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OK a stainless to hot rolled steel question

Posted: Mon Jun 11, 2012 10:53 pm
by MonzaRacer
So I get asked by my buddy to design and build a sign frame to go around his 2 ft by 4 ft 3/4" plywood sign for his computer shop. So we go to local machine shop, order metal and guy brings it all out.
My design is 3/4 in x 1/8in square tube, has 7/8 x 1/4 hot rolled welded along sides except near Marson poly nuts installed in tubing UNDER 1/4in band steel.
I am using 1/8 x3/4 down sides and along bottom, the sides have a cold bent 2 in right angle and will lay on top of the 1/4 band welded on top of tubing.
I am cutting and tigging the sides to the bottom and adding some extra pieces to lower corners to help hold in wood and strengthen corners, all this will be tigged.
That being said I have a Thermal Arc 95S Inverter scratch tig/stick.
Now here is my issue, since was getting issues with my old Astro mig, I thought, I was having decent luck TIGGING a non magnetic stainless 3/8 rod with ER70S2 Crown alloy rod and Argon. THIS should have gave me idea why it looked so bright and shinny.
Well I heated and bent the rod for the hanger easily enough. SO I decide since Tig is such pain on this job Ill go get some new stick welding rods, Got 3/32 E6011.
Well I started welding the first hanger rod and it looks like ass till I get some heat in and literally bury the rod and do some slow over weld.
SO my question is with 3/8 rod welded on both sides, some of the weld looks good, say 60 to 70 % rest not as pretty but flow out looks OK. It only has to hold ply wood sign but in some wind but not bad.
So is it safe? or will it crack and fall off. Some other people posted using stainless rod/Tigging to steel. Would possibly capping the weld with a stainless welding rod help or just hang it and hope it holds?
Oh and reason I kept going , I had first hanging loop partly welded. oh and my welding was in DC. On the max amps of 50 or 60 amps on the 110 hook up, dont have 220 wired yet so can only go so high on amps.
Welder does much better on Tig BUT takes time and was doing it outside and mosquitoes were attacking while I was welding.

Re: OK a stainless to hot rolled steel question

Posted: Tue Jun 12, 2012 5:54 pm
by Otto Nobedder
Wind stress should not be an issue here. If you were dealing with vibration (high-frequency, as with a motorized sign) there might be some reason to reconsider, but I've welded stainless scrap to a stainless wall, carbon to stainless, & vice-versa, with 6010, or whatever was handy at the time, and stood on it with no fear at 80'.

I think you're OK with this one.

Steve

Re: OK a stainless to hot rolled steel question

Posted: Thu Jul 19, 2012 7:16 pm
by ironworker705
Yeah..your good. not much of a load using a rod that offers 60'000 psi support.