how to make a vacuum pump, do they work
Moderators: Head Monkey, kelvin, bigKam, skidesmond, chrismp
how to make a vacuum pump, do they work
so is there anyone that has actually used a vacuum pump to press the skis? if so where do you find the bags to seal it with and what kinda pump did you use?
i haven't used a vacuum setup to make skis yet, but have been using it for various other things like sidewalls and mold construction. I'm liking the vacuum more and more as I use it and am going to use it for skis soon.
I'm using a vacuum generator and bag from https://www.qualityvak.com/index.html and it is the venturi type. Electric ones work just as well and are nice if you don't own a big air compressor. I have a 2hp compressor and it is not really up to the task.
Here is a site that describes how to build one:
http://www.joewoodworker.com/veneering/welcome.htm
I've got a giant bag that fits the mold and everything, but I wouldn't recommend that since its a pain to wrestle the mold into the bag. A better way is to get vacuum film and seal it to the top of your mold. You can get the vacuum film, breather material and other stuff from http://www.fiberlay.com/
-kelvin
I'm using a vacuum generator and bag from https://www.qualityvak.com/index.html and it is the venturi type. Electric ones work just as well and are nice if you don't own a big air compressor. I have a 2hp compressor and it is not really up to the task.
Here is a site that describes how to build one:
http://www.joewoodworker.com/veneering/welcome.htm
I've got a giant bag that fits the mold and everything, but I wouldn't recommend that since its a pain to wrestle the mold into the bag. A better way is to get vacuum film and seal it to the top of your mold. You can get the vacuum film, breather material and other stuff from http://www.fiberlay.com/
-kelvin
Vaccum is a very common pressing system in working with composites. It is standard in aircraft industrie and as my experience with compsoites comes from building aircrafts it was naturally to use it for my first ski.
As i use a relatively small mold (1900x200mm) i put it into a vaccum bag. The pump i use is a laboratory model from KNF (810) :
http://www.knf.co.uk/products/index.htm
(It is the one on the lowest picture.)
In my opinion vaccum is the simplest an safest way to create a relatively high pressure (-0,8bar means 8000kg/m2 pressure!).
As i use a relatively small mold (1900x200mm) i put it into a vaccum bag. The pump i use is a laboratory model from KNF (810) :
http://www.knf.co.uk/products/index.htm
(It is the one on the lowest picture.)
In my opinion vaccum is the simplest an safest way to create a relatively high pressure (-0,8bar means 8000kg/m2 pressure!).
I use vacuum as well, we have a pump in the lab ans it is seldom used.
This is serial production...
A friend of mine made two pairs of skis without using neither the vacuum pressing nor the press.
He has used several clamps. I had the feeling it could be possible, but I have easy acces to the pump, so I never pushed the clamp thing further. I have to aks more details.
This is a good option if somebody does not have a compressor, a pump or if he does not want to spend time and money to build a press.
This is serial production...
A friend of mine made two pairs of skis without using neither the vacuum pressing nor the press.
He has used several clamps. I had the feeling it could be possible, but I have easy acces to the pump, so I never pushed the clamp thing further. I have to aks more details.
This is a good option if somebody does not have a compressor, a pump or if he does not want to spend time and money to build a press.
I think that most here have seen the page on graf about using a refrigerator compressor to use vacuum bagging, though it's a little spare on the details.
I found this page which has slightly more detail. But an old Scientific American Amateur Scientist article shows how to turn a refrigerator compressor into a vacuum pump that'll generate and hold a pressure of about 1-2 mmHg, or basically -1 atm relative. So that's 20% better than just using the compressor alone and getting -0.8 atm with very little effort/expense. But maybe it's not really worth it, just throwing this out there.
(warning ramble: SciAm used to be so cool in the 60's when this article was published. Telling you how to make things like a 2Mev linear particle accelerator, a nuclear magnetic resonance spectrometer, or how to measure the temperture in a cow's stomach. Now it sucks, which is sad. Ok, ramble done.)
davide - Is that cardboard in your pic? Are you using it as a breather fabric or just above the breather fabric?
I found this page which has slightly more detail. But an old Scientific American Amateur Scientist article shows how to turn a refrigerator compressor into a vacuum pump that'll generate and hold a pressure of about 1-2 mmHg, or basically -1 atm relative. So that's 20% better than just using the compressor alone and getting -0.8 atm with very little effort/expense. But maybe it's not really worth it, just throwing this out there.
