13 replies to this topic

[The Creative Explorer]

Ok, this will be my most challenging project to me so far.

What do I want to do? Simple, I want to make a model of my car.
So why don't you do it? Again simple, there is none.
Then you got a problem; Yes I know and here I need your help.

The only solution lays in converting a die-cast model.

Let's start with some pictures;

This is the car I want to make, it is the Renault 5 Gtturbo phase 2.


The diecast modelcar is a Renault 5 TSE, that looks like this:


See the differences?

The actual modelcar looks like this:


The shape is actual pretty close, but a lot of details that are different.

What needs to be different is the following:
-Bumpers around
-Skirts
-Spolier
-fenders
-getting rid of the plastic guards on the sides of the car
-different grille
-different wheels.

The best way is probably to make those parts myself, to keep the costs low.

I hope the resin-casters in here can help me out.

First thing I need to do is make a resin model of this die-cast. This will simplyfied and be easier to modify then the iron.
The guards for example are molded-in, so the need to be sanded all out, which is undoable in iron, but makes it a lot easier when it is resin.

Please some advice how I can make a mold for the model to start with.

[CAL]

Ok, this will be my most challenging project to me so far.

What do I want to do? Simple, I want to make a model of my car.
So why don't you do it? Again simple, there is none.
Then you got a problem; Yes I know and here I need your help.

The only solution lays in converting a die-cast model.

Let's start with some pictures;

This is the car I want to make, it is the Renault 5 Gtturbo phase 2.


The diecast modelcar is a Renault 5 TSE, that looks like this:


See the differences?

The actual modelcar looks like this:


The shape is actual pretty close, but a lot of details that are different.

What needs to be different is the following:
-Bumpers around
-Skirts
-Spolier
-fenders
-getting rid of the plastic guards on the sides of the car
-different grille
-different wheels.

The best way is probably to make those parts myself, to keep the costs low.

I hope the resin-casters in here can help me out.

First thing I need to do is make a resin model of this die-cast. This will simplyfied and be easier to modify then the iron.
The guards for example are molded-in, so the need to be sanded all out, which is undoable in iron, but makes it a lot easier when it is resin.

Please some advice how I can make a mold for the model to start with.

Personally I would take the thing apart and just make the parts you need. Regardless if you do just the parts or the whole thing you need to take it apart.

You could grind fill and sand and smooth out the metal casting just the same as with resin. You just need to be more aggressive with it.

There is a bunch of different ways you can go about make your masters and casting your parts.

Have you done any resin cast before?

Things like the fender flairs and skirts you probably just want to make out of Miliputt.

The hardest thing is going to be wheels.

Funny it's almost the same thing I am doing now. Only with a different vehicle.

[The Creative Explorer]

The car is already parted out.

But to begin modifying, I need to have a Resin copy, I already gave it a try in sanding the iron, but is undo-able.

I never had ay experience with molding and casting, so I need all the help there is to get.

I was thinking the same with the fenders and such. The wheels shouldn't be that hard. They're simple in shape.

[CAL]

The car is already parted out.

But to begin modifying, I need to have a Resin copy, I already gave it a try in sanding the iron, but is undo-able.

I never had ay experience with molding and casting, so I need all the help there is to get.

I was thinking the same with the fenders and such. The wheels shouldn't be that hard. They're simple in shape.

It is not iron but "white" or pot-metal which is pretty soft. You should be able to take a dremal or die grinder to it.

Unless you plan on getting into resin casting you may just want to find someone to cast a one of for you because to get a decent cast of a body with a two part mold you will need some equipment and supplies. The single relief molds you probably can get away with out vacuum pump and spin or pressure casting. The body is a little touchier and tricky you may throw a lot of material away before getting a usable mold and casts.

Basically this is how I do it.


Get a plastic box or build on big enough to put whatever you are going to cast in it. Leave enough room so you have a sold rubber mold when you are done. 1/4 inch on small parts more as you get into bigger parts. I use clay in the bottom of the box and start building up around the part. You want a seem where the rubber will be split in two halves. So at this point you will be building up the clay so half is in clay and half is exposed. I almost forgot, you need a round something to put down first it will go between the part and the bottom of the box. This will eventually be the spout where you pour your resin. Ever part is different so you have to plan ahead. Plan your parting lines and you want to be able to remove the clay later without removing the rubber. This will eventually be the bottom of your mold. Once you have the part in clay I make an index or key in the clay so the mold goes back together exactly the way it should. Use a dowel or something to make 1/2-inch deep keys in the clay on the flat surface between the part and the box wall. Then you will mix you rubber vacuum it pour it and vacuum it again after it's poured into your box. You will need to pull about 29 inches of mercury from your vacuum pump. No a cleaning vacuum isn't going to work. That only pulls about 2. You should be able to find one for $100 $200.

