Heating bottle and clay in over

[CharlieB]

I read somewhere about heating the bottle and clay in a warm oven, but can't remember where I read it.

 

Can anyone help?

 

Thanks...Charlie

[DSiemens]

I've tried this a few times there's a few things to watch out for. Plasticine melts at 150 so it doesn't take a whole lot. What you got to watch out for is breaking the glass. If the temperature goes up or down to quickly the glass can break. Also most bottles aren't made to be heated so there's always a possibility of breaking.

I've put bottles in the oven up to 250 with out a problem but I've actually found using the burner works better. I put a rod into the bottle and hold it over a burner until the plastacine is melted. In small bottles I've been able to get it completely flattened out in 5 minutes. Be careful not to let the bottle roll when you set it down though or you'll have clay going up the sides.

If all you need is to have the clay stick to the glass hold it over a burner for five seconds. This will melt the bottom of the clay enough to get it to stick well. Then shape the top.

[Dave Fellingham]

That depends on the type clay you're using. Daniel talked about Plasticine clays; I assume the temperatures he listed are Fahrenheit rather than Centigrade.

 

The polymer clays (Fimo, Sculpey, etc.) will bake and harden at 130F. All consumer bottles have to withstand near boiling temperatures since they are washed and rinsed with very hot water (or steam) prior to being filled with some liquid and sold. These bottles should withstand an oven set to its lowest possible temperature to soften Plasticine or bake polymer clays. It just occurred to me that bottles with Plasticine or polymer clays can be set up in a water bath using running hot water from the tap. Your hot water should be over 150F (too hot to put your hand in for more than a second). Just turn off the water running into the bath and don't touch the bottle until it has cooled. 

 

Daniel mentioned that rapid heating and cooling can cause bottles to crack and break. Glass with very thick bottoms or generally un-uniform in thickness (which shows up as "wavy") are more prone to breakage from rapid heating or cooling because the different thicknesses don't heat or cool - and consequently don't expand or contract - at the same rate which can cause the glass to crack or break. We often see where a builder has used acrylic or epoxy resin for a sea material and cracked the bottle from the heat generated by the resin as it cured which caused uneven heating and cooling.

 

Borosilicate glass (Corning/Pyrex is one brand), used in laboratory glass, is much more resistant to heat. It is also much more uniform in thickness than consumer glass which aids its heat tolerance. This uniformity in thickness, which results in minimal distortion of the model inside, is the reason many builders favor these bottles and flasks for SiBs over most consumer glass. 

Edited October 27, 2015 by Dave Fellingham

[CharlieB]

Thanks for the replies. I've got something to think about.

Charlie

[JesseLee]

I have meted Plasticine on a burner set on med-low & I have also done it in in the sun in a hot windowsill.

[Taiga]

I have already melt plasticine in a bottle, in an oven. When everything went cool again (room temp.) I was surprised to find OIL on top of my plasticine. A yellowish kind of fat! Beurk! I've had to get all the oil out little by little, it was very time consuming and boring to do since not every part of the bottle was easy to reach. Be warned!!

Edited October 27, 2015 by Taiga

[JesseLee]

I made a mistake in my post above. I have melted Platalina not Plasticine.

 

Jesse

[Dave Fellingham]

I have already melt plasticine in a bottle, in an oven. When everything went cool again (room temp.) I was surprised to find OIL on top of my plasticine. A yellowish kind of fat! Beurk! I've had to get all the oil out little by little, it was very time consuming and boring to do since not every part of the bottle was easy to reach. Be warned!!

 

Plasticine is petroleum jelly based so it seems likely that too much heat or too long caused some separation.

 

Dave

[DSiemens]

I have seen the yellow stuff too when putting plasticine in the oven. I think Dave is right it's probably caused by high heat and length of time.

Holding the bottle over a burner I haven't had any problem with yellow stuff. If I do a full melt I pull it off right when it's done so the time factor isn't an issue. Melting just the bottom to get it to stick leaves the top unmelted so no problem with yellowstuff there either.

[Dave Fellingham]

Did a bit of more research plasticine and plastaline - they're essentially the same. In one place I read a review in which the sculptor wrote about warming plastalina in a double boiler when mixing colors and softening it for first use. The double boiler is much like the water bath idea. The bath would allow more precise temp control to prevent separation. 

 

Dave

Edited October 28, 2015 by Dave Fellingham

[JerseyCity Frankie]

The last bottle ship I did, I was not happy with how well the model was seated in the sea when it was in the bottle and complete. I put an inch of water into a saute pan and heated it and then I held the bottle in the water for a while. The water was not allowed to boil but it was hot enough to soften the plastecene right through the glass. Back at the workbench I was able to reach in with a tool and press the hull down into the now soft sea.

The bottle was a cheap rotgut quart liquor bottle so it was thin and likely brittle and of low quality. But it behaved fine.

[Jim Goodwin]

I use Zap Gel to glue the plasticine into the bottle.  It's a slow-drying, non-forgiving, superglue gel that has a working time of 3-4 minutes.  After that sets, I let

cure overnight with the bottle upright so that vapors can escape.  Then seat the ship into a gouged-out area with the Zap Gel.  

 

Had one bottle break to the gallery I deal with on Ocracoke Island.  Shipped via UPS.  The Manager said that the box looked like it was used for a soccer ball  (& I double-box all items).  She said that the glass was broken, yet the clay & ship were attached to the glass.

 

Have tried that Super Glue Jel glue...like Zap better.