Project #9 from Worntorn - tig weld broken bandsaw blade

[worntorn]

It's Sunday morning, and I am looking forward to building a Stainless steel kickstand for the Egli project. I have thought about the design for a couple of days and I'm ready to go. Almost.

I forgot that the last time I used the Wellsaw the blade broke. I don't have a spare at the moment and the Industrial suppliers are all closed.
It was still cutting like new when it broke. It got jammed in some 1 3/4" solid stock I was cutting to build a 75 HP. pto shaft for my tractor mower.

I was ready to write the day off to lawn mowing and weed eating rather than metal work then thought I should try tig welding the blade back together. Some metal cutting bandsaws have blade welders built right into the machine , don't they?

It's back on there and cutting nicely. It will be interesting to see if the weld holds up.
The filler rod I used was some 1/16" 309L stainless. I can't tell you what is happening Metallurgically when using 309L on a bimetal blade, but it seemed like it might just work, given past experience.

Glen

[jakeru]

A bandsaw blade I TIG welded a couple months ago is still holding like a champ!
http://www.everlastgenerators.com/fo...Bandsaw-Blades

[worntorn]

Hi Jake

Looks like you came up with a similar method for holding things with your 2nd method.

This blade is a bimetal blade so I figured it might be hard to weld.
It wasn't really, it was just a case of starting the arc low (10 amps) then pushing the pedal a bit until things start to flow.

There is one small trick for welding small profile material like this. This was shown to me by a welding instructor. If you light up on the filler rod rather than the item to be welded, then you have a better chance to gauge the amount of heat needed without destroying the item. The filler rod forms a small molten ball first, then you add amperage carefully until the filler and the two blade pieces flow together. As soon as this happens start moving. In about 1 second you are done!

Glen

[jakeru]

Yep, jigging the blade for welding with "nothing but air" on the backside of the weld, and using relatively low current to allow heat to soak and build into the blade material and getting the whole weld area glowing red hot (and also allow it to cool slowly) is what worked well to weld my high carbon blade material while keeping the welded area soft and annealed.

I've used the trick of a short, quick burst of heat over the end of a filler rod, to deposit a controlled, small amount of the rod right where you want it to go, with minimal heat input to the part. (It's a great way to patch a small hole in very thin material.) I'll have to try the "slow heat build up over filler rod" idea sometime. I would imagine that would allow the tip of the tungsten to come up to operating temperature, and stabilize the arc for low-current welding. Actually I would like to try that on aluminum sometime.