going to build a pipe for my 660

[PLAYINWOOD]

titanium eh, I would love to see some pics.That would be cool.
Whats the welding procedure for that stuff?

Brian, aluminum sticky tape on all open joints with a hole just big enough for the argon hose to be inserted.No biggie.
With a small gap,more penetration, and if cooled slowly it may help some of the joints from cracking.

 

[Crofter]

If you tacked it all together and kept the purge in it could be done and certainly the backside on thin stainless need protection. Problem is keeping the sticky tape on when your welds are close together like that and the glue is a mess. Plan on using far more gas for purging than for the gun! I did virtually nothing else but for 14 months in a fab shop! Solar Flux paste can be brushed on inside of joints if you cannot purge but if floats on your puddle and the flare makes it hard to see fusion at the edge of the puddle.

You will find you have to backstep all your welds with tig or torch or warpage will haunt you on sheet metal! The sweep out of the exhaust will tighten up considerably unless you watch your direction of welding and have a bit more inches travel to the outside of the bends. Distortion is double with stainless what it is with mild steel and stainless work hardens which is the cracking problem. At 250 cps you accumulate a lot of fatigue in a short time. Cracking is a matter of when, not if!

 

[timberwolf]

Sounds like the big issue with titanium is the reactivity, NO O2 or N2 at all until the part is cooled down to 450 deg f. Full purge and a trailer of shielding gas.

Totally clean, then welds much like stainless with low thermal conductivity but a lower coefficient of expansion than mild steel.

Filler rod is killer $$$, it's explosion extruded, think thats about the only way to make it.

If we ever get to making one out of Ti it will be a copy of a tested design done in mild steel first. I won't be doing the welding, might get to practice on some scraps if i'm lucky.

 

[Hddnis]

There were a couple of tubes of thin wall Ti at a local scrap yard here. He didn't really know what to do with them so he put $20 on each. I'm guessing about 30ga, 2" OD, and about twelve feet long. I really wanted to get them to see what I could do with them. Common sense prevailed as I knew I didn't have the tools or know-how to use it effectively.



Mr. HE

 

[Tzed250]

Hamaguchi Ti exhaust...

 

[timberwolf]

Its said the welds should look wet like liquid mercury.

Would be a fun project, but I'd bet on $300 plus in gas and materials alone, plus a good bit to get the sections cut out on a water jet.

 

[breymeyerfam]

here is timing: exhaust opens at 97°atdc then transfers at 124°. exhaust duration: 165°

 

[breymeyerfam]

chamber design program by iwt racing

 

[breymeyerfam]

that sure doesn't look right to me... but what do I know.

 

[husq2100]

Brian, im not sure of Franks experience with exotics.... so dont take this the wrong way, look for Engloid on welding forums. He is very knowledgeable.

on another note, there should be no reason a pipe cant be mig'd successfully.
"pulsing" may work but id never use it on structural work and there is chances of porosity being included due to stop starting

Serg

 

[timberwolf]

??? cant see the attachment, could you just attach it? I have tried about every free pipe design software out there and have yet to find one that really worked for saws, IWT's is one of the better though. Keep in the back of your mind that most of them are intended to work for motorbikes with very different engine designs, porting and work loads. A couple of the free download pipe design programs flat out don't work and will be a waste of good metal.

I have MIG'd more pipes than I have TIG'd, with out a doubt it works, ran .023 wire and essentially stacked a few hundred tack welds. Even pushing downhand can't really run a bead more than about 3/8 of an inch without getting too hot. No major porosity issues, but sometimes get the odd pin hole if there was not enough overlap on the tack welds.

The weld profile with MIG on sheet metal is pretty high, but grind too much off and then cracking is a problem. Did a couple pipes with MIG and then a wash pass with the TIG torch, extra work but gave a reasonable apearance. worth puting some flux off or other anti spatter stuff on to keep the MIG spatter from sticking.

 

[tdi-rick]

Brian, I remember reading about the blokes that form and weld up Litespeed's Ti bike frames and the tubes all had to be back purged with whatever gas they used.
And as you said, just like stainless it was all clean, clean clean, and exact fit up.

High end race car exhaust builders tend to use 321 stainless, unless you're in F1 and maybe Sportscars, then they use Inconel, but no one else can form or weld the stuff.

 

[breymeyerfam]

i'll repost pic when i get home the pic somehow didn't get loaded to my attachments...

 

[husq2100]

Even pushing downhand can't really run a bead more than about 3/8 of an inch without getting too hot.

??? mostly MIG is pushed or forehand, if you pull or backhand you will reduce the heat a bit, its sometime used on thin materials....

re pulsing or tac tac tac.....im just not a fan of it personally...but then i dont weld sheet.... i would never use it on structural.

Serg

 

[timberwolf]

My bad on the terms, Trying to say running it vertical down but pushing so the puddle rolls down rather than pointing the wire up which would build more heat with the slowed travel speed.

Yep would be bad ideas for structural welds.

 

[Metals406]

Brian, im not sure of Franks experience with exotics.... so dont take this the wrong way, look for Engloid on welding forums. He is very knowledgeable.

on another note, there should be no reason a pipe cant be mig'd successfully.
"pulsing" may work but id never use it on structural work and there is chances of porosity being included due to stop starting

Serg

Engloid is a badass TIG welder! I first saw his stuff on a welding forum years ago... Dudes got like 150 certs.

His welds are like a dang robot... It'd be cool to chat with him again.

 

[breymeyerfam]

 

[troutfisher]

Looks a little bit short to me, but your RPM's is set at 13K. I think that's a bit optimistic for a stock saw in the wood. I'd try it again using 12K. I like the belly diameter it gave you.

 

[troutfisher]

I'd also lengthen the reflector cone about 1 inch. I like to leave a little room in case I bang a changeover or push a little too hard.

 

[husq2100]

My bad on the terms, Trying to say running it vertical down but pushing so the puddle rolls down rather than pointing the wire up which would build more heat with the slowed travel speed.

Yep would be bad ideas for structural welds.

ok i can picture what your doing now...... makes sense.

funny i always thought of standard vertical down like backhand(pulling)... have you tried it vertical down with the wire up? been doing a bit of this in night school on flat plate 2mm thick(yes heaps thicker than pipe) but i found it gave a concave weld on vertical down fillet. now i know concave is not correct as there is no weld reinforcement,let alone throat thickness for a proper structural weld( i consider 2mm structural as my truck chassis is 2mm box section) but im wondering if it will give a flater weld with a little less heat on the pipe

then again im sure youve tried it all ....not much you havent

ill shut up now
Serg