(warning ramble: SciAm used to be so cool in the 60's when this article was published. Telling you how to make things like a 2Mev linear particle accelerator, a nuclear magnetic resonance spectrometer, or how to measure the temperture in a cow's stomach. Now it sucks, which is sad. Ok, ramble done.)
davide - Is that cardboard in your pic? Are you using it as a breather fabric or just above the breather fabric?
vacuum press maybe one useful link for vacuum bag
Hi in there. first I'd like to thank you for your site and wish you a very good year from france.I'm half french and finnish skier and wood carpenter and I wanted to ask you if a vacuum bag and vacuum pump from the retailer roarockit.com would be suitable and enough powerful to give shape to a telemark ski.
best regards
samuli
best regards
samuli
Yes, it is card board used as breath fabric.
I have also this special fabric, but most of the time I use cardboard. Actually I have the feeling now that the breath fabric allow a better pressure distribution. And it is possible to use the breath fabric several time if it is protected from the epoxy with a plastic sheet.
I have also this special fabric, but most of the time I use cardboard. Actually I have the feeling now that the breath fabric allow a better pressure distribution. And it is possible to use the breath fabric several time if it is protected from the epoxy with a plastic sheet.
vacuum pump
I have pressed four sets of skis using a vacuum pump. It accually works, but it took me 3 pairs to accually get a ski that I could use. I get my vacuum pump from United Rentals. Just ask them for a the vacuum pump off of a concrete coring machine. You can get the bags at www.fibreglast.com, It is also a good site to buy fiberglass and epoxy.
Don't know if you folks have seen this.
http://www.joewoodworker.com/veneering/welcome.htm
I plan to build the V2 venturi pump soon. They have a kit with all of the parts except the PVC pipe and end caps. The price is right and all available in one place.
http://www.joewoodworker.com/veneering/welcome.htm
I plan to build the V2 venturi pump soon. They have a kit with all of the parts except the PVC pipe and end caps. The price is right and all available in one place.
My parts came in for my vacuum press Friday and I was able to put it together Saturday. It hasn’t snowed in a week or two so staying home and working on this was a good thing. I’m using the Project V2 set up with my 20 gal compressor that I already have. It took me a couple of hours to prep everything, and another hour to assemble. I still have to get a couple of end caps and make it a four chambered vacuum reservoir.
I was able to draw 20 in. HG easily at 4500 ft above sea level. It would go to 21 in HG with a bit of time. That’s .7 bar or ~10.29 PSI. As near as I can tell I have no leaks and was able to hold the vacuum for over an hour.
I’ll be running some shake down tests this week on a couple of small projects, and get used to bagging my layups.
Hafte
I was able to draw 20 in. HG easily at 4500 ft above sea level. It would go to 21 in HG with a bit of time. That’s .7 bar or ~10.29 PSI. As near as I can tell I have no leaks and was able to hold the vacuum for over an hour.
I’ll be running some shake down tests this week on a couple of small projects, and get used to bagging my layups.
Hafte
-
Bucky Mullet
- Posts: 24
- Joined: Mon Oct 09, 2006 5:26 pm
pumps
Ventury pumps and diaphragm pumps only pull so much vacuum (you'll be lucky to get below 100 torr with the ventury).. Look on eBay for an oil based "rough" pump, also known as a foreline pump.. A decent one will pull down to 50 mtorr, and you can pick them up pretty cheap as the technology is currently changing to oilless pumps (be prepared to fork out a couple grand for those).
I just bought my vacuum pump from a guy on eBay and it cost me $89 delivered with extra oil. I used it to actually build my forms, ie glue the bottom profile to some MDF ribs for the tip / tail and canber shape, and the force ended up breaking the ribs. After some repair, I was able to reinforce the form and repair the bag, and it did what it should.
I would really recommend going with a foreline pump, as it not only exerts an enormous force ( as I found out it does this in every direction) but also removes all air and gasses trpped in your layup.
Check ebay, hope you get lucky.
I just bought my vacuum pump from a guy on eBay and it cost me $89 delivered with extra oil. I used it to actually build my forms, ie glue the bottom profile to some MDF ribs for the tip / tail and canber shape, and the force ended up breaking the ribs. After some repair, I was able to reinforce the form and repair the bag, and it did what it should.
I would really recommend going with a foreline pump, as it not only exerts an enormous force ( as I found out it does this in every direction) but also removes all air and gasses trpped in your layup.
Check ebay, hope you get lucky.
Mixed Information
I am getting mixed information. If I wanted to build a vacume pump at a decent price that could put out 14psi easily, how much would it cost? And would it mold the skis good enough for lets say, Rails.?