Windshield Repair Forum

Have a simple question that I hope you more experienced technicians can help me out here. Recently did a repair which appeared to be a simple starbreak with multiple arms. Fixed it in the following manner:

Scribed off loose glass, used compressed air to remove any loose particles, drilled a hole in the break, made sure hole was clean and used Delta Kits Moisture Evap for 15-20 secs (weather was warm, windshield was at optimal temperature) waited couple minutes to cool down. Went ahead with putting bridge assembly onto break and did 3 cycles with 1st pressure cycle using thumb pressure then going to vacuum for 30 secs then repeating cycles but without using thumb pressure after 1st time. Noticed arms weren't filling out as well so used the Moisture Evap to the inside of the glass for no more than 5 secs when it was under pressure cycle. Used the UV shield the whole time over the bridge.

After the 3 cycles, removed bridge assembly and applied pit resin and let cure with Delta Kits UV lamp for 5-7 minutes with hard plastic tabs. When curing noticed the arms were bigger than what it was when it was first inspected. After curing scraped off and finished off with Pit Polish. Final inspection noted that arms were indeed longer than before but looked filled.

Now after over a week the break has more arms reappearing. Could be existing arms or even new ones.

Any idea what went wrong?? Moisture or air in the break that was not gotten rid off properly?? Any info on this would be greatly appreciated and thank you, sorry for the long post!

Could be several things, Bad resin, not pressure curing, First question are you using heat? If so I would stop, IMO heat will give you a false repair just about every time if your not letting the windshield cool properly. I rarely use heat and it gets cold here

Star breaks are like teenagers. Each (leg) has a mind of their own, and they all are yearning to run. So you need to handle them very carefully. Too much pressure and they don't want to do anything and won't cooperate at all. Be gentle and kind, and maybe talk to them and listen to them, maybe the legs really want to have a nice bond with the parent (main body of the break). ... ok, enough analogy...

It could also be that the injector was too-tight against the glass (also known has head pressure). Because damaged glass is somewhat flexible, too much head pressure can choke off the passage way(s) leading to the legs. Only screw the injector down to meet the glass and have enough torque to keep it from leaking. It is very easy to overtighten the injector to the glass and choke off the passageways.

Also try using light pressure on the resin. Sometimes it takes very little pressure to make it flow, and too much pressure is like traffic at rush-hour... a lot of gettin no-where.

I have trouble occasionally with star-breaks too. They can be tricky. Brian (Repair1) is absolutely correct about heat. Although I do use it (mostly from habbit) you can get a false repair when using it. But once you have been doing enough repairs, you will recognize a false repair vs a real repair. If you look at the legs very very very close, you can tell the difference between a leg that has disappeared because of heat, and a leg that has been filled with resin.

Heat can sometimes help induce resin flow, but don't let a false repair fool you. In my experience on star breaks... (when I used heat) .. if the break seems to clear up rather quickly, chances are that the break is only reacting to the heat. Usually star break legs are tight cracks so that usually means the resin will probably flow slowly, not fast. Just give it lots of time if you have to. "Work the break, not the clock".

Ps. Using less head pressure was a tip I picked up a while back on this forum. It worked!!!

Hope this helps.

Sneck

Thanks to both of you, some great info you have to offer! So are both of you saying to use No heat while repairing or no heat prior to repair?? Sorry I just want to clarify.

As for tightness of injector to glass I usually have it at 3/4 turn as soon as the rubber seal touches the glass.

Also just curious when you are doing your first pressure cycle do you use any manual pressure as in using your thumb to hold the head of the injector or do you just let it do its own thing by itself??? If so how long are you leaving the first pressure cycle?? I know each break has to be treated differently in terms of how many cycles and how long you leave it on.

Thanks again for your input, I greatly appreciate it:)

I dont ever use heat while under pressure only in vac mode. Also on stars heating the glass will often close a leg thus keeping enough resin from it. I find flexing a leg with your probe while inder pressure or sometimes flex from inside with your thumb. Last when it looks like I have it all I leave it under pressure a couple minutes longer removing UV shield half way through.

JT2,

First I'd like to say that was a very good step by step written description of your repair process, makes it easy to see what going on;)

One thing I did notice, you didn't mention anything about probing the legs. Many times the tighter legs will require some light pressure using your probe to open a pathway for resin to flow.

Using heat to remove moisture is ok, however using heat during a pressure cycle is not ok. You not only chance a run out of a leg but will also close legs even more resulting in no resin flow.

Stem head pressure! I would venture to say this was probably the cause of your problem. To much head pressure will pinch legs closed not allowing resin to flow. Next time try backing off stem until you start seeing small amount of resin leakage, then screw back down 1/16th-1/8th of turn for proper seal.

Curing under pressure! I suppose that's ok if you already have legs filled. However, if legs weren't completely filled you just sealed off any chance of completing this repair. Well, not totally but that would require going back and refilling each leg individually! Not much fun.

Better luck on your next starbreak, just keep practicing and it will all come to you;)

The use of the moisture evaporator up front most likely expanded the legs. That's been my experience, too. I believe your main problem was not using thumb pressure on the 2nd or 3rd cycle. All of the other suggestions mentioned in this thread will also help.

Dale...

Thanks for the info guys! I will be sure to use the suggestions mentioned here. Practice makes perfect!