[modeleng] Re: Superheater trouble

  • From: "Barrie Purslow" <bpduo@xxxxxxxxxxxxx>
  • To: <modeleng@xxxxxxxxxxxxx>
  • Date: Tue, 13 Nov 2007 19:01:52 -0000

Keith,

The answer to a tube benders prayers is "Cerrobend". This is a low melting 
point (less than 100 degrees C) alloy of (I think) tin and bismuth. It is 
also known as Woods Metal. You simply anneal the tube, pour in the alloy, 
bend the tube then melt out the alloy. Just don't ask where to get it! I 
liberated my stock when I was employed.
As regards the value of superheaters - well you are getting into the realms 
of personal preferences here. I can certainly vouch for a significant 
reduction in water consumption if you change from simple copper superheaters 
to S/S radiant types.
One final point - to make tube bending easier in the smokebox I change the 
S/S superheater tubes to copper near the front tube plate then the tricky 
bends are all in copper. Oh, and make sure you bend 'em so that it is 
possble to fit a cylindrical spark arrestor around the blast pipe.

Good Luck,


Barrie

----- Original Message ----- 
From: <Gmx22@xxxxxxx>
To: <modeleng@xxxxxxxxxxxxx>
Sent: Monday, November 12, 2007 10:44 PM
Subject: [modeleng] Superheater trouble


> Hi all, I don't normally write much here but do read with interest most of
> your comments. I am getting on well with a simplex but can't seem to get 
> the
> super heater right. The people I have spoken to have two schools of 
> thought. 1
> because it has slide valves Don't use a radiant one something to do with 
> wet
> steam being better. make it out of copper. I have just come in from the
> garage  having turned another peace of copper tube into scrap, lots of 
> heating and
> i  just can't get the tight bend required to make it look neat. Other 
> school
> of  thought is make it radiant using stainless and use thinner tubing 22g 
> I
> think.  any thoughts on how to bent copper tube or where the hell do I get
> stainless  from, tried GLR and the guys a Polly. I have seen lots of super 
> heaters
> made out  of SS and look neat with perfect bends but nobody can tell me 
> where
> they got the  stuff.
> I have a tube bender but the radius is not small enough and of course it 
> is
> metric 10mm and I am using 7/16 18g copper......... well I was! I know you
> will  probably think how has he got this far if he can't bend copper tube 
> but
> things  have gone very well up to this point, I just can't afford to keep
> throwing  copper in the bin.
> Great site keep up the good work
> Keith
>
>
>
>
>
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