Help needed in selecting 1/4" plywood for a woodie

[Bucko6]

I know there have been a lot of threads about selecting plywood; however, I am hoping to see some discussion tailored to my build question. I am skinning the roof in aluminum and will be doing the exterior sides in 1/4" plywood over framed walls with maple trim. Other than what is at the box stores, I found a local lumber supplier selling made in the USA 1/4 ply. It is a 3 ply verity with very few if any voids. They offer it in birch or oak. They also have a mahogany ply but I have heard bad things about using luan. I do prefer the look of mahogany though and it is about half the price which tells me it is not as good? I will be protecting the plywood and maple trip with I think it is called CEPS and then spar varnish. Any thoughts as to which ply to select? Thank you in advance!

[bve]

If you can, find a boat building shop (kayak builders). They should have marine ply - likely Okume <sp?> - which is very good quality and not terribly expensive when quality is compared to a box store ply.

I will be using 3mm (roughly 1/8") ply.

[doug hodder]

I've built a couple of mahogany woodies using the marine grad ply as the exterior. I also went with the thin ply and laminated it to the substrate 5/8" side. Colonial red dye on it. Luan from a big box store is not the same critter. The difference between the marine grade plies and the others is that the plies are much thicker and not just a thin veneer on top. It can be sanded much more heavily than a veneered ply. You won't find it at any of the big box stores. It has to come from a good grade lumber/cabinate supply house. Some reported that it is treated with chemicals....not the case, it's marine because of the grade of the high grade material in it, no voids/knots and the quality of the glue used in it. To qualify for marine grade it is also tested and registered/stamped like the FDA does on meat. Doug

[Starwatcher]

I will use okume plywood, i know two places who sell it near Montreal. Just hoping they had 1/4 sheets with the grain parallel to the width for the top or the teardrop.

[Bucko6]

Thanks for your input. I did some checking. 1/4" marine ply (nearest I can find is abut 400 miles round trip) runs about $87 per sheet. The cabinet grade birch & oak run about $27 per sheet. My build will take 6 sheets so the difference ends up pretty significant. If anyone else has some insight, I thank you too!

[synaps3]

You're not building a boat, you're building a trailer! With the aluminum skin, I'd go with the cabinet-grade Birch.