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This weekly video is all about how to tig weld lap joints. My brain was all over the place while I was making this video so if you need to rewind to watch something twice, that is perfectly ok. we like it when folks are watching our videos over and over. Its like our policy.
I used 4 different tig welding machines for the lap joints in this video and you know what? As far as dc tig welding steel goes, there just is not that much difference from one machine to the other unless you need a low amp start or pulsing capability.
AC is a whole nutha deal. for aluminum, there are big differences from one tig welder to another in wave forms, ac balance, amplitude settings, etc.
But that is a topic to be handled in a future segment.
Here is a short summary of what is in this video…
Tig welding lap joints in 11 ga (3.2mm) cold rolled steel….without filler metal, and with filler metal….and without pulse and with pulse.
welding a 11 ga (3.2mm) aluminum lap joint with a tapered electrode.
welding a multipass weld on 4140 lap joint
and a practical application lap joint of a bearing sleeve on the inside diameter of a heavy wall steel tube.
All of this was done using a 3/32″ (2.4mm) 2% lanthanated electrode and either 3/32″ (2.4mm) or 1/8″ (3.2mm) filler rod
Here are some of the settings for the different jobs…
11 ga (3.2mm) lap joints dcen current with no pulse
with no filler 105 amps
with filler 115 amps
11 ga (3.2mm) lap joints with pulse
50% pulse on time
40% background current
0.7 pulses per second
.500″ 13mm 4140 steel
1st pass 170 amps 3/32″ (2.4mm) er70s2 filler rod
2nd pass 180 amps 1/8″ (3.2mm) er70s2 filler rod
4140 steel is used extensively in aircraft tooling and fixtures because of its strength, machinablity, hardness, and dimensional stability.
Even though plain cold rolled steel is a lot cheaper, cold rolled has built in stress and can move all over the place when machined. especially after welding.
4140 will harden and preheat and post heat treatment are sometimes required in order to have a quality product with no brittle areas prone to cracking.
But for the sake of this video, and since the pieces I welded were headed for the scrap pile, I just focused on welding technique.
The job that cropped up while I was messing around welding scrap pieces was a roller with pressed in bearings on each end.
My job was to weld in the sleeves that were machined to hold a sealed bearing. That created a lap joint on the inside diameter of the heavy wall tube.
The machinist made the sleeves to a dimension too tight to press in so the plan was to heat the heavy tube to expand it and then quickly push the sleeves in.
Guess what? the first one went in too far and locked. so we had to cool it off, reheat the outside and use a ram from the other side to tap the sleeve to where it belonged.
The other side went in like cake.
But the fit was so tight, It probably did not even need to be welded. but to be safe, and not shrink the bearing sleeve too much, I only needed to weld one small tig pass on it.
that pass went in using about 150 amps.
( As always, feel free to visit us at our sister site, WeldingTipsAndTricks.com. )
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September 6, 2012 at 10:30 PM
just wanted to drop a line in i just got my order of tig fingers and i cant believe i put off buying these for this long best $ ive ever spend on welding short of my miller tig damn things so good one of my friends already took one for himself
August 30, 2012 at 11:04 PM
hey Jody,
thanx for all the great videos- learn something everytime i watch’em.
tig finger heat shield is da bess n i hope u find a way to make a tig
welding glove out of that stuff. the boys here at Hawaiian Electric
Company (HECO) watch yer videos. mahalo nui (thanks a lot)! k
August 30, 2012 at 8:17 AM
Thanks for another great video . Always look forward to finding them in the inbox every week. Thank you for sharing your knowledge with us . And stay thirsty my friend .
August 30, 2012 at 4:33 AM
Great videos. My problem with welding is I wear reading glasses. +1.75 and I just can’t seem to get a good focus on the weld pool. I also have a focus lens on my welding mask. But Still just cant seem to get a good view. Very frustrating when you are a beginner. Any tips on how to overcome getting correct focus. Again great videos.
September 1, 2012 at 4:57 PM
Hey Stevo, I have been in the same situation the past few years, especially whenI have to weld in the field. The only way I can a good focus is to have the right tint filter plate and to make sure I stay in the distance range of the reading glasses.I cannot wear my bifocals because I cant keep my head tipped back and see thru the helmet, the reading glasses allow me to look straight on. Hope this helps.
August 29, 2012 at 11:31 PM
Good video, keep it up, my students enjoy them also
Russ Bowling
August 29, 2012 at 10:48 PM
Damn I do enjoy your videos, and I to learn something ever time I watch one, Your institutions are so dowm to earth and easy to fallow and all I can say is THANK YOU!!!
Jerry oh! did I say THANK YOU yet.
August 29, 2012 at 5:57 PM
Thanks for a great web site.
Just wanted you to know that I don’t agree with your comment about “not suitable for PhD’s” on your main page. I have a PhD in Philosophy and I am a College Professor. I have also been a mechanic all my life and thoroughly enjoy your videos and instruction. I learn something new every time I watch one. Love machines and welding. Great counterbalance to academia. You do a very professional job with your videos. Good luck with them.
By the way…my College has a good Welding Shop and certification program. I have taken a few of their courses muyself.
Don Piche
Professor Emeritus
Behavioral Sciences/Performing Arts
Palomar College
San Marcos, Ca.92069
August 30, 2012 at 10:30 AM
Don-
Thanks so much for sticking with me, in spite of my “No PhD’s” tag line.
Just know this… It’s only a tag line, and really nothing more. It definitely has served me well in getting “no nonsense” welders to be open to hearing what I have to say. I’ve thought many times about just cutting it altogether, as I really have no problem whatsoever with PhD’s… So long as they don’t talk in circles and try to make other folks feel stupid (which I’ve definitely seen a time or two). I’m quite sure you’re nothing like that, and I’m not saying all PhD’s are like that. It’s just a tag line that gets attention, albeit some admittedly negative attention here and there!
Again, thanks for sticking with me, and all the best to you in your welding. You may see that tag line disappear very, very soon.
Regards,
Jody
September 1, 2012 at 6:31 PM
Taht is a very good video to whatch, it is very helpful. Continue doing it and would like to practice it . thank you