Alternatives to the MDF plate

Mostly Printed CNC - MPCNC Advice
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Hi everyone!

I’m having a bit of a problem here and would really like to hear your opinion.

 

The thick mdf plate (800x700x35mm) I had warped before I even got a chance to finish my build.

I live near the ocean without AC so it’s rather damp all year round. The plan is to have the MPCNC sit on a table rather than being a table itself.

Right now my options are limited since shipping something that big is costly…

Stuff like “enhanced” wood panels (Valchromat, hydrophobic panels and such) should do the trick, but the only local reseller of valchromat sells the entire panel (~240€); regular hydrophobic is a little less expensive but still gotta buy the entire thing. Kitchen counters are also expensive…

An aluminum plate would work, but no one sells something that big locally.

Then there are plastic cutting boards. I may be able to get a custom sized HDPE cutting board from a kitchen shop. Way cheaper than the wood panels.

But I have no idea if that’s a good material, if it will remain dimensionally stable, or at least do better than MDF.

Anyway I thought about using that, with a metal sheet covering the entire plastic plate from the well-insulated heated bed.

 

Or should I just bite the bullet and get the Valchromat?

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Laminated 18mm mdf isn’t an option?

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I’d try a leveling bit to take out the warping in the MDF, then seal it with something like a wipe-on poly (i.e. polyurethane mixed with mineral spirits). Thinned poly will soak right into the MDF and may require multiple treatments. I’ve had good luck with this in other settings where pieces were submerged in water for short periods of time. I’m thinking of this being a cheap and simple solution.

You could also try hardboard (the stuff they make pegboard out of, but without the holes). It doesn’t usually come as thick, but you could just use it for the top layer of the spoilboard, combined with something more substantial underneath. I find it to be resilient to getting wet, but it might also benefit from the thinned poly treatment that I mentioned above.

As for HDPE, I think it is to slick to use for this purpose.