Windshield Repair Forum

Cryatal_Image wrote:

Dr.Chipster wrote:Wouldn't the heat coming from a torch be too intense and cause a crack out?

This is why i asked the question. Ive seen many videos of both and the ones using the torch was kind of a quik brush by a few times. Even with a hand held lighter but the guy using the lighter used it on the inside of the windshield and kept the flame on the break for 30 sec or so.

Ihave used a lighter inside the glass (usually for cracks) I feel that it helps the resin to flow down the crack. The heater tool that delta kits has is what I use for chips because I feel like I have more time to spend on heating it.
I would not leave the lighter on it for 30 seconds though as it heats it very fast. I also do not hold it so the flame actually touches the glass. Im still a newbie but I have done this on several cracks and havent had it crack any of em out yet. So personally I like the lighter on cracks and the heat tool on chips.... But thats just me

ok good to know thank you

How do you know that the heat has not caused the glass to expand shutting the crack up?

Heating behind glass, difficult to explain in writing for me at least but here goes. Do all you guys know how a bi-metal spring works and the physics of such a thing? if so you will understand how the inner layer of glass will expand at a different rate to the outside when heated from the inside, this expansion of the glass and pvb will push up on your break.

I am not saying do not use heat, I am however pointing out one of the problems that may occur, personally I have not used heat inside for the last 12 years.

screenman wrote:How do you know that the heat has not caused the glass to expand shutting the crack up?

Heating behind glass, difficult to explain in writing for me at least but here goes. Do all you guys know how a bi-metal spring works and the physics of such a thing? if so you will understand how the inner layer of glass will expand at a different rate to the outside when heated from the inside, this expansion of the glass and pvb will push up on your break.

I am not saying do not use heat, I am however pointing out one of the problems that may occur, personally I have not used heat inside for the last 12 years.

I never said it was right or wrong. I googled something and happen to run acoss it on a video i watched which is why i asked about it. I would PM you with the link but for the past week, ive been filling my brain with vid after vid watching different things on things to do or what not to do. I dont remember the keywords i used to hit that vid. Irregardless, that was the ONLY video where the kid used a lighter, not to mention within the vehicle itself so a common practice? No!

My reply was to the Jhickman post.

Dr.Chipster wrote:Wouldn't the heat coming from a torch be too intense and cause a crack out?

Yep, if you just hold the flame right on the chip for a few seconds. Key is that you always keep the flame moving. I run it in quick circles around/on the break.... just for a second or two at a time, flame, pause, flame, pause... careful to observe what's going on with it. You will see it working, and doing it a bit at a time will help prevent over-doing it and causing a crack out. And I'm referring to a small butane lighter torch, not a larger propane plumber's torch. I've used those too, but mainly to warm the repair area to a good working temp. You can also remove moisture with a big torch, but it's trickier and I don't recommend it.

Listen to screenman, he's an expert on drying breaks.... I think he deals with moisture in breaks on a daily basis. I deal with it some, but try hard to avoid working in such conditions if possible

yeah... heat on the inside is not a good idea. ever. for any reason, even if you were taught to do it.

great post guys, thanks

Glassdoctor, I did have a dry damage to repair once, I think it was in 1991 or may have been a bit before then.

so,you heat the outside with a torch like you would with a evap.tool but in a circular motion?

Yes, working from the outside of the damage inwards towards the center.