Cylinder Boring Techniques for Steam Engines

A borax based flux will do the job. Mix with water to a paste.

You will also want a high pressure regulator on the propane that will give at least 2.0bar

One other point, when you come to solder the two together put a light punch mark in each corner of the curved face of the valve block. This will just raise it off the surface of the cylinder slightly creating a gap for the solder to flow into.

J

Hi Jason,

Thank you very much for your advice.

I've a feeling that I'll go a bit quiet about this for a while - at the moment I can't think of anyone with a regulator and burner suitable. I'll give it some time and thought and see what happens.

(There is the oil fired heating boiler in the cellar - that's a giant oil fired blow-torch inside a water jacket - if I arranged some fire bricks and the workpiece inside that it might get it hot enough - seeing my efforts, my landlord might also decide that he wanted to determine whether it was possible to send me into space simply by kicking my backside hard enough... )

Thank you for your advice about the light punch mark - I can see that this will create a tiny gap perfect for capillary flow of the solder - many thanks.

Will

Back on the subject of bees an interesting story from France:

**LINK**

I heard elsewhere that the blue honey is turning into a bit of a novelty...

Will

This is the bane of a bee keeper, his bees are opportunist and will collect what is easiest to collect. One of the biggest honey processors would receive honey in bulk containers and empty them and put them outside, it did not take long for the bees to find these containers and start foraging on honety from all over the world with the possibility of worldwide diseases in the honey.

This is all sorted now and the processor washes the containers before outside storage.

I would like to explain about honey, the image of a beekeeper and his bees is that he takes the honey filled combs and uncaps them and spins out the honey in a centrifuge (honey spinner)

The honey is then bottled for sale or gifts. In this process the Esters and Essences and flavours are all preserved as there is no heating or manipulation of the honey from its raw state, it is Pure Honey !

Meanwhile the big honey processors import honey from all over the world and it comes in large quanities of different types. They have to blend it and make it palatable.

smaller beekeeping concerns have no time to uncap and spin out the honey so they use a hot air machine which melts the wax and honey together which is then run into containers and allowed to cool and then the wax which has solidified is taken off and the honey is put through a filter to remover detritus. Then it is bottled for sale.

My feelings are that this process removes a lot of the esters and flavours and makes the honey a mish mash of poor quality. I feel it cannot be called pure honey. Also because it is finely filtered the pollens are removed which can help a person with allergy to self immunise.

There is a caveat here that honey should not be heated higher than 40C or it changes and can become contaminated with HydroMethylFurFural which is harmful to humans.

Incidently I have taken a further 120lb of honey and I still have some more to take, weather permitting.

Clive

Hi Will,

I regularly use paillons of solder as it does help to reduce wast, and solder is so expensive these days. I doo tend to flatten the rod as it helps to prevent the tendency for the solder to roll away at some critical moment. this comes from my time studying silversmithing and jewellery work when we bought solder in flat sheet form and snipped off the paillons. In that work there was often staged soldering using from low to high temp melting silver solders (even enammelling temperature solder) and it was important to get just the correct amount of solder to keep the joints as neat as possible.

We also used borax cones and flux trays with water to grind the borax into a paste. It works well and is cheap but needs some experience to work with successfully. we first worked in copper for practice before working in silver and some of our work was as large as a small boiler, e.g. coffee pots and tankards. I suggest experimenting rather than just go straight into valuable materials.

Just my experience.

best regards

Terry

Edited By Katy Purvis on 19/06/2015 09:49:33

Just a couple of points Will, if you are flattening the wire then make sure its done on a clean surface and you have aclean hammer face as you don't want to embed impurities into the metal.

Also pallions can be just as wastefull as feeding in the stick until you can judge how much to place on the joint, always best to have the solder in your hand incase you have not placed enough then you can dab a bit more on. The other problem with pallions is you can't get them to stay in place on things like the underside of this top rim.

I suppose quite a few of my fabrications are done to look like castings so a bit of a fillet is useful and maybe that is why I prefer to feed in the stick. There are some recent ones here and the cylinder fabrication is not tha far off.

J

Edited By JasonB on 12/10/2012 10:23:33

You can sometimes get borax powder from pound shops. It behaves differently from easyflo flux, but seems to work just as well.

Neil

I must admit that i tend to use Ramon Wilsons approach to this problem as JB weld is a lot cheaper than 55% silver.

Regards

Terry

If you look at the rest of that thread Terry you will see quite a bit of JB Weld and Plastic Metal being used where a bigger fillet is required or unstressed parts are stuck on with it.

You just can't build a big fillet with Silver Solder as it will just run where the flux has gone though on a small joint you can keep feeding in the rod as the heat is removed and the cooling solder can form a bigger fillet but on the otherhand you can end up with a blob of expensive solder on the floor. CuP used to do one that formed a fillet and had better gap filling qualities but I think it was cad bearing so is no longer available.

