Windshield Repair Forum

This is my first topic on here. Its been raining and cold here in Cali and had some questions about using the Moisture Evaporator tool in regards to long crack repair. Should I pop a bulls-eye at the end of the crack prior to using the Moisture Evaporator. Or does it matter? My thoughts are to pop one prior just in case the crack decides to spread based on air expansion. Am I correct on this? Thx

I always pop before I do anything else apart from inspection, this helps to stabilize the crack. Do you have access to compressed air as this is what some of us use for long crack dry out.

I would agree with screenman, without the use of some type of compressed air supply to blow out long crack moisture it would take some time only using a drystar moisture evaporator or other.

I was visiting with a fellow w/s repair tech the other day and he showed me his technique on drying out breaks. He placed a drop of acetone on the break and then heated the inside of the windshield with a butane torch. Are any of you familiar with this technique, and what are your thoughts?

Although acetone, denatured alcohol or even ether can be used to absorb residual moisture, all three can and probably will compromise the integrity of the glass-to-PVB interlayer bond. Compressed air is the medium of choice for drying long cracks.

Cheers;

Puka Pau

You do need to create that bulls-eye first to stop the crack before using the moisture evaporator. If you don’t, you’ll be chasing that crack across the windshield.
I personally wouldn’t put acetone on a crack to dry it out, and certainly would never use a butane torch on a windshield. I find a torch’s heat way to concentrated for the glass. I’ll keep my torch in my humidor where it belongs.

9 down, 1 to go!!

Acetone, well the jury is out on that one does it lower the boiling point sufficiently or does it evaporate off and leave the moisture behind, either way it certainly dramatically weakens the PVB. Blow torch inside well lets try the little experiment get a piece of card cut 1/2 way through it with a sharp blade and then bend it keeping the cut to the outside, well there you go the crack opens up and gets bigger, this is what happens for the first few seconds that you use heat from the inside. After a few seconds the heat will progress through the PVB the outer layer glass will then expand and shut the crack. So why would anyone want to heat through a nice dry piece of glass to get to the wet bit, waste of time and effort along with the risks involved.

Blow torch, never a problem here I have used one for 23 years, more controllable than a lot of heat sources, that said I like the drystar on a windy day. How can it be concentrated heat, you could not have a more variable control surely, just by adjusting the distance you hold it from the glass changes the amount of heat hitting the glass.

Heat expand glass and shuts the crack/damage whatever you use make sure the damage has cooled back to the ambient temperature before fill and curing, this can take a lot longer than most people think without using a heat sink.