Will wet plywood shrink back to it's original size when dry?

TQA

TQA

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My galley worktop has two square hinged opening doors for my top loading fridges.

The base material is 5/8th plywood covered in a formica like material. When single handed I only use one fridge and did not open the other for two months. When I tried opening it, it was stuck shut. I eventually managed to open it and it was clear that water had got in and had caused the plywood to swell. As a temporary fix I removed the edging strip to get some clearance.

Will the plywood return to its original size when dried out. I am in the tropics so drying out is not a problem.

What I don't want to happen is to glue the side strip back on and refit the door only to find it has stuck again. It was a week long struggle to get it open last time.
 
If soaked through and swollen. No not to original size but it will shrink a bit as it dry's out. It will probably delaminate to some extent depending upon how wet. Marine ply is more resistant. Exterior Ply is more resistant.
regular ply, not so much.
Not as bad as OSB or Pressboard.
 
Uricanejack said:
If soaked through and swollen. No not to original size but it will shrink a bit as it dry's out. It will probably delaminate to some extent depending upon how wet. Marine ply is more resistant. Exterior Ply is more resistant.
regular ply, not so much.
Not as bad as OSB or Pressboard.
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+1 Once it's got far enough to be a problem, it's usually too far gone to recover.
 
There is a very small amount off delamination and it looks like it is fairly good quality plywood as there are 5 equal layers. The boat was built in 1978 in the US and I suspect that the galley is original.

I guess I will let it dry out and soak everything in epoxy before clamping it up to fix the delamination then shave some off the end before fixing the end strip back on. I am not looking forward to the shaving as I will be working up to top formica layer which is still mostly firmly glued on. I have a surform hand plane which I will use for the shaving but is there a better tool. You never know I might find it in the local hardware store here in the Eastern Caribbean.

BTW The sun is shining the trades are blowing at 10 to 15 knots and the water temp is 81 F. So I will be sweating buckets as I fix this.
 
TQA said:
There is a very small amount off delamination and it looks like it is fairly good quality plywood as there are 5 equal layers. The boat was built in 1978 in the US and I suspect that the galley is original.

I guess I will let it dry out and soak everything in epoxy before clamping it up to fix the delamination then shave some off the end before fixing the end strip back on. I am not looking forward to the shaving as I will be working up to top formica layer which is still mostly firmly glued on. I have a surform hand plane which I will use for the shaving but is there a better tool. You never know I might find it in the local hardware store here in the Eastern Caribbean.

BTW The sun is shining the trades are blowing at 10 to 15 knots and the water temp is 81 F. So I will be sweating buckets as I fix this.
Click to expand...

You might manage Ok with a sureform - but a belt sander would be a lot quicker if you can get your hands on one.
 
>There is a difference between plywood and marine plywood
>>Not necessarily.

The is a Dutch marine ply, from memory one of the Kuyper products, that has a 25 year gurantee after it was suberged for 25 years and didn't delaminate.
 
KellysEye said:
>There is a difference between plywood and marine plywood
>>Not necessarily.

The is a Dutch marine ply, from memory one of the Kuyper products, that has a 25 year gurantee after it was suberged for 25 years and didn't delaminate.
Click to expand...

A non-sequitur gilded by sloppy typing (or thinking). Keep it up, KellysEye, your reputation is safe.
 
>The is a Dutch marine ply, from memory one of the Kuyper products, that has a 25 year gurantee after it was suberged for 25 years and didn't delaminate.
>>A non-sequitur gilded by sloppy typing (or thinking). Keep it up, KellysEye, your reputation is safe

It's true.
 
KellysEye said:
>The is a Dutch marine ply, from memory one of the Kuyper products, that has a 25 year gurantee after it was suberged for 25 years and didn't delaminate.
>>A non-sequitur gilded by sloppy typing (or thinking). Keep it up, KellysEye, your reputation is safe

It's true.
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The marine ply that you happened to mention may indeed be splendid stuff. I've no reason to doubt you on that. But if your intention was to be helpful to the OP, you might have directed him to a source of it rather than offer a blinkered precis of something you turned up on the web which offered a view on the subject of plywood in a country to which neither you, me, nor the OP have convenient access. To repeat: the expression 'marine ply' is meaningless in many parts of the world. It is not defined, except on the whim of the supplier.
 
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TQA said:
soak everything in epoxy
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Epoxy penetrates very little - I can't remember the figures, but it certainly doesn't soak, it coats. As builder of a couple of epoxy/ply boats I think it's great as a glue, but over-rated as a sealer. It needs UV protection, it's brittle, it doesn't wear all that well, it's very difficult indeed to top-up, especially if over-coated with UV protection.
 
macd said:
Not sure UV degradation is a telling factor on the underside of a fridge lid, Max.
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Edges. And they're open some of the time. I wouldn't be happy with any epoxy coating that wasn't UV protected.

Why not a one-pack polyurethane? You can get as good protection as with epoxy, and easy to top-up, which in a used boat is vital.
 
Max Campbell said:
Edges. And they're open some of the time. I wouldn't be happy with any epoxy coating that wasn't UV protected.

Why not a one-pack polyurethane? You can get as good protection as with epoxy, and easy to top-up, which in a used boat is vital.
Click to expand...

When I finish the repair no plywood will be exposed to sunlight, in fact it will be totally covered with a formica style laminate on the top and sides plus a stepped grp underside.

After drying I will warm the wood before painting on some warmed West system epoxy then some clamps to hold the layers and top formica layer.. When that is green I will epoxy on the edging strip I removed and pray that I removed enough wood on the edge to get a good fit.
 
>To repeat: the expression 'marine ply' is meaningless in many parts of the world. It is not defined, except on the whim of the supplier.

I have been holding this off to see how any times macd will say that marine ply is meaningless. When I bought our steel boat the owner is a shipwright who can make anything in wood and specialises in teak decks. I had worked out the the space on the aft deck could take a box that I could put all our warps in, a petrol container and spare gas cylinder. I asked he was happy to do it and he said yes. SIT DOWN FOR THIS MACD.

He recommended Dutch marine ply and explained why. When I picked up the box it had a small curve in the bottom that matched the deck shape at the bottom of the box and to my surprise a nicely curved lid. If a shipwright says there is marine ply I believe him.
 
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