Can I bake....

[TreeTree]

a plastic birth control case?  I'm prepared to hear a resounding no, but I was thinking...aren't things like that heat treated?  I'm doing a birth control swap that's why I'm asking.  I supposed I could make the clay and then glue it on...or give up on the clay obsession and decoupage something.

[Jillie]

I'm guessing it would probably melt.  Most plastic melts at much lower temperatures than what you bake clay at.  It might be a better idea to bake the clay then glue it to the case.

[Diane B.]

Plastics come in various types and also melt or slump (depending on the type of plastic they are, recycleability, etc.) with different degrees of heat.  Most will shrink and/or soften though rather than melt at our temps, for those that would eventually melt.

Prescription pill bottles, for example, although recycleable (#5) are made from "medical plastic" and are okay at our temps; I would guess that the contraceptive case was also medical plastic by default, but not sure.  Another type that works at our temps are "food grade plastics" like containers for applesauce, yogurt containers, M&M's, etc.

(You can check out more on some of the specific plastics that can work for covering with raw clay and baking on the Covering page of my site, if you're interested:
http://www.glassattic.com/polymer/covering.htm
... click on Plastics or it's subcategories)
Btw, one whole type that's interesting for clay is the #6 recycling plastics (though that's not probably what you have), particularly polystyrene foams.  Some polystyrene foams will shrink in our heat, but they'll also hold up long enough to act as an armature or form under a layer of clay (if they're not covered with alum. foil first) and so can make fairly hollow items or mini-caves, etc. (for those, the shrunken foam would be removed from the clay after baking).


You could certainly try one of the cases in the oven, but I'd maybe also do some kind of "enclosed" or partially enclosed baking method (e.g., a pile of baking soda or cornstarch) to be absolutely sure you're not exceeeding the recommended temperature (or use a convection oven)... both with an oven thermometer used as well.
http://www.glassattic.com/polymer/baking.htm

Sometimes plastics are kind of on the borderline temperature-wise, so will be fine as long as they're not baked too long, or will be fine in areas which are actually covered by clay (if the bottom part of the case isn't covered with clay too, you might want to sit that lower part at least in a pile of baking soda, etc., just as an extra precaution).

As you said, the other way to do it would be to make the covering first and bake it separately (supported in the proper shape with tissues or baking soda, etc. if the top of the container isn't flat), then glue it back on after cooling.  (if you do that, you can lay a sheet of plastic wrap or aluminum foil over the top of the container while you shape the clay, then remove and bake... and maybe even allow the baked and still fairly hot clay covering sit on the top of the case while it's cooling to conform to the shape of it even better).

Or you could also just make like polymer things (from molds or just free-shaped, etc.) that you could glue onto the case... if the case is curved, just press the items against the case to get the general shape right if they're large enough to matter, then bake (and glue back on later).  And of course, polymer bits like that could also be glued on top of other coverings as well --like decoupage, air-dry paperclay, etc.


HTH,

Diane B.

[TreeTree]

Thanks so much for your replies and especially for the extra detailed reply from Diane.  I'm being sent one case...so I can't really afford to mess up...even if it doesn't melt it sounds like it may fuse shut....  It's kind of a small flimsy looking case as well.  I'm not sure what method I'll use yet...heck I don't even know which of her themes i'll be choosing yet.

[chromegrrrl]

You could test it. Shave a small piece off with a razorblade and wrap it (very loosely) in crumpled tinfoil and bake for 10 minutes (too long it's not a fair test because it'll be such a tiny piece). If it comes out looking mostly like how it went in; the plastic is safe. If it's a pool of melted tinfoil shaped plastic, then probably not.

[TreeTree]

chromegrrrl that's an excellent idea! Once I receive the case I'll test it out.  If it doesn't work out I need to figure out how to paint glossy plastic.

[Jillie]

I've painted my BC case before.  The paint holds a lot better if you sand the case first.  You can also buy special paint that is better for use on plastic.

[Diane B.]

Just be aware that if you wrap it in tinfoil, it will be as if it were baked using an "enclosed" baking method, which usually creates a better result simply because the heat is totally moderated to what it should be everywhere on the item.  It could also take longer to achieve the same amount of heating than without the foil, so don't know if you could be sure of the comparison.  

If you only want to see if it will "melt," then doing that might give you an idea, but if you want to know if it would slump a bit or deform, or even shrink, a bit, not sure that you could tell.

Still think the best idea since you don't have one to experiment with would be to create the covering or items right on the case (perhaps over a sheet of plastic wrap because some plastics can be eaten into by raw polymer clay, though it can take awhile), then remove and bake the piece(s) separately... and glue back on with an epoxy glue, E6000/Goop, superglue, or a strong "white glue."


Diane B.

[chromegrrrl]

chromegrrrl that's an excellent idea! Once I receive the case I'll test it out.  If it doesn't work out I need to figure out how to paint glossy plastic.

Np. What Diane B. said about it sagging makes sense, when I was on the pill my case was vinyl (easy to find out if the one that you are getting is vinyl, superglue won't stick to it but superglue will stick to styrene) Vinyl is usually bakable, styrene is very meltable.

Prep for acrylic paints-- Future floor wax is an acrylic coating that does work on styrene, you dip it and hang it from a wire for 12 hours. PVA (white glue) will hold onto *most* vinyl plastics, if it rolls off the surface the glue is too thin or the surface needs a little tooth (sanding with a manicure sponge does wonders)

Just in case something does go wrong; check your local family planning clinic and ask if they have just the cases of the same rx that they'd be willing to part with. They might boggle or giggle a little at your request but I'm sure they'd be willing to see if they have any extras in the supply closet.

[TreeTree]

Ok, so I definitely need to find out if it's vinyl or styrene....the bc is called trivora and here's a website:  http://www.oralcontraceptives.com/brand_trivora.asp