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Cliff and Carsten, Did you use a vacuum pump or shop vac to pull the partial vacuum? Isn't it hard to draw air into your lungs from SCUBA when the vacuum is trying to suck it out of your mouth? I had planned to do a unmanned test using a vacuum pump to do some basic low pressure leak testing on my sub before taking it for actual water testing. Just let the pump go down as far as it can, then turn off the valve and see if the partial vacuum holds. For infusion molding applications they some times use ultrasonic leak detectors and stethoscopes for detecting leaks on the out side of the mold plug layup. Like seen here at Fibre Glast. http://www.fibreglast.com/showproducts-category-Vacuum%20Infusion-20.html We used a chalk duster when testing the seal of large concrete CA apple cold storage rooms. I've seen a couple of subs that didn't do a vacuum test at the shop before they went and put the subs in the water for there first water test, such as the Alicia sub, and if they had, they would of saved a fair bit of time. Not to mention all the people that came to see the sub do it's first test dive laughing at you for being wet behind the ears. ;} I've been using a vacuum on my sub a lot lately. Shop vacing all the rust, paint and copper slag out after blasting that is. Regards, Szybowski > Subject: Re: [PSUBS-MAILIST] Vacum test > From: MerlinSub@t-online.de > To: personal_submersibles@psubs.org > Date: Mon, 25 May 2009 21:01:00 +0000 > > I use my lungs, a ballvalve and a snorckel to evacuate the internal of > Sgt.Peppers some 50 milibars to check for leak as predive procedure. > > vbr Carsten I pulled a partial vacuum on my boat to look for leaks. I actually had someone working the vacuum pump and I climbed in the boat with a bottle of soapy water which I squirted at each fitting. While this works to look for leaks, it is not a good test of the structural integrity of the boat as the max depth you can simulated is 34 ft (10m) of fresh water. Cliff > > > "glen brown" <glenbrown@vodamail.co.za> schrieb: > > Hi > > Can anyone be so kind to tell me if any one has used vacum to test there sub > > for leaks and the integrity of there hull when i used to dive for diamonds > > on the west coast of south africa we used to prime our gravel pipes and > > pumps with vacum either using a venturi ,milkmachine, car airconditioner > > motor ect I remember one day we had nothing to use so i decided to use a > > 300hp tractor engine making an adapter to the air intakeof the engine and > > using a 44gal drum as a safety resivoir to protect the engine from water i > > clearly remember how the drum was crushed by the pressure differance any > > coments. > > All the best > > Glen S.A > > > > > > > > > > ************************************************************************ > > ************************************************************************ > > ************************************************************************ > > The personal submersibles mailing list complies with the US Federal > > CAN-SPAM Act of 2003. Your email address appears in our database > > because either you, or someone you know, requested you receive messages > > from our organization. > > > > If you want to be removed from this mailing list simply click on the > > link below or send a blank email message to: > > removeme-personal_submersibles@psubs.org > > > > Removal of your email address from this mailing list occurs by an > > automated process and should be complete within five minutes of > > our server receiving your request. > > > > PSUBS.ORG > > PO Box 53 > > Weare, NH 03281 > > 603-529-1100 > > ************************************************************************ > > ************************************************************************ > > ************************************************************************ > > > > > > > > > ************************************************************************ > ************************************************************************ > ************************************************************************ > The personal submersibles mailing list complies with the US Federal > CAN-SPAM Act of 2003. Your email address appears in our database > because either you, or someone you know, requested you receive messages > from our organization. > > If you want to be removed from this mailing list simply click on the > link below or send a blank email message to: > removeme-personal_submersibles@psubs.org > > Removal of your email address from this mailing list occurs by an > automated process and should be complete within five minutes of > our server receiving your request. > > PSUBS.ORG > PO Box 53 > Weare, NH 03281 > 603-529-1100 > ************************************************************************ > ************************************************************************ > ************************************************************************ > |