heating starbreaks

[desertstars]

We discussed this sometime back in another post. Nothing definite was resolved.

My comment now pertains to certain physical laws of pressure, vacuum, heat, and resin properties.

OK. I heat from the inside of the windshield under a mild vacuum rather than from the outside and distribute the heat using a circular motion. ( I use a match rather than a butane pencil torch. I use the butane torch to light my cigarettes on a windy day. If it has been a particularly lucrative day, I use it to light my cigar or a firecracker.)

Heating from the inside during a mild vacuum cycle expands the air into the resin. The resin absorbs the air and the heat expands the legs of the starbreaks. I then spray a 50/50 solution of alcohol and water on the inside of the w/s and as the w/s is cooling, SLOWLY re-apply pressure. The contraction of the cooling w/s helps to pull resin into the breaks.

Admittedly, I have simplified this procedure in my telling. A leg that doesn't fill presents another problem. And so on to the use of probes, blah, blah blah and etc.

What I'm dealing with here specifically is the basic technique.

Inside heating or outside heating?

Under pressure or under vacuum?

Or a combination of any of those.

[shermfiddle]

Your techique sounds like you really know your stuff. The only thing that I would do after all vacume and pressure cylcles have been completed is that while on the last pressure cycle I very quickly heat the inside for about 1 or two more seconds to complete the repair. It seems to cap the repair for a final inspection. No more than 2 seconds!

"I still love this business"

Sherman

[boyd]

Desertstars,
I know we try to drill as least as possible however, how about just drilling the end of the crack and filling back. It's much quicker and you don't have to do it that often. Maybe one in 25??? Beleive it or not. I never use heat. I use to my first few years but not anymore. It takes so long to cool. The only time i did use it was when the resin would flow 2/3 of the way in the leg and i just needed a little help to get it into the end of the crack. Flex the crack and hold for 2-3 minutes, if that doesn't work flex inside the pit, or create a small bullseye inside the pit, or use a thinner resin, if nothing works then drill the end of the leg. Thats what I do?

BOYD

[desertstars]

Boyd.

Yes, I do use the other techniques you suggest but drilling would be my last resort.

We all know the perils of starting a NEW drill hole and we avoid that whenever possible. (I was originally referring to a starbreak.)

Flex or a needle created bullseye is a much safer bet when heat doesn't do the job.

Thanks.

desertstars

[Repair1]

Heat???? Me personally use heat very rarely if it’s 65 degrees out side your window will be plenty warm you shouldn’t be using heat. You have to be dam careful if you cure it while it’s warm and the glass is expanded you will think your repair is complete then to find out everything opened right back up I’ve seen this so many times. If you just remember heat is one of your last resorts you will find you really didn’t need it all that often.

I do use it more in the wintertime that’s for sure burr.. Warm it up on the inside slowly touch it with the back of your hand if it’s too hot to hold your hand there you’ve gone way to far let it cool and heat less. Really all you need is about 70 to 80 degrees ALWAYS COOL UNDER PRESSURE.

Drill??? I hate to drill the end of a crack maybe one out of 500 rarely ever drill the end. I think drilling and heat are the two parts of repair techniques that are used way to much you don’t need it every time. You really do get a better repair without em less missing glass etc. etc.


Happy Repairing
Brian