Noob m/s T joint round tubing

[Paul-n]

Hi all

Back to bicycle tubing , this is my first stab at the tricky fish-mouth 90' tee with my R-Tech TIG Inverter Welder.

Bike tubes about 1.125 " diameter and because they are short I am able to look into the tubes and see the penetration , ok on the no fish-mouthed tube and a little lacking on the fish-mouthed tube [ afraid of burning through it ]

Whilst not the most visually pleasing weld it seems nice and strong the lumpy areas are where the joint was not accurate enough.

Someone has suggested a gas lense would help especially when the angle is not 90' and the access becomes restricted ? where do I get them from , which one do I want for 1.8mm & 3.2mm electrodes ?

Any tips to improve it , apart from practice , practice , & more practice

regards Paul

 

[hotrodder]

Fit up is EVERYTHING on thin wall coped tube joints, talking daylight tight fit. While it is a case of 'practice, practice, practice' things like arc length and torch angles are uber important.

Lumps, craters/fisheyes and undercut are killers with respect to fatigue failure. Really need to be able to produce the goods on sheet metal before moving to tube IMO, it will speed up the learning curve as you can concentrate on arc length and weldpool control without the angles of attack constantly changing

Gas lenses are available from any welding supplier. Collets are the same, collet body and ceramics are different and with some torches an additional/different insulator is needed (the white ring between ceramic and torch head). What size torch?
Gas lens collet bodies are matched to tungsten size as with normal collets. Won't need a tungsten larger than 1.6mm for this sort of work, a 3.2mm tungsten would only be used at over 200A. Probably get some differing views on ceramic size, my general rule of thumb is to (within reason) use a larger one unless access dictates otherwise. Typically i end up welding most things with a #7

What's the wall thickness of the tube? Filler wire diameter? 1.6mm wire is too large for thin wall stuff, needs more heat to melt than the base material wants

 

[Paul-n]

Hi there

Torch is a WP17 TIG torch according to the web site :-

http://www.r-techwelding.co.uk/welding_equipment/Tig_Welder/Tig_Welders_R-Tech_Tig160PDC

however when I look at that torch up on Google it looks different ? could be new model ?

I am using collets/ceramics like this :-

http://www.r-techwelding.co.uk/Welding_Consumables/TIG_Torch_Standard_Consumables_WP17-18-26/tig_welder_ceramic_cup_6

Although I do have a Tig Welder Torch ceramic No.5, 5/16 bore, to suit WP17

Metal is <>1.5mm are you saying I should use 1.00mm Tungsten and filler ?

Just found gas lenses here :-

http://www.r-techwelding.co.uk/Welding_Consumables/TIG_Standard_Gas_Lens_Consumables_WP17-18-26

But they don't go down below 1.6mm ?

Thanks for your input

Paul.

 

[malcolm]

I'd not worry about a gas lens. Those dudes just reduce untidy surface oxidation a little turning spectacular welds into slightly more spectacular welds. Fine tuning doesn't look to be the issue here.

The thing that made me 'get' fillet welds (and this was only yesterday) was running them autogenously (without filler rod) as a practice. You've got to have a tight arc gap or it won't work at all (see hotrodder's link).

All the filler rod does is make up for the shortcomings in autogenous welds. It doesn't make the weld much bigger (welds should be half the size or less than you would expect from MIG).

 

[hotrodder]

Might be detail differences with torch handles but wp17 is the important bit regarding the correct collets/ceramics etc. Consumables in the rtech link are on the pricey side, typically under a fiver with the VAT for a gas lens collet body. Part # for 1mm wp17/18 gas lenses is 45v24 FWIW. Complete wp17 parts listing... http://www.weldcraft.com/pdfs/WP17ENG.pdf

Properly sharpened a 1.6mm tungsten will be fine even welding 0.5mm thick stuff. Bicycle tubing had me thinking thinner wall than you're playing with, 1.6mm wire will be OK. It gets trickier if the wire is thicker than the base metal i.e. trying to weld 1mm steel with 1.6mm wire not likely to end well, or at least neatly.

Malcolm's got a point in that a gas lens isn't going to transform the results. Gas lens demo... http://www.mig-welding.co.uk/forum/showpost.php?p=148488&postcount=4, they do make a difference, moreso when welding outside corners or working with tube where the geometry is directing the gas flow away (unlike say a fillet on flat plate which'll naturally 'trap' argon).

 

[langy]

I use a gas lens on some stuff but it won't help you there on your job, Are you using a pedal ???
whats you gas flow ???
It also looks like your tungsten is too far away from the joint, you can poke the tungsten out a bit more to get in the corner.

 

[squazy84]

Perhaps you are not comfortable in the position you are welding in? maybe something to prop on would help, I found the laywire method makes my welds look a bit better on steel (compensating for my retarded filler hand) provided your hot enough, im afraid this is all advice from a fool as I could do no better lol

 

[Paul-n]

Hi all

Thanks for all the advice , yes I need to practice more , but I also need to build something , it won't be perfect but as long as the joints are strong maybe perfect will will be bike number 8 , 9 or 10 ......

No pedal , mixed blessing really one less thing to master but less control at the weld end.

SO I will leave gas lenses alone and concentrate on the welding.

Better positioning has help I think , but as the tubing is so thin and small diameter I have to keep stopping and starting somewhere else on the joint to stop heat build up in one place.

I did another last night and it was noticeable how much easier it was when the gap was smallest.

regards Paul

 

[citizen kane]

Paul-n,

Keep going, you will get there.

Picture of one I did today, 0.8mm thick tube 1.125" to 1.25".

I'm still learning and wish I could spend more time/money welding up test pieces.

This was my first attempt with a water cooled torch, still getting use to it, its nice and light and a lot more flexable than my aircooled which helps trying to go around tubes.

As others have said, keep the arc length short and move quickly, easy to say I know and only practice will get you there.

I use an 11mm gas lens and a 1/16" tungsten with a foot pedal. The gas lens is to allow me to stick the tungsten way out for those tight internal angles.

The foot pedal was the best upgrade, it allows so much more control.

I weld the tubes in opposite quarters and allow to cool between each run or wrap the tube in an insulating blanket so I can rest my torch hand without burning it.

Your first attempt is way better than mine ever was so keep going and as others have advised me, dont forget to breath.