This is a short edited extract from MAINSTEAM MODELS "The Complete Guide to Miniature Steam" which is available on CD ROM or via Internet download.
Building your own model steam launch can be a rewarding & sometimes a frustrating experience depending on how you go about it. Most people that I speak to seem to be worried about live steam models in some way or other. If you build the steam boat & install the steam plant correctly, then the whole process of building & running model steam boats can be very enjoyable.
Here are a few initial tips for beginners:
Before you start - choose your model very carefully. It is not a good idea to get into the project completely "out of your depth". One branch of the model steamboat building seems to be the "floating doll's house" type of steam launch, usually 1/12th scale, so that doll's house figures & accessories can be used in the boat. These models if built correctly can be very beautiful things, but they can also be very difficult to build.
I don't recommend building a large complex model steam boat to start of with, a model of around 3 feet on length would seem to be a sensible choice.
Which type of hull?
You have the choice of fibreglass, ABS or plank on frame.
If you are a raw beginner to model boat building, I would not recommend plank on frame, as the build will take a lot longer & can go seriously wrong for the inexperienced. I recommend building a steam launch from a kit, obtained from a well-established manufacturer.
If you are building from a kit, before you start, please study the instructions carefully. A steam model boat is not at difficult to make, but mistakes can more easily be avoided if you have a map of the construction sequence in your head before you commence.
Assemble the boat stand first, to support the hull as you work on it.
If there is not a boat stand in the kit, then make one before you start.
Place the stand on a level surface.
It is a good idea to obtain some water pipe lagging from a DIY shop; fitted to the boat stand, this will prevent any scratching of the hull as you work on it. Cut a length of the foam into 4 equal lengths & slit along the pre marked line. Seat the foam padding over the top of the boat stand. Once the boat is finished, the stand can be painted & the foam or other suitable resilient material can be glued in place on the top of the stand.
With boat stand temporarily out of the way, place the hull upside down on the bench.
Propeller shaft & rudder holes in the hull:
At the stern end of the keel, make a mark with a felt tipped pen, for the position of the hole for the propeller shaft. The position of the hole will be marked on the plan.
Measure twice, cut once!
Make sure that the mark is in exactly the right position before drilling the hole. The propeller does not want to either foul the underside of the hull, nor does it want stick out below the level of the keel. Take your time with this & get it right 1st time.
Next, drill a small pilot hole where you placed the felt tip pen mark. Now open it out using the small drill as a cutter, to suit the diameter of the propeller shaft.
A large drill bit may grab & crack the hull material, so I find it better to open up the hole gradually with a "Dremel" type hobby drill. Approach the drilling of the rudder hole on the same way. Mark the centre of the rudder mounting area with a felt tipped pen, then drill a pilot hole first in that position.
Open this hole out to allow the rudder mounting bush sleeve to fit snugly.
Next, place the hull the right way up on the stand that you built earlier.
Lining up the main floor ribs:
It is very important indeed, to make sure that the floor in the boat is 100% level & parallel to the keel. Do a "dry run" first, to find the positions of the floor ribs in the hull, so that the floor panel will be level & correctly aligned in the middle of the hull. By careful measuring, from the keel to the top of each floor rib, which should have the rib centre line marked on it. If there is no centre line, you need to measure each rib individually & mark the centre line. You will then find the correct positions for the ribs, but if working from a kit, even though the plan tells you to fit the ribs in certain positions, always check the level of the floor ribs very carefully, as any mistakes made at this stage will be very difficult to rectify afterwards.
This next step is critical:
Place the floor ribs in order in the bottom of the boat, but do not glue them in place at this stage. It has been found from experience that glass fibre model boat hulls vary in dimensions slightly so a little adjustment here & there is necessary. Now measure the distance once again as before, from the top of both of the hull sides & make sure that the ribs all sit perfectly level & centrally in the hull. If you fix the floor ribs in the wrong position, then the finished floor will not be level relative to the rest of the hull - this would not be good! You will need a straight piece of wood now, in order to find the correct position of the ribs in the hull so that the floor will sit level in the bottom of the boat. When the correct positions are found, mark the position with your felt tip pen.
If the odd rib is a fraction lower, this does not matter too much, because strips of wood can be added on top of any low ribs in order to level the floor. When you are absolutely sure that you have got everything right, mark the position of the ribs in the hull.
Fixing the floor ribs in place:
The system that I use seems to work very well. Lightly sand (preferably with fairly coarse sandpaper) the area all around where a former is to be secured to the hull, then apply a little "Cyanoacrylate" (Superglue) to the area. Rub the Cyanoacrylate into the sanded area of the hull with an old dry cloth, but make sure that you do not stick yourself & the cloth to the hull!
Fix the ribs in place with "Cyano" adhesive. Let the "Cyano" cure & try your straight edge to verify that all the floor supports are level. Once you are satisfied that all is well, with the first former in position, run some more Cyano along the joint to make a strong bond. Before proceeding further, wait until the Cyano has set thoroughly (If you are in a rush - you can buy spray type Cyano accelerators to speed up the curing of the adhesive).
When all your main formers & supports are in place in the hull using this method, use "Milliput" Epoxy Putty rolled into thin lines between two wooden boards, of approximately 1/4 inch diameter, then apply this in the way of a fillet on each side of each former.
If you have never used "Milliput" before, it is very important to make sure that you mix two even lengths of the putty together very thoroughly or it will not set. Please read the directions on the "Milliput" box before use.
Do not be tempted to use car body filler, as a substitute for the "Milliput", as polyester based resin fillers may get hot while curing & locally distort the hull. Once mixed thoroughly, roll out 2 lengths of "Milliput" and use these as a fillet around the wedge to hull joint. "Milliput" is water- soluble until it sets, so use a drop of water to smooth it out.
Now leave the "Milliput" to set for at least 24 hours.
If you have carried out the instructions above, you should now have a steam launch hull with the floor ribs fitted, which add much strength to the structure, and are ready for supporting a level floor in the boat.
In these early stages, consider fitting an onboard water tank to supply your boiler with water. In a fibreglass or ABS type of hull, you do not need a separate tank. Just make a plywood bulkhead, fully glass one side of it using suitable fibreglass mat & preferably epoxy finishing resin, then after drilling the holes in the former to take the pipe fittings for the water outlets & bypass return (if fitted). Now just use the same method as above, to make a permanent, strong watertight seal.
Very important: after all the formers & supports are fitted in your hull & the "Milliput" has set, you must give all the wooden parts at least a couple of coats of varnish or paint, to prevent warping, or worse - rotting when they get wet. The formers are bound to come into contact with water, either by residual bilge water, (usually coming up the propeller shaft), or water & oil residue from the steam plant itself, which also finds its way into the bottom of the boat.
There are some more useful informative articles relating to model steam, on my Mainsteam website.
I hope that this short guide has been of some use to you.
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