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

Hi Rich,
I use Stainless steel. The problem with using brass screws is that their 
tensile strength is not that good.
The reason for Brass Boiler fittings being bad news is the problem of 
dezincification in some water areas. This problem seems to be spreading, 
possibly as water is pumped between areas. This is another reason for not 
using brass screws.

Regards

Clif
----- 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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