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I was wondering what you would use for the hirst arts molds, and have a few basic questions really: (preferably answered by people from the UK, makes things easier)

1. What should I use for casting?
2. What brand?
3. What hw many casts roughly can I get from each mould before they deteriorate?

Thanks! my beloved Dakkanauts!

Go on the hirst arts site
He recommend either a dental plaster or something similar you can get at a model train shop.
They use high grade plaster for scenery.
Also if you clean them thoughly as per directions the mold should last a real long time.

Eisenhorn wrote:Go on the hirst arts site
He recommend either a dental plaster or something similar you can get at a model train shop.
They use high grade plaster for scenery.
Also if you clean them thoughly as per directions the mold should last a real long time.

I would just like to add +1

www.tomps.com carry several of the recommended plaster types.

Sevenups wrote:

Eisenhorn wrote:Go on the hirst arts site
He recommend either a dental plaster or something similar you can get at a model train shop.
They use high grade plaster for scenery.
Also if you clean them thoughly as per directions the mold should last a real long time.

I would just like to add +1

I read that, I was more asking for some tips on people who had used the molds.

i use plaster of paris from a art store
and mines in perfect condition in, over 100 casts


Automatically Appended Next Post:
i use plaster of paris from a art store
and mines in perfect condition in, over 100 casts

Dental plaster is what you should be using. Plaster of paris deteriorates way too fast IMO.

If you are using plaster the molds will last for thousands of casts. If you are using resin, they will deteriorate rather quickly.

For the molds I used resin for, I made duplicate molds so that the original didn't get torn up from the resin.

My roomate use to run a small side business in the US making the blocks from the hirst arts molds, we were room mates for a year and he made thousands of castings in our basement, I even helped him several times.

I NEVER saw a mold go bad. They really last and are excellent.

He used a product called homosote, here in the us, and a 2 part resin to make nicer plastic blocks called alumalite, which was a 2 part resin. Neither caused the molds to deteriorate. (These are US products sorry, no idea if in UK).

I still have a few terrain pieces I made form the blocks!

The trick with the plaster is to lay the glass on the backs, it makes the open face bricks exactly perfect every time! We had probably 50 4x6 inch glass mold backers we use to use for that. Awesome.

Also whatever you buy be sure and get something that can be de-molded in less than 60 seconds, because ALL the hirst art molds need MANY repetitions of casting to make anything, I think even the small tower was like 16 or 32 castings to make a single tower. That's how they are built!

Good luck, that stuff is meticulous but awesome! If you post any qustions I'll do my best to answer them!

Thanks a lot guys! So plaster would be the best?

I was thinking this stuff:

http://www.hirst-arts.co.uk/products/00102-kilos-of-crystacal-r.html

which seems pretty god value. Do I need to use mould release?

winnertakesall wrote:Thanks a lot guys! So plaster would be the best?

I was thinking this stuff:

http://www.hirst-arts.co.uk/products/00102-kilos-of-crystacal-r.html

which seems pretty god value. Do I need to use mould release?

Yea thats good stuff.

Mold release, short answer, no.

SLightly longer, maybe... it will provide longer use of your molds and is really pretty easy to mix in a spray bottle, ours (for plaster) was water based. We dind't always though, remember, your making molds of cubes and such basically, not a lot of wear popping them compared to say minis or more complex peices.

GL

You don't need a mold release with plaster, you should use it with resin. It will help protect the silicone rubber from being eaten up by the resin so fast.

Plaster on the other hand is mixed with water, and thus has no effect on the mold.

Thanks for the help! I have the mould ordered and will be getting the plaster shortly. Will let you know of the results!