I usually let it sit a few days before pulling it out. Now you want to pull it out and clean off all the clay trying to be careful not to pull the part out of the rubber. Once all the clay is removed and it's clean flip it over and put the mold with the part back into the box. Now the top is the bottom. At some point you will, especially if you are spin casting want to cut some relief in the rubber - outwards so you don't trap air in the mold when casting, I use a gouge and make a few clean cuts from the part to the outside of the mold. You can use dowels or sprus to do this too. Just lay them in when you are claying your parts, spray a little release agent and mix and pour another batch of rubber the same as before. Wait a couple days and remove the rubber separate it and remove the part. Now you have your mold. Inspect it for defects and bubbles and such. You can do some small repairs to a rubber mold but anything significant wrong you toss it away and try again.

Now it's just a matter of casting some parts, which is the easy part. Use release agent. let it dry. Assemble you mold back in the box and your ready to pour your resin. Now depending on if you are spin casting or pressure casting. If you are spin casting you set your mold up on the table spin it up and pour your resin, and you will have a part in 30 mins or so. If you are pressure casting you pour your resin and put it in the pressure pot and pressurize it 90-100 PSI, again you have a part in 30 mins or so.

That is basically how to do it. I am sure others do things a little differently, perhaps better or something I haven't tried. Experience goes a long way. Trying different things. It's a learning curve like anything else. There is a book worth of the million little intricacies and is somewhat of an art in itself. Different rubber react different, resins respond different, temp is critical, moisture is the enemy, how you start your mold, your master, and how it builds and on and on and on.

HTH

[The Creative Explorer]

Thanks Chris,

I knew it isn't Iron, but didn't know the exact name, I do know it is probably not whitemetal.

I am not planning on doing a lot with Resin, but who knows if I can get this project to a good result.
If I get a realistic GTTurbo, I do plan to make several, so I can make a couple different variations.

I'm not really looking forward tough to buy a 100+ dollar pump, which I might never use again.
But trial and error seems to be unavoidable.
It's going to be very tricky. And I am thinking of making a 2 part mold for the body. I think it is doable.

[CAL]

Thanks Chris,

I knew it isn't Iron, but didn't know the exact name, I do know it is probably not whitemetal.

I am not planning on doing a lot with Resin, but who knows if I can get this project to a good result.
If I get a realistic GTTurbo, I do plan to make several, so I can make a couple different variations.

I'm not really looking forward tough to buy a 100+ dollar pump, which I might never use again.
But trial and error seems to be unavoidable.
It's going to be very tricky. And I am thinking of making a 2 part mold for the body. I think it is doable.

you welcome if have any questions feel free to ask.


100+ pump is just a part of it. You will still need a vacuum chamber or bell, a compressor if a pressure pot, or a spinning table, rubber, resin, clay and some basic tools for resin casting and master making. You are probably looking at closer to a $500 investment to get started.

You can always try doing it without a vacuum and pressure or spinning table, some people have moderate luck with it. In fact, I have pretty good luck doing basic simple molds and casts without, but everytime I have tried to cheat with something large or intricate it hasn't come out that well without going through all the steps.

You can also try urethane rubber, they claim it works better without vacuuming it, but I still get lots of airbubbles if I don't.

HTH

[The Creative Explorer]

Thanks again,

A 500 dollar investment is not an option here tough. I need to find cheaper ways.

Why the rubber? aren't there other mastermold making stuff? I heard of something called plasticine or something.

[CAL]

Thanks again,

A 500 dollar investment is not an option here tough. I need to find cheaper ways.

Why the rubber? aren't there other mastermold making stuff? I heard of something called plasticine or something.

the rubber keeps it shape and picks up the detal. I have used sculpy for simple molds, but the parts are not as crips as rubber.

[Ettore]

Why not use the Tamiya kit? Ettore

[The Creative Explorer]

Simply because the kit doesn't exist.

[Claes Ericsson]

Simply because the kit doesn't exist.

I believe it does. Admittedly, it is a race version which brings some new problems but I think it would be helpful to have...

[The Creative Explorer]

Thanks for the effort guys, but that is entirely a different car.

This is a Renault 5 Turbo, it has the engine in the back and is rear-wheel driven. The car was introduced in 1981 and stopped in 1984.


The car I want is the Renault 5 GTTurbo, this is the second series Renault 5, called the Superfive.Introduced in 1986 and ran until 1991. The car is frontwheel driven and the engine in the front.
So the kit will be unfortunately no help at all.

In these two pictures you will see the differences.

The Gen1 Renault 5 ( Turbo )


The Gen2 Renault 5 (GTTurbo)


When you compare, you will notice the differences.

[Ettore]

I was not aware of the differences, which I see now. Having done a bit of resin casting and scratchbuilding, I am certain it would be less expensive and less work to convert the plastic kit. Ettore

[The Creative Explorer]

If the kit was from the right car; it would've been less work.

But, the proportions, size, shape, wheels, interiour, basically everything, is different from the Tamiya kit. So the Tamiya kit not an option at all. Unfortunately.

The best shot I have is converting the diecast. and altough I do know it isn't easy, it is not impossible either.

First I need to make a resin cast of the diecast, so modifying would be a enormous lot easier.