Vacuum Bagging

[DC Ross]

I've been wanting a vacuum bag system for quite a while, but the price has always put me off. $450 for a decent one from Rockler... Yikes. I saw this refrigerant vacuum pump at Harbor Freight and knew I was on to something:

http://www.harborfre...tors-96677.html

My wife bought these clothing storage bags a few years ago, in an attempt to declutter her closet:

http://www.bedbathan...sp?SKU=16698563

With those two pieces, and my existing compressor making the three major components, I dug through my box of miscellaneous fittings and came up with this contraption:

IIRC, it's comprised of a 1/2" to 3/8" reducer, a 3/8" ball valve, a 3/8" to 1/4" reducer and a quick disconnect. The 1/2" to 3/8" reducer fit into the vacuum port of the bag perfectly, so it just needed some epoxy to glue it in.

I also put a quick disconnect on the vac pump:

After a couple promising test runs, I tried it for real:

The bag was punctured where it was going over the sharp edges in the roughed-out control cavity, so I patched it up with some packing tape and gave it another go; this time with some protection. I used thin shelf lining foam rubber, since it's what I had lying around, and placed a square of wood over the control cavity opening:

The bag held vacuum overnight with no leaks at all, and worked a treat.

[kpcrash]

nice!

[Dave_B]

That is really cool!

[DC Ross]

Thanks guys. I went on to use it for headplate veneers, and the outcome was perfect. I forgot to mention that the white rectangle bit in the pics is a scotch-brite-type pad. After using it for these first few times to allow more space around the air valve, I don't think it's necessary and just adds another step.

The air consumption is very little and is only running for a minute, so this would even work with a small pancake compressor. For a minimal outlay of cash, I'm very, very pleased with the results.

Edited April 21, 2011 by DC Ross

[plinky]

Awesome! We have an old Robin Air a/c refrigerant recovery & charging station at work that is no longer used because the controls are shot, but the

internal electric vacuum pump is still intact. I may see about snagging the pump and some of these bags and giving it a go. Thanks for the tip.

[erikbojerik]

Cool!

What sort of pressure do you need at the high-pressure side of the vacuum pump?

[MiKro]

Cool!

What sort of pressure do you need at the high-pressure side of the vacuum pump?

between 85 to 125 psi is what I have found using the venturi from harbor freight.

In 2009 I posted a thread about this venturi(see here thread), similar setup to Joe woodworkers design for about $100 total with gauge,valves, 5gal tank, fittings, but no bag. I purchased a 32x60 bag for $85 from woodcraft.

Mike

[erikbojerik]

Ah OK - I didn't realize the pump was a ventui thing until I read the Harbor Freight description.

Those bags are a steal though! I have a Bed, Bath & Beyond about 20 min away - and am now wondering if they carry a bag large enough to do what I want, which is to laminate acoustic guitar sides!