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stormbird
11-08-2010, 04:45 AM
Hi all

Just getting to grips with my TIG welder :-

http://www.r-techwelding.co.uk/welding_equipment/Tig_Welder/Tig_Welders_R-Tech_Tig160PDC

Everything goes well on 3mm plate [ see picture ] but on 1.5mm I am having problems [ see picture ]

On round bicycle tubing it looks even worse , like a bird has tried to join the parts using stuff from it's bottom !

For 3mm I have a 2.4mm Tungsten and about 80 - 90 amps.

For 1.5mm I tried the 2.4mm and had to turn the amps down to <45 and it is hard to start the arc and the arc is feeble.

Should I try with a 1.6mm tungsten ? and what current ?

regards Paul

Odd Man Out
11-08-2010, 12:35 PM
Stormbird
1/16 inch filler rod is what I use at 120AMP. That is on 1/8 inch aluminum though. Looks like you should practise with adding filler -- you want that neat row of leaned dimes (or pence??) look. You get that with practise, rythmic putting the filler rod into the puddle as you slowly move along. Also realize that the heat builds up in the materiel so you need to ease the amps back as you get to the edge of the weld or you will blow the edge out -- the peddle is an art form all unto itself. Keep practising -- it gets better.

stormbird
11-08-2010, 02:22 PM
Looks like you should practise with adding filler -- you want that neat row of leaned dimes (or pence??) look.

that was with filler ! The 2 lower pictures are somewhat magnified.



Also realize that the heat builds up in the materiel so you need to ease the amps back as you get to the edge of the weld or you will blow the edge out -- the peddle is an art form all unto itself.

Sorry no pedal , I suppose I could raise the torch a little to spread the heat further ?



Keep practising -- it gets better.

Well I have a few more nights at my night class , however they don't want me to go anywhere near 1.5mm and shock horror ' round tubing '


regards Paul

Odd Man Out
11-08-2010, 03:04 PM
With TIG you are kind of chained to how far from the weld you can keep the torch -- 1 to 4 mm is about it -- you are working with amps and not so much heat. When you pull your torch away from the weld you will see the arc become more diffused and less concentrated. This is bad.

Sorry -- thought you had a pedal. If you are only dialing in the amps and then going for it I would say that you are not being taught correctly or your learning is being hampered. The pedal is essential in TIG welding -- it is the accelerater and brake for the amps. See my last post.

Yes welding round tbing can be a pain in the mule.

badcheese
11-08-2010, 06:30 PM
The pedal is not strictly necessary. I used to work as a structural aluminum TIG welder, and we used a simple trigger button switch (momentary contact on/off, no pot for amp control) taped to the handle of the torch because we were standing and constantly walking around the workpiece (sections of trussing) to weld the joints. HOWEVER, that was 1/8th-inch wall tubing, not thin material. The thinner the material is, the more important the pedal becomes.

You'll be happy to know that the vast majority of our work was on round tubing, and I did occasionally weld 1/16th-inch material with the same setup. In other words, what you want to do with that machine is well within the realm of possibility. It just takes lots of practice!

Here's my only piece of advice to you at this point: Obviously, since you don't have a pedal you have to find other ways of controlling the heat. As OMO said, increasing the arc length is not going to work well. Changing the angle of your torch can help, but only a bit. The best trick you can learn for controlling your heat without a pedal is using your filler rod as a heatsink. Every time you dip your filler rod into the puddle, you rob the puddle of some heat. It takes a lot of practice to be fast, precise, and rhythmic with both hands, but as you get to that point, you'll find that you can control your heat by moving faster and feeding filler rod into the puddle very quickly.

The thing I really miss about TIG is having my heat source and my filler material separate, so I could choose how quickly to add filler. If the piece is cold, hold your arc for a while before adding filler so you get enough penetration. If the piece gets hot, stuff that filler rod into the puddle as fast as you can to avoid burning through! You just don't have that kind of control with a stick or wire feed welder. I used to keep my machine set at a constant 245 amps, and I was able to control the heat just by adjusting how fast I added filler. That was almost 20 years ago, using a fancy Miller Syncrowave with a water-cooled torch. I'm not that good anymore, and I can't afford that machine. At least not for building bikes in my garage! These days I don't even think I could afford the argon!

Odd Man Out
11-08-2010, 07:02 PM
The pedal is not strictly necessary. !

I agree -- but it sure makes learning a lot easier. I don't think I would have been successful without it. I have tried the trigger on the torch types and they feel really foriegn -- maybe Graucho with his experience in double action air brushing might find it intuitive.
Best advise -- practice. do don't get discouraged, practise.

stormbird
11-09-2010, 02:50 PM
Hi

Thanks all for advice , as no one is trying this thin stuff with a torch equipped with a switch [ no pedal ] I seem to be out on my own.

