Cracked Ultracal mold

[cunningham]

Hello,
I have just recently noticed a large crack running about 6 inches through my ultracal mold. It hasn't broken apart yet, but I am afraid it will inevitably. Does anyone know if it is salvageable? The original sculpt was of course destroyed in the process of molding, so if this mold is done for I may just go on a 4-day bender.

 

[Fizbin]

Depends on where, how deep, how wide the crack is. Pics would help a lot.

Also depends on what you plan on casting in it (I assume latex).

 

[booksandcorsets]

Pics would help a lot. Minor cracks can be fixed with superglue, but this sounds a bit more major.

 

[cunningham]

It is my Red Skull mold I am using to cast latex masks. The crack is hairline, but does go all the way through the thickness of it, but not across the width. Nothing is separated yet. I will post a pic though. I think I may have caused the crack by warming the mold up to quickly, although I probably shouldn't have warmed it up at all. I found the warm mold made the latex dry almost immediately - I was impatient and foolish.

 

[Fizbin]

Well in that case, superglue should do the trick.

 

[fabrik]

If it's hairline you should get away with it. As Fizbin said hit it with some super glue and don't be too rough when demoulding. The latex should shrink when you are moulding so it shouldn't be to rough on the mould when you release anyway.

 

[MrGzilla]

You could also mix up a thin batch of ultracal that's really watery and let that seap into the crack and cure, and it'll be like there wasn't ever a crack. Just don't let it get into the details of the mold when you do it.

 

[Radfxrob]

How old is the mold ? If the crack is running through to the outside take a rasp or a chisel or something and rough up the area about 2 -3 inches around it ... then grab some of that bondo with fiberglass chop in it... mix it up and spread a decent layer over it ... that will keep it from busting ... as far as saving your details are concerned yes you can always use superglue thats a great cure all but not permanent and you'll see it in your pull which you will have to patch later ... something I've done in the past with success especially for large areas ... (and by large I mean more than a hair line crack ... something thats actually disrupted the detail in your sculpt). You can take some WED or White Laguna and fill the area. You can actually sculpt back your details that will be missing from the break. Allow this to dry very well because the moisture will inhibit a lot of materials ...(not sure what you are using) but once its dry its like nothing happened. There will be a slight shrinkage of clay but thats easy to add to. Unfortunately this isn't permanent fix and has to be done prior to every run. So it basically just boils down to your patience with each run ... might be easier just to resculpt if its not too difficult. They can last MANY years but dont always last as long as we need them too! lol ...

Now I've never personally used the bondo resin on the INSIDE of an ultra cal mold. But it stands to reason that since lots of fiberglass molds are made with tooling resin, gel coat, etc. and resin will bond to plaster, you might be able to experiment with some fiberglass resin in the crack and see how that works ? If its something you are baking like foam latex it may change the cook time a bit but I dont know that it would inhibit anything ??? Half the fun of this is the experimentation GOOD LUCK!
Rj~

 

[cunningham]

Hey Radfxrob, I just got your post - thank you. I am going to give that a try. The superglue didn't really work all that well afterall. I have the patience as long as I don't have to resculpt.

 

[Mr Mold Maker]

I've used plumbers epoxy to fill quite a few cracks. It generally comes in a tube with part A on the outside and part B on the inside. You tear a piece off and then mix it until its uniform and smear it into the crack. You can smooth it out with some IPA and it wont affect the latex at all.

 

[FX builder]

if you fill the crack with preferably super glue, this will help great. as the plaster is porous the superglue pulls it together. alternatively you could use pva. the crack is probably as you cooled the mould too fast (or over heated it .) hope that helped!!

 

[Tea]

If your worried about the mold in the long term, you might consider melting down some monster clay and making a cast of the clay. You could then just clean it up and make a new mold without having to sculpt up a new head.

Its always a good idea to make a master - Just make your typical latex mask but pour some expanding foam into it once its set & dry and still in the mold. This way you have a nice sturdy cast in case you need to make a whole new mold.