castings for tube plate, backhead and others

[Alan]

Hi
Someone has asked me if it is possible to use castings in place of formed copper for the tube plates, backhead and other plates in the boiler. He has loads of old copper to melt down and the quality of his castings is very good. He has access to all of the modern toys to make patterns.

I think its a 'slege hammer to crack a walnut' situation with the added complication of porus/faulty castings, im also concerned at the inspectors point of view whether castings were allowed in a boiler anyway, 'Lion ' has a casting in its boiler.

Any thoughts please

[ettingtonliam]

Gunmetal castings were used for boiler plates back in the late 19th and early 20th centuries, but have long since fallen out of favour.
Is it worth it? Formed copper plates are not that difficult. What is his material quality control like when hes reusing scrap, possibly of unknown origin.

[Jo]

Ask your insurer's boiler inspector if they would insure it.

Jo

[JonL]

Something about it makes me very uncomfortable. How will they/you know if the casting has any weak spots or similar?

[ettingtonliam]

I'm surprised that Lion (Titfield Thunderbolt) has a casting for the top of the firebox casing, but it does, and is in Reeves casting list for the loco.
I'd be very very wary of a boiler utilising home made castings made from scrap copper.

[runner42]

Considering it from a code point of view where specifications for the materials used are defined, to reprocess copper by melting and casting it, the traceability of the copper is lost. To re-establish this is beyond the capabilities of the average ME. To set aside this significant stumbling block and consider the problems with producing a casting that is representative of a flanged copper plate are significant. To maintain the thickness over the cross sectional area, to establish the radii of the transition from plate to flange require investment type processing. The casting would probably require machining. I suspect that the casting for the Lion is not a copper, but gunmetal. Copper has a melting point of 1085 deg C which is high, so it appears to be a non runner from a few aspects. 

Brian  

[Alan]

Im still not happy to accept cast copper as a suitable substitute for proper flanged plates. I also know that once cast, these plates will to just like the 'real' thing. I have never come across cast copper, but assume its basic features are not compromised much by being melted and cast.

Keep the answers coming in, it will be a few months before this project looks to be getting started.

This is a simple boiler, no combustion chamber, no'pacific'type slope to the throat plate, why to people have to make simple tasks difficult

[ettingtonliam]

Key question is- will club boiler inspectors accept a boiler incorporating cast copper plates? I strongly suspect 'Aussie Rules' ones won't, at least.

[JonL]

If they are doing it for the cosmetic effect maybe they could just put a cast cover over the properly made copper boiler.

[jordanleeds]

Cast copper is a interesting one , how do you maintain traceability of the material and prevent any inclusion in castings