Member postings for Luker

Hi Nigel, I can't help with the types of wood you have listed, but getting a small offcut and checking how it reacts in the oven will be a good indicator. I don’t think you need something that will handle 200DegC.

For the cladding I’ve done; I used scrap sleeper wood. It smells and looks like rosewood for these two models. I chamfered the corners and glued the strips to the barrel using RTV silicone. This allowed movement and kept the strips from bowing outwards. Then strapping doesn't really matter. The unpainted wood was treated with linseed oil, and the Fire Queen painted by brush using 2K. Hope this helps….

Gentlemen, I don’t think it’s necessary to scare newbies to the hobby… A dash of respectful caution maybe, but anything more for this little kettle may be unwarranted.

Matt…

From the limited pictures and views it looks like the boiler and other bits and pieces are exceptionally well made, and I would be very surprised if there’s anything wrong with the boiler. It also looks like its silver soldered which is more than adequate for a small gas fired boiler like this. This set is something special, and I would enjoy and cherish it for as long as you can.

The copper tubes are circulation tubes and are common on smaller boilers that are externally fired, especially when built by experienced model engineers.

The blower at the chimney is probably to make the boiler look ‘cool’, with a little condensate (‘steam&rsquo coming from the chimney that would otherwise be clear when gas fired. It will also help pull a draft and keep the flame healthy. The lower the safety valve is set the more you'll see 'steam' in the exhaust plume.

It looks like the safety valve is behind the whistle on the steam dome. I would check that this lifts with a bread knife (just a fraction, if it moves its working). It should have a small groove at the top. If it’s stuck just leave it overnight in a little citric acid-water solution.

Fire it up! Post a video! It all looks fantastic and I would love to see it working…

PS: the sat temperature at 60PSI is around 145DegC according to the steam tables; the energy release quoted in calories is based on some rather bold assumptions of direct heat transfer not taking into account secondary convective heat fluxes and latent heat removal…

Sorry Noel, missed your reply! Thanks, but all credit goes to the original designer of the Fire Queen. He was a brilliant young engineer, and his design was ahead of its time. Sadly, if you read up a little on him he was clearly not as good as Gresley or Crampton in promoting and selling his work, which is often the case with brilliant engineers.

Totally agree with the traction engine modification! I’ve finished the calculations and design for a lovely little traction engine of a similar era, again with the original designer far ahead of his time, and not receiving half as much credit for his work than what he deserves! Some of the castings are done already!

For everyone following the Fire Queen series, here's some pictures that show scale a little better than the ones in the magazine...

Yep, I split the pattern. I was curious to hear how the other guys would have done a pattern like this. The discoloration is actually a very interesting point. This is a type of bronze that I’ve developed for my cylinders that casts at a higher temperature than gunmetal. This alloy requires coal dust as a cushioning additive (to prevent burnon) same as when I cast iron. But on this day I cast a number of low melting point alloys like aluminium and brass where cake flour works better, and I only made one batch of facing sand. This is why there is minor oxidation on the surface. The breathers and ingate is the correct colour because my backing sand is my standard iron mix. Here’s a few pictures which illustrated how I tackled the moulding…

Hi Gents, I recently cast the following cylinder and steam chest for my next project. I thought some of the other foundry-men might enjoy some pictures (as it came out of the sand). The interesting part of the mould is how to extract the lip that bolts onto the smokebox from the sand (if you ram sand into that recess when you extract the pattern the sand will brake out). There was only one parting line which is visible in the pictures, and the only core was the core for the cylinder hole. Normal green sand was used. I’m curious to hear how you guys would attempt this.

Hi Stephen,

I make alloys from base metals often, with no issues. The pickup (amount that goes into the charge) for the bronze alloy elements is high so you don’t need to worry about losses. Fade (the amount of additive/inoculant or alloy you loose during melting) is not significant with Zinc so you won’t have any issues there. The mass loss due to the fumes typically seen is very small. 3% Zinc will dissolve very quickly and should have very little fuming. When you do the brasses you should add a capping inoculant, I placed a recipe for one somewhere on this forum. If I don't have Zinc granulate then I use brass as a zinc source, but you need to do the calculations for the amount needed on a mass basis.

Cast iron is a little different. I melt from pig iron and scrap and then you need to add carbon which has a 50% pickup. FeSi is added at the end of the charge to prevent fade.

