Mold Making / Slush Casting - Whre do I start?

[Vandark]

Hi there,

I'm wanting to have a go at molding a mask sculpture and turning it into a wearable mask, but I have virtually no experience in doing this.

As far as I can tell, I need to make a rubber mold, backed by some sort of resin to hold it's shape, then do a `slush cast` in a type of resin?

I've seen a few tutorials on Youtube, but I have no idea what brand or type of rubbers and resins I should be trying.

I'm from the UK, so I need leads UK brands and suppliers. Any tutorials??

Any help would be GREAT!

thanks

 

[Trooper Of Doom]

Well, what we did first once the master was ready.

Placed a ¼ or so thick coat of clay (porcelain) real fine clay. Covering the entire master and place the master on a stand or base. I can’t find the pictures, but once I do I will post them here for you.

then we cut out a silhouette of the master on a sheet of sheet metal the thinnest possible, and place it in the middle of the master (divide it in ½) will find pictures for this as well and post latter.

Took it to a fiberglass shop and had them place the fiberglass jacket on it for me.


Once I got it at home, separated the two half’s removed the master and took of the clay and cleaned it out for the next step.


Brushed on a few coats of silicone (to make sure you get all the detail of your master)

And once you have it with a decent coat of silicone, place it back in the fiberglass jacket. ( I will find the pictures ) once you sandwich the master into the jacket, if done correctly, it should be held by the base and the master should be sort of floating in the jacket. (the space is the thickness of the clay you used. DON’T go too thick as the first time we made it about ½ inch thick and it was hard to remove. :angry

On the top of the jacket, we place a 2 inch pipe to leave an opening and in the opening we poured sloooowwwly the silicone until it filled up.

Next we opened the jacket and out came the master and mold.

Now we cut a ZIG ZAG on the back part of the mold to peal off the copy this way we did not have a seam al the way around the middle of the copy.

Here are some pictures hope this helps.

I'll PM you some pictures

 

[Cpl Potter]

www.smoothon.com has been a great place to get molding materials ( for me anyway )

 

[Vandark]

thanks for these replies.........all help is appreciated.

Hopefully i'll be able to get some final photos of my finished masks up in the new year.

 

[clonesix]

Here is a picture that may add to Trooper of Doom's description:

I will add a little comentary for clarity:

In the first picture, that is a piece of masonite with the silhouette cut into it. This serves as the dividing wall. The uprights were all cut the same size to be supports to the dividing wall and were hot-glueed in place.

#2 & 3 are reverse order. First cover your model with a layer of saran wrap to protect it from the clay. Then add a (1/4" - 1/2") layer of clay to act as a place-holder for the silicone.

#4 add keys for relocating mod section into right orientation, and apply several coats of lacquer to seal. NOTE: if you are making a fiberglass jacket, remember that fiberglass and water (from the clay) DONT mix, and it needs to be sealed very well. Several coats of lacquer, and then several coats of PVA ought to be fine.

#5 shows a jacket cection put back into place after the clay was removed. You can see the 1/2" space that remains between the model and the jacket; That space with be filled with the silicone RTV when the other half of the tope is added.

 

[zorg]

since your in the uk this might help.

alec tiranti for fast cast resin biresin g28

cfs fiberglass supplies for gel coats fiberglass matting cheap brushes general purpose resins and silicone under craft making section. get the medium.

thats who i use and where i go.

examples of what i make with these products are in my sig pic.

cheers

zorg

 

[Weps]

Hey C6, does that last pic show the rtv mold in the fiberglass jacket? How do you actually make the copy once you have the mold, rotocast it?

ToD I'd appreciate it if you could pm me those pics too.

I want to make a simple helmet of some sort to learn all these techniques for other projects but info's been kinda scarce, so pardon all the questions!

-Weps

 

[clonesix]

There are several ways to get a helmet out of a mold, depending on meaterial, time, and effort.

