altertantive material to mdf for spoilboard

[DanOSB]

for spoilboard ill be routing some aluminum sheets and will have a coolant for it.. so i would need something that is water proof.. maybe plastic but would rather have something soft like mdf and hopefully they do come in 5x10 sheet too

any suggestion?

[Hirudin]

I've only done one job that needed a spoil board, I used a piece of acrylic for it. I figure it's waterproof, readily available, cheap (buy remnants from plastic supply stores), and is probably fairly uniform in thickness (I haven't measured any though). I tried it first without coolant which didn't work too well, but with coolant it worked great.

[CarveOne]

Lay a sheet of 4mil or 6mil polyethlene sheeting (painter's drop cloth material) over your table to protect the table, then use scrap MDF for the spoil board on top of the sheeting. Unless you cut through the sheeting it won't leak.

You can also make a wood frame to staple the sheeting to in order to form a "pan" to contain the fluid. Make the frame as large as your table to keep splatter off of the table top.

Where you have to put holes in the sheeting for clamping, use some thin adhesive foam insulation strips to form a gasket.

CarveOne

[analogman]

I have not found a good solution for this either, so I just use the MDF, and then a light amount of coolant, so it does not soak to far into the spoil board. Then I resurface for the next job. Not sure if this can work for your jobs though.

Since our shop really only uses the CNC once per week or so, it allows time for the wet MDF to dry between jobs. We also schedule the Aluminum cutting as the last job.

[ger21]

You could try Medex, which is a water resistant MDF.
http://www.sierrapine.com/index.php?pid=68

[DanOSB]

will look into that one.. seems perfect material..

im not sure if im still getting that job cutting 4x8 sheet of alumimum 3/4 inch thick

would be nice if i get it and run the coolant pump and leave it running for a while till the job is finished

[rowbare]

If you aren't cutting one of the really sticky grades of aluminum, why not just just cut it dry or with a bit of WD40.

[DanOSB]

cutting 6061 alum and from my experience when i cut it dry it will heat up the bit really fast and i dont want stand by the machine all day (i think its aprox 8 hrs of cutting for that whole sheet (i cut it .02 per step using 1/4 bit) unless someone has a better trick..

[Miguel-]

Why not to use a lacquer at the table? a fine layer of it sould prevent coolant from soaking to table. I think that you can surface the lacquer if its not planar.

[Hirudin]

Originally Posted by DanOSB ...cutting 4x8 sheet of alumimum...

Oh, you're talking feet aren't you? When I read "5x10" in the OP I figured you meant 5" x 10" How big will the parts be when they're done being cut? Does the spoilboard need to be one solid piece or can it be several pieces laid out in an array? How much are you willing to spend?

Have you thought about using machinable wax?
Here's an idea, how about a big sheet of that pink foam/insulation? (This stuff.)

[analogman]

Wow, between the Medex and the rigid foam insultation, I think there is a solution out there...

The only problem I have with sealing MDF, is that all my work is cut through, then the coolant gets under the sealing. For others, it might not be a problem.

[CarbonKevin]

Based upon the heat issue, this seems to be right up your alley...

http://www.vortec.com/cold_air_guns.php

If not that, then perhaps a setup that mists coolant across your bit, with a suction tube on the other side to keep it from dripping down onto the spoilboard?