Making a mould is not so difficult as you may expect. In fact it is quite simple!

On this page we will explain

the facts and tricks about moulding and casting.

We are going to make a mould of the often missing grill for the large Route master.

This is what you need:

A libra, a rolling pin, a spirit level, clay,two component liquid silicon rubber, silicon spray, a microwave and patience!

We use chamotte clay, you can provide in almost every

art hobby shop.

Gently roll the clay out to ± 15x15 cm (6x6 inch). The thickness ± 2 cm (1 inch). It is important that the clay has an exact level. Put the grill on the clay and take a spare of 2cm(1 inch) on all sides, than cut out .

Typical for Holland, make a "dyke" around the bottom to get a little tray. Take a spare of 2cm between the top of the grill and the height of this "dyke" .

At this moment we encounter the most difficult act of moulding. To fill the mould we use a two component liquid rubber. The ratio between the two components is 100% rubber and 5% harden. Because our mould is very small, we use a libra to weight the exact ratio.

If you don't use the right ratio your mould will become a mess! We take 60cc rubber and 3cc(!!) harden.

Don't use too much silicon rubber, it is a quite expensive stuff. The minimum amount of rubber we can buy in Holland is 1 kg for which we payed £30.

Take a look at the photo , this happens if you

use a wrong ratio. (as we did!) A real mess!

For the mould we used silicon rubber from a German factory called Wacker. Click here:

www.wacker.com/cms/en/home/index.jsp

Mix both components together and mingle hearty .

To prevent that the rubber fits on the grill and the clay we spray a bit silicon on these parts.

Push the grill in the clay tray. Because the grill is very detailed, we first rub some rubber with a brush on the grill.

Pour the tray very slowly with the mixed rubber.

At this stage we have the most easy part of the moulding process. We wait for at least 8 hours to let the mould harden.

We are waiting for 8 hours till the mould is harden!

In the meantime we go shopping. To cast the mould we use poly-urethane. This is a clean, fast and easy product to pour a perfect grill. We use Por A Kast liquid urethane casting system Mark 3. 

It's made by Hyperlast North America.

It is available in Holland so why not in your country.

This is their web site, click on it :

www.bare-metal.com/index.html

Por A Kast is a two components system with an easy ratio of 1-1. (For one set we payed £28)

After peeling off the clay the mould turns up as an exact

copy of the original.

Now we are ready to cast the first reproduction.

Put the mould for at least 6 minutes in the microwave. The reason is that the poly-urethane flows easier in a hot mould.

While the mould is in the microwave we put two equal amounts of the Por A Kast in two different

cups. The colour of the cast is ivory.

To get the right colour we mix half a teaspoon aluminum powder into the cup with the Prepolymer B (red can). Keep a third cup standby to put the two components together.

Take the mould with a cloth out of the microwave.

Level the mould on a surface. Spray a bit silicon and spread it out with a cloth or brush.

Mix cup A with cup B, mingle heartily.

At this moment you have just 2 minutes to pour!

Gently fill from one point the mould. Not too fast otherwise you get air bubbles in the new grill.

(Through a chemical reaction the mould gets pretty hot)

After 45 minutes you can release the grill.

In stead to an original grill, you can not bend a  reproduction. This might be difficult ,because a lot of Tri-ang's have a rounded shape front. We solved this problem this way: After 15 minutes the poly urethane is harden enough that it would not float away if you remove the mould. Take two tie-rips and fasten the mould on the front of the Tri-ang. Wait another 30 minutes and you have a perfect rounded shape grill!

A reproduction of the Junior Diesel series grill

Another problem you might encounter are the so called lips on a grill. With a couple of split pins we solved this problem. Poly urethane has the property to stick on any surface so just place these pins on the right position and your reproduction is equal to the original.

You can spray or brush poly urethane very well. Before starting you have to de fat the grill. The silicon spray we used by casting the mould should be removed, otherwise the paint will not fit. Absolute the best stuff to do this is brake cleaner, one uses to clean the brakes from a car or motorbike.

              Do you see the difference?

A reproduction of the 300 series grill

A reproduction of the 200 series grill

The same Diesel with and without a casted grill. What would you prefer?

This is the way, Dion Farrell from Malta made

a new grill for his Tri-ang 300.

Dion, thank you for this contribution!

These two pictures (Front Grille and Rear Grille) are photos of a grille I made for  the 300 series trucks. 

It is made of tin, just like the original item. 

Can you guess how it's made?  Well, just pick a tin can of preserved peas and open it up. The lines of the can are those you can see on the grille! Then with a piece of flat iron and a  hammer, I made the outline, the central vertical line and the bumper. 

The bumper and the  grill are then soldered together. 

It's not very difficult to make but it is VERY time consuming! 

That's why I have ordered the front grilles from you because otherwise my two other trucks will remain without the front grille for quite some time! 

Another note is  this:  as you may know, the colour of the tin can is of a gold colour (as you can see from the Rear Grille picture). 

To make it look silver (just like the Front Grille
picture) just brush it with acid.

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