Would a small pool/spa pump work for vac bag, etc applications?
I know nothing about pumps or vac bagging, but there is a free one (sm. pool/spa pump) if i want it.
Thanks in advance.
a water pump probably won’t generate much of a vacuum by itself. Water pumps can be hooked up to aspirators (filter pumps) that in turn form a pretty high vacuum, but to use it you still need to run water through the pump. A lot of water, actually. So after a bagging run you’d have to deal with a big tub of water which is now contaminated with additive F and whatnot. A used mini frig is probably cheaper than a filter pump.
Here’s another pump question:
Do the compressors from mini refrigerators pump down fast enough for vac bagging? I’m planning on having a vacuum reservoir/vacuum switch for my system, a la joewoodworker, so the initial drawdown won’t be too bad. I do want enough capacity so that the pump can cycle off most of the time though.
no they hopeless
you just have a shop vac standing by and get most of the air with the shop vac
Hi silly, Another question thats sort of relavent to this thread…
I have my fridge vac pump going (free off trademe), Have done initial vac tests and it gets to pretty much 100% vac or 29hg", but have to leave it on the whole time, is there an easy/cheap way to make a vac controller so that it can cycle on/off ??
And yea, i tested the time it took to suck the air out of a 6’2 bag with a board in it and it was a fair while so will definatly have to use the shop vac to remove the initial air…
Silly - that’s what I needed to know. I’ll look for a compressor from a full size frig.
My plan was:
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let vac pump evacuate PVC pipe reservoir while it’s isolated from the bag.
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seal the bag and let shopvac pull the bulk of the air in the bag.
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close the connection to the shopvac and open the one to the reservoir/pump.
For a vacuum switch: I’m planning on mounting a 60cc syringe in a frame and attaching a spring to the plunger. Vac will pull the plunger in, spring will pull the plunger out. Then extend the toggle on a toggle switch (rated for 120V, etc) and link it to the plunger as well. 5 psi of vacuum should generate ~5 lb of pressure on the plunger (though I’ll be measuring vacuum with a proper gauge), which should be enough to throw the switch. A toggle switch should also help create a dead band, and fiddling with the length of the spring and the length of the toggle should get the on/off points right.
If it doesn’t look promising after an hour or two, I’ll be ordering one from ACP.
A guy on instructables site was having better luck with those mini tire pumps for cars etc, I should have the link somewhere if you want it.
converted tire inflator pumps - has anyone on sways had much luck with them?
I thought about trying it (basically you just epoxy on an inlet valve), but …
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those buggers are @#$ loud
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the ones cheap enough to make it appealing are only rated for 15 minutes of continuous use.
I’m afraid I’d work out some soundproofing, ventilation, and a 12V power supply for one just to have it fail in the middle of the night.
If anyone has had luck with a cheap inflator or airbrush/nailgun compressor let me know the model and I’ll quit looking for a frig compressor.
That said, for people looking at buying a used/new vacuum pump, keep your eyes out for Barnant 400 series pumps.
At work we abuse them pretty much constantly -they’re practically swimming in trifluoroacetic acid, methylene chloride … stuff that would kill rotary vane oil pumps in a few days. The barnant pumps are almost indestructible. They’re diaphragm pumps, smaller and not much louder than rotary vane pumps. The diaphragms and pump heads are cheap and easy to replace if you manage to wear them out, especially compared to a $300 rotary vane pump rebuild. The motor won’t overheat if you stall it. The check valves will hold a vacuum for hours when the pump is turned off, and since they are oilless there’s no worries about oil getting sucked out of the pump. The single head ones pull 20 in Hg, so they might work for making flat laminates and fins too.
If you’re looking to buy a used rotary vane pump, there’s a great resource for checking them out, using, and maintaining them:
here is the link,
never tried one,
would love to hear some real world experience though. While Im at it, the tunnel fin ala rs style, Not tryin to jack here though.
I read the posts on “tunnel fin” in the archives and it reads like debate minutes with basically no proof of application besides rs’s of course.
I just wanted to see someone actually try one and report without bias. End up with headaches. Then something about bernoulli, venturi and counards swimming and swirling around in the amalgomated aftermath. wtf??
http://www.instructables.com/id/convert-a-tire-inflator-type-air-compressor-into-a/
here is a site where i got a vac controller its pretty cheap and works well and you can adjust how much vac you want it to pull. only thing is you need a resivouir for it to mount to. i used a 4 inch pvc pipe with the ends cap and mounted the controller to the top and sealed it with silicon. also i taped and mounted a vac gage so i know when i want to cut the vacuum. this is probably the best way and also the pump doesnt have to run continuous, some time i have such a good seal on my bag the pump never kicks on but if it does loose pressure the controller kicks the pump back on till it reaches the vac i had it set on. http://www.veneersupplies.com/product_info.php?products_id=58