First the use filler material that closely matches the base metal is not intirely true as there are many factors that dictate what filler material to choose.
Tig welding chromoly filler rod.
A common filler metal choice for welding chrome moly is er80s d2 this filler metal is capable of producing welds that approximate the strength of the 4130.
E70s2 mild steel tig welding rod use for welding 4130 chromoly tubing all mild steel and even cast steel.
Try to weld chromoly slower than normal especially if.
Tig welding filler rod high performance tig welding filler metal for every application the most complete line of high quality washington alloy brand 36 cut length filler metal for virtually every tig welding brazing application.
Er70s 2 is also an acceptable alternative to er80s d2 as well as 70s 6 although weld strength will be slightly lower.
Tubing with a 1 16th inch filler 0 063 in is a bad idea because the tubing wall will melt before the filler rod is up to temperature.
Yes 4130 chrome moly has been tig welded in the aerospace and aircraft industries for years.
As with all welding proper procedures and techniques must be followed.
Trying to weld 0 035 in.
Filler rod in tig welding you feed the filler rod into the molten puddle by hand.
Stainless steel mild steel copper alloys aluminum alloys nickel alloys titanium alloys.
As for filler rod diameter use a rod diameter that matches the thickness of the base metal.
Tip if you have a roll of bare mig wire like e70s3 or e70s6 it will work great in a pinch just snip some off and straighten or better yet if its too small double it up and chuck it up in a cordless drill and twist it tight so you wont have to feed so much wire.
The thickness of the material you will be welding also determines the required diameter of the filler rod.
But research has been done to prove that tig welding can be the fastest cleanest and best way to weld 4130 chromoly tubing without risk of compromising material properties provided the thickness does not exceed 120.
For tubing over 0 120 a 300 400 fahrenheit degrees preheat is required.