[Steam-engine] Hard water & soft plug

[Andy glines]

--- Richard Strobel <Richard_Strobel7 at msn.com> wrote:

>   Howdy all;
> Well the boiler inspector should be out sometime
> this week and am ready for 
> him.  Can't wait!!!  The fusible plug came out
> easily and with a little 
> blasting it cleaned up nicely.  Looks like 1" npt. 
> Not allowed to reuse 
> this, right?..if so why is that and do they need to
> be changed at an 
> interval?
> 
>   Out here in the sticks, we have pretty hard water.
> What is the accepted 
> method for treating this water to reduce mineral
> deposits, scale and such?
> 
> Thanks in anticipation!!
> 
> RickinMt. 
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> 
The bronze plug should be filled with pure Tin which
has a melting point of around 450 degrees F.  The
problem with old plugs is that the Tin oxidizes as a
result of being exposed to the extreme heat of the
fire.  What you end up with is a plug filled with Tin
oxide instead of Tin.  The melting point of Tin Oxide
is well in excess of 1000 degrees F meaning it won't
work.  There is no way to prevent the oxidization of
the Tin so we change the plug regularly.  For most of
us hobby guys every other year is a good schedule. 
Frequency will depend on how much you fire your
boiler.  We have known about this problem for a very
long time.  The Steam Boat Inspection Service (later
Coast Gaurd) requiring that soft plugs be renewed in
steam ship boilers every 6 months around the time of
WWI.  Bruce Babcock wrote an excellent article in
Steam Traction on this subject a couple of years ago. 
Maybe someone here can help us find it.  
You have already gotten some suggestions on your
water.  Rain water is a good idea.  Pond water can
work good as well.  You don't want water from spring
fed pond because the spring is the same as your well
water.  Look at the runnoff into the pond.  I would
think you want one in a grassy field.

Andy Glines
Evansville, IN


	
		
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