Vacuum pump

[Jim Jones]

Jim, say a 32x45" large, 2" thick easel has two inner compartments connected with a tunnel. The inner vertical third is separate and doesn't have a grid of holes on the top surface. The pump's inlet is on top and connects to the middle of the aforementioned tunnel. Could this design minimize the pulsations from this particular pump?

The inner compartmentation isn't critical with a vacuum cleaner pump. However, the front and back of the easel should be seperated by a number of spacers so the vacuum doesn't distort the front of the easel.

[LF_rookie_to_be]

Could the compartmentation help with a diaphragm pump? I know it isn't the best, but this little pump is the best deal I found so far.

[Sevo]

That right, it pulses as the diaphragm moves vs say the continuous suction of say a vacuum cleaner.

Enough of a buffer space will settle that issue. Membrane pumps are standard wherever a modestly strong vacuum pressure is needed and not much air transport is required - using anything else for an easel would not save money, and nonetheless have more issues and worse results.

[LF_rookie_to_be]

Sevo,

How to create buffer space and what volume is needed for this purpose and size?

[Erik Larsen]

Could the compartmentation help with a diaphragm pump? I know it isn't the best, but this little pump is the best deal I found so far.

Give it a shot, for 25 bucks it isn't going to hurt much if it doesn't work as intended plus you can use it for a contact frame pump if you want. I'm just passing on my experiences with my setup.
Good luck
Erik

[Sevo]

Sevo,

How to create buffer space and what volume is needed for this purpose and size?

I use a empty 100cc gas-washing bottle (from a laboratory glassware shop) with my darkroom easel, as that was cheap and available off the shelf at the place I got the pump from. But even a longer bit of hose would probably do the job.

[Drew Wiley]

It requires very little to draw down even a print this size. More often people make the mistake of having too much pull. Diaphragm pumps pulsate enough to make most easels jitter a little. You can see this under an easel grain magnifier. But don't expect much help from Thomas. They're out of business for all practical purposes unless you're a mfg yourself. Even an ordinary household little vac will pull paper flat, though I
can't recommend this route because you'll be recharging the batteries way too often. Regular home vac cleaners throw a lot of dust around unless you bring the hose in thru the wall and have the unit itself outside.
You'd need a bleeder valve or handle too to reduce pressure. Variable power HEPA vacs are nice but not exactly cheap.

[Jim Jones]

A 32x45" easel 2 inches thick has plenty of volume to even out pulsations from any vacuum pump. It could be considerably thinner and work as well. The old vacuum cleaner I used years ago on a small easel drew maybe 5 PSI vacuum. This would mean over three tons of suction between the front and back of your easel. It sounds like a lot, but with spacers every few inches apart within the easel, there should be no problem. That pressure is exerted merely in trying to draw the front and back of the easel together, and to some extend, drawing the paper down onto the easel. The more powerful pump on almost as large a vacuum table for graphic arts used a 1 quart canning jar to even out any variations and perhaps to catch some dust in a set-up with short hoses.

[LF_rookie_to_be]

I use a empty 100cc gas-washing bottle (from a laboratory glassware shop) with my darkroom easel, as that was cheap and available off the shelf at the place I got the pump from. But even a longer bit of hose would probably do the job.

Sevo, thanks for this bit of advice, I'll try to tame the pulsing with a gas-washing bottle.

[Larry Gebhardt]

The vacuum pump I have for my easel sounds just a vacuum cleaner. It does move too much air in the room, so I don't use it. Someday maybe when I get a longer hose.