Strangely I can sometimes do 1/2" to 3/4" of acceptable weld then I seem to blow a huge hole in the work and spend the next few minutes trying to fill it.

I think I need :-

a) more practice
b) move around the join more to spread the heat
c) try to weld faster to minimise heat and reduce the penetration.

I need to have more confidence/prettier welds before I would commit myself to riding a bike I had welded :jester:

regards Paul

wiretie
11-09-2010, 03:44 PM
Trikeman posted this awhile back. Hope this helps...
http://forum.atomiczombie.com/showthread.php?t=3197

imamedik
11-09-2010, 07:10 PM
I need to have more confidence/prettier welds before I would commit myself to riding a bike I had welded :jester:

regards Paul

But that is what makes it interesting :rolleyes4:

savarin
11-10-2010, 12:39 AM
The thinnest I've welded in tig (40 years ago) was 15 thou stainless sheet.
It was a covering for the roof of the records building in Kew UK so had to be perfect (the original Magna Carta is housed there)
We used the thinnest dia tungsten electrode sharpened to a long tapered sharp point.
That had to be touched up regularly.
The lincoln diesel welder had a huge bank of wire wound resisters on the output dropping the lowest output amps down to IIRC 5 amps. fine mig wire was the filler rod when required.
The arc was tiny producing a weld pool about 1mm or smaller dia.
The filler was for when a hole appeared and wouldn't fuse back together.
It was very easy to touch as the gap was so tiny hence the frequent re-sharpening of the electrode. Probably the worse welding job I've ever had to do
The purpose of my "bragging"? keep the tungsten sharp, turn the amps down to the lowest you can keep an arc at and practice fusing a straight line, then practise making fine beads as OMO said - a roll of coins laying down, once you master that you will be able to weld anything.
(I'm not suggesting you actually weld your frames at this low amperage just use it for practice to get the feel of fine control)
Burning holes usually means uneven speed control, ie stayed too long in that spot or the gap got wider this is why pedal control is a huge help.
Dont forget that the lower the amps the lower the gas pressure needed.
If you have high frequency starter arcs its easier. You couldn't scratch start that stainless job.

wiretie
11-10-2010, 11:04 AM
Tig welded roof, that musta' been some roof. Do you have any photos?

ken will
11-10-2010, 12:56 PM
Tig welded roof, that musta' been some roof. Do you have any photos?

I don't think it is this first one ... But it might be the second one.

http://www.mygenealogist.com/Clare_Dolmen.jpg

http://www.york.ac.uk/ipup/images/tna.jpg

savarin
11-10-2010, 04:50 PM
I never saw the finished building.
The roof in question was the flat one.
It was a long time ago so my dimensions may be way off.
It was comprised of large channels approx 2 feet across and very very long
The sheets were folded into the channel shape, a small flange about 1/4" was raised at the edges and the two edges clamped together in 12" runs and fused together.
The major trouble was the architects specified a particular thickness sheet that was unavailable in the UK so it came from Canada. When it arrived it had an embossed pattern, this embossing was what caused the major problem, it was ok when the pattern caused the edge to meet but when the opposite happened was when the filler had to be used. The amperage barely melted the filler.
It really was a pig of a job, I'm glad I only had a week of it, I went back to my first profession of chef at three times the pay and better conditions all round except for weekend work.
Sorry Stormbird, seem to have hijacked your thread there.:oops:

stormbird
11-11-2010, 03:00 AM
Savarin

No problems a good story , odd cheffing paid more than welding as it is notorious for being underpaid as a profession ?

Yes it is a ' proper' TIG with HF start just no foot pedal.

I will get some MIG wire from my friend and crank the amps down.

regards Paul

savarin
11-11-2010, 03:52 AM
Savarin

No problems a good story , odd cheffing paid more than welding as it is notorious for being underpaid as a profession ?

Ha Ha. not in those days but I was at the 5* end of the job




I will get some MIG wire from my friend and crank the amps down.

regards Paul

no no, you dont need mig wire as filler for what you are doing.
The small rods will be fine.

stormbird
11-12-2010, 03:05 AM
no no, you dont need mig wire as filler for what you are doing.
The small rods will be fine.

Savarin

But I don't have any ' small rods ' I only have 2.4mm although they may be cooling the weld puddle helping to stop burn through ?

So the MIG wire is 0.6 mm [ IIRC ] which I will try to see if it makes a difference.

I have a friend with a MIG so he has just run me off a metre.

regards Paul