Ask your WELDING questions here.

[ADV8]

If you mean the flat bar the box section uprights are welded to,all that was needed was open your vice up,set the box facing down and dolly the flat bar.
A test of your hammer skills is all.
The weld put heat into the flat,it skunk and pulled up,hammer it back down.
Just a matter of working it as you fabricate and weld.

[Nailhead]

Originally Posted by ADV8

If you mean the flat bar the box section uprights are welded to,all that was needed was open your vice up,set the box facing down and dolly the flat bar.
A test of your hammer skills is all.
The weld put heat into the flat,it skunk and pulled up,hammer it back down.
Just a matter of working it as you fabricate and weld.

I don't have a vise yet-- it was all done on the floor of my garage, or on a steel plate resting on my table saw. It needed to be done on short notice.

What's "dollying", anyway?

[ER70S-2]

Hammering like a blacksmith, beat the warping straight/flat; like body and fender hammers.

[ADV8]

Originally Posted by Nailhead

I don't have a vise yet-- it was all done on the floor of my garage, or on a steel plate resting on my table saw. It needed to be done on short notice.

What's "dollying", anyway?

In that case the vice jaws would be the dolly and ease the post down
A 32 oz ball pein hammer would do the trick.
It not hammer and dolly in the true sense. (sheet metal)
It more like 16 lb sledge hammer and the apprentice on the other side holding the plate dolly.

A solid bench and vice is a good start.

[sakurama]

Originally Posted by Twin-shocker

Does the waveform make quite as much difference if you are using DC rather than AC current?

Yes, it's pretty huge actually. That nice bead you see is a result of the welder pulsing on/low just a bit more than once a second. The "off" phase is allowing the puddle to cool slightly and reducing the total heat put into the work piece, significantly actually. I'm moving the torch at a steady pace and keeping pretty constant pedal pressure so the "dimes" is the effect of the pulser.

It's like cheating really.

I posted some shots of my exhaust in here before but haven't made too much progress but perhaps I'll post some more.

Gregor

[Twin-shocker]

Originally Posted by sakurama

Yes, it's pretty huge actually. That nice bead you see is a result of the welder pulsing on/low just a bit more than once a second. The "off" phase is allowing the puddle to cool slightly and reducing the total heat put into the work piece, significantly actually. I'm moving the torch at a steady pace and keeping pretty constant pedal pressure so the "dimes" is the effect of the pulser.

It's like cheating really.

I posted some shots of my exhaust in here before but haven't made too much progress but perhaps I'll post some more.

Gregor

That sounds very interesting............whats the fastest pulse setting you have on your machine?

[sakurama]

Originally Posted by Twin-shocker

That sounds very interesting............whats the fastest pulse setting you have on your machine?

The pulser will go into the hundreds of hz and there are applications for that sort of frequency but I don't know what they are yet. I'm still learning how to use it for what I'm doing and that is using the slower end of the pulsing spectrum.



Above on the right is adding .035 308L filler so you can see the bead is much tighter as I'm going slower feeding filler. On the left is fusion only and the travel speed is faster so the same pulse spreads out the "dimes".



This is a test fusion weld on my exhaust tube with the same settings. Here I'm working on torch angle (following the tube) and trying to be able to weld more than 1/2" at a time and then tying the welds together. If you saw my welds about 3-4 pages back this is a big improvement.



Getting the chance to sit with Sean of Vertigo Cycles and watch him encouraged me to spend more time working on pulsing fusion only welds and helped me make a big jump. This tube above is another test. Still testing and practicing...



I made this "X-crossover" and did it with and without filler. It was one of the harder things I've done but, little by little I'm getting better.



This is the right side all tacked up. Hopefully the next time I get in the shop I'll be able to finally put it all together and weld it up. I'm worried about distortion so I plan on adding a lot of tacks and then welding a little bit on each joint going back and forth from front to back and side to side to try to balance the heat and the inevitable distortion. Any advice here would be appreciated if you think that might not be the way to do it.

Gregor

[Twin-shocker]

I cant see that distortion is going to be much of a problem on tube. Its going to move a bit if you are not welding your pipe in a fixture of some kind, but if tube is thin then you should easily be able to tweak it a little when fitting to the bike so it fits perfectly.

Welds look excellent, and as I have been thinking of getting a TIG with pulse the results are very interesting to me.

[NitroAcres]

Gregor,

Why would you not add wire to the welds?..and are you purging the tube when you weld it, what is it looking like inside?

[Twin-shocker]

I would guess the reason why manufacturers such as Akropovic also dont use filler wire, probably has something to do with this helping to reduce the chances of cracking on very thin material?

[sakurama]

Well, I wanted to add filler but many people who knew better suggested otherwise. I had originally beveled the tube and was planning on adding filler as I thought that was the "right" way but I was instructed that for thin wall tubing in stainless (it's 16ga or .065 wall which is thick for exhaust but thin for tube) the correct way is to make perfectly flat joins with no bevel and to join the tubes with fusion only.

I thought perhaps that might not be as strong but after doing some tests it's obvious that it's more than strong enough, much easier and certainly looks better. I'm not purging for the tacking but I have a full purge setup for the final welding. I did purge for the crossover:





You can see it's smooth and there's no burn through or carbonized crap in there. I didn't want to put too much heat into this and melt the knife edge. Purging keeps the inside of the weld smooth and wetted out with no contamination. Overall better for flow too.

My thread below in my sig - Mission Creep - has a lot more photos of the fabrication but I just posted the more welding related here.

Gregor

[David R]

Beautiful work. I too have found stainless welds best with no filler. The biggest reason is it takes more heat when
I use filler. More heat = bad with stainless.

I still keep a pice of .030 stainless wire in my hand in case things get out of control.

Because I am not using filler, I make fitup best ever. Everything welds better with good fitup.

David

[Nailhead]

Originally Posted by ER70S-2

Hammering like a blacksmith, beat the warping straight/flat; like body and fender hammers.

That's what I figured, but I wasn't sure.

ADV8-- what's "eas(ing) the post down"?

I hope it doesn't involve the apprentice you mentioned, 'cause I don't really have one of those handy.

[R-A-M-O-N]

Well ive been following this thread for a while and is so great it almost looks like a forum on its own.

My dad has been doing cylinder head machining and leveling for a long time, so Ive been toying with the idea of starting to weld aluminium cylinder heads.

I have a couple of questions if there is anyone with knowledge in the area.

- I was wondering if you have recommendations on the specs for a tig welder for regular shop use. For example how many amps should i go? ive been told 350 at least.

- From what i heard is common practice to preheat the heads, is this always recommended? cant the alu head be affected by the heating process? Do you have any special advice on preheating, how much, what to use, etc.

- Is pure argon the best compromise between cost and benefit for gas use? i heard of 30% helium mix or even more so you would need less amps in the welder, i wonder what works best for this kind of weld.

Thanks for any answers.

[Twin-shocker]

I wonder how much TIG welding experience have you had in the past, do you have the facility to remove and refit valve seats, and capacity to re-machine the valve seat housings?