Outer Limits 4x4 Board

I have some steel pipe I need to braze or solder, basically want to cut a notch out, then bend it and solder the joint, to turn a straight piece into a 90 degree elbow. The walls of the pipe are about .7 / .8 mm thick just at a glance, comfortably less than 1 mm anyway. OD is only 12mm or so, it's not a large size of pipe.

Any tips? I have never tried this before, thinking of basically getting a torch for my bbq bottle, then using some silver solder and flux... but it will be a bit experimental. Which solder? Which flux? I've seen it done but never done it.

The pipe is too short and rigid to bend without kinking it and I can't just make a new one because it has fittings on it that will cost too much to replace.

Or if anyone in Melbourne does this kind of stuff it's well worth a slab to me!

Have you tried packing it with fine wet sand then heating & bending it.

longlux wrote:Have you tried packing it with fine wet sand then heating & bending it.

No. I guess this might be worth a go first.

Get a scrap piece & try it first

Fine sand yes.. but not wet. Water will turn to steam, expand and aerate the sand. You also usually add the packing sand a bit at a time and hit the pipe with a piece of wood to make the sand settle as densly as possible.

RED60 wrote:Fine sand yes.. but not wet. Water will turn to steam, expand and aerate the sand. You also usually add the packing sand a bit at a time and hit the pipe with a piece of wood to make the sand settle as densly as possible.

I have never tried it dry as long as it packs hard it should be good.

I should have said damp sand.

To braze it, the joint has to lapped pretty well it will probably clog the pipe pretty well too if the joint is open. Most plumbing supply's joint's will have the correct sort of flux but $$$

Best bet is to actually oxy weld it (lots of practice) try the sand and heat practice first on some scrap! use something round to roll it over to keep the bend somewhat uniform, dont try bending it any tighter than about 2.5 time's its OD.

What's it being used for? cant use a couple of hose clamps and a rubber hose or finding something similar in a scrap bin somewhere?

Simon

If its half inch , 12.7 then if suitable a compression fitting would do the job , but if it needs welding tig would be the go , if you have a oxy that would also work , brazing , silver solder , solder rely on capillary action to weld the joint , butt welding can be done but you might end up with a pool of solder in the pipe , Cheers Paul.

Thanks guys, I am going to go back to the drawing board for a bit!

Hmm, if I cut the pipe and get an elbow that slides very tightly over the two ends then I should be able to just braze or solder that... I think. The solder should wick into the gap provided the gap is very small. Is that right?

You don't normally lead solder steel, it sticks to tin. Braze will do what you want easily. Silver solder may, if you can get it to stick.
Harsh cut 90 will flow very poorly, if that is a concern. Much worse than a press bent peice of pipe. Assuming this is exhaust type pipe, thin wall.
LPG alone has trouble getting enough heat. $99 buys you a Turbo Torch that will get a lot more heat in using MAPP Gas (yellow disposeable cylinders). HUGE difference.

Paul

chimpboy wrote:Hmm, if I cut the pipe and get an elbow that slides very tightly over the two ends then I should be able to just braze or solder that... I think. The solder should wick into the gap provided the gap is very small. Is that right?

"capilery action" geez chimp, I thought you new big words and stuff

yep that'll work well, silver solder, should be able to scam most plumbers a stick or 2

What is this fitting for?