What's Up with Brass?

[GoldenSpike53]

Greetings.

I was reading a post in another thread in a different forum that, in a roundabout way, said that brass should not be used in components for a boiler or boiler fittings. Would this include the turret? Our club steamer has what appears to be a 1" square brass turret with valves tapped in where needed. I was getting ready to order some square brass stock so I could work on one, but thought....maybe I better check first!

Does the type of brass make a difference? What I was looking at is Alloy 360. I would think that, at 1" thickness, it would be plenty strong for the turret. Maybe the brass thing was in regard to a copper boiler anyway.

Any comments?

Thanks!

Dale Dennis

[Bill Holland]

worried about the lead content, not holding up to the heat? Bronze should be used I think.

[GoldenSpike53]

Aha...so if bronze is desired, should it be 932 (bearing bronze) or 954 (corrosion-resistant bronze)? From looking at the specs, I would think 954, both because of corrosion resistance and high temperature properties. Am I on the right track?

Dale

[Bill Holland]

I would also look at how well it machines, which shouldn't be a problem, and also check how well it brazes, shouldnt be a problem, but wouldnt hurt to look. 660 is GREAT stuff for bushings.

[pkastagehand]

In the his book on the A3 Kozo calls for phosphor bronze for the boiler fittings.

[GoldenSpike53]

Yes, but is there a difference between a "boiler fitting" (which, I would think, is something welded into the boiler proper for the attachment of outgoing lines or valves) and the "manifold" or "turret" which would be attached to the boiler via a boiler fitting and pipe nipple? I don't see why brass would be a big problem for that application...you have steam and steam pressure in the manifold, but it's not superheated or super saturated, and although the temperature may be as high as 600 degrees, I don't see how that would be a problem for brass.

Any other thoughts?

Dale

[siggy]

I don't claim to be a metallurgist nor do I play one on TV but I would take a "common sense" approach to this question.

There are many many fittings on the backhead and elsewhere on Kozo's designs that are specified as brass parts. Secondly, take a look at any of the many other LS forums and they all have pictures and discussions of various fittings, valves, etc that are made of brass. With all of that anecdotal evidence that virtually everyone in the hobby attaches brass parts to their boilers I would have to conclude that there will be no ill effects should you do the same.

I wonder if maybe the discussion was misunderstood and the intention was to keep brass out of any location that would come in direct contact with the fire or something?

Robert

[pkastagehand]

I can't find it now but I thought I remembered reading that it has to do with silver soldering fittings to the boiler. But I could be way off base. Anyway, since this part is apparently threaded to other fittings, not soldered, as Siggy said, should be allright. Sorry if I muddied the waters. I wasn't clear on what the part did or how it attached.

[doug]

goldenspike53 said:

Greetings.

I was reading a post in another thread in a different forum that, in a roundabout way, said that brass should not be used in components for a boiler or boiler fittings. Would this include the turret? Our club steamer has what appears to be a 1" square brass turret with valves tapped in where needed. I was getting ready to order some square brass stock so I could work on one, but thought....maybe I better check first!

Does the type of brass make a difference? What I was looking at is Alloy 360. I would think that, at 1" thickness, it would be plenty strong for the turret. Maybe the brass thing was in regard to a copper boiler anyway.

Any comments?

Thanks!

Dale Dennis

Dennis,

Brass is not usually used around boilers, but bronze is. The difference is the zinc content, which is the problem. Brass in contact with boiler water will have the zinc pulled out of it until the brass part crumbles. How soon it does that is a function of how much you run your locomotive, but it will happen.

I once saw a small copper boiler off of a tiny 1" scale loco where the builder had used brass stays in the firebox. I don't remember how many years it took, but the stays were eaten away and let go in a chain, leaving a boiler that looked like a puffer fish! The copper shell held, but was very deformed.

I used to have a brass blowdown valve around her that was eaten away on the inside of the NPT tread that screwed into the boiler. I never did find out how long it had been in service.

I have seen turrets made out of 1" square brass rod that were 20 years old and appeared to be fine, but then the wall was pretty thick also, and the turret is not subject to as much water contact as a blowdown valve either.

Doug Edwards

[GoldenSpike53]

Thanks, Doug.

It is still sounding to me like part of the issue with brass may be when it is combined with copper. Since I'm building my boiler out of steel, I wonder if it would still have like issues. I know copper and zinc react rather readily; that's why any plumber who knows his stuff will tell you never to directly connect copper pipe to galvanized steel pipe. The zinc reacts with the copper, and creates an electrical flow, which results in electrolisis, which eats away the copper and develops the "pin holes" that have been described by others. Copper and galvanized pipes have to be separated by a dielectric (insulated) connector.

So, if I have a steel boiler, would that issue still exist? Is the zinc in the brass what causes the problem?

Thanks.

Dale

[jones]

Hi,

The problem is caused by the zinc being leached out of the brass by the water/steam.
Whether the boiler is copper or steel has no bearing on it at all. (Or so I have read)

Andrew

[doug]

It is also my understanding that brass is not to be used with steel boilers either.

Doug.