Building a Vacuum Easel

[philipmorg]

I just finished building a 20x24" vacuum easel and wanted to share how I did it, in case it's of any use to others. I was able to complete the project on a budget of $150, which is less than I've seen any 20x24 vacuum easel sell for, except for a few lucky eBay deals.

The video here tells the tale of how I built the easel: http://www.youtube.com/watch?v=ryL241DKQ10

[John T]

Nice video. I agree with your assessment of using contact cement. I used it years ago when I made one. However, I've noticed that many commercially produced vacuum easels are only attached at the edges and the middle floats.

[philipmorg]

Thanks for those thoughts John.

[BetterSense]

I'm not sure if you mentioned it in your video; where did you get the metal grating?

Also, it seems you are using vacuum cleaner for the vacuum source...do you have any ideas as to a quieter vacuum pump?

[philipmorg]

I got the perforated metal at OnlineMetals.com. Here's the exact item I used: http://www.onlinemetals.com/merchant...04&top_cat=849

I had the folks at OnlineMetals do the cut for me, and they did a nice, accurate cut with no crimping of the metal.

Apparently you can use some models of refrigerator compressors (hooked up in reverse to reduce air pressure rather than increase it) as a vacuum pump that generates less noise. Or you can use a vacuum cleaner style pump located outside of the darkroom with a long enough hose to reach the easel. Or you can do what I plan to, and build an enclosure for the pump and use sound-absorbing foam inside the enclosure to keep the decibel level down.

[Harold_4074]

One thing that you might consider is that MDF will absorb water and swell; depending on where you are geographically, the winter/summer changes in humidity may cause the assembly to bow, particularly if the perforated steel is firmly bonded to the top surface. Thoroughly sealing the board with something like polyurethane would help, although there is no practical coating that is an absolute barrier to moisture penetration. Letting the steel "float", by using screws in oversize holes, would probably be the best solution, although a bit more complicated.

I like the idea of the hinged picture frame for positioning the paper, but I wonder how effective the flocked paper will be in eliminating reflections from the inside edges of the frame. A sheet of acrylic, to which you can hold the paper until you get it onto the easel, would eliminate this problem and allow you to do borderless prints; you would just lift it away once the vacuum was on, and wouldn't need space for the hinged frame to open.

Given the way that you have glued down the steel, it seems that only the holes directly above the routed channels are participating in the air flow; it would be pretty easy to route the channels, then contact-cement on a layer of phenolic laminate (Formica or the equivalent) through which vent holes would be, or have been, drilled. Since the laminate is fairly inexpensive--$42 for a 4x8 sheet in my town--it would be reasonable to cover the back and edges as well, which would balance the stresses and eliminate the humidity/warping issue as well.

As you have probably guessed, I've put some thought into building one of these, but, unlike you, I haven't actually tried it. Congratulations on a nice job, and I hope that it works well for you.

[philipmorg]

Thanks for all the interesting improvement ideas Harold!

I am interested in seeing if my two-ply easel swells and bows. It may, and if it does I'll report back here. It's about to get rainy in the next month or two and so I should have some data on that fairly soon.

I like the formica idea. I think if you didn't mind drilling the holes yourself--and sanding to remove burrs, which I had to do anyway because glue leaked through the holes in my perforated steel--then that'd be a cheaper way to build this easel.

The arcylic sheet idea is also interesting. If you implement that, I'd love to hear how it works!

Thanks again for the great ideas,
--Philip.

[BetterSense]

This kind of thing is hard to visualize, but I also noticed that only the mesh directly above the channels is actually sucking the paper down. Your pattern of channels seems pretty sparse to me. Depending on the fortitude of your vacuum source, and the fineness of the holes in the mesh, it seems like almost the opposite approach would work, and the whole metal mesh could be spaced 'upward' except at a few places where it was supported by spacers. Then basically every individual little hole in the metal mesh would be sucking downward independently, and you might not need the frame for the edges.

[philipmorg]

This kind of thing is hard to visualize, but I also noticed that only the mesh directly above the channels is actually sucking the paper down. Your pattern of channels seems pretty sparse to me. Depending on the fortitude of your vacuum source, and the fineness of the holes in the mesh, it seems like almost the opposite approach would work, and the whole metal mesh could be spaced 'upward' except at a few places where it was supported by spacers. Then basically every individual little hole in the metal mesh would be sucking downward independently, and you might not need the frame for the edges.

Your observation is correct. I patterned my design on a smaller Kostiner vacuum easel, which uses the same design where a small percentage of the paper's surface is exposed directly to the vacuum.

If I understand you correctly, the design you are suggesting might look like a sealed box that's 2 or 3 inches thick and as large as the paper, and instead of a sealed top, it would have perforated metal for the top (with some supports to keep the perforated metal flat). Thus the entire area of the paper would be exposed to vacuum. I think I've seen vacuum easels that use this design, and I don't see why it wouldn't work, but my woodworking skills are so rudimentary that I went with a simpler design.

I haven't used mine much yet, but I can tell you that the smaller Kostiner easel keeps the paper perfectly flat, even though a relatively small percentage of the paper's surface is directly exposed to vacuum. And in preliminary tests, it looks like my larger design will do this as well.