O/A Welding Question

[Furu]

I will be the first to admit my O/A welding skills have been unpracticed for nearly 4 decades. I was taught in my teens and was able to make strong welds on the farm but can't remember ever welding lighter weight steel to much heavy duty steel.
I have been practicing lately in preparation for a fabrication bracket and am a bit frustrated. I am trying to weld a light weight 1"x1" sq tube to a 3/8" plate. I have not been happy with the results. Even with major preheating of the 3/8' I am burning holes in the tube even without directing the flame on the tube. The tip ( #4) I am using right now is too big for the tubing but too light for the plate but is the best that I have tried. #2 Tip (correct for the tubing) was worse because it just does not heat up the plate enough. Any suggestions?

As an additional question I have never gotten the stacked dime look with O/A like with arc. Is it even possible to get the "pretty weld" look with O/A?

 

[Baby Grand]

What kind of steel are the tube & plate: plain-old-plain-old mild steel?
What are you using for filler rod?
What position is the weld - tube vertical on plate horizontal?
Are you prepping both parts really carefully/clean steel/close fit-up?
If there's any way you can pre-heat that 3/8" plate, even if it's just in the area of the weld, that could be a huge help. Can you throw the 3/8" plate on a gas grill, heat it up and do the welding there?

 

[Furu]

What kind of steel are the tube & plate: plain-old-plain-old mild steel?
What are you using for filler rod?
What position is the weld - tube vertical on plate horizontal?
Are you prepping both parts really carefully/clean steel/close fit-up?
If there's any way you can pre-heat that 3/8" plate, even if it's just in the area of the weld, that could be a huge help. Can you throw the 3/8" plate on a gas grill, heat it up and do the welding there?

Both are mild steel
Using RG45 but am having the tube burn through/melt before the plate puddles or re-puddles depending on the preheat I use thus not much use
Plate horizontal Tube vertical
Both are clean close fit-up
As I stated in the post I have preheated the plate. Actually have tried at different levels up to and including puddling the area in a 1 " square but obviously it cools as I bring the tube in.

 

[Soundguy]

Are you determined to gas weld it and avoiding arc welding? or just don't have an arc welder? IMHO.. your task would be a couple minute job with an arc welder..e tc..

soundguy

 

[deereman75]

You can get the nice fish scales quite easily. You just have to get in the rhythm of dipping the rod, and moving the torch. You do it just the same as when tig welding.

 

[Gary Fowler]

Your predicament is what was basically discussed in another forum on OA welding where someone stated that gas welding was not practical for structural welding although we had a couple of folks who thought otherwise. TIG welding give you the same type weld but with localized heating like SMAW welding. You should be able to gas weld it IF you dont have arc weld capability. You are obviously not preheating the thicker plate long enough or big enough area. If you get the plate red hot in a circle at least 6" in diameter and keep it hot while you align your small tubing it should work. Make sure you dont have the thick plate laying on a steel table as it will suck all your heat away. Put it on some firebrick if you have it for support and insulation. It will take a while to get it hot but just keep at it. You may also need some heat on the back side of the plate while you weld the tubing on which may require you to weld it in a vertical up position or at least have your tubing horizontal rather than vertical. A $99 used Lincoln Tombstone would sure be worth its salt at this point. There is also a way to weld with 2 each 12 volt car batteries hooked in series. There is some info on TBN about a guy who welding on his gate hinge in the boonies with a car battery.

 

[Soundguy]

seems like alot of material usage ( gas ) on gas welding if that much preheat and prep is needed vs buzzing a few rods or feet of wire..e tc.

good luck with the project. hope it turns out like you want it.

soundguy

 

[yomax4]

Actually, Doing the joint above, You should be able to do the 1st pass with no filler rod. If the plate is molten, Just wash the puddle down to the tubing and let it fuse. Then go back and fill in what ever you need to with RG45 or Stainless or Coat Hanger or what ever. Should work with patience and practice.

 

[Soundguy]

man.. still seems like alot of work... vs a couple minutes of buzzing and some rods or a few feet of wire..

just sayin..

 

[IslandTractor]

man.. still seems like alot of work... vs a couple minutes of buzzing and some rods or a few feet of wire..

just sayin..

I agree. Oxyfuel is not the best when welding two dissimilar thicknesses of steel. At least not for those of us who don't have loads of experience.

A cheapo wire feeder or stick machine would do the job in a few minutes.