Chimney and Dome Materials

[triton]

Can the experts provide some guidance on the correct materials for the chimney, petticoat pipe and dome for my Stowe loco?

The drawings do not show the material to be used for each piece, so I need some recommendations.

Several articles show Chimney - Cast Iron or Gunmetal; Petticoat Pipe - Gunmetal or Stainless steel; Dome - Stainless Steel.

Any suggestions on a metal casting, 3D printing in metals or machine from a chunk of something!!

[GWRdriver]

Hello Triton,
To answer your question . . . for the chimney my choice would be cast iron although GM would work. For the petticoat a mild steel will do very well, although SS would also do.
As for the dome, you didn't say whether that's the inner or outer but let's assume for the moment it's the inner, and also assuming you boiler is copper, then either GM or SS would work.

I am curious though as to how a 5"ga Schools has come to be built in Kansas. Is there 5" gauge activity in your parts? I can completely understand though, that you may admire the Schools class so much that a lack of 5"ga track doesn't matter.

[mbrown]

In the past, I have made chimneys from gunmetal castings, steel fabrications and composite fabrications (steel, copper for the base and brass for the top cap).

For petticoats, I have used copper tube, gunmetal castings, solid brass and aluminium.

Here are a couple of pictures of the fabricated steel chimney and aluminium petticoat on my current project - more details on my main thread.

IMG_20210626_181104 by malcolm brown, on Flickr

IMG_20210626_181116 by malcolm brown, on Flickr


IMG_20210405_181738 by malcolm brown, on Flickr

Best wishes

Malcolm

[triton]

Thanks for all the help.

Hi Harry (GWRdriver): Although I live in Kansas, very much English!! Love the old steam engines, particularly the Schools class locomotives, so purchased a set of plans from Polly modelling and started building. Model train building not a big thing here in the US so have to buy a lot of stuff from England. I think I own half of the UK and US postal service shipping to the US!!
GM is hard to get here. Most people look at you as though you've had too much to drink when you ask for it!! (I think its commonly called red brass here!)
The dome I am working on is the OUTER dome that covers the steam regulator valve, SS may work fine for this part.

Has anyone got any experience with gunmetal 3D printing?? My son made a model of the chimney and petticoat pipe in plastic which looks really good, so I was thinking on 3D gunmetal or SS printing as I'm still not sure how I would even machine the chimney after looking at the the plastic model.

If I can figure out how to add a photo to the thread, I will add one.

[92220]

Hi Triton.

You can almost use any metal for chimney and petticoat. When I bought the chimney and fitted petticoat, for my 9f, from Doug Hewson, about 20 years ago, it was supplied as CNC machined parts, made from brass bar. Doug Hewson also supplied the chimney and petticoat for the Britannia, in brass, so it would seem that almost any model engineering metal would do.

Bob.

[doubletop]

The outer dome on my Dart is a very bad and porous aluminium casting which has resulted in it being aluminium and filler. It is only cosmetic so anything you have to hand really.

Pete

[triton]

Thanks for all the help.

Does anyone have any recommendations for a company that does 3D printing in BRASS?

[GWRdriver]

Hello Triton,
My guess is that in Kansas, just as it is in Tennessee, good Chippies are few and far between. :-)

I misunderstood what you were referring to earlier as the dome and I suggested SS, which actually would NOT be a good material as SS can be so difficult to work and I'm surprised the drawings recommend that. As the exterior done cover is essentially non-structural, brass or even aluminum would be a better choice. I'm surprised Polly doesn't, or didn't, offer a casting for this item.

I'm trying to find contact information on a lost wax castings service I know of in the USA which specializes in model work, but I haven't yet found it. I'll post it when I come up with something.

[triton]

Hi GWRdriver: You are correct - chippies are non-existent here. We found a really good one in Charleston, SC where my son lives.

Polly did not offer a casting for the chimney or dome. I have contacted then and asked them to price a casting for me, but don't seem to get any response. A little disappointed with their customer service lately - probably because they are in the process of being sold!!

I put a post on the 3D printing board and got a couple really good suggestions. Got a quote for a chimney in stainless (3D printed) of $110 + shipping (About 90 pounds). Brass was about 3-4 times that cost.

So still looking!

[weary]

Dave Smith, aka 'kipford' of this parish, has had some fine 3d printed brass, bronze, and steel items printed by Shapeways (in the Netherlands?). See reference here, tho' a search on this forum for 'Shapeways' will turn up other references.

If he does not spot this thread it may be worth you contacting him for opinions/advice?

Regards,
Phil

[kipford]

Shapeways are very expensive when it comes to large items like chimneys, domes etc. For my back head details I have had them lost wax cast by Owl castings (Coniston gave a link in your other thread). Owl like Mike Jack's 3D print the wax used for making the mould. As you have an stl file of your parts then it is a simple matter of sending it to them for a quote, they are very reasonably priced at an average price of £18 per part plus £10 p&p.
Regards
Dave

Backhead Castings by Dave Smith, on Flickr

[triton]

Dave: Sorry for the late reply. Thankyou for your recommendation. Photo shows how nice the castings are.

[eightpot]

A while back I had to machine the gunmetal dome casting for Martin Evans' 'Enterprise', an LNER V1 2-6-2 tank loco. Mounted it on a spigot for the lathe work, but when it came to filing the flange that was another matter. Due to the toughness of the metal it was obvious that it was going to be hard going. Why does the trade cast things like this - and I would include chimneys - in such a metal? My solution was to fabricate one by silver-soldering bits of brass together, which after the lathe work, was much easier and quicker to file the flange.

[ettingtonliam]

I've had thin iron castings that were hard, but never gunmetal. Given new files, or at least files that have never been uswed on iron or steel, they usually work just fine.