Steam Boiler Build (PM Research Boiler #1)

Hello all,

I'll be posting a build diary of PM Research's #1 Boiler build. This will hopefully be used to power a steam donkey as part of my garden railroad project (G scale).

I have plenty of experience with aircraft pressure vessels, repairs, and the importance of properly executed engineering data. Nonetheless.....

....grouchy boiler of doom comments are welcome for part of my/our educational edification.

Here's an unboxing video I just did of the boiler kit in case anyone's interested on what tools one might expect to build one. I was surprised to find that one could get away with more basic tools (and a small lathe). The bigger mini lathes would eat the project for lunch.

As a side note, I've also started machining the skidder's gear train, which will be setup like this (rotate CCW 90° ) .

Here's one of the gears and pinion already cut with home brewed cutters...

Now that I have a boiler with dimensions, I'll be able to move forward with the tricky part of tying geometry together and getting things to (sort of) look to scale.

Anyways, the boiler itself will keep me busy for a long while. I'll be running some of my other little engines on it, which have yet to run on steam.

Regards,

-Z

*Helpful References:

• PMR Drawings
• Boilers: Types and Design (ICS)
• The Steam Donkey Engine (Harris)
• In Search of Steam Donkeys (Johnson)
• Mechanics of Materials (Beer, J)
• Practical Stress Analysis (Flabel)

Edited By Zeb Flux on 14/05/2021 22:18:42

Hi Zeb

Lost track of this thread. I will be interested in following along as I have three or four of the PM boilers tucked away awaiting construction/assembly.

They have an interesting construction method, relying partly on rivets for structural strength for the boiler shell ( end plate attachment ). A bit old school in these days of fully silver soldered construction.

If I remember correctly ( I don't have my plans to hand at the moment ) the 'silver' solder supplied with these kits is a silver-tin eutectic ( ~4% silver, 96% tin ). I would think more than adequate for the type of construction and use of a boiler of this size, but I will leave it for others to comment on that aspect.

Good luck with the build.

Pero

Hi Pero,

Yeah, it seems the solder is mostly there for the fittings and to seal the riveted gaps non-structurally. I thought about trying different grades of silver (cooler/lower % throughout the build), but for now I'll stick with the print.

I'll need all the luck I can get!

Hi Zeb

Not sure if you are aware of this but:

In terms of melting point the silver/tin eutectic solders sit about half way between the lead/tin soft solders and the lowest melting point high silver ( 55% ) silver brazing alloys ( hopefully the boys from Cup Alloys will correct me if they see this and I am too far off course ). I suspect also in strength but I have not researched this.

The advantage is that there is no lead present which can interfere with other operations. Commercially it is ( was? ) used for such things as attaching the spouts to stainless steel kettles as it forms a good joint and is a good colour match. Completely irrelevant in respect of a copper boiler but interesting nonetheless.

Cheers

Pero

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@Pero Interesting on the solder. I've always done welding and brazing but new to silver solder. I bought extra to practice on.

@br Nice. I'll have to look more for the videos. Probably need to work more on my Google-Fu.