Fuzzy plywood

[Bill Root]

I'm getting ready to repaint the engine and generator rooms on BUFFALO GAL. There are several small areas on the plywood bulkheads where the paint has flaked off and the surface of the exposed plywood has become "fuzzy". Poking at it with an awl the panels also still seem to be solid.

Any ideas on what would cause this fuzziness and how best to repair it? I suppose I can just sand it off before painting, but I'm really curious what would cause the problem. The batteries are housed in the generator room, so could it be caused by gassing from the batteries? That wouldn't explain why it's happening in the engine rooms, though.

 

[bigbill]

bill, any chance water got to that area? i have a spot like you describe under my a c compressors. i think it might be from the sweat that returns back to the compressor on the low pressure line. if its not that, i dont know what else could have caused it.

 

[SKYCHENEY]

Battery acid will cause that.

 

[YBbroke]

Hi Bill,
Being a gen. contractor, this may be a query I can actually help with. A picture of the fuzzy area would be beneficial but I suspect it may be caused by one or two (possibly both) items. I'm assuming marine grade plywood was used and it's not an issue with surface ply delamination. First, I think it's possible that when the primer was applied, the moisture content of the plywood was high and trapped in the wood. Over time this trapped moisture will cause blistering of the paint as it tries to escape into a warm lower humidity environment. Second, if the primer was not allowed adequate curing (drying) time before the finish paint was applied, blistering could result.

Either way, the fuzzies you are seeing are merely small strands of the surface ply curling due to drying below the woods' optimum moisture content. It's not a structural issue. Before you repaint you may want to borrow a moisture meter from a painter and probe the ply in various locations just for peace of mind. Sand any fuzzy areas, primer any bare wood and finish paint after primer recommended cure time. Be sure to check for any unpopped blisters before repainting.

Hope this helps.
Terry

 

[YBbroke]

P.S. It would be VERY beneficial to know what type of paint was used originally ( oil based, epoxy, manufacturer????). The last thing you want is to repaint both rooms and find out there is a compatibility issue.


Experts: Can this be referenced by the hull number?

 

[saltshaker]

I always thought that was from the salt mist from the air intakes. Almost every Hatt I've seen has fuzzy wood in The ER were the intakes pass through the floor.

 

[SKYCHENEY]

Interlux Bilgekote is an exact match to the OEM stuff. I think that's what it is. Basically just a standard oil based paint like Rustoleum.

 

[dsharp]

You just need to paint it with something that will dry hard enough to stand the fuzz up so you can sand it off. I always assumed it was from the fir plywood that was used.

 

[34Hatt]

I always thought that was from the salt mist from the air intakes. Almost every Hatt I've seen has fuzzy wood in The ER were the intakes pass through the floor.

This is also what I was told by many and had it near my intakes and some spots on the bulkhead. I got it good and dry sanded lightly and coated it with Epoxy, let it soak in re-coat a few times leveled it off with epoxy and filler prime and paint. Did this in 2006 still perfect.
If its fuzzy there is no paint left so no need to worry about what was done way back when!

 

[Boatsb]

You just need to paint it with something that will dry hard enough to stand the fuzz up so you can sand it off. I always assumed it was from the fir plywood that was used.

Don't you mean "Fur" plywood?

 

[rsmith]

It's Dry Rot.


http://en.m.wikipedia.org/wiki/Dry_rot

 

[34Hatt]

It's Dry Rot.


http://en.m.wikipedia.org/wiki/Dry_rot

Sorry I have disagree this is not like dry rot and doesn't even look the the picture in the link.
Dry rot gets soft through out this is just a surface thing very different when you see it. I would say its close to a mold type of thing then Rot

 

[rsmith]

Sorry I have disagree this is not like dry rot and doesn't even look the the picture in the link.
Dry rot gets soft through out this is just a surface thing very different when you see it. I would say its close to a mold type of thing then Rot

Fungi/mold

"Dry rot refers to wood decay caused by certain species of fungi, also known as True Dry Rot"

 

[YBbroke]

Hey Bill,
Did you get this fuzzy issue figgered out? If so, what was it? I have a differing opinion than Mr. Smith but would rather keep it to myself if the problem is solved. He looks rather formidable standing in that doorway. ; >

Terry

 

[rsmith]

I've seen this a lot over the years on all different kinds of boats. It's always in an area that has been exposed to salt water spray and saturated with salt yet it's in an area that is not truly wet. Engine vent areas especially. The areas are never wet but the salt crystals hold moisture in the top layer of the wood. I have an area over one of my raw water pumps where the seal had sprayed the engine hatch above the pump. It didn't spray for more than a couple hours but a couple months later the fuzzy wood started. I've scraped the wood in these areas down to good wood resined painted and it still comes back. Their was a product called "git rot" years ago don't know if that would work or not.

 

[Bill Root]

Sorry for the delayed response...been away from the computer for the past week.

I appreciate all the advice. The problem is behind and around the plate that holds the main engine raw water strainer, and also part of the shelf that the generator sits on. I'm inclined to think it is probably surface rot caused by salt water getting under the paint.

I plan to scrape off all the loose paint, then use Smith's clear penetrating epoxy sealer (CPES) to saturate the effected area. I've used this product as a first coat sealer under varnish with great success on my antique wood runabout and on the handrails of the 43' Hatteras I sold to Robby and Bren. The runabout was varnished nine years ago, the handrails about five. There is still no varnish peeling.

Once the CPES has soaked into the wood fibers and dried I should be able to sand the area smooth, prime and paint. My plan is to paint a section at a time, removing the clamps that hold down the stuff that's fastened to each section, paint behind the stuff, then re-fasten the stuff with new padded clamps. I think I'll try Sherwin Williams industrial enamel for the bulkheads. They have a wide color selection and it's easy to get. I used it on one of my boat trailers and it seems to hold up well.