Author Topic: VacSys for vacuum bagging - any issues or advice?  (Read 528 times)

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Offline Richard/RMW

  • Posts: 1937
VacSys for vacuum bagging - any issues or advice?
« on: March 25, 2019, 08:40 AM »
So I have a VacSys now and I've always wanted to try vacuum bagging. Amongst other uses I am contemplating using it to wet-form leather for sheaths etc. As the name of the technique implies the leather is slightly wet when formed and dries over the form. So, 2 questions:

  • Should I have a concern about the very minor amount of moisture I'd be introducing to the pump when wet-forming?
  • Any advice from anyone who has used the VacSys for typical woodworking bagging, such as limits on the size of bag or ??

Thanks!

RMW
As of 10/17 I am out of the Dog business and pursuing other distractions. Thanks for a fun ride!

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Offline cpw

  • Posts: 170
Re: VacSys for vacuum bagging - any issues or advice?
« Reply #1 on: March 25, 2019, 09:27 AM »
So I have a VacSys now and I've always wanted to try vacuum bagging. Amongst other uses I am contemplating using it to wet-form leather for sheaths etc. As the name of the technique implies the leather is slightly wet when formed and dries over the form. So, 2 questions:

  • Should I have a concern about the very minor amount of moisture I'd be introducing to the pump when wet-forming?
  • Any advice from anyone who has used the VacSys for typical woodworking bagging, such as limits on the size of bag or ??

Thanks!

RMW

I haven't done a lot of it yet, but I have had a couple successful panels with my VAC-PMP and the bag from veneer supplies.  I adapted the vac-sys coupling by buying the hose, and then a 3/8" barb fitting which was a tight fit into the Festool hose, but worked when persuaded with a heat gun.

I can't tell you much about the moisture, but the Joe woodworker kit comes with a filter/and if you look in the back of the vac pump there is a filter there too.  I don't know how well they'll respond to moisture.

Offline Gregor

  • Posts: 1526
Re: VacSys for vacuum bagging - any issues or advice?
« Reply #2 on: March 25, 2019, 03:19 PM »
Moisture (in the form of water vapor) can be a problem for oil based (wet) vacuum pumps, this leads to the oil foaming (needs plenty of water) while lower amounts can reduce the end pressure a little (as the water evaporates out of the oil into the chamber, raising the pressure there so it won't pull, that much or any, from the then lower pressure inlet). Letting an oil based pump run for a while can regenerate the oil (unless it's already foaming from too much water, then disassembly, cleaning and new oil is the method of choice) as the operation heats up the oil enough for the water in it to evaporate.

That being said: Oil free pumps don't have that problem, but usually a higher absolute end pressure (= they make less vacuum). The Festool VAC-SYS pump is, according to the manual, an oil free (dry) rotary vane pump, water shouldn't be a problem on normal use, unless you flood the inlet hose.

But stuff like glue or dust can be. I would put a water separator (to catch glue and whatnot) and a fine air filter (to catch dust) between the bag and the pumps intake to remove non-air that might get sucked into the hose from your bag. Having that you shouldn't expect any problems, except the pump needing a trip through festool service every 5000 to 8000 working hours (the rotary vanes basically are consumeables).

Bag size basically just scales to time needed to evacuate (as the pump moves a certain volume per time), in case you have a big bag you could use a shop vac to remove the bulk of the air inside it quite quickly (could be done through the bags seam, before sealing it) and then switch to the vac-sys pump to do the fine work.