SpudFiles

I'm getting ready to sleeve 56" of 1.5x.188"wall DOM steel(1.124"id) over 56" of 1" type k copper(1.125" od), for an interference fit of .001"+/- a little bit... A friend has a 10ft powdercoating oven capable of 400fahrenheit+, my thought is to heat the steel to 300ish and to cool the copper to about 20fahrenheit, and if all goes well they should slide right together and then heat/cool to a nice tight fit.... Any suggestions on is 300 too hot or not hot enough, will cooling the copper make much differance, and how fast will i need to work to get them together before the steel cools enough that they become "one" ...

I know you engineering guys prolly can figure this out in short order, and I'd like to have this done tonite, so feedback please...

Well, anytime an object is heated it expands, and anytime an object is cooled it will contract. I think you're on the right track.

But I'm not sure if 300 degrees is going to do much to the steel tubing and if 20 degrees is going to do much to the copper. To get the copper colder, you could use dry ice / liquid nitrogen or some sort of salt-ice bath. As far as heating the steel goes, I have no idea.

Your right on track I beleive. I myself have placed a bunch of timing gears (for the crankshaft) in a 250 degree oven and they slide right on with very little effort. If your cooling the copper, I wouldn't cool it below like 60F. You might wind up warping the steel pipe.

Do you have a filler for the copper pipe to keep it ridged? I would find something to have a safty net, getting it back apart probly wont happen once it reachs a normal temp.

Let me know how it turns out.

jrrdw wrote:Your right on track I beleive. I myself have placed a bunch of timing gears (for the crankshaft) in a 250 degree oven and they slide right on with very little effort. If your cooling the copper, I wouldn't cool it below like 60F. You might wind up warping the steel pipe.

Do you have a filler for the copper pipe to keep it ridged? I would find something to have a safty net, getting it back apart probly wont happen once it reachs a normal temp.

Let me know how it turns out.

Yeah, I know on MC engines youheat the jug to 250 and cool the sleeve to 20ish and the sleeve drops right in, and that's with .004" interference...

I'm trying to make sure i don't warp the steel....

Get the hot steel pipe on end and drop the cold copper down it in one go?

Hotwired wrote:Get the hot steel pipe on end and drop the cold copper down it in one go?

That is indeed what I'm hoping for...

Have something hefty but soft to whack the copper with in case.

If you have short pieces of the materials handy, a quick test with a kitchen oven will provide the answer. Do you have some trimmings from other projects that could be used to test with? It would be cheaper than firing up a full size powdercoat oven.

Technician1002 wrote:If you have short pieces of the materials handy, a quick test with a kitchen oven will provide the answer. Do you have some trimmings from other projects that could be used to test with? It would be cheaper than firing up a full size powdercoat oven.

I second that. Without experience, guessing at this could prove erroneous. Test it on a small piece if possible. I could ask some shop guys but I won't interupt their day for spudgun advice.

Sorry for the bump, but filling the inner barrel sleeve with dry ice or flowing (safe far away from ignition points) liquid propane to cool the inner may give a little more gap.

crushed ice and salt water might be a safer option

Coefficient of thermal expansion for steel: 7e-6 in/in/deg F

Going from (say) 70 F to 400 F is a rise of 330 degrees. Thus, steel will expand 0.00231 inches per inch.

ROUGHLY speaking.... 0.5" diameter pipe will therefore increase in ID by 0.0011".


At the same time....

Coefficient of thermal expansion for copper: 9e-6 in/in/deg F.

Going from 70 F to 20 F is a drop of 50 degrees. Thus copper will contract by 0.00045 inches per inch.

ROUGHLY speaking.... 0.5" diameter pipe will therefore increase in OD by 0.00023".

So... You've managed to create a 0.0013" gap when none previously existed.



edit: Of course, the one VERY scary part about this is the fact that you're putting the material with the larger coefficient of expansion on the INSIDE but your plan primarily revolves around heating the outter pipe (the cooling of the inner pipe isn't doing much!). What does this mean? It means that you better work FAST and if you don't pull it off on the first try, you may very well be screwed (all the more reason to test a small piece as stated by others).

A BETTER COURSE OF ACTION... If you have access to such, that is. Liquid nitrogen. Drop the copper to -321 F and you open up a (roughly) 0.0015" gap even without heating up the steel. Even better is the fact that you open up a 0.0005" gap even if the steel is chilled as well! This means that by going cold rather than hot, you can try again and again. That's huge.

0.5" diameter pipe will therefore increase in OD by 0.00023".

Am I missing something or do you mean decrease?

MrCrowley wrote:

0.5" diameter pipe will therefore increase in OD by 0.00023".

Am I missing something or do you mean decrease?

LOL... That's what I get for cutting and pasting.

Yeah, decrease.

Why is this being sleeved anyway?