Homemade vacuum pumps

[Prostheta]

I've been thinking about how to bring vacuum pressing for veneers, etc. into the range where an enthusiastic amateur (is that an "enthusiast"?) could throw one together for a project or two without investing in Venturis that require compressed air, etc.

Essentially this is a vertical bike tyre pump but with both valve's air flow directions being reversed. Instead of pumping air it becomes a positive displacement pump.

What are people's thoughts on this? My first concern is about the quality of vacuum this might be able to pull and as to whether an auxiliary vacuum reservoir would ensure that it could be held indefinitely. Certainly, the pump should be isolated from the target once sufficient vacuum is achieved with the auxiliary reservoir chamber smoothing over any softness in the vacuum.

I'll have a look around the local hardware stores to see if suitable materials are to hand, which I would have thought they would be. Generally that is the first test for any project of this nature :-)

[Prostheta]

Hopefully this thread being quiet is nothing to do with it triggering people's spam filters.

[Ripthorn]

There is a company called roarockit that caters to skaterboard makers that sells a kit like this for rather cheap. I watched a video of a guy laminating a 335 top with it and it turned out quite nicely. I think the kit was like $60 and came with a bag and breather mesh. I've wanted to try it, but I also would like a vacuum hold down system for my little milling machine, so I may go that way.

[acpken]

It should work, after all vacuum pumps are compressors with the connections reversed. If you're looking for cheap vac pumps, couldn't you buy a used diaphragm airbrush type compressor, switch the input and output connections, and add a vac gauge?

ken

[Prostheta]

I'm hoping that this will be something I can use as a how-to more than a "look what I did". Vacuum pump systems can get expensive very quickly. I figured that using readily available materials to produce a pump that can at least produce a few finished items is within the scope of pretty much any builder, not just those who can invest in permanent setups. It'll also demonstrate that people can dip their toes into vacuum pressing without committing cashloads!

[ansil]

quick question why not re-purpose a fridge compressor? there are plenty of people online who have done this.

[Prostheta]

As cool (no joke intended) an idea as that sounds, my objective is to bring what is normally a "higher investment" tool down to a hobbyist level. Something one could throw together in an afternoon and get good results on a couple of instruments at the very least. Whilst a compressor might be relatively available for some, it is not as easy for others or perhaps as easy as dropping down to the local home building store for off-the-shelf components.

The compressor idea is great for a future project, especially as I've wanted to incorporate vacuum workholding to my workbench.

[ansil]

where are you located at? most scrap yards will let you have one for free if you ask nicely. many restaurants have broken down equipment in the store. refrigeration is the no. one thing that goes down in a kitchen. most of the time its not the compressor. but if it is a simple rebuild is quite easy with the youtube videos online.

[Prostheta]

Back end of nowhere. Recycling centres here are unlikely to give out a compressor from a broken refrigerator for many reasons. I'm not too bothered to be fair. I might look at a Venturi further down the line but at this stage I'd like to build something that is very very basic and achievable for anybody with zero experience other than with a saw and a drill. The objective is the simple pump build and not on getting a more advanced bagging system. At least, not at this stage anyway.