Warning! Do not mig weld 4130 tubing, do not pre heat it, do not stress relieve it and do not powder coat it. This very light, very strong metal is at it`s strongest from the foundry. Expert tig weld only. Every heat cycle you put it through weakens it. The key is perfect full pen precision welds with the least amount of heat as possible. Don`t risk your life, use the right process. I am an aerospace tig specialist of many decades. Ask any top fuel chassis builder, he`ll tell you the same thing. Fly safe, your life depends on it.
Feb 28, 2010 Rating
4130 Material by: Anonymous
We weld 4130 material all the time in our shop, we preheat it to about 500 deg, then tig weld and stick to finish, then put in a hot box to cool down at a controlled rate. We are welding lubricators for wellheads, that have flanges on them. The welds are full penetration. I have seen pipe vessels and such welded out completely with mig before and they worked out fine, but they are pressure tested to make sure they will work at the proper working pressure. Unfotunaltely for you, you cant test your plane before you use it.
I agree with the other post, tig weld definately will yield a better weld, but if you are completely confident in your mig, try some test pcs. It is your life at risk here.
Feb 13, 2010 Rating
Not recommended by: Gerry
I am an EAA Flight Advisor. Mig welding 4130 tubing is not considered proper due to the difficulty of ascertaining proper penetration. Gas welding is an approved technique, as well as Tig. It is generally recommended that all welds be stress relieved. With gas welding, this can be accomplished by heating the tubing adjacent to the welds. An alternative would be to weld the entire structure and then heat it to stress relieve it.
I can't stress this enough- you are betting your life on your welds! Why take a chance with a technique that is not recommended? I have been to too many funerals for homebuilders that cut corners.
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