TIG welder advice

[froggi]

Hi again Kev

Sorry to hear about the TIG set frying itself but glad the customer support sounds A1.

Agreeing with Eric on the contamination of the tungsten but as for the back purging, sorry Eric but I've got to disagree......if you are welding 2 pieces of stainless together and are looking for any sort of penetration you WILL get the "coking" of the penetration unless you back purge.... Believe me, I've TIG welded enough thin stainless to know that this will occur... and by thin I mean 0.5 mm and less.

As for combatting the distortion, weld short lengths (stitching) and on opposing sides if you get my drift (stitch and then mirror it on the opposite side from the original stitch - helps to keep to a minimum any pulling/distortion)... Use the lowest setting you can power-wise and let each pair of welds cool before moving to the next pairing. Another method of reducing the distortion can be by using copper strip/blocks to conduct the heat away from the weld area. Place the conductor close to but not touching the weld area.

Also you could tack weld (not stitch) every inch (25mm) or so, maybe even closer - 3/8" (10mm) and then link the tacks together using the mirror stitching technique.

Another tip is move the torch as quickly as you can as long as you are getting the fusion you need between the 2 components. Problems can occur when you "dawdle" too long on one spot.... Cool and quick if you understand me!!! Offer still stands for the tutorial mate if you want me to pop down - it's been a while since I welded but it's like riding a bike, honest!!!

Again good luck mate
froggi

[Kev888]

Thanks very much indeed!! With info like this, there are times when I almost think this may be possible

I've been poking around the welding forums too and they seem to say that coking or sugaring will happen on thin stuff, but as I understand things it depends on the application as to how much that actually matters; for food use its thought to be worth bothering about though. Apparantly you can use flux or heat resistant tape for back purging, but the advice they've given me is that for delicate or hygenic work it should really be argon.

But that should be okay now; I was shocked at the cost/use of argon with my 9L no-rental cylinder, at about £70 a refil for 1200L, but it looks like energas do a 5000L-ish cylinder for about £35 a refill, so about 1/8th the price (theres also about a £5/mth rental on top but I'll save that dozens of times over) - those prices may be a bit out of date but it sounds much more potential. I may even swap to them for cellar gas too; with their cylinder rental charge they cost a bit more than my current supplier but are a lot closer and probably safer.

The stitching sounds excellent. I've managed to create a small lap joint by (eventually!) getting one pot wedged just inside the other so hopefully that will help keep things together, I'm thinking I could tack small opposing spots to hold it, and then stitch between them until its done. I doubt it'll look pretty but if i can join it and not blow holes I'll be happy - I'll have to grind it almost flush afterwards in any case so that may recover some of the aesthetics!

Thanks for the offer too! I'll see how I go to begin with - with the welder failing I haven't really had chance to try joining thin stainless yet; I'm very encouraged by early progress but if I turn out to be pants at delicate stuff I may well cry for help!

Cheers
Kev

[Kev888]

Just a quick post to credit R-tech and their excellent customer service; I only emailed them sunday night and the UPS van has just been and swapped a new parcel for my broken one -all very efficient. Assuming the replacement is okay then I'm very impressed!

Quite a relief; after waiting in all day I was beginning to wonder if my usual courier jinx had struck again - but for once, no!

Cheers
Kev

[froggi]

Great news with the gas.... Sounds like a serious saving... Also I'd not bother with the grinding off of the surface weld.... Try wire brushing it initially and see what you think.

Just be careful with the tacking as you can "coke through" with this also Kev, but persevere and you'll get there marra!!!

Good luck once again

[sparky Paul]

Apparantly you can use flux or heat resistant tape for back purging, but the advice they've given me is that for delicate or hygenic work it should really be argon.

I agree with froggi, back purging with argon is standard practise for dairy-type pipework and fittings, that's how I was taught to do it and it always worked for me.

[Kev888]

Excellent - thanks; sounds like the way for me then, especially at this stage I need all the chance I can get!

I've got a 'Y' adaptor and a couple of cheap flow meters on the way, so before long I should be able to split the Argon regulator's output to both the torch and back of the weld.

They probably won't be here by this weekend though and I'm away next one - I may soon be forced to start buying beer!! <sigh>

Cheer
Kev

[froggi]

Buying beer? Shame on you Kev lol

[Kev888]

I know; I was gloomily considering that last night. Think I may have to re-instate the boiler and get a couple of brews in before I start cutting holes in it..

Cheers
Kev

[froggi]

I know..... I have had to revert to a sneaky purchase for the relaxation session this and tomorrow evening and until I get the boiler, mash tun et al sorted, I'll be having to resort to the odd sojourn to the very fine Mitchells off licence in my beloved hometown.

[gnutz2]

Thats bad news about the tig Kev but good to hear they sorted it out pronto, thats a service i dont think you would get from ebay sellers.

[Kev888]

Yes, I was a bit concerned having heard some scare stories about other suppliers, but you can't fault R-Tech's responce at all - superb! I put a plug on the new one last night, but I've not had chance to trest it yet - fingers crossed!

Cheers
Kev

[edit1now]

If you're going to use lots of argon, refills from Air Products cost about £24 - but they charge about £20/month cylinder rental.

[Kev888]

Ah that useful, thanks. I think the Energas lot do a 5000L refil for £35 so may be more costly, but their rental is cheaper so that may suit me better, but thats old information so its possible air products would be just as good. I need to speak with energas to find out - the've got electronic/email contacts but every time I try those I just get a response saying to phone them about it.

Cheers
Kev

[bungle666]

TBH kev, i think id have enrolled at a local college for a tig welding course before embarking on the self learn process! that way your burning their gas and metal at their expense! NOT yours!

B..

[Kev888]

Yes i did consider it, but frustratingly I'm struggling for time to practice even at home, theres no way I can fit in with course schedules at the moment. Hopefully I'll be able to make up for it at some point - I seem to be picking up enough to at least get started, though I've not dared anything as thin as my pots yet; maybe this easter when I've got a few days off.

Cheers
Kev