First attempts at tig welding
- Thread starter Larry G
- Start date
Rob Murray
Registered User
Unionville, PA & Pointe au Baril, ON
What does the inside of the tubing look like at the weld? Any burn through or distortion?
mike mcs repair
Registered User
chugiak AK
Left side of first picture looks great, right side touch cold, and work on not leaving crater at end by backing off slow...
Try cleaning you tubes first with sand paper then wipe with acetone or such.....
But that is a perfectly good weld that won't let you down..
Excellent for a first try!
Try cleaning you tubes first with sand paper then wipe with acetone or such.....
But that is a perfectly good weld that won't let you down..
Excellent for a first try!
D.A.
FRIEND
Free America
The pictures of Larry's destructive test brings up a question I've had for a long time; how does Joe Schmoe working in his home shop/garage test his welds? I asked an old timer 40 years ago how to know if your welds were good and he answered "Clamp 'er down in a vise and beat the live'n tar outa 'er and if it don't break, she's good to go."
I guess I understand the basic principal in that illustration; You join one tube to another tube (with a weld) and if you can hold one tube and then exert enough energy to the other tube to distort both tubes without compromising the join (the weld) then the weld is stronger than the tubes which is what you want. But is there an even more clever way to perform your backyard test than just beat'n the smithereens (spl.) out of it?
Mike you usually have clever alternative ways of skin'n a cat?
I guess I understand the basic principal in that illustration; You join one tube to another tube (with a weld) and if you can hold one tube and then exert enough energy to the other tube to distort both tubes without compromising the join (the weld) then the weld is stronger than the tubes which is what you want. But is there an even more clever way to perform your backyard test than just beat'n the smithereens (spl.) out of it?
Mike you usually have clever alternative ways of skin'n a cat?
Marty57
PATRON
Nipomo, Ca
D.A.
Destructive testing; so much fun. Before I started welding my fuselage, another build who I trust completely (he offered to test fly my plane when I am finished) came over to check on my "coupons"; practice welds. He did the sledge hammer thing and he also cut across the welds and polished them and looked at the cross section under bright light. I had tagged each weld with specifics such as tip size, pressures, rod size, etc. He pointed out what welds were "A+" and ones that would work just fine and some re-do's. His efforts gave me a lot of confidence and helped me to repeat the good welds and avoid the bad ones. Worked great.
Marty57
Destructive testing; so much fun. Before I started welding my fuselage, another build who I trust completely (he offered to test fly my plane when I am finished) came over to check on my "coupons"; practice welds. He did the sledge hammer thing and he also cut across the welds and polished them and looked at the cross section under bright light. I had tagged each weld with specifics such as tip size, pressures, rod size, etc. He pointed out what welds were "A+" and ones that would work just fine and some re-do's. His efforts gave me a lot of confidence and helped me to repeat the good welds and avoid the bad ones. Worked great.
Marty57
D.A.
FRIEND
Free America
Thanks for chiming in here Marty. If you don't mind, could you expand on "The bad ones" please. What made them bad? What do you do differently so that those specific issues aren't repeated? Thanks for sharing, otherwise I'm sure I'd go right down the same path. Thanks to Jason Gerard, I too have begun a dialog with a respected welder here in the Seattle area and I plan to do the exact same thing with him as you did with the guy you trust.
Speaking of welding, check out the latest update: http://davidadamflyingcircus.com/137.html
Thanks in advance.
mike mcs repair
Registered User
chugiak AK
you only want to see very little anything on inside on a thin tube like that.... too much will rip out at weld edge especially with a tig.....
Marty57
PATRON
Nipomo, Ca
D.A.
The few bad welds I had starting out I was able to look at and cast off with out subjecting to much of a test. The "bad ones" were cold welds; not enough heat. On those the rod was built up as filler but I didn't get the parent metal hot so it just built up on the surface. On the other side of the spectrum, burning through 4130 is pretty easy but at least you know you have the heat range where it should be. Something to keep in mind when scratch building vs repairing existing is that scratch builders will do hundreds of tack welds before any final welds. So, when you are at the "good" stage start welding. A scratch builder will get a lot more practice before any final welding is done. Like anything, more practice and you will get pretty darn good.
Marty57
The few bad welds I had starting out I was able to look at and cast off with out subjecting to much of a test. The "bad ones" were cold welds; not enough heat. On those the rod was built up as filler but I didn't get the parent metal hot so it just built up on the surface. On the other side of the spectrum, burning through 4130 is pretty easy but at least you know you have the heat range where it should be. Something to keep in mind when scratch building vs repairing existing is that scratch builders will do hundreds of tack welds before any final welds. So, when you are at the "good" stage start welding. A scratch builder will get a lot more practice before any final welding is done. Like anything, more practice and you will get pretty darn good.
Marty57
D.A.
FRIEND
Free America
Do they ask specifics about your welding?
Marty57
PATRON
Nipomo, Ca
D.A. Some one probably told me that the airworthiness inspection might include a look at the welding; can't remember for sure. In any case, I kept my welding samples for some reason. Bugs recently had his exp. inspected; he could better answer the question. I bet it is up to the individual inspector.
Marty57
Marty57
Rob Murray
Registered User
Unionville, PA & Pointe au Baril, ON
From what I can tell from your photo the area on right looks pretty good. As others have said good welds are mid way between being too cold (not enough penetration) and too hot (burn through and distortion). Practicing on scrap the only way to find out. And for pieces of small diameter tubing I sometimes run a rat tail file inside the tubing. It will show any high points (distortion) and make inspection with a flashlight easier. Cutting the tubing apart, as you have done, an even better way to see what's going on. And besides the appearance of the weld bead try to match the color of your good welds.