J

Hi Jason,

I've seen your previous posts but was simply stating my own viewpoint and experience in the use of silver solder since I first started using it in anger on sizeable copper (later silver) fabrications which had to be step soldered due to the complexities of the work we were doing back in the early 1970s.

I wasn't commenting adversely on your practices or work, which I often admire here and on HMEM and I think Madmodder. No slight was intended.

Best regards

Terry

One attraction of pallions was that I reckoned that if I got the pallions and the flux just right I could get the two parts soldered together without any solder being visible on the outside - just polished brass - which would look very neat.

JB Weld does sound very attractive at the moment...

I've got a 3 phase supply so could try and build an electric furnace from old electric cooker parts - here they sometime run off 2 out of the 3 phases to give a 415 volt supply (if I can find an old cooker to dismantle that is...). Another option would be to try to build a diesel fired burner out of old exhaust pipes and direct it into a furnace made of fire bricks. Either way seems potentially tricky and unsafe.

I'll ask around and see if anyone has suitable heating equipment. Folk are beginning to learn about my efforts now but that's backfired (excuse the pun) in a way because some good friends are now bringing treasured but assumed-irreparably-broken instruments and machines to me for repair...

I agree with Clive entirely about the honey. My great uncle used a centrifuge which he turned by hand. A simple centrifuge isn't a particularly complicated machine and I think there's no excuse for using heat to melt the wax and extract the honey that way - I agree that this level of heat is likely to evaporate or damage the esters and other volatile substances that give the honey its flavour. The supermarkets are awash with cheap, revolting honey - people need to learn the difference between that and the good stuff.

Edited By Will Robertson on 13/10/2012 19:30:12

Ha Will

"...... good friends are now bringing treasured but assumed-irreparably-broken instruments and machines to me for repair..."

The curse of the workshop owner I'm afraid! Resist this very firmly from all those who are not good friends and tell good friends that you will " Have a look at it when you get time" Then, according to how good a friend ( or maybe your response to their tale of woe) ensure that the " when you get time" is a long time! Believe me the world and his friends all think you can fix their problems and expect you to do it today!

I, of course, have no personal experience of this problem ( I wish!)

Regards

Norman

Hi all,

I just realised that maybe the solder designed for soldering/brazing at 600 C might be the wrong sort of solder for this application. This solder was sold to me by a local engineering firm that makes steam models and I can understand why it would be used in building boilers (particularly the superheaters where there's a significant risk of overheating) but I think this solder may be excessive for soldering the cylinder to the valve.

What is the maximum temperature of superheated steam used in stationary models? I think I could maybe make things much simpler by using a solder with a lower melting point to solder the cylinder to the valve and still have the melting point of the solder safely above the maximum expected working temperature of the steam and therefore the engine.

Will

I would not consider using anything less, its not just the melting point but also the tensile strength of the solder you need to think about.

There's been a bit of a pause here while I get to grips with DraftSight and repair a precision valve grinding machine.

Hi Jason,

You mentioned that I needed a burner with enough heat output (BTU). Roughly what heat output in BTU or kilowatts would I need? I've found a supplier of heating wire and components designed for furnaces and so I could make a simple small electric furnace by arranging the heating wire inside a structure of dry fire bricks. If I use one phase and one heating element I can have 3 kilowatts of heat but using all 3 phases, a high current supply and more heating elements can give me significantly more if necessary. An electric furnace has the advantage that I don't have to buy or design a burner and I don't lose heat in the flue gases. (NB - the way of building a furnace I've outlined is inherently dangerous with risk of electrocution, fire, explosion, etc. and I'm in no way recommending it.)

Hi Michael,

I'm designing this engine at the same time as the rebuild of a knackered S50 which is giving me a lot of interesting experience - at the moment workshop time is a bit of a problem since the workshop I have access to closes at 6pm sharp and I'm seldom out of work before then. I'm also having to buy all the tooling with delivery times of a week or two on most things. This means that, unfortunately, I have to do more planning than I'd like.

Yes - most of what I'm doing is completely pointless for a tepid fog engine. If I can make an engine which runs on tepid fog or compressed air my next step would be to build or buy a better boiler and see how the engine performed with higher pressure and superheating.

Yes - talking about efficiency of a single expansion engine is dubious - but if I can make a single expansion engine that runs well it opens the way to making a double or triple expansion engine at some time inthe future. (The single expansion engine I'm designing looks suspiciously like part of a design for a larger double expansion engine...)

Having said that, the Stuart Sirius was only single expansion and apparently achieved good efficiency (can anyone cite any figures to prove or disprove this?).

