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  #21
Old 04-11-2009, 5:15 PM
TheJoker
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If you want to head for an exposed exhaust system, I'd say you want a polishing kit, but before that a sanding/grinding kit!
Some parts of that weld are well penentrated (too well) and as such they'll probably keep the exhaust in one piece. But if you want it to look pretty you need more practise... way more.
Just so you know, my SS welds aren't much better than those. I've mainly been welding small box section mild steel so far. Tried a bit on some 1mm SS the other w/e and it works quite well, but pretty I wouldn't call it.
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  #22
Old 04-11-2009, 6:10 PM
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Quote:
Originally Posted by TheJoker View Post
Looking good!
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Originally Posted by TheJoker View Post
But if you want it to look pretty you need more practise... way more.
Very contradictory replies there.
I'm going to sound a little harsh here but you've asked for opinions on your welds. They look pretty awful, they're very inconsistent in both appearance and penetration.
Now I'm no tig welder by any means so I'm jot the right person to say where you're going wrong but I can clearly see you need a lot more practice before you're ready to move on to doing 'proper' jobs.

If I was to post pics of my welds and ask for advice I'd be expecting critical advice, i.e. if they're crap, tell me they're crap...don't build my hopes up and make me think I'm capable of doing something that I'm not.

Apologies if this sounds abrupt but people learning to weld need to know where they're going wrong if they're to improve, that's what this forum is all about.
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  #23
Old 04-11-2009, 6:26 PM
TheJoker
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Originally Posted by Wozzaaah View Post
Very contradictory replies there.
Come on there - put it in context.

Picture is posted after he (I guess ) has been asking real newbie questions. Which implicates that he's trying, and the topic is "First foolings around". So, good efforts there. The metal is fused, there's gas, etc. Don't forget that I also said.
Quote:
...it's time to start focusing a bit on beauty now (which might take years
In short. Encouraging was my intention.

If you then put that weld into the context of a beautiful exhaust then it's crap. If he's looking to sand it down then he can weld it as many times as he wants and sand the bad welds down.

If you want to achieve something like this: http://www.mig-welding.co.uk/forum/s...ad.php?t=11529 then you're far, far, far away. How far I don't know, as I'm not that good. But I do know that the path to getting there is through more practise. Which needs encouraging.

Context was it now..?!
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  #24
Old 04-11-2009, 7:59 PM
Delgado
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Quote:
Originally Posted by yorkie_chris View Post
Thanks for that, most helpful.

So forward-back technique you move forward a little letting puddle advance, then back off and dip rod, then forwards again?
Yes, exactly that.... count 1, 2, 3, 4 etc in your head, 1 forward, 2 back and dip filler at same time , 3 forward, 4 back and dip filler etc.. When you get the hang of it, it will be like a fluid motion with no obvious pauses.

The middle of the weld pictured(the part with the line/scratch pointing to it) looks about right technique wise, but try to keep the back and forward movements fairly small (about 3mm ish) and your arc length short(about 2mm) and even throughout the whole weld, you'll know when you've got it right because the " blobs" will be round and not oval shaped (elongated). Also, you need to add a bit less filler in the previously mentioned part, but melting off the right amount(in this case just a little bit off the end of the rod for each dip) is just something that you need to get a feel for.

Don't worry though, Tig welding is all practice (lots of it), take your time with your welds, relax, and you'll soon get the hang of it!
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  #25
Old 04-11-2009, 10:20 PM
busa
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yorkie_chris,
The biggest problem with the beads in your pics is that there is absolutely no consistency. Tig welding, apart from machine setup is all about torch control. Getting comfortable is absolutely essential before even thinking about striking an arc. Try to arrange the work piece at a comfortable height so that you are neither struggling to reach it or to see what is going on, getting yourself sat down would be an added bonus. If right handed, bring the torch lead up the front of your body on the left side, over your left shoulder and pass the torch under your right arm and in to your right hand. Allow just sufficient slack under your right arm to move the torch freely. What this does is take the weight of the torch lead away from your torch hand, you will find it much easier to control the torch this way.
Always try wherever possible to stabilize the torch by resting some part of your torch hand on the workpiece, bench or some other fixed object, even if it is only your little finger making contact, you will be able to keep the torch much steadier, very few welders tig 'free hand' unless absolutely necessary.
Once you actually strike up, establish your pool and note it's width, adjust forward travel speed to maintain that width, and most importantly, use the newly acquired torch control to maintain a constant arc length. Many people will tell you that tig is all about practice, unfortunately that is only partially true, you need to learn basic tig fundamentals, torch control, filler wire control, and the coordination of the two. There is a huge amount of information freely available on the net, study the basics and then put them into practice. If you start off with bad habits then 100 years of practice will be of no benefit at all.
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  #26
Old 04-11-2009, 10:41 PM
yorkie_chris
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It would be unreasonable to expect to do good welds straight away.

Feel free to tell me they're rubbish, tell me what to do different.

Ok that was first time I did a butt weld with TIG.
Here is little more practice. 1.1mm plate, a shade under 30A, 7lpm. 2.4mm thoriated tungsten.
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  #27
Old 05-11-2009, 1:02 AM
hotrodder
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Those last ones are a lot more consistant and cleaner but...

Quote:
Originally Posted by matt1978 View Post
If your welding Stainless steel and you are also melting the back of the plate then you need to protect the back of the weld from the atmosphere. You can do this by purging with Argon.

Your welds are black for 2 reasons...........welding current it too high in the first place and the back of the weld is not protected an is oxidating when in turn is pulling all of the crap to the surface.
You're making life far more difficult for yourself practicing on stainless, ESPECIALLY without a purge on thin sheet- as the backside oxidises all the crap is drawn through the puddle adding to your problems. Get some mild steel sheet or plate and some A15 or A18 wire and work with that until you've got some consistancy. Then you can think about moving onto tube/pipe (maintaining torch angles as you progress around the tube adds another element of torch control)
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  #28
Old 05-11-2009, 8:05 AM
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Quote:
Originally Posted by TheJoker View Post
Come on there - put it in context.

Picture is posted after he (I guess ) has been asking real newbie questions. Which implicates that he's trying, and the topic is "First foolings around". So, good efforts there. The metal is fused, there's gas, etc.!
I appreciate that you're trying to encourage him but constructive criticism is the way to promote improvement. One thing we see too much of is that people seem a little scared to criticise peoples welds. I say tell it like it is, if they're rubbish, tell them they're rubbish but more importantly why they're rubbish, after all, that's why they post the pics in the first place.

Looking at Chris' latest pics we can clearly see there's an improvement from the last efforts, as Hotrodder says the welds look much cleaner and the beads are a consistent width but you can still see they're by no means perfect.
Now do I think he's ready to tackle an exhaust? Not quite but I don't think it'll be long.
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  #29
Old 05-11-2009, 9:46 PM
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more filler by the looks of it.
not bad though.
as said in previous posts, try m/steel.
try a bit thicker sheet as well. 2 mm maybe. or 3-4mm and bevel the edge slightly and do a butt weld. leave about 1mm gap, lift it off the bench though.
hth scott
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  #30
Old 06-11-2009, 1:20 AM
yorkie_chris
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Those looking a little better I think are mainly because of resting my arm on the bench. Cheers for that tip.



OK I've got some mild rods now and some 1/8" plate. Can't get any thicker stainless though (not free anyway!). Will have a play around tomorrow.

cheers folks
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