Thread: Bending brass pipe and flats

First time posting in metal work forum, mainly concentrate in woodwork area.

A project I am making is a small model wooden steam train for my grand son. It involves a fair bit of wood turning. ( A new experience ). It also will have some approx 6mm brass pipe that needs to be bent so it can be attached to the side of the boiler and inserted into a drill hole.

Flat brass needs to go around the circumference of the boiler which is approx 75 mm in diameter. I would also like some brass on the cow catcher

I have a plumber friend that I can impose on if necessary but would prefer to battle through by myself if possible.

Would heating the brass with a butane torch help or is their a better way?

Brass can come as half hard or annealled, anealled would be much easier to work with.

To bend the tube, it could be done by hand with some flattening if annealled, but the standard trick is to do it with a former. Often the former is a steel spring wound with a bellmouth opening. The spring is wound onto the tubing (firm fit) so that it extends beyond the ends of the bend, the bend is formed by hand, and the spring is wound off again.

If you have facility to turn wood or metal, you might be able to turn a hardwood former, basically a wooden cylinder with a full depth radiused base groove machined around circumference. Would need a profiled roller to form the bend, and a fixed stop at one end to hold the material in place while the bend is formed in the groove.

I suspect that plumbers type tools will be generally to large (diameter and bend radius) unless it is a huge model.

For the brass strapping, a hardwood former, roller and stop will get you close. Aim for the former to be about 10% larger than the finished size, and try to get a decent wrap about 90% of the way around it. Then fix one end to the base of the model boiler and use cord wraps to pull it up firmly around the boiler and fasten the free end.

More normal method is a set of metal rolls, two parallel rolls with a gap between them, and a third roll over the gap and able to be fed into it in a controlled fashion. Seem to cost a min $100 for a mini unit so may not be worth while for a 1 off job.

Used to be able to get the springs from hobby shops (K & S brand) but I think as sets of 5 sizes. Mine were about $30 15 years ago so again might be unviable.

Annealling of brass tube is easy as well, which may help you with the task. Just heat to red and let cool slowly. You will have to pollish it after with Brasso or some such.

Tube benders for 6mm tube are very cheap. I have seen crappy Chinese benders about for under $10.00.

Sounds like a nice project. I bet you Grandson loves it.

Originally Posted by STAR

First time posting in metal work forum, mainly concentrate in woodwork area.

Welcome to the Metalwork section - you will find we are a friendly group and are always willing to help our less fortunate woodwork colleagues.

A project I am making is a small model wooden steam train for my grand son. It involves a fair bit of wood turning. (A new experience ). It also will have some approx 6mm brass pipe that needs to be bent so it can be attached to the side of the boiler and inserted into a drill hole.

Flat brass needs to go around the circumference of the boiler which is approx 75 mm in diameter. I would also like some brass on the cow catcher

You can purchase a small sheet of brass - thin gauge (but wouldn't copper be better - more authentic and less brittle to work with) and bend it around a wooden former of 75mm diameter.

Regards
MH

Sounds like an interesting project Star. Hope it goes well and dont forget to post some pics of your progress/finished loco.

Chipman

To preserve the shape of the pipe cross-section, fill with sand and plug both ends before bending. This can enhance the effectiveness of the rollers.

Joe

Thanks for all the replies. Gives me something to practice on. What type of stores would have small metal forming tools, I have only been interested in wood so have never taken much interest in metal work.

Thanks

STAR

I would start looking through yellow pages for Model Engineers supplies and or Live Steam supplies.