Mamod and other steam engines -- Information on Mamod & other steam engines

Mamod and other steam engines
Information on Mamod & other steam engines

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Restorations

Eventually a collector of Toysteam will come across an engine that need some work. From a dissapointing ebay purchase, cheap find, or that engine that has had a hard life, you won't avoid it.

Below are some tips and a step by step restoration process for engines. I have to thank Mamodman for his help during my first ever boiler endcap removal. Without his help, I don't think it I would have done a neat job.

Disclaimer: I will not be liable for any burns, explosions, stress, or other problems caused by my information. All information is based on my experience, and while safety has been considered, I cannot guarantee the safety of a resoldered boiler. Please use all appropriate safety gear and methods when soldering or firing a repaired boiler.

Painting: Whether to repaint or not is entirely up to the engine owner. Sometimes an engine needs it. Rust has taken over, or a meths spillage has damaged the base and the only way to protect it is repaint. On the other hand repainting can lose it's originality. The decal may have to be removed, or it's hard to match pait.

If you have to repaint, it's quite and easy job. Simply strip the engine down, remove all exisiting paint, and go for it. However you will need a heatproof paint on the firebox, and for the base make sure you use a primer and enamel paint. Also, the paint will need baking in an oven. I have no troubles with base paint, and don't bake it. Others do, usually at about 100degs C for an hour. Baking the heatproof firebox paint will need a higher temperature and longer baking times. Follow the directions on the can for best results. I have only baked paint in a electric oven, never used a gas oven and would advise against doing so.

Soldering: Sometimes threaded collars on boilers break, or a steam pipe disconnects. It will need resoldering. You will need a small butane blowtorch, and some lead based solder. The thinner the solder, the better. You will also need flux. Below is what I use.

(PIC COMING SOON)

Some general tips for soldering are:

* Make sure the area to be soldered is clean. Use steel wool, or a fine wet and dry paper to clean the area. Also clean the solder with some steel wool.

* Brush on some flux to parts that are to be soldered, but do not get it elsewhere, as the solder will go wherever the flux is. Start heating the area. Dip the solder in flux, and after a while touch the solder to the area you wish to apply it too. The solder should melt, and flow.

End cap Removal: Below is a step by step guide to removing a boiler endcap, fixing the whistle or safety valve thread, then resoldering the end cap. Fixing a thread on the inside of the boiler will give a better result. It will be stronger, and look much better. I have seen some poor soldering jobs out there, on rare engines, that just ruins the look.

Tools needed: Blowtorch, flux, solder, wet cloth, hammer, block of wood, vise, wet and dry paper, small file, steel wool.

1) With the boiler completely removed make sure it is free of any solvents. Usually a broken thread comes from trying to remove a stuck safety valve or whistle. While trying to remove it, you may use WD-40 or similar. It is not a good idea to have that in or on the boiler when using a blowtorch, so clean it.

Firstly take not of the position of the overflow plug hole. Usually they are at the highest point, or just off it. You need to mount the boiler in a vice. This is one of the trickiest parts. I use bits of wet cloth to protect the boiler and a wet cloth in the chimney protects the paint. I usually resolder all the collars in a boiler while I have the end cap off. But if you don't want to, us some wet cloth to protect the solder on exisiting ok collars. I have never had them desolder, but just in case. The other thing is if the collar on your end cap is ok, you can leave the overflow plug in, minus it's washer, as this helps take heat away from the collar. Again, I resolder it anyway.

Put the boiler with the end cap you wish to remove, facing down. Clamp tightly, but not too tight. The following pic is labelled so you know what I am talking about with parts.

How to fit boiler in a vice.

2) Next step. You need to heat around the boiler end cap wall with your blowtorch. Heat evenly. Time will depend on size of torch. Generally 2 or 3mins is what it takes. If there is any water left in the boiler it will take longer. Once you see exisiting solder going silver at the end cap lip, it is ready.

When it's all hot, get the block of wood, rest it on the end cap lip, and give the wood a hit with a hammer. Sometimes it will come off straight away, other times it needs a few hits, reheating, a few hits, etc. This is because limescale in the boiler acts like a glue.

End Cap Removed (should really have put something soft for it to land on)

3) Now with the end cap off, you need to fix the broken collar. If it is a collar in the middle of a boiler I suggest you fix the one next to it, as the heat may desolder it anyway. It's also easier to solder the collar in the middle, with the one closest to you removed, so it doesn't get in the way.

