[Kosh]

Hi all, I'm wanting to replace my 1st gen vacuum holding fixtures (MDF with polyurethane sealant) with some less porous to increase the holding power.

My only requirements are that it be dimensionally stable (won't warp!) and non-porous to keep the vacuum in. At this point I don't care so much about cost.

I've tried VHMW from Tap Plastics, but it actually arrived too warped to use.

One of the jigs needs to be about 4" x 28" x 3/4", the largest would be about 16" by 20" min.

So far, it looks like the options are

1) hard acrylic (not sure I like this one as it's so brittle). But IS flat and stable.

2) Corian. I've read good stuff about it, I've also read the opposite (breaks easily, chips easily etc). Seems more positive than bad comments though. Would have to laminate it for thickness.

3) Phenolic resin. Used for TS zero clearance and router tables. Must be stable? I've seen comments about it being a nightmare to work with, but also that it "works easily with carbide tools.

I'll be CNCing all the fixtures of course.

Any input?

Here's a picture of one of the jigs:

Attachment 357898

[cr2]

I vote for corian if you have a free source.

[RCaffin]

19 mm Corian is certainly possible.
But I have also used softer PE on a flat cast iron mill table. Fly cut carefully to get a flat surface with micro-grooving, and use a single central vacuum hole. Put painter's tape around the part edges to seal the vacuum in (so to speak). The micro-grooving will distribute the vacuum fine.

Cheers
Roger

PS: ignore what look like other holes: they are pin location holes, not vacuum holes.