help wiht a back purge

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I recently did this job, welding the flange on the top of a keg. There is a chance I will get more of these to do. I sealed the keg and filled it with argon, used tape to seal it off. It was fine for the first one,  but I know there is a more efficient way to do this. the tape on the top is taking a lot of heat and wanting to melt. If I can get around it, I would like to not purge the whole tank. Any suggestions?- Christian M.C3 Welding & Fabrication - CNC Plasma Cutting-Mobile Welding-Custom welding and fabwww.c3welding.com
Reply:What about a small purge box that you can fit inside and clamp against the joint? You would need to move it a few times to weld all the way around, but wouldn't waste all the time/argon purging the whole keg.Airco Ac/Dc 300 HeliwelderMillerMatic 200 (stolen)Miller Maxstar 150STLMiller AEAD200LE (welding and generating power) Hobart MIG
Reply:pretty simple and easy... hmmm do most of you make your own boxes?- Christian M.C3 Welding & Fabrication - CNC Plasma Cutting-Mobile Welding-Custom welding and fabwww.c3welding.com
Reply:Not to  much around from purging the whole tank. I do a lot of wine tanks and wine lines and you want an even coating of purging. I use a Tri clover clamp  with tri clover gasket setup with a cap and welded in fitting with an extra line attached to the cap for purging. Here is a link to where I buy the fittings from or you can ask your welding supply store if they can get them.http://www.mcmaster.com/#standard-sa...ttings/=s2yt5sGalenMiller TrailBlazer 302 EFIThermal Dynamics 252i w/WeldCraft WP 9F tig torch and foot controlThermal Dynamics Pak 52Millermatic 250 w/Spoolmate 30aLincoln SA-200 gas driven welder from grandfatherBlacksmith shop
Reply:I've used a semi clear tape made for purging that is heat resistant. Sent from my SGH-M919 using TapatalkLong after the price is forgotten, the quality will remain.Both of my Poppy's 1954 Short Hoods -Third generation to weld with it and teaching a fourthSA 2## - Bought and sold more than I can remember or care to list, 8 in the shop right now
Reply:thanks for the suggestions. I am thinking about buying a cap to fit the flange and adapt the necessary fittings.- Christian M.C3 Welding & Fabrication - CNC Plasma Cutting-Mobile Welding-Custom welding and fabwww.c3welding.com
Reply:Make a small purge box with holes and steel mesh that you can tape on the back of the joint.That or use backing tape.Purging the hole tank in completely uneconomical.
Reply:Christianwhere in SC are you?  I have a keg I need some fittings on and have relatives down there.
Reply:If you're looking to save argon and not have to fill the whole keg with argon, or have problems with the time it takes to properly purge it, you might consider an alternative that would involve running a hose and deflated large heavy wall balloon setup that could be inflated with normal air and displace most of the space you'd otherwise have to fill with argon.  Inflate the balloon, then fill the rest with argon and you have your back purge with a minimum of argon useage...
Reply:Originally Posted by OUTBACK FORGE I use a Tri clover clamp  with tri clover gasket setup with a cap and welded in fitting with an extra line attached to the cap for purging.
Reply:Build a little assembly similar to that flange but a little bigger diameter. Weld a thin plate on the flat end, then cut the whole thing in half and put a hinge in the middle. That way it can collapse and fit thru the hole. Install a fitting for your purge hose on the plate.
Reply:This may be off the wall but, what if you filled the tank with water up to say one inch from the top and filled the rest with argon.  Much less gas and easy too.  Just thinking.  Best regards Bob
Reply:Water gives off oxygen. We used to weld pipe spools that had been hydraulically bent and still had water in them, never could get a real good purge on them. He could use something else, maybe sand...
Reply:Definitely a candidate for Solar Flux "Type B".Weld like a "WELDOR", not a wel-"DERR" MillerDynasty700DX,Dynasty350DX4ea,Dynasty200DX,Li  ncolnSW200-2ea.,MillerMatic350P,MillerMatic200w/spoolgun,MKCobraMig260,Lincoln SP-170T,PlasmaCam/Hypertherm1250,HFProTig2ea,MigMax1ea.
Reply:Originally Posted by TimmyTIGBuild a little assembly similar to that flange but a little bigger diameter. Weld a thin plate on the flat end, then cut the whole thing in half and put a hinge in the middle. That way it can collapse and fit thru the hole. Install a fitting for your purge hose on the plate.
Reply:Just a thought.   They make flux coated tig wire I have some in 308/316, it works Great!!  Can't remember at the moment who makes it, but it leaves a beautiful root!!!