little bit of extra positive pressure to make sure the foam pushes into all the gaps and crevasses as it expands. I left this for a few days to cure.

Sand back and feather

Sand back and feather

The foam was sanded back and feathered with the random orbital sander on low speed with course sandpaper. Here you can see the holes (RED ARROWS) where the foaming resin was injected. Holes were drilled all the way around.

Epoxy a layer of glass and high density foam

Epoxy a layer of glass and high density foam

I cut the high density foam into three pieces and proceeded to fit them into the void. I did my best to make it a snug fit, by sanding and shaping the pieces. I use three pieces so they would follow the curve in the deck. When they were ready, I cut out a piece of glass matting and mixed about 1/2 a cup of slow hardening epoxy resin. Using a 1" wide stipple brush, I applied a layer of resin in the void. Next I placed the glass mat on top, pressed it down into the void using the stipple brush and applying extra resin to wet it up toughly. Finally I pressed my high density foam pieces into the resin wetted glass. I applied enough pressure to squeeze some of the resin out between the gaps. I used Gaffer tape to strap the foam to the board to keep it firmly pressing against the resin wetted glass mat. This was left to cure for a few days.

Sand and feather edges

Sand and feather edges

Next I used the random orbital sander with course sandpaper to sand down the excess high density foam and feather the edges. I also used the rotary tool with the bur tip on low speed to remove some of the excess glass mat around the edges first just to make the job a bit quicker.

Fill remaining gaps with foaming resin

Fill remaining gaps with foaming resin

Finally I filled the voids between the high density foam pieces with a small amount of foaming resin. This is better than using straight epoxy, because the foaming resin will have similar flex characteristics to the high density foam, whereas solid epoxy resin may stress this area.

So far so good...

This has been surprisingly quick and easy so far. While it has taken a good week to let each step cure before moving onto the next, the actual amount of time it has take is relatively little. Maybe and hour all up so far.

In PART 2 of this article we apply the outer layer of epoxy glass using a vacuum bagging process to remove air bubbles, sand, feather and fill, and finally use contact cement the stick down the EVA foam. It comes up good as new...

Posted by Henry Thomas, 6 years ago on Thursday, August 11, 2011

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