# Breaking Glass...



## kroutonz (Feb 8, 2011)

I have broken the plate underneath my glass 3 times now trying to heat AR. I had aluminum sheet underneath a stoneware dish which held my beaker and I still broke the plate. I also heated this very slowly, just barely boiling after an hour..

I'm at a loss for what to get next in terms of vessel to hold a beaker. Will graniteware work, I know probably not the best since its a base metal with coating on it, but these glass/pyrex/stoneware isn't working. I haven't seen exactly "corningware" but I assume the stoneware is the same material or close. 

http://www.amazon.com/Proctor-Silex-34101-Proctor-Silex-Burner/dp/B000690WNU/ref=sr_1_3?s=kitchen&ie=UTF8&qid=1297212507&sr=1-3 Is the hotplate I use,

Is the problem maybe with the temperature outside (30f), and me heating to about 200(f) or so may leave the outter edges of the glass cold enough to break it? Or is it possibly the burner just being too hot (1000w) and I should get a more precise one with temp guage? Open to suggestions, I thought about sand but it doesn't really seem ideal, and I feel like its just going to take longer to heat up and have the same thing happen.


----------



## lasereyes (Feb 8, 2011)

kroutonz said:


> I have broken the plate underneath my glass 3 times now trying to heat AR. I had aluminum sheet underneath a stoneware dish which held my beaker and I still broke the plate. I also heated this very slowly, just barely boiling after an hour..
> 
> I'm at a loss for what to get next in terms of vessel to hold a beaker. Will graniteware work, I know probably not the best since its a base metal with coating on it, but these glass/pyrex/stoneware isn't working. I haven't seen exactly "corningware" but I assume the stoneware is the same material or close.
> 
> ...



I've heard that a very specific type of corningware dish holds up well against the heat. Also the type of hotplate your using is not really designed for lab use.

GSP recommended this one:
http://www.shopworldkitchen.com/corningware/stovetop-just-white-casserole-jw-5c-b


----------



## Palladium (Feb 8, 2011)

http://goldrefiningforum.com/phpBB3/viewtopic.php?f=39&t=8758&hilit=+corningware#p82327


----------



## godofwar (Feb 8, 2011)

kroutonz said:


> I have broken the plate underneath my glass 3 times now trying to heat AR. I had aluminum sheet underneath a stoneware dish which held my beaker and I still broke the plate. I also heated this very slowly, just barely boiling after an hour..
> 
> I'm at a loss for what to get next in terms of vessel to hold a beaker. Will graniteware work, I know probably not the best since its a base metal with coating on it, but these glass/pyrex/stoneware isn't working. I haven't seen exactly "corningware" but I assume the stoneware is the same material or close.
> 
> ...



if the temp is not adjustable or if it goes full throttle till it reaches temp could be a issue....

if a 1Kw element is on full blast to temp that is 2000 BTU's ..that is alot of concentrated heat... it all varies though....

i use this one http://www.walmart.com/ip/Rival-11-Electric-Skillet/10598475#ProductDetail

this is not lab quality but with the pan it will catch majority of material dumped incase of break...... 

how do you store your materials to make AR..... you keep them outside??? if so i would recommend allowing to reach room temp before application of heat...

hope this helps


----------



## nickvc (Feb 9, 2011)

Try using a sheet of 1/8+ steel under your pans and raise your heat slowly leaving the pans on there until cool, I used this method for years with the beakers directly on the steel and had very few break,thankfully!


----------



## FrugalEE (Feb 9, 2011)

Krountonz mentions using a sheet of aluminum, but it must be awfully thin and Al is a very good conductor of heat. If Al is used I think it should be 1/4 inch or more thick. Al doesn't store or slow down heat flow near as well as steel/iron and cast iron skillets or griddles are very cheap. Having the pan or griddle overly large should help warm the air around your glass as well and reduce thermal shocks. 

I"m inclined to agree with Godofwar about your hot plate controller might be a big part of the problem. My litte hot plate is 750 watts and I barely crank it open when I'm heating a small beaker set in a little Corningware fry pan rated for direct stove top.

