| Casting your own parts |
Today, there are excellent sources for ready made castings of track plates. However, there may be some of you who would like to make your own links. So here is a basic instruction on how to make them. If you have questions on Tiger tank you can contact me on Tiger tank H E 181 Making Casting Mould in hard silicone (RTV) Fig.1 Make a thin wooden box, size depending on scale. Allow 1/2" clearance all round for RTV. Cut out a flat slab of plasticine ( hard, or use clay). Push it into the frame evenly. Allow 1/8th " at bottom to clear tracking lugs. Now push evenly and slowly your master model until it is at the parting level Fig2.With fine strip, level all gaps between clay and the model. Be very neat here. It does not matter if the rest of clay is not even. Fig.2 With a fine brush apply thin film of petroleum-gel without leaving brush marks. RTV will pick up every detail. Fig.3 Gently split the box ( you will need it in a while) and slowly and very gently remove all the context. Remove the clay / plasticine from the silicone rubber. DO NOT separate mould from the MASTER . With spirit, clean the remains of clay from top surface of silicone mould. Fig.4 Re-assemble the box around the RTV piece. This time lay the work with master exposed. Again, lightly apply parting gel, and mix fresh batch of RTV and carefully pour the stuff in, lightly gyrating the box and tapping. When satisfied, place on flat surface and leave it till next day. Fig.5 Finished mould. ready to make 1st casting. |
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| Fig.1 | Fig.2 | Fig.3 | Fig.4 | Fig.5 |
Never be afraid to make a mistake. A mistake can be rectified, and you will not make the same mistake again. A Greek philosopher said " I am not ashamed to make a mistake, but I am ashamed to repeat the same mistake ". Once I have decided on a model, I go straight into the project and push aside all "technical" procedures, keeping to plain and simple designs. The simpler the design, the better the thing will work. This "go for it", can be done after I have satisfied myself with all research, BEFORE starting a project. Nothing can be more frustrating, than to find oneself in a situation that makes it impossible to proceed further, because some important detail is missing or is not available. The frustration can be depressing, and can discourage some from getting on with the project. Avoid the "know all" sites, (except for very few) that use German terminology, without understanding what the word means. This points to the fact that the information passed on is copied from another site parrot fashion. If you need to know a phrase or word, then get a good technical Anglo- German dictionary, or contact a good German site and ask. I have seen sites that are smothered with German phrases, even whole sentences, presumably to impress visitors. If a web site wishes to impress in German, then at least offer a translation in English. The fact remains, that site owner does not understand one single word and is unable to translate. Avoid expensive and unnecessary electronics and mechanisms. If you build 1/35 or 1/24 model, then there is a vast number of sources from where you will get material. Many people throw away kid’s toys, containing gearboxes. Also, cheap radio control cars etc. This material can be used if you want simple movements Using Perspex or acrylic sheet, makes it easy to use Methylene Chloride, because it welds parts instantly. But be very careful, because the chemical not only welds instantly, it also softens plastic parts, if not handled properly. This applies only to PLASTIC KITS. |
BEFORE USING METHYLENE CHLORIDE, PRACTICE ON SCRAP PIECES, BOTH VERY THIN AND THICK. NEVER START YOUR KIT WITHOUT TESTING THIS CHEMICAL FIRST. |
Advantage with
Perspex/Acrylic sheet is, that it can be easily turned on a lathe, easily sanded
and shaped. Acrylic sheet and rod, is a must, because it saves a lot of time,
and gives an excellent finish requiring very little sanding. Both
materials can be preheated (WITH CARE) and bent to desired shape. Take a large turret – One piece wall is made from one
Perspex piece, heated and formed round a wooden former, whose size is MINUS the thickness of the
Perspex/Acrylic plate.
A good variation in material is a quality plywood,
which I cover with 1/16th plastic sheet. It is now possible to
apply parts by using liquid glue.
Another thing
that puts people off ,is the construction of tracks. It is quite understandable,
but with a little patience and thought, one can make a master model of a track
link and then make a mould in hard silicone rubber or similar material. If
you are building a large-scale tank, then it is "easy". Should you make a
static model, with turret and gun animation plus sound effects, then you
can cast all road-wheels, drive sprockets and idler wheels including track
links, in liquid urethane casting material. This two part, room temperature
curing system quickly sets to a rigid (Shore factor D73) solid. It can be
tooled, turned, drilled and ground. It can also be pigmented (prior to casting).
It is made by Synair and costs about $ 40.00 for 2 litres. That is a lot of
casting. Mould can be made from the same company product and Por A Mold will
cost about $ 40.00 for 2 litres. This will make a lot of moulds. The compound
when set at room temperature sets rigid hard. A medium elasticity compound will
cost about $ 48.00 for two litres.
There are many small establishments that deal in copier and printer repairs. Most of them throw away used pars, like geared motors, gears, drive belts and cog wheels. It is cheaper to replace the offending part with new one. The rest is thrown away. Most of such places are more than willing to get rid of the "junk", and will accept a small payment. This can be anything from $ 5.00 - $ 50.00. You now have electromagnetic clutches, geared motors that require very little
current, run on 12V – 24V
DC and are continuous rated, . They will also operate
on lower voltage giving more than enough power to shift a tank. You also
collect some roller chains and sprockets not to mention cog gears and belts of
different sizes.
However, I am "building" a tank from scratch and I want to have some results now. This way, I can put either as much detail, or as little to get the desired effect. "That is the secret". If you will never see some part, then don't bother wasting very good time which can be utilized on visible parts. If it is just to satisfy your "ego", than that’s
fine, but think how your wasted time could be put to better use, such as detailing something that is very visible to
people.
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