UV resin master to latex

[TheDragon]

Hi,

I was after some advice on how to go from a resin printed master of a mask to a hydrocal mould to then make a latex cast from; As it's a whole head it was infeasible to print the negative. What i've been told as a way to do this is to do the following process:

Resin master -> silicone mould -> wax cast -> hydrocal mould -> latex mask

But this seems very convoluted as two moulds need to be made and it will take quite a lot of material; I was wondering if there was a better way of going about this, and I would prefer not to destroy the master in the process. The model has a few undercuts in it that would make it hard to directly mould in ultracal and not get stuck.

Any advice on this would be greatly appreciated

 

[lmgill]

We have done it this way many times. But I would suggest a rubber master, this way if you have an issue with the plaster mold, you can remake the mold. We typically use a 40 durometer urethane rubber, slushed into the mold, then a soft foam fill.

Although, plaster matrix molds of the 19th and early 20th century were made of virtually any shape complex and simple. More time and skill involved though.

 

[TheDragon]

We have done it this way many times. But I would suggest a rubber master, this way if you have an issue with the plaster mold, you can remake the mold. We typically use a 40 durometer urethane rubber, slushed into the mold, then a soft foam fill.

Although, plaster matrix molds of the 19th and early 20th century were made of virtually any shape complex and simple. More time and skill involved though.

You're a legend, thanks.

 

[stopmo]

You're a legend, thanks.

If you need a cheaper way of doing it, I did something similar recently as I started a digital sculpt but wanted to refine and finish in clay and I made a quick waste mold with alginate and a plaster bandage jacket. Heated up monster clay and poured it into the alginate mold, just treating it like a lifecast.

 

[TheDragon]

If you need a cheaper way of doing it, I did something similar recently as I started a digital sculpt but wanted to refine and finish in clay and I made a quick waste mold with alginate and a plaster bandage jacket. Heated up monster clay and poured it into the alginate mold, just treating it like a lifecast.

I've never used alginate before, is there much shrinkage? If it gives similar results to silicone i'll have a look at using that to make the rubber master like imgill suggested. Cheers

 

[stopmo]

I've never used alginate before, is there much shrinkage? If it gives similar results to silicone i'll have a look at using that to make the rubber master like imgill suggested. Cheers

Alginate needs to be used immediately after the mold is complete. If you use it fast it will not shrink, this is what dentists use to take impressions of teeth so it reproduces things very accurately and picks up the smallest details like skin pores.

That said it is a water based product so it will dry if you leave it out for a while and then it will shrink as it loses moisture. Make-up artists also use it for lifecasts of actors for prosthetic appliances etc. I have no idea if you can cast urethane rubber into it. I know you can use urethane resins in it, waxes, oil based clays, stone and some silicones. If you want a mold that will last a while or want to cast rubbers into it silicone is probably a better option.

I mentioned alginate as you were thinking about making a wax cast and mentioned the waste of material in making two molds and thought it might be a cost issue. Alginate and hydrocal are cheap materials. If budget isn't a problem Imgill's suggestion is the way to go.

 

[JPH]

Hi,

I was after some advice on how to go from a resin printed master of a mask to a hydrocal mould to then make a latex cast from; As it's a whole head it was infeasible to print the negative. What i've been told as a way to do this is to do the following process:

Resin master -> silicone mould -> wax cast -> hydrocal mould -> latex mask

But this seems very convoluted as two moulds need to be made and it will take quite a lot of material; I was wondering if there was a better way of going about this, and I would prefer not to destroy the master in the process. The model has a few undercuts in it that would make it hard to directly mould in ultracal and not get stuck.

Any advice on this would be greatly appreciated

Is there a reason you don't want to just make an outer mold and then slushcast with a fast curing rubber like Task 16 or Eco-Flex?

 

[TheDragon]

Alginate needs to be used immediately after the mold is complete. If you use it fast it will not shrink, this is what dentists use to take impressions of teeth so it reproduces things very accurately and picks up the smallest details like skin pores.

That said it is a water based product so it will dry if you leave it out for a while and then it will shrink as it loses moisture. Make-up artists also use it for lifecasts of actors for prosthetic appliances etc. I have no idea if you can cast urethane rubber into it. I know you can use urethane resins in it, waxes, oil based clays, stone and some silicones. If you want a mold that will last a while or want to cast rubbers into it silicone is probably a better option.

I mentioned alginate as you were thinking about making a wax cast and mentioned the waste of material in making two molds and thought it might be a cost issue. Alginate and hydrocal are cheap materials. If budget isn't a problem Imgill's suggestion is the way to go.

I'll have to look into it further but i would like the peace of mind of having the silicone mould in case of an issue with the urethane rubber cast.

Is there a reason you don't want to just make an outer mold and then slushcast with a fast curing rubber like Task 16 or Eco-Flex?

I can't get the desired finish on the final piece in a urethane rubber or similar.