Fiberglass Boiler???

Very ambitious!! what I would do is apply sheet plastic (or metal) and putty OVER the existing "standard" steam loco.  That is how the 1/1 railroads did it, and the chassis  below would already be a perfect match. You can do it!

Another possibility once you have the wood master made is to use vacuum forming with plastic to form the shell.  I think they sometimes use this method in military modeling to create aircraft canopies and so on.

I remember reading once of a gent that had made all sorts of locomotives via this method.  The article may have been in the old O Scale News.  Unfortunately I haven't the faintest clue where you might find that article now.

Jim

Once you have made the wood master, why not just coat it with sanding sealer and paint it?  I make tenders that way when I am in a hurry, and one has won a prize along with its Challenger locomotive in brass and bronze.

Usually I make a wood block tender just to test the locomotive, and finish up with a brass replacement.  I sold a wood Daylight tender on eBay for more than a Max Gray brass tender lettered by George Stock!  To the same bidder!

I like the idea and you have the experience to do it.   If if 1/8 inch thick that still leaves lots of room for a mechanism.

Hi Bob, I have a couple of diesel shells made this way.  The castings are about 1/8" at their thinnest. Not my work so can't add any tips on the process.

regards

 Bob C

Bob C., how did the exterior surfaces look?  Was there any detail molded on or did you have to add it later?

With a wooden master, I believe I can apply appropriate-sized rivets to it and they should show up on the mold.  Grandt Line makes brass rivets, but I don't know if they have what I need.  I had even thought about using HO track nails (round head).

Bob T., I was thinking that if I made a wooden master then a mold I could offer it to folks who might want one (like there's more than a 1/2 dozen folks who care to model SAL here ).

What I'd like to try first is to see if I could make a shell that would slip over the existing boiler, I'm getting a WbB 4-6-2 from Don Jones soon and thought of using it as the guinea pig/test subject.

If it won't fit over the existing boiler, just remove the boiler and make the fiberglass boiler with attachment points where the existing mounting screws are located.

Bob Delbridge posted:

Grandt Line makes brass rivets, but I don't know if they have what I need.

Better get them soon; Grandt Line discontinued production of brass part quite a while ago - what they have left is all that remains in their stock.

Martin, I thought I saw that but wasn't sure, too bad.

the O-scale rivets they show are conical in shape, not sure if that's what I need or not.

I posted on the ACL/SAL Yahoo site and apparently there's no drawings to be had of the 3 engines that were streamlined , according to Warren Calloway and one other member.

I still think I have enough photos to give this a try, more later, I hope!

I got the Williams by Bachmann 4-6-2 today from fellow forumite Don Jones (thanks Don!) for this conversion.

It's a nice looking engine, I haven't run it yet but plan on doing so before I make any changes.

I compared it to the Williams/Samhongsa USRA (heavy) 4-6-2 and it is smaller.  here's some photos:

Actually, the WbB engine is almost a match for the Seaboard Class-P 4-6-2.  Even if I don't make the streamlined engine I can convert this to the regular P/P1/P2/P3 class engines easily by changing out the domes for 2 of the more round type and put them in their proper locations.

Any idea what wood I should use to make the master pattern?  I don't want to use balsa, dings too easily.  I need something that is fairly easy to carve and shape and has a fine grain.

The engine, not including tender, is just under 12" long, 2-1/2" wide, and 3" high.

Once the fiberglass boiler shell is made I need to figure out how to attach it to the existing boiler, just like the prototype.

Use pine for the master.  I  too have a WBB 4-6-2 I converted to Canadian National...a great runner and one of my favorites!!

So far I've gotten the following suggestions on what to use for the master:

Basswood

Poplar

Pine

MDF

Styrene

Plexiglass

I've used Basswood in the past for a few projects and it seem to work well.

I'm still in the planning stage so everything's still on the table.  I don't know if I want to carve a block of wood, build it layer by layer, or build slab sides and carve the roof line and nose.

I know nothing about it, but I think I would look into that clay they make auto bodies out of, when they are considering making next year's cars even uglier.

poplar or basswood. once carved give it a couple coats of thinned lacquer. it will soak into the soft wood and harden the surface. you can also use thinned oil based polyurethane, but the lacquer will soak deeper into the wood.

I like Bob's suggestion about clay, if you know how to work with it. a wood armature in it's interior will give it rigidity and save clay.

Poplar is not too bad and reasonably hard to take a dent now and again particularly if you can find some that's well dried & aged.  I have a few clerestory roof sections in poplar.

Walnut is a good carving wood; fine close grained and reasonably hard & workable.

Woodcarvers I know love dogwood, but it's only slightly harder than soft steel. Got a good sized chuck of it sitting in the garage right now since I didn't toss it into the fireplace last week.  Been ages and dried about 6 months now.....  I could cut you a block out of it, but I'd need a new saw blade 1st.

Thanks guys, hadn't thought of clay.

Martin, thanks for the offer, but you just reminded me I have a friend that's into woodworking (need to call him soon).