How do you know when to end a leg/crack?

[Auto Glass Rescue]

Yesterday I was completing some repairs with my practice windshield and a certain star break made me think of something I really don’t know. The star break had two legs that were about 3 and 4.5 inches long. With this one or any other damage, what do you need to look for to see if you need to end a leg/crack so it what spread? If I’m not clear, please ask, and any other information would surely be appreciated.

[Frank EU]

I like to see that you are (at least) using a test-windshield to be doing some practise work, well done.

Is the crack surface or sub-surface?
What system are you using, why don't you contact your supplier for instant advice?

[Auto Glass Rescue]

Delta and a surface crack.

[Windshield911]

Are you probing it while in pressure cycle and making sure you watch the resin fill the entire leg?

[Auto Glass Rescue]

Are you probing it while in pressure cycle and making sure you watch the resin fill the entire leg?

I do. I guess I need to clarify my question… Before you even start the repair, what tells you that you do or do not need to end a leg with a bullseye? Is it the length, something you see while probing during the inspection or do you just end it if it starts to spread during the repair?

[screenman]

First probing a surface break will shut the break up, then when you release it will introduce air.

With any leg over 2 inches I will certainly drill and pop, before I start any repair I do a full inspection this includes flexing each leg to determine if it is likely to run whilst carrying out the repair. Only experience will really let you fully make up your mind to drill or not, there are no cut and dried fast rules as I know of.

[Auto Glass Rescue]

Thanks everyone, I was thinking it may come down to experience.