Melting alloys is easy; the trickier part is in the moulds. If you’re going to cast patterns with large surface areas and low volumes (plates etc.) you’ll be fine, the trick comes in when casting, for example, cylinders (large volume/surface area ratio) which require careful feeding to prevent draw etc.

PS: your furnace should be built in such a way that the fumes are carried with the exhaust up away from where you stand when casting etc. Be aware of the fumes but don’t let it deter you. I have a tradition of going for a 10Km run after a day of casting to ‘wind down and relax’ and it’s always a pleasant run…

We starting to get the stationary engines running again after the recent vandalism... The members are incredible how they can do so much with so little, hats off to the guys!

A little before my time ...

Hi guys, the Fire Queen series has started in Model Engineer. I hope all the readers enjoy the write-up. I've just finished the copper boiler design and description so that will be included somewhere down the line. I put the following video together with a few additional pictures that never made it to print, please excuse the narration, AI is much better at reading to script than I am!

Yep, we have a big problem, and I think you probably only hear a fraction of what's happening. I wouldn't want to burden you guys with our problems, that's just not fair and it’s not why I started this thread! Once we get a hold of the situation I might reach out to you guys for help on fixing what was damaged, specifically drawings and technical info. I know there are a few forum members with access to museum archives, and this forum is always willing to help!

-14DegC…. No words!

Hi Gentlemen, I've got some sad news from the RSME. We've been battling with theft recently and it's gotten to a point where engines have been seriously damaged. The windows have been welded shut and an alarm system installed. I also did a video to try and get the community involved, or at the very least let them know what they are loosing (added the video below). Other than that, not sure what else we can do?

Been enjoying the pictures (and notes), not an easy thing you doing there!

It’s an interesting exercise swopping between a classic British and a modern bike, feet get a little mixed up...

Not as complex, but some interesting engineering none the less. Designed an automatic lubrication system for my Blackbird recently...

Hi Garry,

The main difference, as you pointed out, is cost. The joint design for the two different boiler construction methods needs to change, but provided the boiler is designed for the specific joint construction method there will be no difference. I have designed and built both TIG and silver soldered boilers and both work perfectly. My personal preference is TIG due to cost, and the fact that a crown stay is safer to construct using TIG (silver solder could let go when heating the stays in the firebox, and has happened once to me. A mission to fix!).

BTW those prices are ridiculous! You can buy a decent second hand vehicle for that (in my neck of the woods)…

It takes great skill for the cameraman to be in the shot and participate ...

Yep we have a fantastic club, and the guys have been great with making these videos for our Facebook page.

A short video of one of the young engineers at the RSME assembling a steam oiler clack valve he made himself for the club loco. This was some of the maintenance done during December 2022. The beginning gambit is indicative of the times we living in, and will probably be more appreciated by the locals!

Hi Nigel, the standard Gooch valve gear is a constant lead valve gear. The animation and video is also for a standard Gooch valve gear I designed and built. The orientation of the expansion link is, as you rightly pointed out, reversed but this doesn't change the valve gear motion. It’s just the eccentric offset relative to the driving crank that changes.

I’ve designed and built a few different Stephenson’s valve gears and the most notable difference to the Gooch valve gear is the expansion link that is lifted instead of the valve rod. Some nice examples are the inside cylinder and frame classical Stephenson valve gear…

The outside cylinder with rocker (changes the set point to get the lead correct when back notching)…

And the most difficult Stephenson’s valve gear I’ve had to design so far (more fun than I’ve had designing anything else!)…

Edited By Luker on 28/12/2022 13:33:10

This does sound like the Gooch valve gear, or a variation of it. Regardless the first principles will be the same. The expansion link radius matches the length to the CL of the eccentric rods for constant lead. If you want to increase lead when back notching this radius needs to change, but then you could just as well modify the setup to be the Stephenson’s valve gear. Because you need to split the expansion link the material thickness needs to be thicker than true scale to prevent pin wear and slack on the valve gear. The mid-gear position isn’t on the CL relative to the driving axel, so I suggest cutting the reversing lever stand slots right at the end. The CL needs to be designed slightly lower to improve balanced valve opening.

Unfortunately, you’ll probably only find passing mentions of these types of valve gears due to die slip issues that was difficult to design out on paper. But with more modern techniques you can actually design a very satisfactory valve gear. Some of my simulations…

And a video after the flooding we had a little over a week ago. The guys have done an amazing job at the RSME!