What can be used in place of Solar Flux for the back of a weld?

admin

Hi all,I just took in a stainless job and ran about 1/2" and checked out the backside and found that I need to back it up to avoid the grain for lack of a backing.  I thought I might be able to get by but not so.I don't have any solar flux which I have used from time to time in such situations and my client is coming tomorrow morning to pick up his job. I have to weld about a two foot seam on a machine part made out of some 12 gauge SS.I do have Heat-Fence paste.  Can I use this in a pinch to get by?  Any thoughts on this?Is there any other material I might be able to use?  I vaguely remember reading about using Playdough for such an application.  Anyone hear of this?Otherwise I will have to cancel out until I get the Solar Flux tomorrow and put off when I can get the job to the client.Thanks,Tony
Reply:Piece of flat aluminum TIGHTLY across your weld points.....zap!I am not completely insane..Some parts are missing Professional Driver on a closed course....Do not attempt.Just because I'm a  dumbass don't mean that you can be too.So DON'T try any of this **** l do at home.
Reply:Hi Zap,problem is that the joint is not flat but curves. It's a lid with pipe connections on it for some type of manifold. I suppose I could shape a piece of aluminum or copper (what I usually use for backing).What about aluminum foil? What if I stuffed that in the joint and held it in place with a plate like you suggest? I tried welding some more with reduced heat but it still grained up on me.  I am welding it from the outside. This is the inside shot of the back side.See picThanks,Tony Attached ImagesLast edited by therrera; 10-02-2012 at 08:38 PM.Reason: to add more detail
Reply:What about doing it from the inside then dealing with the backside?That would be my plan of attack.....zap!I am not completely insane..Some parts are missing Professional Driver on a closed course....Do not attempt.Just because I'm a  dumbass don't mean that you can be too.So DON'T try any of this **** l do at home.
Reply:Have an assistant follow the backside glowing spot with a gas lens and cup from a torch on the end of an argon hose.Welding/Fab Pics: www.UtahWeld.com
Reply:The assistant idea is good. I would have to wait for my son to get home from work and "recruit" him, set up another argon bottle with regulator, torch, etc.Out of desperation and to try and NOT have to run out at 7am tomorrow morning to buy a $50, 1lb can of Solar Flux, I tried the Heat-Fence stuff as a backing on a small area and it worked!!!So I coated the whole back of the joint with the stuff just like if I was laying down some silicone caulking with my finger and welded the whole joint all the way out.The stuff absorbed the heat so the puddle ran cooler and not as runny on the top side. On the back side it formed like a crust that stuck to the metal while I was welding on it and as I passed over an area, it flaked off or started to lift. When I finished I just passed a screw driver over it and the stuff came off like a fluffy pie crust.Granted, the Solar Flux if I remember stays on the joint better and is more like a backing strip, but this stuff kept it from graining up on me. I will now coat the outside and run a fusion pass over the inside of the weld. It will smooth it out and seal any pinholes that may be present.The pics show the stuff fingered on a test area and after I finished the top side. Notice that there are what appears to be burn through. Those are spots where there were corrosion holes eaten through the stainless and I had to run the torch over those areas and feed rod into them. The Heat-Fence shielded them even though they dripped through slightly. When I go over the inside with a fusion pass, I will smooth those areas out.So in a pinch the Heat-Fence paste will work and its around $10 to $15 a jar depending where you get it instead of $50 for a can of it.Whew!!!Thanks for the idea.Tony Attached ImagesLast edited by therrera; 10-02-2012 at 10:15 PM.Reason: To add a additional note
Reply:therreraStandard equipment, thin gray high density cardboard,and 3M tape.  Build a gas dam: in, around, over, and back purge.Solar Flux works, but doesn't produce the quality of gas.Opus
Reply:Possibly aluminum foil could be used or stainless steal is the best option as far my knowledge is updated. Solar flux is formulated to shield the back of the weld from oxygen, dissipated heat and unwanted oxides, and stainless steel provides all these things.