FrugalEE


----------



## dtectr (Feb 9, 2011)

IMHO, these make all the difference - gas or electric burners
http://goldrefiningforum.com/phpBB3/download/file.php?id=4900


----------



## Irons (Feb 9, 2011)

For heat transfer, I use Silicone fluid that was designed for the purpose when heating beyond the boiling point of Water. I keep the flask suspended in the fluid so that the heat is applied over the whole bottom of the flask. This limits the formation of hot spots in the glass that might stress the vessel.
Another thing to watch for are scratches on the surface of the glass. These can cause it to fail much sooner than a pristine surface.


----------



## lasereyes (Feb 9, 2011)

Irons said:


> For heat transfer, I use Silicone fluid that was designed for the purpose when heating beyond the boiling point of Water. I keep the flask suspended in the fluid so that the heat is applied over the whole bottom of the flask. This limits the formation of hot spots in the glass that might stress the vessel.
> Another thing to watch for are scratches on the surface of the glass. These can cause it to fail much sooner than a pristine surface.



does this fluid you speak of also work with cooling?


----------



## Irons (Feb 9, 2011)

lasereyes said:


> Irons said:
> 
> 
> > For heat transfer, I use Silicone fluid that was designed for the purpose when heating beyond the boiling point of Water. I keep the flask suspended in the fluid so that the heat is applied over the whole bottom of the flask. This limits the formation of hot spots in the glass that might stress the vessel.
> ...



I don't see why not. It's designed to remain free-flowing at very low temperatures, so, yes, you could use it for temperatures below freezing, but a cheaper solution would be to use anti-freeze in your cooling water. Anti-freeze is what I use to keep my glassware from breaking from the cold.
You can also add Calcium Chloride to water so that it boils above 100 deg.C if you need a cheap fix and you don't need to get too hot. Silicone fluid is nice because you don't have to babysit it and it cleans up from the glassware easily; just a wipe with a paper towel.


----------



## kroutonz (Feb 10, 2011)

Yes my aluminum sheet was about 1/8inch maybe less.. but I've decided i'm just going to get a cheap scientific hotplate/stirrer combo on ebay. I'm gonna try and finish this batch of ar without a cw dish which i figure the 180w heating power should be fine to not break a pyrex beaker. 

Also I read up that the hotplate i have does go full blast/off cycles until it reachs the right temperature so that could of been the problem.


----------



## OneZip87 (Feb 10, 2011)

Instead of using an aluminum plate we us ceramic fiber paper

http://www.cooltools.us/Ceramic-Fiber-Paper-p/kln-805.htm

it seems to balance the heat better


----------



## kroutonz (Feb 10, 2011)

https://www.pelletlab.com/magnetic_stirrer

link to the one I'm probably going to get. Thinking about the ceramic since I dont think I would need to use a stir bar in hot liquid often.


----------



## Barren Realms 007 (Feb 10, 2011)

kroutonz said:


> https://www.pelletlab.com/magnetic_stirrer
> 
> link to the one I'm probably going to get. Thinking about the ceramic since I dont think I would need to use a stir bar in hot liquid often.



Being able to use a stir bar comes in real handy. I would get it if I were you.


----------



## Palladium (Feb 11, 2011)

You know I’ve been thinking about this for awhile now and trying to come up with a simple effective method. I just wonder..........

Lets look at inductive heating for a moment. With induction heating all your heating is a metal substance. What if you took a glass beaker and placed it on an induction cook top and heated it? The glass would not be affected by thermal shock. All that would heat is the surface of any metals in the solution. The metals would heat up on the surface reacting with the solution instead of you having to heat the whole solution up to react with the metals.

Hummmm...... http://www.walmart.com/ip/GE-Electric-Induction-Cooker/8224072


----------



## Barren Realms 007 (Feb 11, 2011)

In theory you are correct. But in practical experience I can tell you from my point of view being able to stir the solution and heat makes things go a lot faster IMHO. Take for instance now, my heater is out on my hot plate so I have to put my container on a hot plate and then put it on the stirrer to make things go faster.


----------



## Palladium (Feb 11, 2011)

Think i might go to wally world later and get on of these to take apart and see if i can play with it. Hummmm......


