How does the ground sides of a ground glass stopper create a seal? No, I am not going to use the bottles, I am trying to figure out another project. How is the ground glass a better seal than, say slick glass?

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You take the glass stopper and stick the tapered end into that hole on top of the bottle. Thats how they work. Sorry I couldnt resist.


Actually Ive used them and never had a problem other than breakage more due to the way I carried them. The reason Im not using them now is all the bottles I had glass stoppers for have broken. I broke a few by them getting hit on the top of the stopper. The necks of the bottles broke. Im using corks now in my collodion and varnish bottles but as you probably know they can fall apart and leave pieces of cork in the collodion.

> How does the ground sides of a ground glass stopper create a seal?

The way it creates a seal is by adding a tiny bit of vacuum grease on the ground glass surface of the stopper, inserting the stopper in the bottle and doing a couple turns to spread the grease on the tapered ground glass surface. The grease is what provides the seal.

I use a silicone high-vacuum grease made by Dow corning, but it may be overkill.

greg

grease?

if youre using a glass stopper bottle for collodion (and you should be) all you need to do is have a little of the collodion up into the neck of the bottle. Push the stopper in and this will remain liquid forever.

Ive got a bottle thats been unopened for over a year, and the collodion that is in the stopped is still liquid.

What about if your bottles get warm? Won't the pressure buildup from expanding solvents push out around the edges of the stopper?

If they get TOO hot *ether boils at 98 degrees F* the stoppers will pop. If you put them into an ice chest, the collodion will shrink, and the stopper be pulled deep into the opening and then when the bottle was rewarmed it will be very difficult to remove the stopper without running the neck of the bottle under very hot water.

They do have drawbacks. BUT. Ive got a bottle of collodion a customer gave me that she had corked up, its now a dried residue on the bottom, while one of my old stock bottles 2 years old is still fresh and useable because of the glass stopper.

you just need to use some commonsense when you work with them.

Cool... I always wondered how folks got away with it... Thanks for the info!