Windshield Repair Forum

Personaly I do not feel it is either the Drystar or the micro torch that cracks a glass out, it is the person holding and using them. Now whilst we do not have the temperatures to deal with that some of you guys do, we certainly have water in large quantities. The blow torch or the drystar are both excellent tools and are both infinately adjustable in the amount of temperature you need to use.

I tend to use the defrosters when warming a shield although I never like to get the glass to hot. Seem to remember that hot glass is more fragile than colder glass, early science lesson, also if it is too hot to put your hand on it is too hot to work on.

I find that with either heat source I do need to cool back down again and this is where the heat sink tool is great. I would rather do 4 or 5 quick dry out cycles than find out there was some moisture left in the break, or overheat the glass and pVB trying to get it all out in one go.

I would imagine we all understand why the glass on the outside layer can break when the inside is too far out temperature wise when compared with it. So when I use the defrosters I will also make sure I have a little warmth around the damage, so that hopefully they are both expanding at the same rate. A classic example would be say a bi-metal spring where the inside metal expands at a different rate to the outside causing it to curve. T

To sum up, learn how to use the tool, learn and take the time to study every break and work out exactly what has happened and is happening within the damage. Go for several quick dry out cycles rather than one big one, make sure the glass goes back down to a reasonable temperature, before starting the fill.

Try this experiment on a practise glass, make a starbreak at heat it gently from the outside until the legs close, time how long it takes for the legs to reopen. You may well be suprised.

Last but not least whilst on this subject, IF IN DOUBT DRY IT OUT.

Just remember that heating to 106 degrees for 40 seconds does not equal heating to 212 degrees for 20 seconds. Warming water does not make it evaporate very quickly. You need to get water to the boiling point to get it to evaporate quickly. You can warm it to 106 degrees 10 times and still the water will remain.

To test this, cover the bottom of a pan with a thin layer of water (1mm or so) and put it in an oven set at 106 degrees. The water will get hot, but will take a very long time to evaporate. Now try the same test but set the oven temperature to 212 degrees and try the same test again. The water will evaporate almost immediatly after the pan reaches 212 degrees and the water begins to boil. Do this test on a burner and the evidence will be even more apparent as the heat is more direct, just as when you use either the moisture evaporator or torch.

I agree with screenman that it is the hand of the technician rather than the tool that is the most important factor, but we know how hot the moisture evaporator gets and how long it takes to increase the water in the break to boiling temperature. With a torch you do not know how hot the flame is or how long it will take to warm the water in the break to boiling temperature, so you need to watch the break carefully and remove the heat a couple of seconds after the water begins to boil. Not really a big deal since you should be watching the break carefully no matter what tool you are using to dry it out, but I have received far more tech support calls from technicians who have cracked out the glass with an open flame than I have from technicians who use the moisture evaporator.

If you prefer using a torch and are happy with your crackout ratio then by all means let your experience guide you. I have the advantage of learning from not only my own experience, but that of thousands of customers over the years as well. No one solution is going to fit everyone's needs, but it's a numbers game and my recommendations are based on what works for the majority of technicians that we work with at Delta Kits.

Very good point Brent I did not make myself clear on the part about several dryouts instead of one really hot one. I always watch every break carefully even after all these years, I also get the break hot enough to evaporate the moisture and then I stop and allow to cool. thing is it would be really nice if we found a method to get all the moisture out without the glass expanding.

Agreed.

Some companies sell a Dry Out solution basicly alcohol or acitone it bring the boil temp down so when you heat it with a torch it drys quicker the down side is the chemicals are bad for the UV layer so most just use the torch also I know a couple of guys who use a glow lighter from the old car lighter days its what is in the drystar but with less control Guys like Screen deal with wet breaks everyday

Alcohol or acitone and fire don't mix very well . if you want to do a test take an empty soda can put a little alcohol in and give it shake hold a flame over the opening. You don't want that happening on a windshield !

We used dryout solution for years, now I never touch the stuff, first I have seen what it does too PVB, secondly not sure that the acetone does not just evaporate off first leaving the moisture there as before. Snake oil springs to mind.

Time2Shine, Sorry, I think I may have pulled your thread off topic!

screenman wrote:We used dryout solution for years, now I never touch the stuff, first I have seen what it does too PVB, secondly not sure that the acetone does not just evaporate off first leaving the moisture there as before. Snake oil springs to mind.

Acetone does mix with water...if it CAN mix...but in a break, the acetone will only mix with the water in contact with it...so you may have a point there.

It's also a good idea to warm up your injector with a lighter, blow tourch or hairdryer. Keep your resin warm. I put a container of resin in my pocket to keep it warm while working on the glass. "I love this business"