Another long crack question.

[Mr Bill]

A friend of mine for whom I have done several chip repairs in the past, took a trip a few days ago and got a new chip on the passenger side about 2 inches from the edge. It cracked out almost immediately. The crackout looked like an upside down "L" with a rounded corner. The horizontal part was about 4 inches and the vertical part was around 8 inches.
I don't do long cracks, but I figured this would be a good opportunity to get some experience and my friend figured the windshield is shot, why not let me try to fix it.
I popped a bullseye on the point of impact on the horizontal leg, about 1 1/2 inches in from the edge and popped another about 1/8 inch further on from the end of the vertical part of the crack . I applied an injector to each end of the break.
The top injector started to flow into the orizontal part of the crack and it was looking great as I followed the resin along the crack and applied cure tabs. Then I got to the bend of the crack where it pointed downwards and the resin in the crack began to flow downhill. About 3 inches downhill, the resin in the horizontal part started to flow out from under the cure tabs and leave black air space. I guess the weight of the resin created a vacuum and pulled the rest of the resin downhill. I tried removing the tabs and refilling the offending air spaces.
At that time I realized that I probably should have started at the BOTTOM of the crack and worked uphill, wicking the resin into the crack and applying cure tabs as I went along.
How would YOU GUYS have dealt with this?
As I progressed uphill, should I have applied a cure lamp every few inches, to stop the resin from running back downhill.
I was using magnabond resin.
My friend liked the repair. I didn't
I realize that long crack repair isn't cost effective, but I would like to master it. ( just in case!)

[screenman]

Certainly start from the bottom, Judging by your description it should not have taken long to fiil

Drill at and pop at end or just past end of crack, making sure crack enters pop. Drill another hole and pop 1/2 inch in from this first one, and place bridge over this hole. The reason being that even though you have opened the crack with your first hole the end of the crack is still very tight. Once the resin starts to flow see if you can help it spped up by putting a very small amount of resin over the crack just where it has filled to, never go in front of the area already full this will cause an air lock. Then using an injector held between your fingers place this over crack again just behind the filled area and watch that resin flow in move the injector along as it fills. I do not normaly find the need to apply curing tabs as I move along, but before I cure I will run another thin beed of resin along the crack straight from the bottle and apply film. I would guess once that crack was dry for which I use compressed air I would get it to fill in a couple of minutes and I use the Delta 40-14 lamp which covers a large curing area.
I must add that most of the large cracks I do are on trucks and buses and that is because I can charge big bucks $100 plus for saving them big money.

Wish I could get some of you guys over here to show things as these techniquesare easier to show than write about.

[Mr Bill]

Screenman
When you use an injector, held between your fingers; how do you load it?

[gt_repair]

you would front load the injector.

[ghost rider]

Screenman,
have you ever tried not drilling and popping the end of a crack? like i said before, I have not drilled cracks for over fifteen years and do not have any problems. I spend a lot of time drying the crack and use good resin and it just looks better without the drill hole.

[screenman]

I like the added security of drilling and popping a long cracks, this way I know exactly where the end of the crack is. I do not and nor do my customers have a problem with the cosmetics of any repairs we do. A small drill and pop hole filled properly is barely visible in a screen 32 square foot of glass. As I have stated in previous post this is my method and it may not work for others.