View Full Version : !@#$%!^&!!!! plywood!

Pernicious Atavist
12-22-2003, 11:01 AM
:mad: okay...the skiff is in its finishing stages. it's made of 1/4 inch bcx plywood, just the typical stuff you find at lowes, etc. i've been building it under cover but took it outside to paint since its been cold here (hi-30's, 40's)and it needs to warm a bit before painting.
NOW large bubbles are forming under the top layer of wood! the only moisture it's been exposed to has been heavy dew.
IDEAS, other than use marine-grade next time?
i'll withhold precise language as to my feelings about this right now since women and children may be reading this.....
happy holidays, etc to you all...
ed :mad: :mad: :mad: :mad: :mad: :mad: :mad:

Dale R. Hamilton
12-22-2003, 11:39 AM
Ed- You should know better by now. Todays plywood is crap- its not even the proper thickness anymore-and some of it ain't even 4X8. Whatdaya expect? Its only good as core for epoxy and fiberglass.

As to what to do now- I'd get it into proper drying conditions- strip off any paint/primer, and let get as dry as it will. Then epoxy hell out of it- glass over, and finish. Keep fingers crossed.

Jim H
12-22-2003, 12:01 PM
Ed, It was outside and you brought it in to paint it? Depending on how long you let it warm up, it's probably outgassing. Let it warm up for about 24 hours then paint.

Pernicious Atavist
12-22-2003, 12:30 PM
no, t'other way around--it was under cover--a carport--and i took it outside to prime it. heck, it's only 50 outside, so outgassing isn't the issue. it's crappy plywood!
YES! i reckon i shoulda known better, but i didn't want to use 'glass, and i can't afford marine ply right at the moment...guess i should painted the heck out of it under cover, hut, what'll happoen once it's in the water?

Bob Smalser
12-22-2003, 12:44 PM
Relax...no big problem on a project that small.

Get the project in where it's not as humid if you can.

Slit each bubble with an X-Acto knife and inject some unthickened epoxy in there. Weight with something with waxed paper beneath so it doesn't stick...I use 25lb bags of shot.

Then do your fabric and epoxy routine...or not...delamming should be less of a problem once the wood is protected from moisture. But I'd probably fabric and epoxy that particular batch of plywood.

[ 12-22-2003, 12:46 PM: Message edited by: Bob Smalser ]

Pernicious Atavist
12-22-2003, 01:04 PM
bob, thanks.
less humid area...hmmm...the living room might do the trick...
i'm really hoping to avoid having to glass this thing! then intent was to give it enough paint as to waterproof it.
this is disappointing, to say the least. a good lesson though.

Jim H
12-22-2003, 01:13 PM
Ed, I mis-read your post, sorry. BCX shouldn't have done that but before I went any further I would seriously consider scraping the whole thing. If you have a bad batch of ply, epoxy will only slow down the delamination. I say "bad batch" because I have left some ACX & BCX outside for over a year without it delaminating. Why waste $100 dollars or more of epoxy and glass (not to mention your time and effort) on $10 plywood?

12-22-2003, 01:57 PM
I've had ABX fir plywood do that to me in a spot or two. Jim's advise would be hard to follow even if you could afford better wood. I guess I'd do as Bob suggests and hope these bubbles represent isolated spots. Finish the boat. If it falls apart in a couple of years you are out your time and not a lot of money. Use and enjoy it while you contemplate the error of your ways and work toward your next one. They only get better the more you build. And bigger and more expensive and.....

12-22-2003, 02:00 PM
I had some ply do that to me also. What I did was cut out the bubble completly. Got down the the next layer and than filled with thickned epoxy and sanded smooth.


Pernicious Atavist
12-22-2003, 02:11 PM
yeah guys...plywood, sheesh. i wanted to do this up right and use lumber, but that was too expensive at the time. reckon i'll cut out the delams and fill them in w/ epoxy. thin lumber's hard to find and costly...shoulda asked santa for a thickness planer..... :(

Bob Smalser
12-22-2003, 02:14 PM
Even the worst "X" plywoods are done with exterior glue and lots of pressure...and sometimes even a tad of quality control.

I don't know why you have some veneer bubbles...but I suspect either a few spots of a contaminant on the veneer or the uneven moisture affecting the plywood stacked in your humid carport causing the outer wood layer to move with enuf force in spots to overcome the glue's strength.

Either way, my guess is that it's isolated....and fixable.

Pernicious Atavist
12-22-2003, 03:05 PM
yeah, bob, that may be the case. i think it's stopped delaming, so i only have a half-dozen spots to fix for a tatol of maybe 2 sq feet, if that. just frustatin, thas all....
okay, i'm gone for a few days, we'll see what pops up!

Captain Pre-Capsize
12-23-2003, 03:26 PM
Well Ed, there is always somebody worse off than you are. Thus:

I did it right and purchased Meranti marine grade 1/4" ply from Florida and had all six sheets trucked here. Cost a fortune for the ply and shipping but by gosh I wanted only the best.

It took six months until I was done with my eleven foot skiff. Six months of winter in a cold garage but I loved building the thing. It was at about the 5 1/2 month mark that I noticed a weird round sheen coming from the interior floor. There was a bubble about two inches across! ARRGGGHH! I couldn't believe it - wanted to scream.

I figured out how to fix it. I don't look at it. :D

[ 12-23-2003, 03:26 PM: Message edited by: Captain Pre-Capsize ]

12-24-2003, 07:43 AM
We have all been penny wise and pound foolish. Speaking who works with plywood all day I can tell you the glues are getting better, but the end product is getting worse. Productivity and efficency have led to real problems. The exact amount of glue needed to glue a layer of ply is known. no extra is used so none is wasted. Itused to be that extra was used and the extra was considered a cost of manufacture. I had a GP rep tell me it is cheaper to do it this way and replace the ply that goes bad (we send back probably about 2%) than to make sure it is all done right. Also younger and younger wood is being used. Remember a small delam in bcx ply probably wouldnt be a problem in a soffit 15' in the air, so it is alright for the use it was intended to serve.

Rick Tuk

solent sailor
12-25-2003, 12:07 AM
My first woodworking teacher, about a thousand years ago, told us that since we were going to put so much energy into whatever we were making, skimping on the materials was wasting ourselves. I've taken that to heart ever since.

No point in putting all that time, effort and heart into a project if the materials are dross. Don't start until you are really ready to do it properly, otherwise what you end up with will be something you don't want.

12-26-2003, 04:18 PM
It's not just the wood in cheaper ply that's bad, it's on glue, some aren't waterproof! :eek:

Pernicious Atavist
12-29-2003, 09:10 AM
well, all, this is god's way of smacking me down for using plywood when i should have used lumber. my next will be with marine grade if the boat is real light , or lumber if not. this one turned out to be challenging to carry canoe-like, as was intended, so real light weight isn't an issue any more. thus, the next will be from lumber!
NOW the problem is that i'm looking for a new career in my old field and i don't know if i'll have time to build a new one. sheesh. anyone working in hazard eval, industrial hygiene or homeland security-type fields out there...and lives near salt water? than it make sense to build a skiff...if not....well.....
oh....sorry....i'm talking boats and inquiring about careers effecting boatbuilding....this ok?
anyway....happy new year to you all!