So I'm doing Qtrs. Butt welding 9' per side, We all know how long this will take doing the "Jump Around"! I have been doing this for decades, Quench with blow gun, Works Amazing, Only problem, I get tired of holding the damn blow gun....Till today! Found a cheap $8.00 blow gun from Walmart, scrap left over from a jeep bumper, an a magnet set-up from a dial indicator, could be substituted with any type of magnet, a piece of brake line, an hose from the hardware store, it allows you to lay down 3/4 of an inch Easily with Zero warpage! An a Much more uniform weldment as opposed to a Million cold start mountains... Cheer's
So are you doing 3/4 in welds, quenching, the doing another 3/4 inch off the same weld, quench and repeat?
ExactlyOTE="Budget36, post: 11386165, member: 257791"]So are you doing 3/4 in welds, quenching, the doing another 3/4 inch off the same weld, quench and repeat?[/QUOTE] Exactly, start at one end an Go, Hit the air for a few seconds, cool to the touch...
Here's a 12" section welded in 7 minute's, in second picture I'm holding a aluminum straight edge to show No warpage..
Just thinking about it I did leave out one Key step, the blow gun I used had a restricted interface that threads in at the hose end, I drilled the toothpick size it comes with to 1/4 ... Now back to your regularly scheduled programming..
For those that didn't get on board... Having a few... Welding up a couple round holes cut in a o/t Jeep, Zero warpage.. No there not the best I've done, but... Couple cocktails in... Still worth a try ... The whole point is, No warpage, An this took about 4-5 minutes, not as much cold start chicken $! An better penetration
After a few more... My only point is, a blow gun works fine... But when you have a long panel... Priceless...
Back stepping would be to start at the end on the right about four inches from that end , weld to end then go four inches left of that and weld to it. Continue that until you are all the way to the left. Of course have panel tacked all the way before starting. Let me know if you understand this. It is much easier to show than tell. It ends up distributing the heat better.
Here is a link how too! Much better explanation! https://www.bing.com/videos/search?...3BFF7F35E98C2E7C6F173BFF7F35E98C&&FORM=VRDGAR
For those that think cooling a fresh weld with air prevents shrinkage, I'll point out that that is the precise method of how a 'shrinking' disc works. You get metal red hot and cool it quickly and it shrinks. It isn't about how quick you cool it, it is about how hot you get it.
I too cool welds with compressed air but remain skeptical that all warpage can be eliminated. I've yet to see it.
Does a quick cooling, air or water, make the weld more brittle? If not then this method would shrink the amount of work!
Well after welding over 18' butt welded (68 el camino full qtrs. Painting Black) With no warpage, Sorry... That straight edge is sitting on Said quarter, The whole point to this method is less cold start , better penetration, less grinding, faster ,Meaning more heat, sheet metal warp's, Take the heat out as fast as it goes in, I shared what works for me, An anyone that Care's to try... Perhaps it's not to "Everyone's" interest... Cheer's
How about shrinkage at a right angle to the weld, 90 degrees to your straight edge. That is the direction I would think it would shrink.
OP, are these all lap joints? I use air to cool also but on butt joints and still get warpage, laps can stand more heat.
What does the air blast do to the shielding gas while you're welding (or are you using flux-core wire)? I've welded outside with my MIG setup and an occasional breeze would take away the gas shield and the weld would start to get porous. - EM
You don't blast air while welding. After you weld a section, blast it with air. Has nothing to do with the shielding gas. It's all about keeping the panel cool.