Neodymium Earth Magnets to flatten Material

If material is bowed in the centre and I place a magnet to flatten it, how big of a magnet I need that it will work for 1/8 wood or acrylic? I can get some wood for free but some has serious warp.

I been taping 9 pieces of 3mm x 2mm into squares because I have alot of it when my work tried to scrap 1000 of them (advantages of work dumpster diving) but I think I should just buy a big bar magnet as long as it doesn’t interfere with the head

If you have the board so that the edges curve upwards, then you can pull them down with the ‘hold down pins’ often recommended on other threads, and a quick search will give you a link to the design to cut out as many as you need.
That way you avoid the need for strong magnets, and which I only use for paper or veneer.

John :upside_down_face:


You know that solution was so obvious that of course I didn’t even think of that. I make and use the hold down pins too.




For 95% of what I do (lots of 1/8”stuff) magnets work perfectly well, I almost never use pins because magnets are so easy to use.

(Very) Previously:


i was “all magnets” for a while. and for holding things flat, they work great. but when i started using the pins at work on the universal (stupid aluminum honeycomb), i realized that sometimes the pins work better. holding flat, magnets can do more since you can put them anywhere on top of the material. but for holding material firmly in place, like when you may be trying to see if a complicated cut went all the way through with a pick tool, the pins hold material in place more firmly.