Re: Using Vacuum to hold down sheet metal.

--- In CAD_CAM_EDM_DRO@yahoogroups.com, John Dammeyer <johnd@...> wrote:

>>> snip
> But do I really need that many.
>>> snip

Thanks,

>
> John
>

John,

I first tried MDF on my vacuum former, and then used the same
principles learned there to build a vacuum table for my micro mill
(but the principle is the same)

I use a few bits of mdf and it works fine

bottom layer 1/4 mdf, overhanging edge of table with hose connection
under, I used a plumbing water tank connector

middle layers hardwood (ramin) 1/2 inch square frame all round the
outside

inside that frame, 1/2 inch mdf with saw slots underneath in one
direction, and on top in the other direction so that they breal into
each other... (its just a spacer)

top layer, 1/4 mdf

wood glue round the edges, but only a few drops in the main area to
stop the inner core from andering

the top and sides were all sealed with sanding sealer (several coats)

in use, I lay a bit of cling film over the top, trim a hole in it just
smaller than the work, and drop the work on top.

It works like a dream, when the vacuum comes on, it pulls down pretty
uniformly, (within a couple of thou)

there is no need to drill holes in the top layer.


Chris