Remove the existing collar. This may require tapping out, or a pair of pliers and patience if the whistle or safety valve is stuck in it. If you find a whistle or safety valve won't come out try soaking it with some vinegar, or another loosening agent. If flammable wash it after use.

With the collar removed, clean the surface of it, and the area on boiler with some wet and dry. I use a dremel with a sanding pad, or wirebrush around the hole inside the boiler. This gets all the limescale off.

Cleaned areas for soldering. Note boiler end is also cleaned

Once clean, apply flux to the inside of the boiler, and the part of the collar that will be inside the boiler. Careful not to get it on the outside of the boiler. Insert the collar, then heat from the outside. When hot enough, use the solder in semi circle motions at the boiler/collar join. e.g. looking in the end of the boiler, the side of the collar furthest away is 12 o clock, the side closest is 6 o clock. Wipe the solder from 12 o clock to 6 o clock, both sides. Dip the solder in flux occassionally too. You can use as much as you which as it will be hidden. Some may leak through to the outside of the boiler, but thats ok it can be cleaned. Once you are satisfied with the job you are done. I don't use any method to see if it leaks. You can try a bit of water around it, and check it doesn't come through, but thats not guaranteed as it isn't under pressure. Usually a good check with a torch can show any obvious missed bits

How to heat for soldering (note this collar is being heated for removal, but same thing, heat from outside)

4) Now to prepare to refit the end cap. Clean the end cap wall, and the mating surface on the boiler. I use a dremel with a sanding pad and remove most of the exisiting solder, however you might use steel wool, depending on which way you wish to go (more late). Make sure it is very clean either way.

Now which way to go? You can either leave the existing solder, apply flux to both the mating surface and end cap wall, or, "tin" the end cap. If you don't wish to tin it, then apply flux as suggested fit the end cap on, and you are ready to solder

Tinning involves putting a slight layer of solder on the end cap wall. This is how I do it. The only downside is if you get the solder a bit too bumpy, it can leak, but rarely does. I compare it like this. Glue a lid onto a jar. Tinning is like putting glue on the inside of the lid thread, and screwing on. Then add more glue later. Not tinning is like putting the lid on the jar, with only spots of glue, then adding more later.

To tin, put the end cap in a vice after it has been cleaned and flux applied. Heat the end cap wall in one area from the outside, then touch some solder on the inside of the wall. That will get you started with a small solder blob. Once that is done, hold the end cap in a pair of pliers, careful not to damage it. Apply more flux and heat the blob. As it melts, let it flow, around, turning the end cap as needed. This will leave a trail around the end cap wall. You may get a blob at the end, just dremel/sand it off, and it's done

Blob of solder ready to be reheated and run around the inside of end cap wall

Now with the end cap tinned, or not, apply flux to the mating surface of boiler, and inside the end cap, and push the end cap on, making sure the overflow plug (if it has one) is in the same position as it was, or at the highest point. Put it back in the vice as per step one. This time you will need wet cloth on collars, and put the overflow plug in, minus the gasket. Like in step one, heat around the end cap wall, and keep going for a bit once you see the solder melt and go silver at the end cap lip.

A tinned end cap.

5) Final step of soldering. This is also a tricky bit, only because you have to be neat. Once the boiler is cool from step 4, remove the boiler, clean the end cap lip area with steel wool, and then add flux with a cotton bud/earbud. You need to get a neat bead of solder, so remove any excess of the end cap side wall, and place it back in the vice, again with wet cloths.

Now heat the end cap wall. Once the exisitng solder melts, run some new solder slowly around the lip. You will notice it flows, so go easy. Do this all the way around. You will notice any gaps in the solder, so make sure you fill them in. Once done, that's it. Now it's only cleaning

End cap soldered on, and now ready for final bead of solder around the lip.

End cap soldered back on

6) The cleaning process. This is my least favourite bit. To get the excess solder off the bead at the end cap, I put some masking tape around the boiler, so the solder is exposed between the edge of the tape and the end cap. This is as a guide for the file. Using a thin (width wise) file, carefully file existing solder, taking care to hold the file level. Once it chews into the masking tape, it's time to stop and finish off with Wet and Dry (GRADES COMING SOON)