Office of Steam Forum for Model & Toy Steam Gas & Hot Air Engines

PROGRESS UPDATE

Thanks, Brent and Arnold, for the advisement. I've determined that I need to make new seal compression plates, and am waiting for some brass sheet stock to make them out of. I'll continue with the sight glass progress when it arrives.

In the meantime, I've disassembled the engine portion, and am giving the parts a good cleaning and inspection. Many of the plated parts are still in nice condition, having just been lurking beneath a coating of hardened oil residue, and other assorted nasties.

Here's a layout of the cleaned up parts and pieces:

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I've decided to make a new crankshaft for this engine. I previously mentioned that the crankshaft bearings seemed to have a great deal of excess clearance. Disassembly of the engine revealed a major contributing factor as to why. More about this when I get to the point of making the new shaft.

Meanwhile, back to cleaning...

Love seeing an engine neatly parted out like this.

Really speaks to both the simplicity of the steam engine concept, while at the same time showing the complexity of the mechanical aspect to make that simple concept work!

This, even in just a "simple" toy!!

Nice Layout!!!

Thanks for the comments, you guys!

From my experience, sealants in the form of slices cut off (soft) silicone tube work excellently and adapt very well and smoothly to the moulded openings for the sight-glass. I wonder if the red, round washers shown in the (very nice) photo presenting all parts for the assembly might be a bit hard...

Fear not, the seals shown in the photo are silicone rubber o-rings (https://www.mcmaster.com/1173N008/), which are pretty soft. They are great for these high-temp, low-pressure applications. These are the same kind I used on the Doll vertical engine I worked on recently.

Painting the base green is an excellent idea, btw, but what about adding some pink spots and applying a unicorn-transfer to the boiler after painting it with stove-pipe silver??? I wonder why Arnold has not recommended this before... ;-)

I'm surprised as well. Arnold usually shows quite a flair for this type of embellishment. I think the pink polka-dots may be a bit over-the-top on a green base. Unfortunately, I don't have a unicorn-transfer, but I do have some "Powerpuff Girl" stickers that my grandniece left behind over Christmas. I don't think they'll survive on the heated boiler, but they should really "pop" on the base. [ Guests cannot view attachments ]

RE-ATTACHING BOILER TO FIREBOX

When received, this engine's boiler and firebox were separated. I have seen various manufacturing methods used for joining a vertical boiler to its firebox, including a separate roll-formed ring which traps formed flanges on both parts, a rolled flange on one part formed around a rolled flange on the other part, etc. This was the first instance I've seen which used soldered tabs.

Notice in the following picture of the Carette firebox, how there is a nickel-plated ring which has been rolled and crimped to a formed flange on the firebox:

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Also notice the arrows indicating two of three tabs (one of the tabs is not visable in this view), which are also part of the nickelled ring. The tabs are formed in such a way as to contact a circular flange at the base of the brass boiler. The view shown in the picture below is the same firebox looking from the bottom (the cast iron base has been removed):

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Here is a picture of the lower flange of the boiler. The arrow in indicates one of the three spots where the tabs were originally soldered. You can just make out a slightly tinned area. There are two more like this, equally spaced around the rim.

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Re-attaching the boiler to the firebox is a matter of assembling the two parts, radially aligning them in the original position (sight glass directly above firebox opening), inverting the assembly, and re-soldering the three tabs. This is not quite as easy as it sounds, and I don't have any pictures taken during the process (my hands were full at the time!) I elected to use a propane torch and StayBrite silver-bearing solder, with the assembly inverted. This requires that the torch be upended somewhat to enter the firebox bottom opening, and a typical propane torch is not designed to work in this attitude. I wound up using a "TurboTorch" attached to a small propane tank. This is quite a handy item for soldering, where you need to maneuver the torch around to various angles:

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I have the torch attached to a one-gallon size propane tank (holds around 11 lbs. of gas):

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This worked out pretty well. Here is a view looking in from the bottom of the firebox:

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I put the three black marks on the boiler bottom to help me line up the two parts before soldering. I got a bit too much solder on one of the three joints, as you can see on the finished assembly:

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It's not too noticeable, though. At least the two parts are one again!

Paula

Nice work Paula.
 it intrigues me that the factory would use soft solder in an area so prone to the brunt of the heat...lol. Its coming along lovely.😊

I guess no problem about too much heat - if there is water in the boiler
the solder will hold
Good work so fare - this will be a nice one when finished.
Arnold

SIGHT GLASS

As I noted earlier in this thread:

...it looks the sight glass was replaced (relatively) recently, and there is evidence of some kind of clear sealant or adhesive at the connection points. I wonder if it was replaced merely for aesthetic purposes, just to improve its appearance as a shelf queen. Possibly? So, I guess the next step is to disassemble it and see if a better sealing method can be effected.

So, I did get around to disassembling the sight glass. The "clear sealant" turned out to be cyanoacrylate ("super glue"), which leads me to believe that whoever replaced the sight glass last time was intending the engine to serve as a static model only. There appeared to be no attempt to actually seal the sight glass to the boiler. Here's how it looked after removing the screws and the guard:

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The seal compression plates appear to be homemade, cut from light guage sheet metal with tin snips. No seals or seal material was evident in the sight glass holes. The super glue was easily dissolved with some acetone, and everything cleaned up nicely, at least given the age of this old boiler:

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I clamped the boiler (well-padded) in the mill vise, and used a 90 degree countersink to clean up the sight glass holes for a better seal:

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You may only need new "compression plates" and teflon washers underneath the cover to seal it up...

I had a similar repair - made 2 pressure plates and added small pieces of
silicone tubing underneath to the glass. The screws then are sealed with
silicone sealant.

Thanks for the advice, guys. I'm going to use some silicone rubber o-rings to seal the glass tube to the boiler. I have had very good results with this method in the past. These rings are fairly soft durometer, and rated to 400 degrees. The size is 3/16"ID x 5/16"OD x 1/16" thick (McMaster-Carr #1173N008). Here's what the setup looks like:

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The plates which compress the seals to expand around the sight glass tube need to be rigid enough to provide sufficient pressure to make a good seal. The compression plates that came with the engine are only .015" thick, and I don't believe they are thick enough to do the job. I ordered some 1/32" thick brass strip to make some new compression plates, and it arrived last week. Here is a drawing I made for the new plates:

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I used slotted holes in the plates, as the distance between the tapped holes in the boiler varied slightly. Here is the material I used, marked out for sawing the brass to rough size:

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(to be continued...)

Patience, grasshopper... patience.