As you can see with my design I've painted myself into a bit of a corner.
Some of the angles in the frame are too tight to get into even with the no 5 cup I have for the TIG torch.
Extending the tungsten out to get to the root isn't working as its not getting sheilded properly as a result.

At the moment I'm wondering if there's such a thing as a mini TIG torch or some other bit of kit that'll enable me to get in there?

Failing that I guess I'll need to take it to be gas welded.

Got a MIG?
Use that on your internal corners.

you can buy a shorter cap for your tig torch, that will enable you to get into those tight spots with the torch..

Yeah, it's not the cap end thats the issue.
The problem is getting the tungsten into the root of the joint and still have it bathed in gas.

Is there such a thing as long or tapered gas lenses?

I've not got a MIG but I'm sure I track down someone who has that may be the solution.

well, I have a nr. 4 cup, but you could also try pulling the tungsten further out, maybe increasing flow a bit for better coverage although such narrow spaces require less flow

I had similar problems adding the bracing to the book chassis. The advice I got was not to worry about all the internal seams as long as you have 2 good runs you should have enough strength particularly when you have so many tubes converging. When I did try i ended up with some ugly contaminated welds as the gas was not sheilding as you say.

caber

Lots of superbike swing arms only have welds where they can reach on the reinforcing bits. That looks like you could have done with forward planning, leaving a few struts off or welding the inner parts before you put the outers in place.

Is it bad to do a bigger weld further from the join?
I did this with some fuel tanks that had an angled filler. The welds got to maybe 10mm high, not hard to build with a tig. There will have been some space between the weld and the actuall join but no problems so far.

This is how we overcome the problem, it also makes for stiffer joint.

What about brazing?

Stig 2.....

Yep, good solution...

some good ideas coming out.

I'd resigned myself to taking it to get gas welded - brazed and I'd thought of jamming some more 'filler' triangles in there as per the pic. but the thought of the extra welding wasn't filling me with joy. I may go that way in the end through.

The main thing to me is that I'm not missing some 'magic' piece of equipment or a technique (for use with the TIG) that'd overcome the problem.

I don't think I could have overcome the issue with planning and on the whole I'm quite proud of it as the fist bit of the car I've made (so now it's 0.1% complete).

Make sure the tungstun is sharp, extend out and turn the gas up, just make sure you do not touch the tip.

Alternatively weld at 45 degrees from the side, concentrate the arc inwards and keep feeding the pool as it advances, just make sure you do not end up with a big hole !

Probably a totally crap idea, as I don't know anything about Tig, but couldn't you extend the electrode and then feed the sheilding gas to the weld area out of another bit of tube?

If you borrow a mig try flattening your shroud.........or cut the shroud back......turn the gas up in both cases.

If you could borrow a little Arc inverter. Heat up a thin rod in the oven........should get in with that..........especialy if you use a stainless one , as they flow even better. 316 rod aint as strong but better than no weld in the corners.

Alex

you can buy very long and thin tig engs ive forgot theres numbers but you can buy them to get in there ask at a welding suppiler they will sort you out
adam