Vacuum bagging / vac. pumps
Printed From: Yachts and Yachting Online
Category: General
Forum Name: Repair & maintenance
Forum Discription: Questions & tips on the subject
URL: http://www.yachtsandyachting.com/forum/forum_posts.asp?TID=6573
Printed Date: 15 May 25 at 12:39pm
Software Version: Web Wiz Forums 9.665y - http://www.webwizforums.com
Topic: Vacuum bagging / vac. pumps
Posted By: mongrel
Subject: Vacuum bagging / vac. pumps
Date Posted: 23 Mar 10 at 8:12pm
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I've just bought a cheap 2nd hand vacuum pump to hopefully use to do some repairs to an old hull. I'm hoping someone here will be able to offer me some advice. I would like to know - 1) Where's the best place, online, to buying pneumatic fittings & hose? 2) What diameter hose works best, (the port on the pump I think is a 5/8" BSP)? 3) What pressure should I be using for - a) foam & glass, b) glass? 4) The pump should be filled with oil, what type is best & where's best to buy it? Thanks in advance! |
Replies:
Posted By: tomoore1
Date Posted: 23 Mar 10 at 8:53pm
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for the hose and fittings, go to a fish shop. There are air pumps for fish tanks which are pretty good. You can get one way valves, hoses etc etc. ------------- Restoring Firefly 517 |
Posted By: aardvark_issues
Date Posted: 23 Mar 10 at 9:12pm
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Don't know about online, but there are suppliers of pneumatic hose pretty much everywhere - you can get away with compressor style hoses/connectors with a low powered pump which you should be able to get from your local tool wholesaler. Hoses for pressure don't need to be as hardcore as those used for vacuum as they collapse on themselves so would avoid the fish pump idea. Follow resin suppliers guidelines for laying up and vacuum flow times - you will struggle to pull too much vacuum unless the pump you've ended up with is a complete monster. Do a couple of test pieces first... Vacuum pumps tend to use specific vacuum pump oils - can't remember where I got mine from as I bought 5 litres and it's lasted years! ------------- http://www.aardvarkracing.co.uk" rel="nofollow - Home of Rocket Racing |
Posted By: alstorer
Date Posted: 24 Mar 10 at 8:37am
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If a vac pump is losing oil quickly, it would be a hefty clue that there's something wrong with the pump!
Top tip- add some sort of valve between pump and bag to allow you to release the vacuum before you switch off the pump. This stops oil being sucked through into the parts of the pump that the oil shouldn't be in. ------------- -_ Al |
Posted By: Lukepiewalker
Date Posted: 24 Mar 10 at 9:42am
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http://www.absolute-vacuum.com/product_oils.php ------------- Ex-Finn GBR533 "Pie Hard" Ex-National 12 3253 "Seawitch" Ex-National 12 2961 "Curved Air" Ex-Mirror 59096 "Voodoo Chile" |
Posted By: Granite
Date Posted: 24 Mar 10 at 12:14pm
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I have used car washer bottle hose for the pipework, and just put it in through one edge of the bag well wrapped in tacky tape.
------------- If it doesn't break it's too heavy; if it does it wasn't built right |
Posted By: I luv Wight
Date Posted: 24 Mar 10 at 12:51pm
I use blue 1" water pipe for the long between inside and outside ( so the noise is kept outside  ), with the fittings that go with that, to a bit of 15mm copper tube.Then garden hose with the diagonal string in. This is OK at room temp, but crushes if heated in an oven for curing. My pump is a vane pump, so it's oil free ( which would be another reason to put your oily pump outside - smelly  )The min pressure from a vane pump is about -0.9 bar, which is good enough for epoxy/glass/foam/carbon/glass whatever, without boiling off the resin before it's cured. -0.75 bar is just about Ok, I aim for -0.85 bar or better. For vac consumables - try Matrix (MCMC) - I expect they also do fancy pipes and couplers too. ------------- " rel="nofollow - http://www.bloodaxeboats.co.uk" rel="nofollow - http://www.bloodaxeboats.co.uk Andy P foiling Int Moth GBR3467 Freedom 21 Codling |