----------



## HAuCl4 (Feb 11, 2011)

Easiest is to put beaker/champagne bottle/reaction tank/whatever on a thermos jacket (fiberglass-resin exterior. insulation wool middle, champagne bottle inside), and preheat the acids, then the chemical reaction keeps everything warm. If you want good stirring just plug it and shake it if small or put it on a trolley and rock it backwards and forwards if big.:shock:


----------



## godofwar (Feb 11, 2011)

for a stirrer i bought a candy thermometer glass with a steel support.... then i removed the steel section...... so i have temp reference and stirrer in one...


----------



## 4metals (Feb 11, 2011)

I have never had a stirring hot plate last more than 18 months. And they were expensive to boot. For my money a ring-stand, mixer motor, and one of these; http://www.flickr.com/photos/[email protected]/3054421827/ combined with a $39 electric griddle will give you mixing when you need it and all the heat you need.


----------



## goldsilverpro (Feb 12, 2011)

I never used a magnetic stirrer/hot plate much, although I've owned many of them. They can be more of a pain than they're worth. Good for some titrations. Might help dissolve DMG in water. BTW, when testing for Pd, DMG in water is much more sensitive in water than in alcohol, according to some experiments I recently performed. It also reacts more quickly. Many books say to make it (1% DMG) in water.

Lately, I've taken to using a big $40 electric skillet as a heat source for dissolving Au powder in AR. I put a 5 liter Corning Ware, square, white, Pyroceram, StoveTop dish in the skillet and do about 10 oz at a time, plus the filter paper it was on, directly in the dish. If you drive it, it's dissolved, and the paper is pulped, in about 20 minutes. The problem is that you have to tone the AR down, in order to avoid too much gold loss from the large area at the surface. I've thought about inverting the dome shaped Pyrex lid so it would act more like a watch glass. The problem would then be in how to lift the lid efficiently.


----------



## qst42know (Feb 13, 2011)

Is a glass lid available for your stove top dish?


----------



## Palladium (Feb 13, 2011)

Chris, If you take it to a glass cutting shop like for windows they can drill you a hole in it for about $3-5. Then you could flip it upside down and put a wood or plastic handle on the other side attached with a nylon thread screw. :?:


----------



## goldsilverpro (Feb 13, 2011)

Palladium said:


> Chris, If you take it to a glass cutting shop like for windows they can drill you a hole in it for about $3-5. Then you could flip it upside down and put a wood or plastic handle on the other side attached with a nylon thread screw. :?:



The lids are bought separately and have a glass knob that's part of the lid - my employee thinks he can cut it off with a Dremel. That's a very good idea, Ralph, but you can't use nylon with the strong acids. PVC or CPVC (hi-temp PVC) nuts, bolts, and washers are readily available and could be used instead. I think you can get them in Teflon also.

Here's what the lids look like.

http://www.shopworldkitchen.com/corningware/stovetop-glass-cover-6021845


----------



## Palladium (Feb 13, 2011)

For only a couple of bucks, I would trust a glass shop first. I had them drill some holes in some marbles one time so it shouldn't be a problem for them.


----------



## qst42know (Feb 13, 2011)

I have used a glass lid with the knob left on upside down in place of a proper watch glass. It does no harm to leave the knob on. The lids for corning dishes usually fit down into the bottom so using it right side up shouldn't be any trouble either.


----------



## Irons (Feb 13, 2011)

Palladium said:


> For only a couple of bucks, I would trust a glass shop first. I had them drill some holes in some marbles one time so it shouldn't be a problem for them.



You can buy cheapo Chinese Diamond drills on Fleabay, They're only good for a few holes but, for a couple of bucks, it's cheaper than driving to the glass shop. The trick is to keep a trickle of water going in the hole to flush out the ground glass and to keep it cool so the glass doesn't break. Practice on a glass food jar to get the hang of it.


----------



## Sodbuster (Mar 11, 2011)

Most all modern cookware has a lid designed to force the condensate to run to the outside edge and drip down the slightly tapered walls of the pot. This has a washing effect to the inside of the pot above the liquid line and also reduces the splashing that mite cause some foods to crust up on the inside of the pot.

We all know that even cookware will fail to return the condensate back to the pot under a very rapid boil, it wants to blow out and boil over. Some cookware need to go back to the drawing board even. 

I Just can't see that flipping our lids will improve something that's built into the cook ware already.

KO,  , lets all go to the lab and boil some water and we can flip lids and see what becomes of it.

Ray


----------

