Windshield Repair Forum

repare-brise wrote:You need to suck the air out in order to be able to put the resin where you want it. If there is air in the break it may stop the resin from going where you want it to. For a quick demo of air displacing liquid, go back to your younger days and hold your finger over the end of a straw and insert the other end into a glass of water. The air that is in the straw will not allow the water to go into it.

Of course, that's a nifty little trick, but it has nothing to do with what we're talking about. I've got a better one for you. Keep in mind, I don't have a degree in cabinetmaking, but try to work with me.

TEST:
Take one starbreak.
Put one drop of resin on the OUTSIDE of the glass over one of those legs.
Does that crack accept the resin?
Most cracks are surface cracks, and they will pull resin in through capillary action, just from the surface.

So, when you put your injector over the impact point and create a "vacuum," are you really getting rid of that air? Are you really creating a vacuum, a void of air, in that break? All that wondrous vacuum is sucking air into the break from the cracks!

If it can pull resin in like our test, surely it can pull air, since resin is much thicker than air?

That's a rhetorical question, this thread is hopelessly off course, so it's locked. If you want further discussion about it with me, send me a PM.