17 replies to this topic

[tmh983]

For the last few weeks i've been fabricating my own set of dump pipes for my TT.
I've been using an ordinary cheap inverter stick welder - almost everyone i talked to said it would be impossible to weld thin-wall exhaust tube with it and i should have bought a mig or a tig, maybe so, but i've managed to get it to work anyway... behold:




How long have I been welding for? About 2months...
Needless to say, i burned a LOT of holes in exhaust pipe before I got it figured out... But now this has opened up a huge new range of possibilities of what I can fabricate for myself at home now.

In the past had always put mods that need metalwork and welding in the too hard basket and avoided them or payed to have them done. So anyone else that thinks this way, just go and spend a couple of hundred bucks on a cheap welder and get a heap of scrap to practice with, you will be surprised at just what you can do with a modern inverted welder, even a cheap one!

[Adam]

I bought a mig welder.


That weld shits over my expensive mig

[aekOne]

Very tidy mate! Does that mean the cars good for Bolts to come and have a look at now?

[tmh983]

yeah man, i sent u a pm last week, car is back together again now so right to have a look.

[JRod]

Stick can be used. Just need the right sizes and types. 2.3mm 16tc or did you use a stainless rod? Well done either way.

[Morgan]

Awesome work, mate!

[tmh983]

i use a 2.0mm rod at 60amps on the flanges where there is more metal to take the heat, for the butt joints ive been using 1.6mm rods at 30 amps. they are pricks of things to use, real hard to get started at such low amps.

[JRod]

Yep bitch of things start sticking. Did you use stainless rods or normal carbon rods?

[tmh983]

no not stainless, just ordinary garden variety 6013 rods

[Shaz]

Thats a nice weld mate.

[acres]

Good stuff, weld looks good. I just use an inverter too. Am actually half way through fabricating up my headers now. Just got to finish the up pipes then I can move onto the dumps.
I use a 1.6mm at 45-50 amps for the butt joints and a 2.5 mm at 70-75 for the flanges so a bit more amps but I'm using a 6012 rod. I found lower amps with this rod gave poorer penetration of the base metals.

[tmh983]

hmm interesting, I was originally using a 2.5mm rod for the flanges and I was getting some really nice welds out of it, but all the extra heat was causing the flange to warp really badly - one of the them the edges had curled up by at least 5mm making it totally unusable.
I also experimented with doing the flanges with the 1.6's, but they can be so tricky to use, i wasn't able to reliably get it to weld properly. In the end, using the 2mm electrodes and keeping the shortest arc i could gave the best results. I also bolted 2 flanges hard together to provide some extra heat-sink and mechanical resistance to warping.

Are you using thin wall tube for the headers or steam pipe?

[Reevesy]

It is a nice, neat looking weld, dont get me wrong but the problem may be you may not have enough penetration to the weld and after a few bumps and knocks on the road and it may split. You will get this problem if the amps arnt high enough or you weave too fast, which just leaves the welld sitting on the outside. With something like that you should just be able to see the pipe blow away but the rod fill in the gap.

[acres]

hmm interesting, I was originally using a 2.5mm rod for the flanges and I was getting some really nice welds out of it, but all the extra heat was causing the flange to warp really badly - one of the them the edges had curled up by at least 5mm making it totally unusable.
I also experimented with doing the flanges with the 1.6's, but they can be so tricky to use, i wasn't able to reliably get it to weld properly. In the end, using the 2mm electrodes and keeping the shortest arc i could gave the best results. I also bolted 2 flanges hard together to provide some extra heat-sink and mechanical resistance to warping.

Are you using thin wall tube for the headers or steam pipe?

The tube Im using is 1.6mm thick and the flanges I have cut from 12mm flat bar. Your flange in the pic looks to be 6/8mm? so that will warp a little more easily. Best way I found to weld the flanges to the tube is to tack it together in 2 spots, clamp the flange flat in a vice (so the tube being welded to the flange is vertical) and make very short, horizontal passes switching from one side of the tube to the other, to help prevent excess heat from going into the flange. By welding horizontal I found it much easier to concentrate the majority of the heat in the flange rather than the tube so the molten pool tends to blend nicely together without blasting a hole straight through the tube.
As an experiment I also tried the 1.6mm rod on the flanges but even at the rods max power there wasn't enough heat to fuse the flange, tube and puddle together. The best I could manage with that rod was to fuse the the weld bead to the tube and have it 'stick' to the flange with no penetration at all so it would actually just crack apart with a light whack from the hammer.

Did you cut the flanges yourself? If so how did you cut and shape them?

[vicelore]

Golf clap..

[tmh983]

The flanges are just off the shelf from bestmufflers.com.au, 10mm thick from memory.
Actually, these guys have been pretty good, i've ordered the flex joint and original flanges from them and it arrived the very next day. Then when I warped the first set of flanges I ordered 2 more and they arrived the next day also.

And yes, i welded it pretty much as you say, clamped in a vice with the pipe vertical. The rod needed to be at probably 70-80 deg to the flange and only just angled slightly to the pipe so as not to burn through.

An old boiler maker I was talking to about it said that if you can make a stick weld look nice, then chances are it will be a good, strong weld. Where-as a mig weld can look perfect, but be totally weak underneath. I guess time and few heat cycles will tell how well it holds together.

[Roadoro]

stick welding, ugh. took me at least 20 attempts to strike it! Props for a clean weld!