HELP! Sealing Agents for Oil Clay

[Uratz]

OK Here's my problem the sealing agent I've been using for this type of oil clay - an Acrylic Clear coat isn't working
and its inhibiting the cure of silicone.

Any other Type of sealing agents can be used?

what about shellac or wood coating lacquers?
or Acrylic water based floor coating?

Any help would be appreciated.

 

[xdmray]

oh bummer man. you have to deal with all kinds of crappy obstacles in china mike.

i probably cant help since you have to use way different products, but

what kind of clay and silicone is it?

 

[Uratz]

oh bummer man. you have to deal with all kinds of crappy obstacles in china mike.

i probably cant help since you have to use way different products, but

what kind of clay and silicone is it?

Cue the Moby song Natural Blues...oh lordy, trouble so hard, don't nobody know my troubles but God

Yeah you know my pain, trying to create masterpieces that you guys do but minus the availability of the same products.
Anyway I did a test with A:B resin. I coated the same clay with a thin coat of resin then poured some silicone over it. Cured ok.

"Setbacks are always followed by Breakthroughs"

 

[xdmray]

well glad that worked for ya. the resin will probably come off the clay pretty easily too

 

[Uratz]

Yeah its no big deal even if I lose the clay. Its a blend of soft oil clay and the automotive hard clay.
If I want to recover it just scrape of a thin layer or keep the original sculpt if its not destroyed.

 

[Termokk]

Hey for what its worth i had to use sulpher based clay and make a mould, and normaly sulpher inhibits the setup of the silicon, but i applied like 6 layers of this "mod podge" clear acrylic sealer, and i had no problems. I know you said the acrylic spray didnt work but maybe it was a name brand that had somthing funny in it. I feel your pain i have to mail order everything where i live, there are no towns around here, but thats spray is available at any wal-mart in the craft section. (not the paint section, and not sure if china has walmarts) And im sure HEAVY layers are also important. hope that helped.

 

[Uratz]

Hey for what its worth i had to use sulpher based clay and make a mould, and normaly sulpher inhibits the setup of the silicon, but i applied like 6 layers of this "mod podge" clear acrylic sealer, and i had no problems. I know you said the acrylic spray didnt work but maybe it was a name brand that had somthing funny in it. I feel your pain i have to mail order everything where i live, there are no towns around here, but thats spray is available at any wal-mart in the craft section. (not the paint section, and not sure if china has walmarts) And im sure HEAVY layers are also important. hope that helped.

Thanks for sharing Termokk. I just bought an oil based wood sealer and I am trying it out on the clays.
I will thin it down a little as my sculpts are detailed finely and I don't want to lose the details.
So far the best method is the resin that I have which is very thin when not cured and forms a sheet of plastic film over the clay.
I am also experimenting with effective ways to use less silicone to get the best results. I find I put too much "quality over cost" methods of making molds
and its just wasting money on things no one care about buying from me, so I will go the cheapskate movie studio's route and make crap ass molds that eventually break after a few castings.

"Hey, even the Mona Lisa is falling apart" - Tyler Durden

 

[Elkman]

I didn't think you needed a sealing agent for oil clay, actually. Silicone doesn't stick to anything except more silicone, in my experience, so I've made plenty of molds of silicone against unsealed oil clay, and I haven't had any problems with it. It depends on what the maker of your silicone molding compound recommends, or whether there's any concern about little bits of clay sticking to your mold. but you might not need to be all that concerned about sealing the clay.

 

[Uratz]

I didn't think you needed a sealing agent for oil clay, actually. Silicone doesn't stick to anything except more silicone, in my experience, so I've made plenty of molds of silicone against unsealed oil clay, and I haven't had any problems with it. It depends on what the maker of your silicone molding compound recommends, or whether there's any concern about little bits of clay sticking to your mold. but you might not need to be all that concerned about sealing the clay.

Its not the sticking issue, its the UNCURED silicone still in a liquid form after the the rest of the mold is cured. what ever is in contact with the clay remains in the liquid form, what you end up with
is a thick mold with the inner skin still gooey. I still have the overall shape of the model but the entire surface detail is lost.

 

[MasterAnubis]

Sounds like your suffering from sulfur based clay. The sulfur inhibits curing. The ones that specifically say 'non-sulfur' would be the ones you could go without sealing for silicone.

I hope your new sealant will work for you. Unfortunately, it's either seal it or find new clay.

 

[Termokk]

Well good luck, and dont let it get you bummed out. I have lost silicon moulds before too, i know the pain. Your work is fantastic and you will overcome!

 

[ScottAS]

PVA(Poly Vinyl Alcohol). You should be able to find on the net. I havn't used it in 20yrs so not sure where to buy it. Also you can use Elmers glue thinned with water and brush it on, creates a hard shell. All silicones will have a problem with oil inhibitting it not sure what Elkman is doing to get around it.

 

[Uratz]

Elmers glue idea may work. I'm experimenting with thinned down wood sealer and airbrushed a thin coat over the sculpt so we'll see how that goes.
So far the airbrushing retained the details more than if I brushed it on. Also trying out the thin resin liquid over the sculpt.
This one kinda drowns the detail a bit and made it glass smooth.

Thanks for all the help.

 

[MasterAnubis]

All silicones will have a problem with oil inhibitting it not sure what Elkman is doing to get around it.

I can say personally I've not had any curing issues with PlatSil 71-20 on Klean Klay or J.F. McCaughin Classic Clay.

 

[Elkman]

All silicones will have a problem with oil inhibitting it not sure what Elkman is doing to get around it.

I use Smooth-On's Oomoo 30 and Rebound 25 silicones, along with oil-based clays that do NOT contain sulfur. The clays I use are Klean Klay (the cheap stuff) and Van Aken Plastalina. If a clay contains sulfur, the sulfur is what inhibits the cure, not the oils in the clay. That's true for the Smooth-On products I've used -- I'm not sure if there are other silicones out there that react to other compounds in clay.

Here's the technical bulletin on Smooth-On's Rebound 25 that says it won't work with clays containing sulfur. In fact, it says that even if you seal your sulfur-containing clay with a sealer, Rebound 25 won't cure properly. Here's the technical bulletin for Oomoo 30. I found this thread at theeffectslab.com saying that tin-cured silicones aren't inhibited by sulfur-based clays, or at least as much.