Vacuum Pump Questions?

[David Loukides]

Hi Guys,
There is a vacuum pump set up at work. I have my eye on in case it gets scraped. It might be good to stabilize woods but I do not know what to look for. I believe it runs on 220volt, has a gage from 5 to 30? has a separator or 2 on it. The stand has a foot print of around 2' x 2'.
Now what do I really need to know? All system can't be the same?
Thank You in advance,
Dave

[fast14riot]

Sounds like it would be better suited fo making "mycarta" and other scale material but I don't know the pressures needed for stabilizing woods, or the duration under pressure it would need. The guage is in inches of mercury, but may have a secondary scale for millimeters of mercuy. 1 atmosphere is 29.92 in/hg.


-Xander

[ecos]

The higher the vacuum, the better when it comes to stabilizing...especially with dense materials. For small pieces of composite less vacuum is needed or the material can turn out too dry....so making handle material is more forgiving when it comes to weak vacuum.

There are 1 and 2 stage vacuum pumps. 2 stage are typically better because it pulls a weak vacuum, but high volume for the first stage to remove air fast..then kicks into a low volume but high vacuum stage to pull a strong vacuum. For small projects either a 1 or 2 stage typically works. For larger projects a 2 stage is desirable.

Some of the components in resins can be pretty harsh, and can damage cheaper vacuum seals over time. For example I was given a vacuum pump that was used in a hospital (I don't know for what), and after a few uses it stopped pulling hard vacuum. I'm pretty sure the styrene in the polyester resin I was using broke down the seals. SO if the pump is selling cheap it may be worth looking into but if its pricey then buying a pump made for working resins might be the better route.

[Gene Martin]

Without a high pressure injection system you'll be pretty much unable to really stabilize wood. You will be able to soak it with stabilizing material, but that alone isn't all that is required. If all stabilizing took was a vacuum system, the major stabilizing companies would not have invested tens of thousands of dollars in equipment.

The vacuum pump itself can have other shop applications and many vacuum pumps have a low pressure compressor function, too. If you can get a good deal on it, go for it. You can still have fun with it.

Gene

[ecos]

Without a high pressure injection system you'll be pretty much unable to really stabilize wood. You will be able to soak it with stabilizing material, but that alone isn't all that is required. If all stabilizing took was a vacuum system, the major stabilizing companies would not have invested tens of thousands of dollars in equipment.

The vacuum pump itself can have other shop applications and many vacuum pumps have a low pressure compressor function, too. If you can get a good deal on it, go for it. You can still have fun with it.

Gene

Gene brings up a good point and it is especially true for large and dense pieces of material. Usually a piece is submerged in resin, vacuum drawn to remove air, then pressure applied to drive the resin into the material.

However on small and soft pieces a vacuum alone can suffice. For example on palm wood the outer area is dense, but towards the center of the trunk is very soft. In my experiments using vacuum alone will not get the resin into the outer/dense areas, but it does work on the inner/soft areas.

Just don't expect to throw blocks of dense wood in and have the resin penetrate fully with vacuum alone.