Jointing the face of Baltic Birch plywood

[Tony Shea]

This is a strange question but I would like to joint the face of a lamination of baltic birch plywood. I laminated 3 pieces together that is 4" wide to make a new crosscut sled. I do not want to joint the edges and will just use my table saw to get this straight. Even though I have carbide cutters I still don't want to put them through the baltic birch laminations.

I did my absolute best in getting this lamination super flat but I do think it has an ever slight twist, and I mean real slight. I have a Hammer A3-31 with spiral cutterhead and was considering taking a super light pass across the jointer on the face of the lamination. Is this a terrible idea? I think I can get the pass across the jointer light enough that it will not go through the face veneer unless I'm miss judging how thick this veneer is on the Baltic Birch. Has anyone done such a thing and am I crazy for considering this?

[Julie Moriarty]

In my experience, even sanding veneer is risky. I have the same JP as you and I would fully expect to lose some of the veneer if I did what you are suggesting. IMHO, if you absolutely need to save the veneer, don't put it through any kind of machine.

[Edwin Santos]

If you are able to do so, I would suggest laminating some veneer on both sides of your lamination. Maybe 1/8" material. Then run that over your jointer just enough to flatten it.
Then through the planer if you need the opposite side true (not sure you do).
This would be safer than running the risk of going through the top BB laminate and hitting the glue line.

But if you're a risk taker, you can do it the way you were planning and be done with it. If you don't hit the glue line, great, and even if you do, it's not the end of the world since your cutters are carbide.

[johnny means]

Just joint it, it's not that serious. What do you think a single pass over the jointer is going to do?

[Frank Pratt]

I wouldn't hesitate to run BB over carbide cutters. Steel cutters are another matter.

[Scott Winners]

If you clamp it out while the glue is drying what happens when the clamps come off? Asking becasue I don't know, I am about to face laminate two layes of BB myself...

[Wes Grass]

I've done a few laminations of BB, clamping with cauls on a granite surface plate. 4 layers of 3/4 for guitar molds. Never got one to come out flat. Even with trying to orient the pieces so the warps should cancel each other out.

Maybe from using wood glue, swelling the surfaces a bit. or just an uneven coating. Might try epoxy the next time. Maybe add some carbon cloth while I'm at it.

An additional layer of hardwood to joint and plane is something else I'd pursue in your case of a smallish piece.

[Richard Coers]

If the twist is ever so slight, I'd use winding sticks and a hand plane. Since they took the formaldehyde out of plywood glue, the adhesive just isn't what it used to be. I'd expect tear out on power machinery. Also if you happen to go through the veneer, or get one side much thinner than the other, I suspect the twist will get worse.

[Bob Falk]

drum sander?

[Peter Kelly]

If the twist is ever so slight, I'd use winding sticks and a hand plane. Since they took the formaldehyde out of plywood glue, the adhesive just isn't what it used to be. I'd expect tear out on power machinery. Also if you happen to go through the veneer, or get one side much thinner than the other, I suspect the twist will get worse.

Even without planing past the top sheet, the veneer will be thinner on one side and probably lead to more warping since the panel would become unbalanced.

[George Yetka]

I would try another method. You could run 4 rails running with the blade and plane them so that the sled is level. That way the 4 rails are your points of contact

[Matt Day]

Joint it, plane it. It’s just wood and glue. Face jointing or planing won’t be pretty afterwards, but edge jointer or planing will work fine. Do stuff like that all the time for ones and twos.

[mreza Salav]

face/edge jointing won't damage the machine if it's not done routinely. Don't worry about that!
If you are thinking if the veneer will be left, the answer is most likely no. As suggest, you can apply a 1/8" or so solid wood veneer on both sides then joint it.

[Tony Shea]

Well I ended up just doing it last night and set my jointer to a very light cut. Like I said the twist was very small. I took 2 passes on the fence lamination face and 3 paces on the back fence that keeps the plywood together after sawing and the method worked amazingly well. The top veneer on the baltic birch is surprisingly thick and I didn't even need to remove half of the layer to get these pieces flat.

Thank you for the replies! I have been a handtool woodworker for years and am just recently getting some machines to fill out the shop. I also rarely work with plywood as it is not hand tool friendly.