Rough 3/4 Scale Tom Thumb Locomotive Restoration Help Needed

[Harold_V]

Hmmm. Being the eternal skeptic, I'm not sure any of the comments are spot on. Might be a good idea to start by cleaning the exterior of the boiler, so it can be better evaluated. I get the impression it's copper, but is it? Some of the seams appear to be welded, which might indicate it's steel.
If it is copper, was it assembled with SilFos? A good cleaning would most likely reveal the answer. If you happen to have access to a blast cabinet, glass bead would be an excellent choice, or even walnut shell.

Just sayin'

H

[Bill Shields]

Copper can be welded...I have a 4" diameter boiler that a very good friend did for me a while back

[Harold_V]

Copper can be welded...I have a 4" diameter boiler that a very good friend did for me a while back

Yes, I'm aware that copper can be welded, most likely by TIG. It isn't commonly done because of the great heat conductivity of copper, it's difficult to do. Sure is a nice way to go, though.
We really do need more information about that boiler before any reliable advice can be provided.

H

[hddennis]

Scotty, I'm in Middle Georgia. Thank you for the links, I'll check them out.
Bill, the tube the boiler is made from is 4 inches and the tubes make it larger.

Howard Dennis

[milwiron]

I've TIG welder the tube and sheets on a copper boiler. Lots of amperage, lots of burned skin and lots of scars that still show. I sheared strips off copper sheets for filler and a 50-50 helium/argon mix. It wasn't fun but it did make a nice boiler.
Denny

[Pontiacguy1]

Howard: Welcome to the Live Steam hobby. Unfortunately, once you go below the Mason-Dixon line, there are no tracks other than 7 1/2" gauge that are available that I know of. There may be a few 'lone wolves' out there with a small pike in their back yard or something, but in general, in the south, if you are dealing with anything other than 7 1/2" gauge, you are not going to have anywhere to run it. Don't let that discourage you too much, though. A small track can be built to utilize it once you get it operational. I dabble in 1/2" scale 2 1/2" gauge, which is even more rare than 3/4" or 1" scale is.

That being said: I think it's still a nice piece and could be fixed up. Some of the guys above have given good advice in that the best thing to do is to take the boiler and all your pieces to someone fairly local who actually knows a thing or two about boilers and can look at it with you and see what the problems are. It might not be nearly as bad as you think, or the entire boiler could be scrap material. Either way, I would want to know for sure before I went any further. There are several guys in the Atlanta area that are on these boards, and hopefully one of them will chime in and give you further advice. I'd look at it with you, but I'm up in Tennessee, probably at least 4 to 5 hour drive from you.

[hddennis]

Thank you all for responding and offering your opinions and advice. I think the next thing I need to do is get this boiler completely cleaned to further evaluate it's condition. I'm pretty sure what seemed to be a repaired crack is actually just a run of solder. the walls of this tube are 1/8 inch thick and I'd think any pressure able to crack this would have also caused distortion that I see no evidence of.

Using my current assumption that the only damage is the one broken bung and several bent from impact, If worse came to worse couldn't these be soldered shut and new ones soldered on other tubes?

I was finally able to remove the v4 steam engine and it seems to have suffered some connecting rod damage that has caused a tightness hampering some rotation. it will run on air pressure but not rotate easily by hand. I need to find out which of the cylinders is causing this. I have removed them all and the crankshaft spins freely so I have a binding somewhere in the cylinders or connecting rods.

Is it okay to polish the pistons and cylinder walls?

Howard Dennis

P.S. Was just working on the engine and had to move the boiler off my workbench and was shocked at the effort it took to move it. Curious, I put it on my postal scale. This thing ain't no toy. It weighs 6.5 pounds!

[Bill Shields]

polishing is generally OK as long as you don't hone and make it bell-mouthed in the process..

soldering for repairs on joints is OK if you can get it clean and use the correct solder.

a crack i a run of solder...not sure what that means.

[hddennis]

When I said a run of solder I meant it looked like too much solder was used on a joint and the excess ran down the tube.

What would be the correct solder to use?

Howard Dennis

[Bill Shields]

depends on what is there...which is difficult to tell after the fact..

it is going to be silver solder for sure -> generally 25% silver minimum for boiler work.

if it is currently soldered with sil-fos then another think is in order.

This is something that someone who's 'been there / done that' with soldering will know as soon as he sees the cleaned boiler and can look closely at the solder joint.

Sil fos tends to be a yellower looking joint -> and does not hold up well with high temps and Sulphur...and is currently not used for coal burning boiler applications -> although 40 years ago it was 'the rage'.

however if the boiler has been soldered with soft (lead bearing) solder...you are up schitts creek...

[hddennis]

Forgive me if this is a dumb question but I'm a bit out of my element as far as thread sizes and methods go on these model locomotives. I'm trial fitting before I order parts and can't seem to find the proper bushing nor understand how this glass tube is sealed. In the automotive world I'm familiar with this fitting is called 1/8 x 27 National Pipe Thread but I can't find a bushing that size on the model parts sites. Am I calling it the wrong term? I also notice the new 10mm sight tube comes with what appear to be rubber grommets for sealing. I am barely able to get a small thread under the nut and have no room at all for grommets or o rings. Do I have an obsolete fitting on my boiler or can it be used once I understand how to seal it?

Howard Dennis

[Bill Shields]

1/8 NPT is 1/8 NPT (Tapered pipe)...but a bit large for a TT boiler (assuming 3.5" track and boiler under 6" diameter).

I would typically use 1/16 NPT (national tapered pipe) or 1/4-40 MPT (MODEL PIPE THREAD - GENERALLY TAPERED)

Generally, these solder-in bushings need to be made (lathe / tap) from bronze

your picture looks like there is some sort of plastic (teflon) or yarn / bushing already there that will go under the nut....which may make the need for anything else unnecessary.

can you send a picture of each of the pieces such that we can see everything in a bit more of an 'exploded' view?...along with a 'scale' so that we can get a general idea of size...unless the white part (which will be glass) -> is 10 mm diameter...???

obsolete - maybe -> well worn...seems that way -> but may still be usable