vacuum frame??

[Steve Jenkins]

Today I picked up a "vacuum frame". I got it for nothing but don't really know what it is for. I'm going to try to modify it to use for vac. veneering. It is about 48 x 60, aluminum frame. the top is hinged and flips up. the top is aluminum angle around a glass panel, not flexible. The bottom is plywood, sealed to another aluminum frame and about 2" from the top. there is a vac pump to evacuate the space between top and bottom but since the top is not flelxible it won't suck down onto the veneer and panel. does anyone have any idea what this was used for? I'm really curious.
Thanks

[John Gornall]

Vacuum frames, more commonly called vacuum presses, are used in photo or graphic arts as a method of "drymounting" prints onto a backing.

I think yours is missing the rubber diaphragm on the bottom which presses up against the glass when the air is sucked out by the pump. This rubber is an assembly of rubber sheet with built up edges which seal to the frame when you close it.

Most of these presses have a temperature controlled heated top surface and use heat activated adhesive sheets to bond the prints to the backing. The type without heat use spray or rollon glue - not high quality mounting.

Here's a link to one: http://www.drytac.ca/hotpress-dry-mounting-presses/hot-presstm-glass-top-vacuum-presses-heated.html

[Kevin Nathanson]

Lithographic stripping is probably the origin; contacting pieces of film together-emulsion to emulsion-in order to composite images together for print production. This is from the days prior to desktop publishing and digital print production. You might be able to replace the top glass with a vacuum bag designed for a veneer press. (Not the kind for use only with a pump.)

K

[Steve Jenkins]

Actually I think it does have the rubber diaphragm. I haven't turned it on yet to see if it will suck up to the glass. Sounds like it may just work for veneering. I would think that the vacuum will pull the diaphragm and any panel sitting on it up to the glass. If it works it will be pretty cool as I will be able to see the face veneer as it presses. It is a coldpress which is fine.
Thanks a lot for the info.

Vacuum frames, more commonly called vacuum presses, are used in photo or graphic arts as a method of "drymounting" prints onto a backing.

I think yours is missing the rubber diaphragm on the bottom which presses up against the glass when the air is sucked out by the pump. This rubber is an assembly of rubber sheet with built up edges which seal to the frame when you close it.

Most of these presses have a temperature controlled heated top surface and use heat activated adhesive sheets to bond the prints to the backing. The type without heat use spray or rollon glue - not high quality mounting.

Here's a link to one: http://www.drytac.ca/hotpress-dry-mounting-presses/hot-presstm-glass-top-vacuum-presses-heated.html

[Roger Feeley]

Back when I taught offset printing, we modified our plate burner frame to accomodate small silk screen frames by replacing the hard rubber bottom with a flexible diaphragm. So, on top, we had the glass door that tilted up and below that was a sheet of rubber that could wrap itself around a screen. It worked for both functions. To expose printing plates, we simply put a sheet of lexan on the soft bottom with registration pins.

It never occurred to me that you could use an old printing vacuum frame for veneering but you should be able to. You at least good a good pump.

[johnny means]

You wil need to incorporate a ridgid platen into your design. If not, you'll end up with potato chips.

[Steve Jenkins]

I'm thinking that the glass will act as a top platen and I will use a piece of 1/4" mdf under the panel to help distribute the pressure to flatten any bubbles in the veneer. I tossed a piece of 3/4 mdf into the thing this morning and it pushed up tight to the glass and the membrane wrapped up the edges until it too was against the glass. There isn't much space but it will handle 3/4 with no problem. Next step is to apply glue and veneer and see what happens.
Thanks again for the info.

You wil need to incorporate a ridgid platen into your design. If not, you'll end up with potato chips.