Bending aluminum tubing...?

What with roll cage and frame building we've had a lot of questions about bending steel tubes, but I have a question pertaining to construction/repair of motorcycle frames.  Does the mission of bending aluminum tubes for motorcycle frames fall within "grassroots" or is it too sophisticated/difficult to do?  I need to increase the spacing of the downtubes on a GSXR frame and so I'm speculating on what the straightest line from A to C would be.  Does anyone know if that's something that could be farmed out at a reasonable cost or is it too specialized for retail subcontracting?

In reply to stroker :

Since aluminum work hardens I believe the frame will need to be heat treated after bending/welding to prevent fatigue issues. There's probably companies that do it, but I don't know of any

I don't know what aluminum series the frame is made of but I've bent 6061 T6 tubing by coating the tube with a layer of soot from burning acetylene and then heating the tube up with the torch until the soot burns off. In my case I filled the tube with a low-melt alloy to keep it from collapsing in the bender.

Are you trying to replace some tubes or bend existing tubes?

In reply to jgrewe :

replace.  

If you have a bender then it is pretty simple. I'm dusting off old brain cells here but I think I remember reading the tubing will revert to it aged heat treatment slowly or you can reheat it after its bent and quench it.

Some googling with the terms 6061 T6, bend, soot, or sharpie will help.(there is a way to watch what a sharpie mark does as its heated that is like the soot trick)

5052 series aluminum tube is readily available, easily welded and doesn't need to be annealed before use like a T6 hard 6061 will. 

I regularly run 5052 and 3003 aluminum tube through the JD2 bender.

The key with forming Al is to know what alloy you have, and if heat treatable, what level of heat treatment.

6061 is very popular, but if heat treated to T6 for max strength, will crack easily when bent or otherwise formed.

The same part treated to T0 is 'like buttah'.

Once formed, re-treat back to the desired temper.

A T6 part, when dropped will ring, a T0 part lands with a dull thud.

DIY heat treating is pretty easy for smaller parts, problematic for large ones.
Requires accurate temperature, and accurate timing of the treartment periods.

The web is a good source for heat treating specifications.

jgrewe has a good process for removing the heat treatment; soot and torch.

He also mentions that it will revert to its heat treatment.  This is kind of correct.  6061 (and some other alloys) will generally naturally age themselves to a T3 or T4 hardness level.  If you want to go above this you need to find a shop that can artificially age the alloy for you.

Looking on Google, Missouri Heat Treat, just outside of St Louis should be able to heat treat your parts but whether they will deal with one or two items i don't know.  Should give you a place to start looking though.

If the part is important enough that Temper and Heat Treating matters, using a torch is pretty hit or miss.

You need some kind of adjustable oven, a fairly accurate thermometer, a timer accurate to the minute, the heat treatment recipe/instructions, and enough sense to find, read, and follow them.

The last two items are the most important!

Is this GRM or not!!!

Items 1-3 can be scrounged or DIY fangled for under $50 USD.

Just sayin'