Exploding Cup

[Otis Baits]

I was pouring swimbaits today and had my first cup explode.I was lucky that I had noticed a burn mark in the bottom.I set it a side to let the cup cool to use as a scrap cup.I put it on a cold mold and it sat there for 45 minutes or more before it blew up.Moral of the story always check your cups before using them.This is the second cup I have found to have a scorch mark on it.

[superharmonix]

Was this an actual Pyrex cup or Anchor Hocking, or some other brand?

[Otis Baits]

Anchor.But I have been using it for a year.I am now inspecting them before I use them.The plastic had already cooled and I had taken it out.I should not have put it on the cold mold.We got a freeze down here in Florida.The aluminum mold was really cold.Lesson learned.The wurst part was it blew all over my Okeechobee craw trick worms I had to clean the glass off them.

[kipbass]

Sounds like you made it through unharmed..Glad to hear it!

[Dave]

I have found that some of the glitter is arching the bottom of the cups.  It only happens when I re use some plastic that was used for a project before hand.

[Otis Baits]

That is how I found the spot I thought was bad and quit using it.Most times the glitter will flake off the bottom.But this time it seemed burned in to the glass.

[pjmcla]

As I have read about it; Pyrex used to be made by Dow Corning.  Dow sold the "Business unit" to World Kitchens in 1998.  World Kitchen did not change the product composition for Pyrex glass bakeware or where it was being manufactured.  It is made using a soda lime composition and heat-strengthening.  Anchor Hocking glassware is also a tempered soda lime glass.  Both are manufactured in the USA.  Annealed borosilicate is the other typical high temperature tempered glass product.  Is is typically found in chemical laboratory products ( beakers, flasks, test tubes, etc ).   Some say the tempered borosilicate glass is more thermal shock stable, some say not.  Also, borosilicate is said to be less physical shock stable and is said to produce sharper shards when broken.   
 

[Dave]

As I have read about it; Pyrex used to be made by Dow Corning.  Dow sold the "Business unit" to World Kitchens in 1998.  World Kitchen did not change the product composition for Pyrex glass bakeware or where it was being manufactured.  It is made using a soda lime composition and heat-strengthening.  Anchor Hocking glassware is also a tempered soda lime glass.  Both are manufactured in the USA.  Annealed borosilicate is the other typical high temperature tempered glass product.  Is is typically found in chemical laboratory products ( beakers, flasks, test tubes, etc ).   Some say the tempered borosilicate glass is more thermal shock stable, some say not.  Also, borosilicate is said to be less physical shock stable and is said to produce sharper shards when broken.

So P, is it preference between the two glassware? If so, who makes the best one in your opinion?

[pjmcla]

Dave;  I am no expert on this; at all.  I have researched some and tried to read on several forums where I see anything that mentions Broken cups, cracking glass, etc.
Age seems to be a very common factor in the threads.  Either used a lot in the micro for 12 plus months, and a few cases of almost brand new.  This is with "spontaneous" brakes.   The vast majority use either Pyrex or Anchor Hocking.   High temperature silicone seems to be discussed more and it's usage seems to be increasing with postive comments.  I currently am using some pyrex brand cups made in the 1960's. Put into use 8 months ago.   I will be testing some high temperature silicone cups pretty soon.   Be careful as there are different temperature ratings and quality silicone cups.  Spend the money and get the best stuff.  I believe I am heading to silicone.   

[ghostbaits]

Not to argue the science but I have used the same 12 cups for over 6 years now with "knock-on-wood" no instances of any spontaneous breakage (or other breakage).

I believe that cups that shatter have had integral damage like bumped the side/corner of an aluminum moldd, injector hit side of cup, etc. A microscopic flake will be removed in the cup and the integrity may be inquestion, especially at a higher temp or when the cup is placed on something with an extreme difference in the cups temperature.

My thought is that since these cups were used in hand pouring with primarily pop molds and resin molds, the chance they were "dinged" was very small.

I know lots of buys switched to borosilicate beakers that are made for labs and higher temps. I did not switch as the more I read, the more it seemed the Pyrex and Anchor were made for more "everyday" usage and the borosilicate is made for more of a laboratory environment.

Just my take.....

I think Paul is probably correct in saying that high heat silicone is the safest choice as long as you get decent stuff.

Jim

[andrewlamberson]

I purchased the below, but I cut all of them in 1/2 to make them more stable. They are a little top heavy for 350 degree plastic! When I cut them down I cut a little up bump to use as a grab point...keeps the gloved fingers out of the hot plastic!

http://www.amazon.com/iSi-Basics-Flex--Measuring-Cups/dp/B001CDBBY8/ref=sr_1_32?ie=UTF8&qid=1329489309&sr=8-32

Microwave and Dishwasher Safe
Heat Resistant up to 490 Degrees F.
Pours liquid precisely with no spills
Smooth inside, textured outside
Set includes 3 measuring cups. 1 cup, 2 cup and 4 cup capacity.

I like the smallest cup for dipping heads. (it's only  1/2 cup after I cut it down). I'm going to order another set and cut it to the correct depth for dipping the swim shad....I like to dip the entire body.

I also use this silicone spatula for stirring:
http://www.amazon.com/iSi-Basics-Silicone-Slim-Spatula/dp/B000S171GM/ref=pd_bxgy_k_img_b

Another advantage of the Silicone cups is that they hold the heat a LOT better than glass! The disadvantage is that they are a little flimsy so take care when grabbing them (thus the grab tab). If you just grab them from the side you can squeeze hard enough to push plastic the top!!!!!