[modeleng] Re: Regulator and dome screws - offical guidelines on materials?

Times change.
Whereas brass screws for domes were OK in LBSC's time, they arent today.
Gunmetal, bronze, monel, or stainless (EN58J), would be my choice, in that 
order.

As for brass , it is an absolute no-no inside the boiler, but fittings can 
be removed and checked at frequent intervals. (Whether they are or not is a 
different matter!) Thus they are tolerated in those positions.

Personally I prefer GM or bronze when possible.
Alan Stepney

http://www.alanstepney.info
Model Engineering & steam engine information pages
----- Original Message ----- 
From: "R.L. Roebuck" <rlr20@xxxxxxxxxxxxxxxx>
To: <modeleng@xxxxxxxxxxxxx>
Sent: Thursday, August 23, 2007 5:27 PM
Subject: [modeleng] Regulator and dome screws - offical guidelines on 
materials?


Hi there All,

In these times of increased rules and regs governing our boilers, are
there any guidelines on what material our regulator and done fixing screws
should be made of.

Dismantling the Rob Roy I'm currently tinkering with, the badly coroded
STEEL (ouch) regulator screws are in need of replacement (infact three of
them didn't have any thread left on them).

Looking at Martin Evans Rob Roy notes, he says not to use steel or brass,
whereas for Mona LBSC suggests using brass. Many of the more modern
articles I have infront of me don't say what material to use for the
screws!!!

We are also advised in the literature of the tendancy for stainless and
bronze to 'disagree' with each other.

So does this leave something like gunmetal or monel? I have to admit that
the thought of some of the nastier bits of gunmetal supplied by the trade
being turned into screws carrying load doesn't make me feel that happy.

Anyway, so back to my point - is there any official guidelines on
materials for these things?

Also we are told in the literature that it is best not to use brass for
boiler fittings, yet all the off the shelf fittings that are for sale seem
to be made from brass - am I missing something here? Are there again
official guidelines for what materials should be used here?

Yours,


Rich.

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