making a mould... help ?

[shoebox-airbrushing]

hi... im looking at making a mould for a gt shell for the carisma, (as all the shell makers i have emailed said no)... so im giving it a go myself... i will probably modify one of the existing carisma bodyshells... probably the bmw http://www.cmldistribution.co.uk/cml_product.php?range=RACING&productId=0000004922

what would i have to do to this to make it into a mold... rosco said i would have to block the wheel arches off...

what filler should i use.... how thick will it have to be...

[hammerhead]

plaster of paris mayby then tap all the air out but to be honest its gona be a lot more work thatn its worth id just buy a new shell :)

[shoebox-airbrushing]

yeaaa... but all the carisma gt shells come pre painted :(

[hammerhead]

there must be somewhere that stocks em clear or any one racing them would be the same as the guy next to them lol
have you tried hpi site?

[hammerhead]

pm this guy he might be able to get ya one http://cgi.ebay.co.uk/Remote-Control-Carisma-GT14-MK2-1-14-Shaft-Drive-4WD-/120656370724

[shoebox-airbrushing]

for a carisma ?... its for the gt14... 1/14 scale... wonder if the blaze tc shell would fit

theres only the mazda 6 shell that comes clear for the gt14... all the PROPER gt shells (bmw... porche... merc) come pre painted... so its like a one make series

[terry.sc]

Rather than worry about making moulds the first thing to do would be to get hold of a shell and try giving it a rub with nitro fuel. You might find with an hours work you've got a clear body.

If you want to copy the BMW, you can use either a decent casting plaster or a casting resin, polyurethane resins tend to be easier to work with. Block up all holes and build up a support frame to stop the body flexing when you fill it full of liquid.
Spray with a mould release wax or silicone to guarantee you can get the mould out of the body, don't bother and it will give you finer details but you could end up getting the body off the pattern by cutting it into pieces although there's a good chance you could end up cutting it off anyway.
You now have your rough pattern, so you now have to clean it up and modify it if you want. You can vacform bodies off this, but expect the finish to not be that good and for them to be slightly smaller than the originals due to shrinkage in the plaster or resin used, and due to shrinkage from the body when it cools after vacforming.
Don't forget to drill 1mm diameter holes in all the corners where air could get trapped when the plastic is pulled over the pattern.

To get a good smooth finish to the body you need to have a fine gloss finish to the pattern, and then you need to recast it in aluminium filled resin if you want any sort of production run from your new bodies.