Patching Delaminating Plywood

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Sockeye
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Patching Delaminating Plywood

Post by Sockeye »

There's a roughly 3"x12" section of bulkhead in the v berth that is delaminating. I assume it is plywood. I'm planning on cutting the section out with an oscilatting multitool and filling in with epoxy and fiberglass. Does this make
sense? Has anyone done something similar?
20191018_085155.jpg
Thanks.
1966 Alberg 30
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atomvoyager
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Re: Patching Delaminating Plywood

Post by atomvoyager »

I can't tell from the photo if that is the top skin delaminating from the plywood or formica on top of ply or something else but cutting into it will tell you what it is. If the other side of the bulkhead looks fine then maybe it's just that top skin coming off. You can use the oscillating tool or even a small circular saw with the blade depth set shallow if you don't want to cut all the way through the bulkhead. If the repair goes deep and the other side is hidden in a locker it may be easier to cut all the way through with a jig saw and patch in new ply with epoxy and a single layer of glass if needed to strengthen it. But a shallow cut first to see what the problem is makes sense. Let us know what you discover.
svMira
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Re: Patching Delaminating Plywood

Post by svMira »

A laminate router, one of those with a small base can make a flush recess that can be dealt with easily by virtue of the consistency of depth of cut. Just one more option. There are many.
Marvin - s/v Mira - 1971 Pearson Wanderer #174
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Sockeye
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Re: Patching Delaminating Plywood

Post by Sockeye »

Re atom: I'm pretty sure it's straight plywood, I made a small cut with an utility knife to see. The other side of the bulkhead is in the head, so it would be easy to just cut that section out totally and patch new plywood in (although it's have to read up on how to do that). I'll be gone from the boat this next week, but will update when I get back.

I purchased her (a 1966 Alberg 30) a few weeks ago and have a lot of projects to do; I'm sure I'll be asking this forum more questions as I move down the work list. Thanks guys.
1966 Alberg 30
Sockeye
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Re: Patching Delaminating Plywood

Post by Sockeye »

Cut in with the oscilatting multitool (which worked great) and it looks like formica, or something equivalent, on top of ply.

Debating what to do about the patch... The piece I cut out is warped, maybe I'll just glass it - - I'm repainting the interior anyway. I have another section to cut out here; decisions, decisions.
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1966 Alberg 30
Sockeye
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Re: Patching Delaminating Plywood

Post by Sockeye »

Decided to epoxy it. It was my first time working with epoxy, and added in colloidal silica. Came out a bit too thick, somewhere between mayo and peanut butter. As you can see the finish is bumpy, and the silica wasn't completely dissolved. Going to sand tomorrow.
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atomvoyager
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Re: Patching Delaminating Plywood

Post by atomvoyager »

By now you've discovered how hard colloidal silica (West 406) is to sand particularly when applied that rough. I hit it first with an angle grinder with 36 grit pad or other sander/grinder tool rather than a slow random orbital sander to knock it flat then fill with an easy sanding filler like West 407 and then use the random orbital.
svMira
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Re: Patching Delaminating Plywood

Post by svMira »

...and get yourself a dust shroud for your angle grinder if you don't have one already.

https://www.amazon.com/HERZO-Universal- ... 198&sr=8-4

I picked up this one, but it only fit on a 'harbour freight' type angle grinder that I had about. Not the nicer DeWalt ones that I regularity use. Point being, connected to a shop vac it is the difference between an insane level of dust and only mildly annoying. You still gotta cover up though.
Marvin - s/v Mira - 1971 Pearson Wanderer #174
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