Hunslet 5″ Loco

[Brian Brown 1Participant @brianbrown1]

Hi all,

I’m currently approaching completion of my 1st locomotive, a 5″ Hunslet to the Don Young design, but try as I may, I have not been able to form the brass cowling that wraps around the rear of the firebox backplate / outer wrapper joint. The cowl is a 2″ wide brass strip in half round section and is curved through a 17 1/2 ” diameter for 180 degrees, with the remaining legs on either side continuing half round but straight in order to cover the vertical joint.

I hope that makesense!

I’ve tried clamping sheet brass between 2 formers and heating/beating, but I still end up with creases. I’ve also tried forming a half round srtaight section and coaxing it around the radius, again to no avail. Pressing seems to be the answer, but I don’t have the means or wherewithall to machine a set of dies.

I realise that the cowl is purely cosmetic, but as it adds immeasurably to the appearance, I would really appreciate some advice as to how approach this task before I ruin any more sheets of brass!

Many thanks,

Brian Brown

 

[Brian Brown 1Participant @brianbrown1]

[David Clark 13Participant @davidclark13]

Hi There

Could you turn the top bit, cut it in half, make the two uprights and

silver solder together?

regards david

 

[Ian AbbottParticipant @ianabbott31222]

Is this a solid half round, or a shaped piece of metal like half a tube?

 

If it’s the latter, how about starting with a 2″ tube and having it bent at an auto exhaust  shop, then splitting it along the centre line.

 

A casting would work, but rather expensive.

 

Regards

Ian 

[Speedy Builder5Participant @speedybuilder5]

Could you use copper instead – its a bit more malleable.

[mgjParticipant @mgj]

Ian I suspect that may be a very good answer . Sounds like 1/2 a tube over some kind of flange or joint..

 

Otherwise its a former, a set of proper tin bashers hammers, and start shrinking and expanding. And keep annealing! Unless you have access to a proper (English) forming wheel. 

 

To do it round a former is quite simple (in concept!!!!) You need a contracting hammer. You anneal and start deforming the metal (with a soft face mallet is best). It will start to wrinkle – of course. Out comes the contracting hammer. Shrink the wrinkle, and take it out. And so you go on, annealing frequently as you go. You may find as the metal thickens in places you need to file some off.  Finally draw file and polish up.

 

Simples – until you try it. But that’s how to panel beat it.

 

(A blunt file makes a reasonable contracting hammer, if you want to experiment on some scrap. Not as good as the real thing, but adequate. Bit slow, but it will take the wrinkles out.

 

 

Edited By meyrick griffith-jones on 26/02/2010 18:49:33

[calder percival 1Participant @calderpercival1]

the secret is to take it all together steady  and re heat don’t go bashing in one area. heat, beat ,trim, heat it will work just do it slowly

[calder percival 1Participant @calderpercival1]

the secret is to take it all together steady  and re heat don’t go bashing in one area. heat, beat ,trim, heat it will work just do it slowly

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