The big problem is information - Greenlys and John's PDF book based on postings on paddle ducks **LINK** are so-far the only useful books I've found. Other books I've bough have been next to useless. I'm very grateful to people on here for providing more accurate information.

Yes - the laws of thermodynamics are - unfortunately - very clear - lowering the temperature of the output of the engine is more important than increasing the temperature of the input. If I can build a piston valve engine then building a wet air pump and condenser so that the engine can exhaust into a partial vacuum should be possible in the future (though not now!). Despite the laws of thermodynamics, piston valve engines were used extensively on locomotives where the exhaust was via the funnel and no condenser and vacuum system was present.

Turbines are much more efficient - but with them comes the end of the age of reciprocating steam engines - though a thermal power station using turbines is still woefully inefficient. (At much lower temperatures, turbine liquefiers replaced reciprocating liquefiers for medium to large scale helium liquification but in closed loop cryogenic systems I think reciprocating engines are still used.)

Will

Looking at the outputs of gas burners then a 22mm dia burner puts out about 3.1Kw and that is as small as I would suggest you go, a better size particularly if you intend to move onto larger fabrications would be a 28mm dia burner putting out 7.7Kw. I mostly use a 25mm burner so assume thats giving about 5Kw.

So if you aim for around the 5-6Kw mark you should be on the right track, having said that I don't know how the output of a burner compares with that of a furnace. Also the time to reach soldering temperatures may be different so watch if its too slow as that can exhaust the flux.

J

Hi all,

An update - I'm hoping to have some plans for my engine ready for you to scrutinise in a few weeks. It's been a bit like a mechanical jigsaw puzzle and it's taken a lot of work over several weeks but I'm getting there.

A specific question about the restoration of the S50: For the slide valve face Tubal Cain says "use the finest emery cloth you have" (Model Engineer 16 April 1993) and for the port face "fine emery cloth" (Model Engineer 20 November 1992) - I'm not sure what he means by this - would P600 cloth be suitable or should I use something finer? I suspect that the PO polishing cloth to finish would not be suitable because he says explicitly "a nice matt grey surface... not a mirror finish" (Model Engineer 20 November 1992).

Hi Jason,

Thank you for your advice. Sorry to take up your time asking such basic questions. If I use a borax paste, roughly what length of time do I have between the water evaporating at about 100 degrees and the flux being exhausted? I think I need to be careful that I don't heat too slowly - this could be a big flaw in my electric furnace idea.

Hi Michael,

I wish I were on a par with the other people on here - I'm a long way off it. Hopefully I'm at least able to be open about my ignorance and ask for advice from more experienced and able people. To build my engine I need to work to a much higher precision than I've ever done before and acquire new skills and knowledge. I'll never reach the standard of people like Greenly and I'll always be in awe of them.

I know it's a bumpy ride but please bear with me - we'll get there!

Look forward to seeing teh drawings.

P600 will be OK no need to go any finer, Emery or wet & dry paper will do.

Its so so much the time from when the water boils off its more from when the flux starts to go sticky to when its liquid, I don't really know the time but a couple of minuits maybe.

Will If you can get a piece of plate glass and use the 1000 abrasive powder and a thin oil and do figure of 8 on it with the surface you want to flatten .

This will give you a matt surface you are looking for, clean with solvent afterwards. The plate will retain the abrasive for later use.

The brazing, hammer flat a small piece of solder and place under the edge of the join and when the flux melts and the job reaches the temperature to melt the solder then it will run and no need to worry about when the flux is exhausted, something I have never had to worry about !

Looking forward to seeing these plans Will, hope youve got it right.

Its action time now and we want to see some results and photos.

Clive

Hi Jason,

I noticed that quite a few folk had made home-made oil fired furnaces capable of reaching very high temperatures so I'll maybe look at that and try to work out whether that or the electric furnace would get the parts to be soldered up to temperature fastest. Was enviously watching a roofer today with his collection of high pressure, high power propane blow torches...

I'll go to P600 or P1000 with the slide valve for the S50 - good to know that I'm on the right lines.

Hi Clive,

I posted a photograph of the Ifanger boring tool I got - let me know if it's right. It's maybe a little short for my engine so I'll maybe get one a little bigger as well.

I tried to get 1000 abrasive powder but Arc Eurotrade and CTC don't stock abrasive powder. Arc Eurotrade do stock P1000 wet and dry paper so I'll get some of that and keep an eye open for the powder. I've got an old photocopier for this sort of thing in Scotland but no plate glass for this here despite keeping my eyes open for some time - will continue to hunt for old scanners, photocopiers, windows, etc.

Thanks for your advice about the brazing - I'll maybe try with a piece of scrap first to see how it goes and be able to cut the joint open to make sure that all has gone well.

Will