Work with warped plywood

Community Laser Talk
1

Hello, I have some questions about plywood.

  1. How do you deal with warped plywood? I’ve had a few times now where I’ve made a product and the crooked plywood makes the product ugly. Respectively, I know it can probably be done with heat, iron and water. But I have the problem that it has a memory effect and it comes back.
  2. Do you straighten the plywood before using the laser or just clamp it with pins?
  3. How do you store it?
2

I think everyone has this problem from time to time. Typically, it is a question of (poor) quality and or too much tension in the wood due to uneven distribution of the glue or different moisture contents in the layers.
If I have this kind of material, I clamp it down well on my worktop and use it primarily for smaller parts or construction parts which are then pressed during later assembly so that it is not so critical that the parts twist or bend a little.

1 Like
3

Thank you Bernd, maybe it’s time to change suppliers and try someone else too.

4

Plywood can be a real pain
I have roughly 40+ sheets of various thicknesses (1.5mm-12mm) in my shop right now. Poplar ply is the worst. it will warp immediately if the humidity changes.
The best you can do is keep it neatly stacked flat and load something heavier on top. I use a couple of sheets of 19mm MDF to keep it flat. MDF doesn’t move around like wood ply does.
I use pins and magnets to hold down warped ply while it’s cutting or engraving.
Work out where your cut parts will be a strategically work out where you can cut holes so you can insert honeycomb pins or screws to hold your work flat.

5

ok, thank you. I plan to cut smaller boards, about 50x50 cm, and weight them properly to keep it flat.

6

I use 110lb neodymium magnets (https://www.amazon.com/gp/product/B08NVX31VY), that I first place on the honeycomb bed and then another one on top of the plywood (the knobs help me pull them off, they are really strong). It works pretty well as long as it’s not too thick or too warped. I also have some laser cut (out of plywood) and 3D printed hold-downs.

Mag 3
Mag 3844×644 163 KB

7

Hi Paul,
That’s exactly how I hold down warped material.
I like how you’ve attached wooden drawer pulls, excellent idea!
I use spiked garment studs so i can use them as standoffs for odd shaped material and occasionally for painting. After seeing yours i think I might convert some over to drawer pulls.
Cheers!
Rob

8

These are the ones I bought. https://www.amazon.com/gp/product/B0BNT62G1P . Without them the magnets are very difficult for me to take off.