Separating bonded glass

Hello mmerig, I am sure that some sort of solvent or some application of heat will weaken the bond between the two layers. Just be careful and make sure you only do one of the two at a time. If you use a solvent that is flammable and apply sufficient heat, you may reach the flashpoint of the solvent and it will self ignite without any open flame. This is what is referred to as the lower explosion limit (LEL) in the hazardous waste field.:hot: :att'n: :bomb: :RIP:
So, if you try the solvent first and it doesn't work, rinse the solvent off with water and wait until it drys, then try the heat and see if that works. It's quite possible that you could put the whole thing in a container of water for a while (days) and it might loosen the adhesive that way.
Unfortunately, without knowing what kind of adhesive was used, it's hard to say what will or won't work. If I knew the adhesive, I could find people where I work with the information. The company I work for makes machines to bond semiconductor wafers together.
If you have a decent university in your area, you may be able to find a helpful person in the chemistry dept. that can help you do this safely. They tend to have a good supply of solvents, and they have a good collection of heating devices.

Peace,

Dave
 
Thanks for tha advice. I tried the heat method, placing a metal tray with sand on my wood stove and putting the glass on the hot sand. My house got really hot, depsite an open door an -5 egrees C outside, but the bond did not break.

I'll try boiling water next.

I could just get another piece of glass for later bonding, but I did not want to waste the one that fits just right.
 

SY

diyAudio Moderator Emeritus
2002-10-24 10:19 pm
Chicagoland
www.SYclotron.com
Water won't do it. If the adhesive is a cyanoacrylate, a long acetone soak may work (but well away from any ignition source!). If it's PMMA, you'll have to get more aggressive, and a session with methylene chloride might be necessary. The latter should ONLY be undertaken by someone who knows how to handle explosive carcinogens.
 
Thanks Sy. I was aware of these two chemical treatments, but I did not want to use them, especially the methylene chloride. I may just cut another piece of glass and bond it myself, if I can find a good (i.e., cheap, easy to use) bonding material.

By the way, boiling water did not work, except at a corner where the layers may have been a little loose from the fracture.
 
I placed the glass in a 260 degree C oven for about 45 minutes. I suspended the narrower glass piece from the wider one so that it would fall away (just a few millimeters) from it once the bond broke.

The bond never broke, and I tried prying the glass pieces apart with a knife while they were still in the oven.

Apparently, the bond is quite heat resistant.

I am going to get another piece of glass.

Thanks for the help.

P.S. Any recommendations for a clear glass-bonding agent?
 
If you got some moisture between the two pieces when you tried boiling it, try putting it into your freezer. The water will expand and may pop the two pieces apart.

Another thing to try is getting the glass very hot and dropping it into a bucket of ice water. The sudden temperature change may cause the bond to break.

I_F
 

DECKY999

Member
2007-07-18 7:06 am
That will probably crack the glass as well.

I would guess that the adhesive used was epoxy based. If that is the case - heat should work. I suggest use a heat gun and try applying shear force on the bond. Also introduce small craks by scalpell if you can get to the bonded area at all.
 
I_Forgot said:


Another thing to try is getting the glass very hot and dropping it into a bucket of ice water. The sudden temperature change may cause the bond to break.

I_F

I think you forgot that would be a great way to make the glass explode into many pieces.

How about irradiating the glass sandwhich with high intensity ultraviolet light like that from an industrial eprom eraser. Something that makes lots of ozone (not that the ozone is useful here other than indicating the relative power spectrum and intensity of the lamp to be probably useful). The glass will block some of this but perhaps enough will sneak in to the center adhesive layer to cause it to break down. :wiz:
 
SY said:
Water won't do it. If the adhesive is a cyanoacrylate, a long acetone soak may work (but well away from any ignition source!). If it's PMMA, you'll have to get more aggressive, and a session with methylene chloride might be necessary. The latter should ONLY be undertaken by someone who knows how to handle explosive carcinogens.


I was going to suggest the same. MEK is in the same solvent family, but stronger than acetone. methylene chloride, or DCM, is found in gel paint strippers. I like DCM, it will permeate almost anything. I doubt casual, ventilated use could lead to an explosion. Just don't get any sparks/flames near any of this stuff. DCM is similar to formaldehyde, its bad long term, but not particularly bad in terms of single exposure.

It is going to take a long soak in either solvent for the glue to be permeated. I'd let it soak for a number of days. Should be easy enough.

But getting another piece of glass is going to be the easiest solution...