Best way to hold exhaust pipe together for Tig tacking

Next week I will be welding 304 stainless steel exhaust pipe together. I
found that the most important thing in doing this was good fit and tight
joints.
So far everytime I have tried this in the past I tack one side and the
other side opens, expanding the gap.
Does anyone have any good tricks of the trade here. Is there any type of
good clamp to keep the tubes together while tacking.
Also does anyone have any opinions on Solarflux "B"
Thank You
John Roncallo
Reply to
Anonymous
Loading thread data ...
In article , "jr> Next week I will be welding 304 stainless steel exhaust pipe together. I
At last count I have made over 30 different tube welding clamps. Most are based on Visegrip C-clamps, but some use simpler clamp screws.
One solution is to make a pair of clapms that just grab the tube. You place one on each side of the joint and then draw them together using either screws or twisted bailing wire.
Works OK, as long as you never have to remove it. Should work fine for an exhaust system. I do hope the tube you are using is 304L, not just 304.
Reply to
Ernie Leimkuhler
Primitive: Some angle iron and two C-clamps. Starting from there, you can improve it.
Nick
Reply to
Nick Mueller
two worm clamps and centered by a piece of small round stock. Works like a champ!
Rob
Reply to
RDF
Thank You
I will purchase a set of muffler clamps and weld 2 washers to each side of them and use nuts and bolts to draw them together.
How can you tell the difference between 304 and 304L. The place where I got it from says its T304/304L ???
John Roncallo
Reply to
Anonymous
Since I will on alot of ocasions, be running from one bend to another this wont work.
But Thanks John Roncallo
Reply to
Anonymous
In article , "jr> Ernie Leimkuhler wrote:
Most 304 is 304L nowadays so it should be fine. The "L" just means low carbon, so it is less likely to develop chromium carbides during the welding process.
Reply to
Ernie Leimkuhler
If stainless steel is "dual-marked" such as this, i.e. T304/T304L (or, similarly, T316/316L) it means that the chemical composition meets the low carbon grade (the 304L part) while the tensile properties meet the regular grade (the 304 part) requirements. The specified minimum tensile properties for the L-grades are slightly lower than the regular grade but many manufacturers are routinely producing L-grade compositions that meet the regular grade tensile requirements. This way you get the best of both types.
Reply to
tdoodyNS
John, back on the subject of tricks to tack. As you say, often when you try to melt to edges, and get the pools to wet together into one, surface tension causes the pools to ball up and retract away. The solution is to Zap the joint with a very short duration, high current pulse, at a very short arc length. You need high frequency arc starting and a foot pedal to do this. First you need the two edges to be in contact with each other, and it helps if the edges are square and sharp, not rounded or chamfered. To make the tack, you need to have the tip of the tungsten electrode very close to the joint, and equally pointed at both edges. It is best to rest the torch on the gas cup, so stick the tungsten out the right distance to allow you to do this. Set the current at about 150 amps. Get a preflow of gas going by tapping the foot pedal while holding the torch away from the work. Quickly position the torch while the gas is still flowing, and hammer the foot pedal quickly on and off. Adjust the current and on time to adjust the size of the tack weld.
Reply to
Ipeak
I noticed tackiong with rod seams to alivate this problem. What is the big deal about applying filler rod for the tack.
I will take a couple of practice shots with this. 150 amps seems high. The tube is only 0.065" wall 304 stainless. I was thinking of starting with about 50 amps and seing how it goes. I do have high frequency with a foot pedal.
Thank You John Roncallo
Reply to
Anonymous
I know 150 amps sounds high, but think about the very short duration of time, this is the key to this process, we're talking On/Off, very quick. Remember, the two pieces need to be touching each other at the point where you make the tack, and the tip of the tunsten needs to be very close, 0.020 to 0.040" gap.
Reply to
Ipeak

PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.