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jack3140
09-22-2011, 03:50 PM
can anyone tell me what material is used to make the contact tips on small portable spot welders ? i have one, but it seems to be discontinued model , so i will make my own . i have tried different copper and brass stock but they melt before the steel does !!! so no welds . thanks jack

portlandRon
09-22-2011, 06:21 PM
The tips on the portable spot welder I have are copper as are the tips on other spot welders I have used.
The ends of the tips, where they make contact should be about 3/16 of a inch wide and the side tapper from the tip to the thread is around a 45 degree angle.
How thick is the metal you are trying top spot weld?

Mcgyver
09-22-2011, 07:25 PM
they're copper but they maybe some alloy that affects things. Why not just get some replacements tips - should be standard sizes, hopefully, maybe? I've got them from welding supply places before.

what gauge are you welding, what's the voltages at the tips and whats the weld times? I ask as i does seem a little strange that you're melting copper tips

CCWKen
09-22-2011, 07:46 PM
The ones I have are chromium copper. I also bought stock from McMaster-Carr to make spares. Pricey but they last a long time.

macona
09-22-2011, 08:18 PM
There are a couple companies out there that make all sorts of tips for obsolete machines. Dont just try the original vendor.

BigMike782
09-22-2011, 10:30 PM
One of these should be able to help you find material or supply you with tips.

http://tuffaloy.com/

http://www.cmwinc.com/

Weston Bye
09-22-2011, 10:34 PM
I've been making custom electrodes for some production welders lately. Some machined from pure tungsten, others from copper-tungsten. Not welding steel, though.

jack3140
09-22-2011, 10:43 PM
hi i just need to weld autobody sheet metal . the weld area gets red hot but the tips melt instead of welding , these are tips i made out of brass , no good . i found some replacement tips but they cost around 67.00 $ i find that ridiculous . the damn things must be made of pure gold lol so i am trying to make my own i cant justify paying that much for something i use once in 5 years . jack

CCWKen
09-23-2011, 12:29 AM
Use the chromium copper. That's what most of the shop hand-helds use. As I said, it's not cheap either but less than buying ready made. Don't know which welder you're using but you're holding too long. I do auto sheet metal all the time and rarely go more than a second. The metal doesn't need to "glow". That is what's burning your tips up. The weld occurs where you can't see it--Between the two pieces. Clamp pressure, current, time on and hold are all variables you need to master. Practice on scrap pieces and do a pull test.

boslab
09-23-2011, 12:45 AM
with a spot weld the metal 'slug' should not reach the surface to melt your tips, you might be using a non timer set, as has been pointed out by CCWken you need to do a test bend to see how your welds hold, they dont need as much time as your giving them, tips come in all sorts, CuCr, berylium copper [apparently anti spark chisels make tidy tips according to the tech in the welding lab at work, but they were using big static skiarcy pc controlled welders], a timer seems to be the answer!
markj

J Tiers
09-23-2011, 08:49 AM
yes, use a timer....

Do some scrap first, and get the time, then there will be no problem.

We recently had some proto stuff to do at work. Needed a folded and spot-welded cover made of 0.025 aluminum.

We had a lot of trouble finding a shop that would spot-weld aluminum, so we had one of the other guys bring in his Harbor Fright 115V spotwelder. I rigged a timer and a heavy-duty solid state relay, and tested it on scrap until the peel test looked good.

Found that about 0.4 sec was the ticket, and out went the protos with 8 welds per cover.

Absolutely YES... if anything is glowing, you are holding WAY too long.... The most you should see is maybe some sparks off the work where the tongs hit. For thinnish material, you shouldn't need to hold much longer than it takes to say the word "envelope" fairly fast.

jack3140
09-23-2011, 03:39 PM
Use the chromium copper. That's what most of the shop hand-helds use. As I said, it's not cheap either but less than buying ready made. Don't know which welder you're using but you're holding too long. I do auto sheet metal all the time and rarely go more than a second. The metal doesn't need to "glow". That is what's burning your tips up. The weld occurs where you can't see it--Between the two pieces. Clamp pressure, current, time on and hold are all variables you need to master. Practice on scrap pieces and do a pull test.
thanks for the input i will try your methods and see what happens , may be the metal is not clean enough also .i,ll look around for some chrome alloy copper too . jack