help with seaming plywood for a painted finish

[surveytech]

I plan on using a oil paint finish on my tear and will have two seams that will
need to be filled.
What would you recommend to use to fill the two seams?
it's 1/4 inch ply on the roof and they will be backed up with a 2 x 2 .
also the seams will be on the flat parts of the roof, no curves.

I worry that no matter what I do the seams will always show.

Any ideas?

thanks.

Walter

[SteveH]

You could use Bondo body filler and sand it flat. You're right IMHO, it will probably always show.

[SteveH]

On second thought, believe an epoxy with a filler in it would make a stronger joint. You could use micro baloons available from the hobby shop or there is a fiber filler that is used to thicken epoxy called Cabosill, and that might be spelled wrong.

[Steve Frederick]

On second thought, believe an epoxy with a filler in it would make a stronger joint. You could use micro baloons available from the hobby shop or there is a fiber filler that is used to thicken epoxy called Cabosill, and that might be spelled wrong.

While you're at it, get some 'glass cloth you only need to lap about 2" each side. Wood will always move, the 'glass will keep the joint from printing through the finish. You wouldn't need the micro ballons either.
How much cloth would you need. I have some left-overs here, I could mail you a bit!!

[Arne]

I've used a bondo-like product from napa..... it is incredibly strong, stronger than glue for holding pieces together.. Part of the finish problem is that the filler can be sanded more smoothly than wood. So, it stands out because if looks better, not worse. I've used about a quart of autobody filler in mine. It serves a lot of purposes and I really like it.

[jay]

a hundred different products to actually fill the joint. (if it's not too late) chamfer the visible side of the plywood to give the seamfill a place to go and also seal & fill the edges before attaching, taking care to bed them against the batten (with any of the aforementioned sealers).

you can always repair the exposed seam as annual maintenance, but underneath is a one time opportunity...

[Boodro]

Just a thought , has anyone ever cut the edges of the top & side edges at a 45 degree angle , ( like when you make a picture frame) backed by a 1x2 on the inside , glued & screwed together? Would it be strong enough ? Sure seems like it would make a nice clean corner edge. Any thoughts on it?

[DestinDave]

I think the biggest reason a seam might always show is that whatever you use as a filler (Bondo, epoxy, glass, etc.) is going to be smoother and less porous than the surrounding wood. The first couple coats of paint will soak into the wood but not the filler. If you build up several coats of paint and sand in between you can achieve a smooth finish over the full surface that should be nearly invisible.

[Arne]

Seam placement was on my mind when I chopped the top on mine.. wanted the seams in areas that were the least likely to be seen. So, I tried to keep them low on the body, or on top of the roof where they didn't hit me in the eye all the time.

[surveytech]

yes I am laying out the seams on my Rimple so that they fall on the flat part of the roof and the flat part in the front.
Thought this would make for the best seam.

I wonder if its going to show under 2 coats of primer and 2 coats of finish.
(maybe more).

thanks,
walter

[JLaman]

Boat construction faces this problem all the time. Go to some of the many boat building websites and search for "scarf joint" You will be instructed on how to severely bevel the ends of the two pieces of plywood (maybe 20 to 30 degress off the face) with a plane, then flip one of the plywood piceces and epoxy the mating joint. The joint will not be visible, will be water tight, and is stronger than the wood. If it works for a boat floating in water, it will work for a tear!

Jeff L.

[jay]

usually 8 thicknesses

1/4" = 2" scarf

[mikeschn]

Use the fill-it filler as shown in this step...

http://tnttt.com/viewtopic.php?t=5336

Mike...

[Irving]

Perhaps sealing the more major gaps, cracks and screw holes with fill it epoxy while covering the rest of the grain with some type of dry wall mud (to get rid of the texture of the grain) could be a good idea? Anyone tried this?