Stuart Beam ENgine

Having just finished a scratch build Beam Engine which works fine on a low air pressure I have decided to make a Stuart Half Beam Engine as a scratch build.

The only part that I thought I will purchase was the cylinder as it had internal airways.

To my surprise the cylinder and piston are cast iron, why is it made of this as its going to rust if used as a steam engine.

I made a flame eater with cast iron cylinder and piston only to find it will rust up after one firing up, so I remade the piston and lined the cylinder with stainless tube, it worked ok.

I do not intend to buy the cylinder now I know its cast iron, but the dimensions of the ports on the drawings seem a bit vague. It shows dotted lines as concealed but on the exploded view its open.

A personal message with a rough drawing would be helpful.

Thanks Bob

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Steam oil for running.

The cylinders are also normally blown out after running.

Nick

Cast iron has been used for steam engine cylinders and pistons for four centuries without too many problems. A bit of oil does wonders.

There are thousands of Stuart engines running happily with iron cylinders and I think the full size did not have any problems.

As Nick says stean oil is running on steam, if using air then use an inline lubricator and also squirt a bit of oil into the engine once you have finished playing. You can use a lighter oil when running on air as the steam oil is a bit thick without the heat fropm the steam.

The passages are not dimensioned as they are cast into the cylinder, all the maker would have to do is clear out any sand and square up the ports if needed.

All the stuarts with the 2"x1" cylinder have the same ports and passages so 3/8" wide, 3/16" slot for the exhaust, 3/32" of metal and then 3/32" slots for the inlets. You will have to work out the position of the passages so they can be drilled yourself unless you go for a fabricated cylinder in which case they can be milled into the back of teh valve "block"

I bought a set of raw castings and materials off Gumtree for the std Stuart Beam Engine a couple of years ago which hadnt been started and that were originally purchased from Stuart over 30 years ago.

The piston material suplied is gunmetal in my kit. Dont know whats in their current kit. Their drawings then did not spec the material for each item. Dont know if their current drawings do?

Thanks for the replies.

The point I was trying o make about cast iron cylinders is if they are in constant use for which they are made for then that is the material of the time to use,

But if I use my Beam Engine and not use it for a few weeks or months, is oil with water vapor and a blow out sufficient not for any rust to appear. surely a cast iron cylinder for appearance,then an liner of stainless etc is a better option.

Just going back to my flame eater with cast iron it was not used for three days or so and it was jammed up solid.

I am a bit of a novice but have archived working model a good standard in my opinion but I am a little worried with cast iron if not in use.

Thanks Bob

I ran my Stuart 10V a few months back, started straight up and I don't think I had run it for about 15 years so seems a bit of oil does the trick.

Bronze is another good choice if you don't want the worry of rusting has the added benifit of being easier to silver solder so the cylinder can be made up from a number of parts which keeps material costs down.

As the majority of model cylinders are painted or covered in cleading (sheet metal or wood) the metal does not get seen so appearance does not really come into the equasion, it's self lubricating properties are good to have due to the graphite contained withi the iron.

I don't know what's happening to your flame eater, I have two of them, and eighteen Stirling Engines, they all live in my (damp at times)workshop, one has a steel cylinder, the other cast iron, I'v never had rust problems in the bore of either of them, both have cast iron pistons. The older of the two is maybe 25 years old.

Ian S C

Main thing is to make sure you get as much water out as possible at the end by turning it over and pump some steam oil into the cylinders. Just like Jason, I have a ~17 year old 10V that's been run on steam and air and it hasn't rusted.

I think mine is more like 30+ years old Neil, Just that I had not played with run it in 15yrs. Built it in my teens on the Unimat3 and I got the larger Emco in 1985 so a bit before that.

J