Is it ok to tack weld with a stick then use oxy-acetyl to finish the job?

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trimtab

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Are you Normalizing or Stress Relieving? Normalizing means an austenizing soak and then air cool. Stress Relief is much lower temp to relax residual stresses from welding, and yeah, that IS quick. But the word Normalizing is being used, and that title means specifics as to process.
You are correct. No normalizing.



Note the use of heat crayons. You can get a set cheaply from Mcmaster Carr. You can get the hang of it pretty quickly and then won't need them after that.

Also note the lack of requirement for stress relieving. I've seen 5 degrees or more of of torsion get removed from a AB Cub copy fuselage after a guy worked his way down the longeron clusters. You could hear it unwind at one point, and the tone from tapping went way down. There is likely a broad continuum on how much good or bad stress relieving does.

The video that claimed 700F+ degrees was death to 4130 needs no comment. He's simply wrong. The hit on tensile strength to 1100F is minimal. The person implied it made it similar to mild steel, and claimed he had all the test equipment to use, etc, etc, yada, yada. Annealed 4130 is still a huge win over 1018. And every fusion and heat affected zone from welding 4130 should be treated for design purposes as annealed with ER70S rod.
 
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Yes. You can tack with stick, mig, tig or gas. If you’re planning on finishing it out with a gas weld it is perfectly fine.
an E60XX or E70XX electrode is the same composition as an ER60 or ER70 tig/mig wire and a RG45/60/70/80 welding rod is no different. It is standard practice in many industries to tack and root pass with one process (tig, mig) and fill/cap with a separate process (stick, flux core).
after all that is why we weld chrome moly with 45/60/70/80 ksi filler metal, to provide the weld and heat affected zone with enough strength but also some elasticity and elongation.
 

PTAirco

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Also put Poly-Fiber tube oil in each tube and where the tube is small drill a 1/16" hole in the larger tube so the oil can go into the smaller tube.
Tabs of masking tape is over the 1/16" dia holes for injection the tube with oil that needs to be welded up.
I'm against the drilling and inter-connecting tubes: if corrosion does occur in in one tube, it can then spread to others. Once a tube is welded up, it's dry and totally sealed and as well protected as it can be. I might oil the longerons inside separately though.
 

Pops

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I'm against the drilling and inter-connecting tubes: if corrosion does occur in in one tube, it can then spread to others. Once a tube is welded up, it's dry and totally sealed and as well protected as it can be. I might oil the longerons inside separately though.
If your welding didn't leave pin holes and you use the Poly-Fiber tube oil, it will not rust inside. Its hard to weld a 1/16" hole where you injected the PF tube oil on a very short tube without the heat expanding the air inside the tube and blowing a hole as you weld the 1/16 hole close. Lot easier to just drill a hole to the inter-connecting tube that is oiled. PF tube seal will also plug up very small pin holes from a low experienced welder.
 
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