Disclaimer: Please note that you try these at your own risk!
Many model engineering societies require that a steam loco be fitted with a spark arrestor, before it may haul passengers.
I prefer to hide the spark arrestor inside the smoke box, but there is usually a shortage of space. The steam pipes and the dart that retains the smokebox door intrude into the space where a spark arrestor needs to fit.
For this reason, I make tapered spark arrestors. The spark arrestor sits on a spring-loaded tray round the blower ring, and is reasonably firm fit around the outside of the petticoat pipe.
I used to calculate the form of a tapered spark arrestor, but I have evolved a much easier method, with no calculation involved, and a sure fit at the first attempt.
Make two brass or steel discs, about 1.6 mm thick, with a central 2 BA clearance hole. Make one disc just a little larger than the outside diameter of the blower ring, and the second the same size as the outside diameter of the petticoat pipe. Fit one disc at each end of a piece of bar. Make the overall distance between discs the same as the distance from the lower support to the bottom edge of the petticoat pipe; accuracy is not critical.
Then, firmly roll the disc and bar assembly on a piece of card cut from a breakfast cereal packet, so that the two discs leave a perceptible mark. Using a pair of scissors, cut along the shorter of the two tracks accurately. Make a second cut parallel to the longer track and about a quarter of an inch larger in radius.
Using the disc and bar assembly as a former, make a dummy spark arrestor from cardboard. Try it for fit in the loco. If satisfied, transfer the pattern onto the stainless steel mesh for the spark arrestor. Leave the arc of mesh long enough to permit about a quarter of an inch of overlap. The mesh is easier to cut and roll if first raised to red heat and allowed to cool. Roll the spark arrestor round the disc and bar former. Drill 2 holes 6 BA clearance through the overlap, and secure the mesh with brass or stainless steel nuts and bolts.
Finally, with the mesh back on the former, grind off sufficient surplus at the top end, to ease fitting it over the petticoat pipe.
If the spark arrestor is correctly made, it should be simple to remove it for cleaning. I clean my spark arrestors by leaving them to soak in paraffin or white spirit for a few days. This dissolves the oil clinging to the spark arrestor so that it will release its burden of ash and charcoal. Any stubborn debris can be burnt out using a soldering torch.
C B Farnhill, 25/12/2007
This technique (with the two discs) works well to generate any sort of tapered tube, e.g. boiler barrel or chimney. Webmaster.
One thing to try is what I was advised by a vehicle restorer. Get a plastic bucket with a snap-on lid. B&Q do one for a few quid. Place the item in it and fill the bucket with Diesel till the item is submersed in it. Now put in some engine oil (any car oil will do) to between 20 and 30% of the total amount of diesel. Leave it in there for 3-4 weeks, turning the item over occasionally. Remove and clean with some wire wool or brush and it will come up a treat. This worked for me on a similarly heavily rusted and sized 4 jaw chuck for my Super 7. You'll definitely need the lid on the bucket as the mixture stinks the garage out ! Cheap and cheerful solution.
from: Iain Sutcliffe via uk.rec.models.engineering
Have you tried the electrolytic method of rust removal - it works very well for me.
The item is connected to one pole of a car battery, and immersed in a solution of ordinary 'washing soda'. The other battery pole is connected to any old lump of iron or steel also immersed in the electrolyte BUT NOT TOUCHING the item you are cleaning.
As the electrolytic action takes place hydrogen is given off on the item you are stripping, and this combines with the oxygen in the rust to form water and iron debris. There is also a physical effect of the bubbles of hydrogen forming under and within the rust layer.
The opposite effect happens at the other pole, with oxygen being given off and rust is produced so you need to get it the right way round!
But which is the correct way round - - oh dear I cannot remember. Put two same sized bits of metal in, each connected to one battery pole, and the one that produces the most bubbles is the one that gets the rust REMOVED - (H2 O) so twice as much hydrogen as oxygen (The work piece is the cathode and therefore Negative. Connect the Positive to the sacrificial Anode. GB)
Best to try and degrease as far as possible first.
I once cleaned up the (very rusty) lead screw of a Colchester Student that the previous owner had left outside dismantled. Made up a vertical tank out of 4" soil pipe and end cap, and used a length of rod as the other pole - left it in overnight and was amazed how it came out. All the orangey red rust had vanished, and where it had been very heavy there was slight pitting. Most of it was a nice clean matt finish and it looked quite respectable!
Don't forget that the hydrogen and oxygen that is given off is an exactly explosive mixture so no naked flames and leave a window open!
From Andrew Mawson Bromley, Kent 0208-402-0355 via uk.rec.models.engineering
When your files get clogged, take a piece of scrap brass and whilst holding it at an angle rub it across the file along the teeth. The edge of the brass will soon become like a saw blade and scrape the swarf out of the file teeth.
From Alan Crossfield (LeylandSME)
If there is an area which you do not want silver solder to "wet" e.g. threads in a boiler bush or holes in a blower ring, coat the area with "Tippex" correcting fluid.
From Alan Bibby (LeylandSME)
Take one part Genuine Turpentine, two parts White Spirit and three parts Olive Oil. Mix together and apply to work for trouble free tapping!
from "Model Engineers Workshop" via Mike Taylor (Leyland SME)
Take a 2 litre plastic bottle, the sort that soft drinks and mineral water come in, and cut it off with a sharp knife about where the sides become parallel. You now have an excellent funnel for filling your water tanks on your loco from a water container. It has three advantages over a commercial item: It is bottom heavy when in use due to the plastic being much thicker where the top screws on, so it is less prone to falling over, the outlet hole is bigger allowing faster pouring and it's free! I put a bit of "Blue Tack" around the neck of the one I made and this held it in place during our club efficiency run, so allowing easy refilling "on the run".
(I had to think this up when a fellow member sat on my commercial one and shattered it!)
From Geoff Baxendale. (Leyland SME)
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