Where to buy 1/8 baltic birch ply that isn't warped?

[SolarYellow]

I'm looking to buy some quality baltic birch that I can use in my CNC router that is nice and flat, not bowed, curled or warped. Looking at this listing on fleabay,

1/8" (3mm) by 8" x 12" Baltic Birch 40 pcs- Laser Scroll saw | eBay

Find many great new & used options and get the best deals for 1/8" (3mm) by 8" x 12" Baltic Birch 40 pcs- Laser Scroll saw at the best online prices at eBay! Free shipping for many products!

www.ebay.com

it looks like a good price and might be alright quality. That particular size is just right for the 200x300 bed on my router. I expect some chunks will only be usable for non-critical stuff or in small pieces, and I'll have to sort it by flatness and assign different purposes to the different groups. I'm hoping to end up with a decent percentage that's flat enough for fins and other stuff that matters (like fin-jigging centering rings, for example).

It concerns me that a place selling chunks like that might be a shop that uses a lot for their own work, and is just packaging scrap or (dun-dun-dun) stuff that didn't meet their quality standards and slanging it on fleabay to the unsuspecting.

Has anyone bought from that seller? Or have other recommendations for sourcing?

I included a six-pack of Midwest 3/32 five-ply aircraft plywood in a Black Friday order and it was some of the most warped plywood I've ever seen. Losing a dozen bucks to ship it back to the seller and get a refund.

I'd totally go and sort through a stack of the stuff at a brick and mortar store the way I do for balsa and bass sheets if I'd seen any in a brick and mortar store that was even of a quality to be worth sorting.

 

[rharshberger]

See if you have a local cabinet builders supply or a specialty lumber supply (maybe wholesale only though) in your area (in the PacNorthWest we have Windsor Plywood) the sheets will be 60"x60" and it will be necessary to store it flat (horizontally or vertically) usually with something heavy on it to keep it flat. I store mine on a lumber cart (homebuilt) vertically at about a 75° (-15° vertical) angle between two sheets of 3/4" aka 18mm Baltic Birch ply.

 

[Rocketjunkie]

I got some from ebay and is was crappy. Only 3 plies, the outer ones about 1/64" thick and the center the rest. The center ply was full of holes and cracks. I since have gotten it from aircraftspruce.com The Finnish birch has 5 plys in the 1/8" (3mm) thickness and always has been flat. I have it in 1/32", 1/16", 1/8", 1/4", 3/8", and 1/2". All have been flat and I store them flat under a bed.

 

[cls]

I went through this exercise recently.

Midwest was terrible, 3 ply, warped.

Aircraft Spruce 5 ply was warped.

SIG said it was in stock but then didn't ship for 3 months, wouldn't cancel my credit card charges. they are part time staffed and unresponsive. Even my bank had a hard time squaring up with them.

I gave up. Got some 3 ply Midwest, relatively unwarped, from an ACE Hardware. Big fins for 3" Der Red Max clones. Wish us luck. Some times 3 ply holds together for a few dozen flights.

 

[Bill S]

I've dealt with these guys when I needed some plywood, and the product was fine. Note that this was 6+ months ago, so I can't say anything about current product/stock/prices.
https://woodnshop.net/hardwood-plyw...altic-birch-plywood/baltic-birch-plywood-1-8/

 

[QFactor]

I always buy my 1/8" (6-ply) and 1/4" (12-ply) Baltic birch from Boulter Plywood; https://www.boulterplywood.com/

- You need to select "Products" on the top line of the site.
- Then under the Plywood heading select Multi-Layer Baltic Birch

I got my last 1/8" order back in February. They sell it in 4'x4' sheets, but I have them rip it to 16"x16" pieces.
Of the (9) pieces I only had one with a smidge of warp. Once I strategically cut parts from that piece the warp
shouldn't show up.

I keep the 1/8" plywood stacked flat with books or paper reams stacked on top of the 16"x16" pieces - just to be on the safe side.

 

[Titan II]

What is a good source for quality plywood?

It seems like warped plywood is dominant in the marketplace. What is good source for 1/8 inch birch plywood for fins that is not warped?

www.rocketryforum.com

 

[astronwolf]

I've grown inclined to laminating my project (with balsa or thin plywood) with fiberglass or carbon, and epoxy resin. While still uncured the work is placed on a small sheet of plate glass and the whole thing goes into a vacuum bag. One can get some strong and flat parts, like fins, with this technique. It beats searching for some sort of unobtainium wood products or paying a fortune to have it shipped home.

 

[bibbster]

Why not just flatten it? Lots of ways to do this, but here is a good read.

Flattening Warped Plywood ⋆ ThePlywood.com

Anyone who has had plywood sitting around their garage or workshop for more than a few days knows about the problems of warped plywood. It seems that just about any sheet of plywood is likely to bow or warp, even if stored the “right way.” Once bowed, it’s hard to work with and at times ... Read...

theplywood.com

How to Flatten Plywood - Handyman's World

Handyman's World is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and …

handymansworld.net

 

[Gramparocket]

Sig mfg

 

[cls]

Sig mfg

No. See my post above. They don't have any stock.

 

[Maxx Mayhem]

Plywood will expand on the side exposed to moisture, becoming convex on that side. Much of the plywood which is most susceptible to warpage is produced in China. I built cabinets for 40 years and this problem goes back only several years, as imports became the primary source of plywood fairly recently and most imported plys come in unstable. The best way to get it straight is to place each piece you are preparing to use on some dowels so that both sides get even exposure to the ambient humidity and leave it that way for at least a few days. Papering the fins may stabilize them, but you may want to opt for heavier paper, and it usually works as there is tension on both sides of the fin. Alternately, you could laminate tagboard onto balsa for strong, light, and stable fins. Do both sides at once, use a vacuum bag or a number of clamps with wax paper and a couple of sheets of plywood, and use as little glue as possible to get full coverage.

 

[ghuber]

I’ve had great luck with ocooh hardwoods

Ocooch Hardwoods - Thin Wood for Scroll Sawing, Laser Engraving/Cutting, Woodturning, Intarsia and More

ocoochhardwoods.com