welding exhaust tab on titanium dirt bike frame question

[madmike]

is it possible to weld this without a back purge? a friend wants me to try this and i don't have a way to back purge, i also don't want to invest in equipment for this because i don't need it for what i normally do steel (aluminum and stainless rarely)

its only a tab to hold the exhaust, i haven't seen the frame so i don't know much about it but i do know he has titanium tabs and the filler rod for it. its a 2 stroke frame that's getting 4stroke engine and the exhaust is the heaviest part (from what he told me)

any help would be greatly appreciated

[Rocky D]

The thing about Ti, is if it turns blue or gray, it will be brittle, and may not even pass the floor-drop test. You do need to back it up. One way is to have a splitter on your argon regulator, and a back up hose with a gas screen lens in it, and have a friend keep the gas on the back side of the tab till it cools, and when you finish the weld allow the torch gas to cover it till it cools, so you will need to set your post purge to last about 40 seconds. It can be yellow or straw color, but not anything else.

You might consider just putting a big tack on each end of the tab, so you can play the gas on both sides, and hold it till it cools bright chrome color. If it does turn blue, you can reheat it, till you can make it look right.

[madmike]

hmm maybe ill just fab up something to clamp on the the area in question, maybe cut some round tubing in half so i have to "c" shaped pieces then weld some sleeves so it can be nut and bolted

thanks for the reply Rocky as always very helpful thanks again

[MXtras]

I am unaware of any production dirtbike with a titanium frame - interested to know the make of this bike.

Is this for a rear sub-frame?

Scott

[madmike]

ill have to ask him, i know nothing about dirt bikes, he races in a b-class motorcross division or something like that (i dont even know what that means lol) ill ask him and see if he can send me some pics

[MXtras]

A class = Pro
B class = Intermediate
C class = Novice
D class = Beginner

If he's a B rider, he's pretty good and knows what he's doing.

Scott

[Trickasabrick]

May want to check on the frame material. Most MX bikes have either a steel main frame and aluminum subframe (where the seat, airbox, and rear fender are), or an all aluminum frame like the later Hondas. I can't think of any production bikes that used titanium frames or subframes.

[kenc]

Maybe an aftermarket titanium sub frame or something like that?

[madmike]

i asked him and this was his responce, he dont have any pics tho.

"the sub frame is for the rear of the dirtbike basically the rear of the seat the back fender and number plate bolt to it as well as the muffler. most are steel, some aluminum. on the 4 stroke sthey were steel and heavy and this titanium one is liek super light feels like and empty water bottle"

[brucer]

might be chromoly or aluminum..

http://brennraum.ktm.com/issue-02/ktm-factory-inside-frame-production/

[SidecarFlip]

Unless it's a one off works chassis, I also seriously doubt it's titanimum. I bet it'a aluminum alloy.

[Christabel]

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[SidecarFlip]

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