Making a flexible/re-useable mould.....

[Army of One]

......hello all....many years ago when I worked at British Aerospace in Kingston,with the help of a mate,I made a small mould for some figs.....out of rubber sealant....meant for the GR5's.....used a form of resin poured in having sprayed the interior with a release agent. I made a small box,poured the flexible sealant in and pressed in the item,having sprayed it first then poured in the resin after it had dried. Using this method I was able to make some small bits....if in halves I would just sand down to the app line and glue together....worked for what I wanted then. All the stuff I needed was aready available.......I would like to try it again........I have a large hobby craft just around the corner....can anyone suggest what stuff I will need to make the re-useable mould and also what type of resin to use for the moulded part. I have had a look and the choice is very varied.....and confusing.....I have searched the site and found a squash press method which is not suitable for me.....basically I am trying to mould underwing stores...LGB's,designator pods,missile bodies.........any help would be greatly appreciated........H

[lancer]

Army,

Try these people - www.sylmasta.com
They do all the stuff needed for casting - rubber, resin the lot. They also do complete casting kits as well as a shed load of other modelling accessories. I can attest from personal experience their stuff is very good. Hope this helps.

[Army of One]

I thank you......

[Aircav]

There's Alec Tiranti Ltd as well at 27 Warren Street, London or in Thatcham, Berkshire.

http://www.tiranti.co.uk/

[lancer]

Holy crap!!! Thats only 20 minutes down the road from me!!!!

[Army of One]

Thanks for the suggestions.......but does anyone have any advice as to what type of rubber/resin to use.....do certain products have an adverse reaction with other products.....will the rubber/mould compound affect the plastic of the part being moulded.....will the resin/solution used to pour into the mould react with the mould materiel??/ Basically any rules on what to use with what....?......H

[thedarkmaster]

to answer your question, I used to be a mould maker for Games Workshop some moons ago, ( I would delete the warhammer referance if i were you, they will prosecute if they find out!!! believe me I've seen it ) and generally you shouldn't need to worry if your using rubber and resin compounds, the heat generated is not great and thats the biggest problem.

Always follow the instructions for the particular product carefully especially mixing compounds as this is were you can make the biggest mistakes. However do not use any of the PTFE based lubricant sprays as they cause untold problems down the line with mould break up, though this is more a heat and white metal problem than cold casting.

When you do mould do check for undercuts and possible items that will tear the finished mould, you will need to learn the art if slashing the mould to aid release, and how to cut into the moulds serface the pouring lines and the channels anf drill holes to aid escape of air.

Two part casting is very similar to what you have already done but you need to put into the surface locating lugs
which will help when you pour the second half ontop of the first when it's cured, always remember to put something onto the cured mould when you do, graphite powder or talcum powder are industry favourites, which will stop them sticking together an bob's youe uncle.

The internet if full of instructions on how to do this but if you cannot find one pm me and i will take you through it step by step

tim

[Army of One]

Tim,many thanks for advice/help......to be honest you might get a pm next few days.....

[Rafael]

I did, but not finished, this: http://www.whatifmodelers.com/index.php/topic,18745.0.html

Hope it helps

Rafa

[Army of One]

Rafa.....that is the sort of thing I had in mind......many thanks........hope you finish it and it works out for you.