Home-built vacuum easel

[Dan Henderson]

The next project I have in mind to complete my darkroom is construction of a vacuum easel to handle up to 20x24" paper. I have the vacuum system worked out and built my darkroom cabinets to accomodate the easel. The only design question remaining is whether to use a perforated steel, masonite pegboard, or wood top drilled with holes for the top surface.

Steel allows the use of magnets as paper guides, pegboard is probably the fastest and least expensive. I'm not sure why someone would go to the trouble of drilling a bunch of holes in wood vs. using pegboard.

I know several people here have built vacuum easels. I would appreciate hearing about your practical experiences with these top surfaces, along with any other hard-won advice you would care to share.

Thanks in advance.

[cyrus]

Steel is too heavy; pegboard has too many unneeded holes. You only really need a few slits to make sure that the paper is kept flat enough (in fact the paper can bow a couple of millimeters with still no consequence to print sharpness, due to enlarger's DOF.)

[Drew Wiley]

You want the holes small and not that many of them. The pattern is more important, so
that the paper or film is drawn down evenly. If you've ever seen the kinds of vac easels
used in the graphics industry this will give you a clue. Pegboard is wretched for this.
And remember to install internal struts so that the board won't flex downward as vac is
drawn. And it doesn't require a lot of vacuum. If you have too much, you'll need a bleeder
valve system to keep it tame. Some sort of peripheral frame helps too, to keep the print
margins flat. I select something stiff and flat, whether black melamine over plywood or
better, Formica laminate, or sheet aluminum or phenolic, or steel - whatever. Just drill it
yourself.

[Jim C.]

Why not use garolite ? There's quite a few different types -http://www.mcmaster.com/#garolite
you would have to drill your own holes.
Having built something similar to a vacuum easel ( it's a platen for a vacuum form machine ) I used 1/16 in aluminum
and MDF as the back, wire mesh was the spacer, drilling the holes was a bit tedious but it works.

[Drew Wiley]

If you select Garolite, there's a black machinable type which fabricates nicely. It's a bit
expensive and relatively heavy per thickness. Don't get the fiberglass-filled kind - it will be
hard to machine. Garolite can warp a bit if it's too thin, but if its put in a sandwich with
channel spacers in between will be quite rigid. The advantage of steel on top would be that strip magnets can be used. I personally like to include a fully adjustable masked border system, but this creates a lot more work than the basic easel itself. For the proper
kind of Garolite you can use woodworking machinery, blades, router bits etc - but don't
use anything wimpy. The thicker sheets can fry a toy saw.

[Greg Blank]

I disagree with the the steel is too heavy contention/especially if the easel is stationary. You can get many gauges of steel so thickness does not have to make it a back breaker. I have intended to construct an easel with a steel top for sometime- for 34x40 inch printing. The nice aspect is you can weld a set of hinges to the outer edge and make the frame and box portion from wood. The magnetic aspect is the best part of using steel, however keep in mind stainless steel is NOT magnetic use carbon steel.

[Drew Wiley]

My last 30x40 was a piece of cake. I simply cannibalized the precision pin-registered vac
easel from a big graphics copy camera. It weigh a couple hundred lbs but that's fine with
me. Dead flat and strong as an ox. Most of the work I put into it was the masking blade
system and, of course, the support underneath. This is the kind of equipment that sometimes gets hauled to the dump if no one wants it, but you'll never see anything of
this kind of quality manufactured again. Mine was from a 22ft long Japanese process camera.

[vinny]

817738177481775Dan,
I don't know if you saw any of the pics while I was building mine this summer but I used galvanized steel atop MDF. 3/4"mdf on bottom spaced by strips of 1/2"mdf for spacers and 3/4"mdf on top. The inside corners were caulked before assembly as well as the glue to insure there were no leaks. I glued the steel (not sure what gauge but a 32x42 piece was $18) to the top with construction adhesive that I spread out with a tile trowel. The mdf is routed flush with the steel so that it's smooth/seamless all the way around. Vacuum connection on bottom. I haven't drilled the holes yet since I needed the enlarger and haven't done any large prints yet.

[quine]

I built mine entirely out of wood: http://www.largeformatphotography.info/forum/showthread.php?82194-Yet-Another-DIY-Vacuum-Easel

Higher-grade birch plywood seemed flat enough.

The most important thing WRT hole pattern is to go up to the edges of the paper so that they stay down. This can be a challenge with double-weight fiber. IIRC pegboard didn't have the right spacing.

The other thing to watch out for is to avoid constricting the vacuum channels so that you don't lose suction, especially when going from horizontal to vertical and vice-versa. My article talks about this in more detail.

[Peter De Smidt]

Remember to try and minimize vibration.

[Ironage]

I built one as a kid, and used a drafting board, and just drilled holes in it. The board was very flat, and it worked great. The biggest problem was that I used a regular household vac which was too loud in my tiny darkroom.