What type of welding rod should I use????

[JBIRD1]

Hello Again,
I'm ready to start welding and wanted to know what the accepted / preferred welding rod I should be using. Aircraft Spruce has No.32cms and No.7 wedling rod. Which one should I use and what size????
Thanks in advance,
Jay

 

[Idaho Spud]

I'm assuming you are using Oxy/Acy. I asked this same question months ago when
I stared my project. After a lot of reading and research and contacting people
that make welding rod(Lincoln was one) I came up with what I was already using.
Lincoln R45. Which is the same as the Oxweld #7. As far as size 1/16 can be used
for most of the welding. This is just from my expierence and some people may not
agree and may have used something different.

Jim C.
Idaho Spud

 

[Skybob2]

Back in the early 80's John Monnett told us that if we ran out of rod while welding that a coat hangar wire would suffice. My understanding is that the metal in the weld should be softer (not brittle) than the tubing.

 

[ltusmcret]

John Monnett's expertise not withstanding, coat hangers are made of very cheap (and unreliable!) steel wire. It may be ok to use something like that if you never plan on getting it off the ground, but I for one would not want to trust it. Welding rod is too cheap when you consider the total investment we make! #7 is the best I've found and a couple of friends who own & operate welding shops agree.

Claude Elliott

 

[Sonex522]

I don't just have an opinion about using coat hangers - I actually tried it (on non-airplane stuff). The short version - they weld like crap. Don't do it. I heard somewhere that the plastic coating would provide some flux action, but it just hosed up the weld. It was like welding on painted metal. Sizzle sizzle pop pop.
If you're talking about gas welding, then something equivalent to Oxweld 7 is the way to go. For TIG, Lincoln Electric found through scientific testing that ER80S-D2 is the thing for thin wall 4130 steel. They also found during their tests that post heat treatment with a torch is not necessary, possibly detrimental, and unlikely to be correctly accomplished anyway, but I'll likely get punched for saying so out loud. My own testing of samples to destruction has shown no difference with post heat treatment, so the only question mark I personally have is related to how a non-post heat treated weld will stand up to years of vibration. Taking a fresh weldment and pumping a bunch of heat into it has always seemed counterintuitive to me, so it was encouraging to me to hear Lincoln preach against it. I highly recommend sitting through a Lincoln welding forum at Oshkosh - it's quite informative, although I did get into it with the speaker about whether brass can be welded. I find it interesting that everything from titanium to unobtanium is welded all the time, but if it's brass they say it can't be done. But that's how it goes - put two welders in the same room and you're liable to get a fist fight.
Have fun.

 

[DanMcC]

Try ER 70 S-6. I used 1/16 dia. but .040 is better if you can find it. Don't bother with the 4130 wire recomended for tigging as you must post heat treat.

 

[JohnB]

The ER-70 is the recommended rod. It does not require post weld heat treatment. In defense on John's statement about coat hangers some things have changed. Years ago they were made from as us old guys remember larger diameter wire than they are now. They used to be formed from simple wire about a 1010 grade of steel. Now they are made from higher tensile strength stuff that is very brittle. Have any of you tried making a coat hanger device to break into your car lately. They break when you bend them.

Cheers,