The quickest way to get a hollow helmet is the rotation method. The way this is done is to pour resin into the mold and keep the mold rotating while the (urethane) resin cures. This can be done by hand or by machine. Doing it by hand take some muscle power, as the mold + resin can weigh 30 - 40 lbs. And you must keep it rotating until the resin sets, up to 10 minutes. As the resin sets, it become thicker and coats the walls of the mold. If you rotate it right, and distribute the resin evenly, you will have a uniform shell come out of the mold after it cures a few hours.

This works pretty well for a helmet of average strength. Meaning that the helmet may survive being dropped once or twice, but may shatter if droped onto concrete.

For a stronger helmet, leave the mold in separate pieces and laminate fiberglass into each piece. Let cure and bolt the mold together, then add fiberglass tape and (polyester/epoxy) resin to the seams and let cure. Then pull a fiberglass helmet out of the mold.

It is more work, but the resuling helmet will be stronger and able to endure more punishment.


I want to add here that "RESIN" is a generic term for 2-component polymers. And there are more than one type of resin. Today, it is common to refer to polyurethane resin as "resin."

Polyester resin is what is the comon fiberglassing resin. It is very smelly, even after cured, and may not be something you want to encase your head in.

You can also use Epoxy resin for fiberglassing. It has a lower odor, and is stronger than polyester, but is thicker and more difficult to laminate. It might take some practice.

I use the rotational method with polyurethane resin for all my helmets and it has worked fine, but it is taking its toll on my back. I will be building a rotation casting machine to do future projects.

 

[Vandark]

The thing that's confusing me most, is what materials are compatible, what release agents work together etc.

I've heard that certain resins can destroy a silicone mould given time?

 

[Weps]

Thanks C6. Are you using clay for a master mold?

 

[Goldenrod]

Just let you guys know you have 2 of the best guys on the RPF here giving you advise. And when i say best thats exactly what it means. Great as a person,knowledge and fabricators.
My hats off to C6 and Zorg for their continued generosity to both new and old members.
-Goldenrod

 

[Weps]

And I do count myself very lucky to be profiting from such advice! For two years I've been witness to the great things C6 does from being on CT.N, and I look forward to seeing a lot more of his excellent work in the future!

Many, many thanks to you both for your help!.
-Weps

 

[Fettster02]

i used to use tiranti's however i now use mouldlife.

www.mouldlife.com

they are cheaper than tiranti's and will give you all the advice you need.

their tinsil7025 is the best silicone i have ever used and they have a range of polyurethanes to suit most purposes

 

[Vandark]

This is all excellent information, just what I needed.

Thanks to those who take the tame to reply to my message.

Everyone was a beginner once, I hope one day I can do some great things too!

 

[zorg]

Just let you guys know you have 2 of the best guys on the RPF here giving you advise. And when i say best thats exactly what it means. Great as a person,knowledge and fabricators.
My hats off to C6 and Zorg for their continued generosity to both new and old members.
-Goldenrod

thanks micheal :thumbsup

one of the best guys on the rpf? i dont know about that :lol

z

 

[zorg]

The thing that's confusing me most, is what materials are compatible, what release agents work together etc.

I've heard that certain resins can destroy a silicone mould given time?

if your using silicone molds you wont need a release agent.
resin will destroy the silicone over time anyway, they dont last forever. the heat of the curing resin doesnt help either.

on avarage i would say i get 20 pulls from a helmet sized mold. if you use a spray barrier like tb enhancer from thomson bros. it can extend the life of the molds to 30 or more pulls which more than pay for the cost of the stuff.

the resin from tiranti i menioned works fine with silicone molds. it sets in a few mins so you can just rotate the resin by hand till it sets. you can then use gel coat or fiberglass backing to reinforce the casting.

thats what works for me. i have tried other products but i keep going back to the ones i mentioned. they are probably the most expensive but you get what you pay for, a bit like the stuff i make. if you want crappy castings made with crappy resin then go and see goldenarmor:lol

z