Un-doing Metal Brazing?

[Ohio-Rider]

Not sure if this is the correct place for this, but maybe you guys can help me out.

I have an old set of WL handlebars that have seen better days and I’m hoping to salvage the center section casting from those to begin making myself a new set of in-line speedster bars.

The donor set of bars appear to have the pipes brazed into the center casting. Will I need to cut off the bars at the casting and machine out the remainder of the pipe from the casting?
Or….. Can the casting be heated to cherry red and the pipes will then be able to be persuaded to come out?

[Chris Haynes]

Look carefully and you will most likely spot a very small spot weld. Grind the weld away then heat the casting hot enough to melt the braze and pull the bar out. Red hot is way too hot.

[exeric]

Hang the bars from the ceiling and chain a cement block to the bar you want to remove. I think the bars are pinned as welll, so you'll have to do some exploritory work to eliminate the mechanical hold of the pin. With the pin removed you can heat the joint with your torch until the cement block pulls the bar free. Don't get the joint too hot because you can permenantly damage the forging if the brass alloys into the steel. I don't know the proper metalurgical terminology for it but it will turn your forging into junk. You have to get it ridiculously hot to have that happen but it is possible with oxy/acetylene. I think machining would be the preferrable way to do the job but that's a compound angle and would be a b*tch to set up.

[Ohio-Rider]

So it can be done with out a saw. That’s good news.

Eric.....I agree about that setup completely. That’s why I decided to ask here first. I may substitute a come-along instead of the brick, though. -----This could get ugly!

Chris….. Yep, I just looked and there is a tack weld I hadn’t noticed. By the way, You didn’t fool me a few weeks back with the “henway”, but I have to ask, what’s a Curmudgeon?

Thanks to you both. Enjoy the holidays.

[Chris Haynes]

I have to ask, what’s a Curmudgeon?

Look it up in yer Funk & Wagnall.

[Ohio-Rider]

I've learned something new today.

Chris, You are aware that not all descriptions of a Curmudgeon are very flattering. LOL

[koanes]

Steve, Tom Faber in Michigan will restore your bars to perfection for a reasonable price. Having the equipment and experience to do this job is critical. I am a do it yourself guy as you obviously are, but some jobs are best left to a pro. Just getting the old tubes out of the casting without damaging it will make you use every cuss word you know.

[Ohio-Rider]

Oh… I’m sure to do some cussing, that’s for certain. This is one of those things I want to try just to see if I can. My expectations aren’t very high but I’ll give it a shot anyway. Not much to lose but a few pieces of pipe and my time.

If I do destroy the donor casting getting it apart, it will go on my wall of shame along with all the other parts I’ve senselessly destroyed while trying something I shouldn’t have.

[T. Cotten]

Steve!

I think the term for when brass is over-heated into steel is called "admixture".
Keep your torch on the rich side; After doing some myself, I wouldn't hesitate a microsecond to send the next one off to Mr. Faber!

And I want to thank you for the sprocket you donated to my security system... I at least owe you for the postage ( but "priority" certainly wasn't necessary!)
There are still large windows on my storefront to 'shutter' with H-D drum sprockets before I can rest peacefully.

....Cotten

[Ohio-Rider]

Cotten… You don’t owe me a thing. I’m glad you could use that old saw blade.

[Chris Haynes]

I've learned something new today.

Chris, You are aware that not all descriptions of a Curmudgeon are very flattering. LOL

Main Entry: cur·mud·geon
Function: noun
Pronunciation: (")k&r-'m&-j&n
Etymology: origin unknown
1 archaic : MISER
2 : a crusty, ill-tempered, and usually old man

[Lyle Manheimer]

Rich Flame

A rich flame is called an oxidizing flame.
Capillary action joins the two metals.
Getting the bars out of the forging would more than likely leave some brazing material in the forging and require machining to get a proper fit.
Heating until red hot may change the molecular structure of the forging, not good.

[T. Cotten]

Lyle!
It 's the other way around:
A rich flame is a reducing flame, and a lean flame is an oxidizing flame.

Oxygen and a hot lean burn is what we want to avoid.

....Cotten
PS: I am not a pro welder, but I portray one on computer monitors.

[Lyle Manheimer]

You beat me too it

I just logged on to correct myself. Non oxidizing is acetelyne rich. Oxidizing is oxygen rich.
I can't remember which way you set the flame for brazing, non oxidizing I think, to put less heat on the braze joint.
I learned this over thirty years ago and have some difficulty pulling info out of the hard drive. I will consult a book before my next brazing job.
Thanks, Lyle

[Ohio-Rider]

Sorry to report but even with all the help from here, I managed to ruin the casting of the donor handlebars last night. I’d don’t think I ever had a chance. At no point did the tubes even try to release from the casting for me.

Here’s what I tried. I welded a length of chain about 12” away from the casting to one side of the bars and attached that to my truck. I then welded another length of chain to the other side of the bars and attached that end to the concrete floor with a come-along in-between. I applied a small amount of pressure with the come-along and began heating the casting, keeping the tip of the flame concentrated on the casting and avoiding the pipe entirely. I continued heating the casting until I could see the metal begin to dance. That’s what I call it just before metal goes from red to cherry red. I then cranked the come-along a bit more. I kept at it for a while.

Then I started thinking this shouldn’t be taking so long, so I got out my biggest pipe wrench, and while still maintaining the come-along pressure and heat I gave the pipe wrench a try. I could continue but I think you all have an idea of what happened. I’m sticking to my day job.