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What type of welding rod is best for TIG welding gun metal that will be charcoal blued? I had a trigger guard TIG welded and the weld would not charcoal blue or hot blue. Is there a welding rod that will charcoal blue and not show a visible difference from the surrounding metal?
Thanks

when they were cleaned of varnish coat hangers worked fine for no stress areas
Tom

I don't know the answer offhand, never have needed die steels (air, oil and water hardening) to be charcoal blued after welding- I would check with Doug Turnbull in NY-- Coat hanger wire is a mild steel, but as wire coat hangers need ductility (to be bent and wrapped for the hanging loop) it should flow under the arc of a TIG - surface condition of any filler rod used in TIG is critical- any contaminants can cause weld porosity and possibly undercut at the edge(s) of the weld bead-- IMO, as 90% of a good quality weld, no matter the process, depends of proper preparation of the weld joint and knowledge of the parent metal to be welded,I would never "skimp" on filler rod and only use those rods certified by AWS from a reputable welding products distributor--just my approach, others may see it differently--

Fox
what still sticks in my mind from weld school was eating lots of bannanas and everything had to be perfectly clean. What i was taught to weld flew so it got xrayed. Coat hangers old autobody filler rod cheap and handy. Go to a good weld supply shop if u cant get help from Turnbull
Tom

Few things to consider.
When welding gun parts to be blued, you really want to try and match the steel composition of the base metal. I suspect the trigger guard is made out of low carbon steel such as SAE 1010 or 1018.

I’ve seen folks used old spring wire, and coat hangers with some pretty crummy results.
Spring wire is about SAE 1095, way too much carbon.
Coat hangers are kinda like Spam; nobody really knows what’s in it. Especially those made in China, cheapest scrap the manufacturer can buy, one time use, and if they fail…which they often do no serious damage.Do not use screw stock i.e..12L14 (anything with an L), the L means the steel has lead added, which causes it to weld like crap.

So best to use simple SAE 1018, any Lowes or HD will carry it, usually called Cold Rolled Steel.

The other piece is that the welding has changes the heat treatment of the metal. So now you have hard spots (generally the welded area) and soft spots. Both will blue differently. For a quick test of this, take a case hardened part and hot blue it, it will come out a nice red color.

Best thing to do for the trigger guard is to anneal (Bring to critical temperature and allow to slowly cool) the parts. This will ensure that the entire piece is dead soft, ridding the part of any hard spots caused by welding.

Good luck,

Mike

Mike Hunter
Hunter Restorations
http://www.hunterrestorations.com

Doublt if I have any buisness putting my 2 cents / nose in this, considering the kind of talent present. We have had trouble with this before.....and after several E mails to RWTF RE welding, we started getting serious about the CLEAN part. Now, my buddy Joe, who has the Linclon precision TIG, and is a hell of a welder - (get a 6 pack of Bud in him and he is steady enough to weld the lid back on to a snuff can), is sold on the 3 1/2% nickel rod form Brownells. Me too. When we started trying really hard to keep it CLEAN, the pinholes and inclusions went away, and there has been no problems with the blueing - be it hot salts or rust blue. Like so many things ... attention to detail. And CLEAN. Works for us rookies.
As always, hoping this finds everyone well;
Kraft

Clean is 100% right- also, no air flow from shop fans to move shielding gases away from the TIG torch cup- and any spatter inside the ceramic cup gave give the Argon (or 50-50 Argon-helium for Titaniam and Copper TIG work) a turbulence, like the swirly from a bathtub drain, whic AIN'T GOOD-The 1010 or 1018 analysis is 100% correct- and all cheap Chink made metal stuff is very ductile (think Salt Water Taffy here troopies)- go with an AWS code, spark test, and 12L14 screwe machine stock or any leaded (for a greater machinability index) is Poison to any Weld- no matter the joint configuration or process (TIG, SMAW or MIG)--I "made my bones" not only in power plants doing root pass on schedule stainless pipe with backing rings with both TIG and SMAW, but also doing custom biker frames (Harleys Only- don't even think about bringing a "Rice Rocket" into that shop on Western and 10th--) with a Miller 300 amp Gold Star, Linde water cooled torch, 100% argon, foot rheostat control and soft-start on the Hi-Freq- a Steinway TIG welder (before the square wave series came out)--best practice for TIG welding- be an accomplished gas (oxy-acetylene- No MAPP) torch hand and welding, brazing and silver soldering first--IMO

Fox
Takes a good weld to keep a vibrating harley together. Ever been on a BMW. Whole different world. The hardest certification I had was the Inconel .250x.060 tube in the .375 plate. Magnified xray seperates the good from the bad. They didn't want anything coming loose in the hot section in flight. I retired from a development shop at General Electric Aircraft Engine Division. Clean was absolutly necessary. Inconel is very dirty. Ill let go of the chain now have a good evening.
Tom

I'm not a REAL welder but have done some daubing on occasion(G) in TIG, MIG, SMAW and oxyacetylene. I worked in the nuclear business for many years around some mighty fine welders and even some Welding Engineers (BS in Metallurgy, etc). We welded seats on stellite-lined valves and added inconel buttering to the nozzles on the RPV (reactor pressure vessel) among other things, and everything had to be dead-nuts to pass the X-ray and other NDEs (non-destructive examinations). Tom and RWTF have it right, cleanliness and smooth flow are the 2 main keys to a good weld.

We (and I in my own experience) have found that the heat-treatment is critical in not ending up with hard spots in the weld, usually at the point of weldment. If not preheated, the larger mass of unheated steel will act as a heat sink and, as soon as the welding heat is removed, will SUCK the heat right out of the red-hot welded area and quench it. One effective procedure is to pre-heat the entire area of the weld to 500F or higher before ever striking the first arc, and to extend the cool-down period by wrapping in insulation. This not only avoids the quenching action that causes hard spots but also minimizes the warpage caused by the uneven pinpoint heating of the weld.
HTH, regards, Joe

THREE WORDS
CLEAN HOT FAST