Boiling PC

[BigguyZ]

OK, so I forget where I saw it, but I read an article online about boiling PC in the microwave. According to the article, there is no way to over-cook the clays, and you don't get the discoloration you can get in the over. Also, as I am too cheap to buy a toaster oven, I like the idea of boiling in the microwave instead.

So I recently tried this, probably boiling for 20 minutes total. I put in sticks probably about 3/4"-1" thick in a plastic container. Immediately after the blanks were taken out of the microwave, they were really mushy and crumbly. Definitely not a good sign! I was sure the whole batch was wasted.

However, I let the blanks dry, and afterwards I found them to be incredibly hard. I'd say that with this method, the blanks are harder, but more brittle. The colors had definitely remained much brighter than with baking, however. I took a small chuck and turned it on the lathe as-is. I found that the brittleness made if difficult to get a clean cut with my skew. I get tearout with baked clay, but this was more consistent (yet less severe) tear out.

The blank was able to be sanded quite easily, and smothed out to a polish as well.

So, assuming you don't want a PC-only polished blank and will be finishing with CA, I think this might be a viable alternative to baking. I'd say take light cuts and plan to sand to final dimension, and you should be good to go.

I only did the one test peice to see how it worked... but I have 2 or 3 kits ready to glue up in the boiled blanks. I'll update once I have them turned (might be a loong while, however).


Anyone else try this?

 

[creativewriting]

Here is a link to a site that tested the process as well.

http://www.garieinternational.com.sg/clay/shop/comparison.htm

There are several other microwave tests he did on the same site. Go back from the article and you should find the other tests. This site is for the mad scientist type so enjoy. He compares all aspects of the different brands of clay.

 

[BigguyZ]

Ah, that's the one I read! So has anyone else tried it? I'm just wondering if what I've found to be the norm, or if I managed to still overcook it...

 

[snyiper]

Ok all well and good but what about the brass tube in the microwave?

 

[randyrls]

Ok all well and good but what about the brass tube in the microwave?

Was wondering about that myself, but could you boil in a pot over the stove?

 

[rjwolfe3]

but could you boil in a pot over the stove?

You don't boil pot silly, you sm... oh never mind, wrong forum, lol.

 

[jleiwig]

Ok all well and good but what about the brass tube in the microwave?

Most modern microwaves have no problem with steel. My microwave came with a steel shelf in the middle of it. It's only when you touch the steel to the steel walls of the microwave itself that you have problems. I microwave my dogs stainless steel dish a couple times a day with no problems what so ever.

 

[snyiper]

Really!!! Honey it was Justin on the forum told me it was ok...no really hun it was....no I dont have a pen....sign what? No I dont think he wants a roomate.

 

[Glass Scratcher]

According to the article the curing temp for the clay is 275F. Water boils at 212F(at sea level). No mater how long you boil water, water that is in liquid form in the pot, is 212F. Steam on the other hand...

Does the poly clay fully cure/crosslink at a lower temp?

 

[creativewriting]

Does the poly clay fully cure/crosslink at a lower temp?

NO. Most clays need to reach 250 to cure. Microwaves are different and have successfully cured clay submerged in water. I don't know or understand the science nor have a tried this myself. I will stick with the toaster oven in the garage for now. If microwaving effects the hardness (harder) then I will have to give it a try at some point.

 

[BigguyZ]

NO. Most clays need to reach 250 to cure. Microwaves are different and have successfully cured clay submerged in water. I don't know or understand the science nor have a tried this myself. I will stick with the toaster oven in the garage for now. If microwaving effects the hardness (harder) then I will have to give it a try at some point.

From what I found, my blanks were harder, but more brittle (lke a ceramic). This is after they've dried, of course.

And again, I didn't have tubes in the blanks, as I currently do solid blanks and drill (wasteful, I know).

 

[erebus]

NO. Most clays need to reach 250 to cure. Microwaves are different and have successfully cured clay submerged in water. I don't know or understand the science nor have a tried this myself. I will stick with the toaster oven in the garage for now. If microwaving effects the hardness (harder) then I will have to give it a try at some point.

I'm guessing that the temp of the blank is greater then the 250/275 cure point as a microwave oven heats solid items from the inside out. I imagine the water is there to help even out the temperature change in the blank and probably keeps it from exploding from a fast heat buildup in its center.

Just my .02

 

[BigguyZ]

I'm guessing that the temp of the blank is greater then the 250/275 cure point as a microwave oven heats solid items from the inside out. I imagine the water is there to help even out the temperature change in the blank and probably keeps it from exploding from a fast heat buildup in its center.

Just my .02

I think it's a process close, but not quite, to what you describe. I think the blank gets hotter than the boiling temp of water, but the water actually cools the blank enough such that it dosen't get hot enough to burn/ char. Since the clay will heat up without water, we know that the water is not necessary to heat the clay. Therefore, I believe that the opposite is the case- the water is necessary to cool the clay.

 

[jleiwig]

Question, was there anything in the water when you were done? Anything floating on the top like an oil slick? My thinking is that boiling it may leach out some of the plasticizers causing the issue you describe of being ceramic like..

 

[BigguyZ]

Noot that I noticed, though that's an interesting thought...

 

[Glass Scratcher]

Perhaps a call to tech support could settle some of the speculation. I know that when I called Amaco about some things with their clays I ended up talking to a chemist in their lab.

 

[leehljp]

Travis,

What tool are you using to turn it? I ask because I know that the skew and scraper exhibit different results with different material, and in some cases they tend to be the opposite of each other.

A scraper makes a very smooth finish cut on hard wood with segments of metal, but not on soft woods. A skew makes glass smooth cuts on soft woods but not as well when used with metallic segments with wood.

Changing and experimenting with tools might help with the problems you mentioned earlier in this thread. Just a suggestion. This thread is interesting to me!

 

[BigguyZ]

Hank,

With the baked blanks, I had to use a skew as the scraper causes much too much tearout. However, for the boiled blanks, the scraper worked MUCH better than the skew.

I definitely agree that different materials need different tools- I'm just seeing (so far) that the method of curing the PC is causing a difference in the material's properties...