Long Crack Problems

[StellarChip]

Hey everyone,

Been having a problem with longer cracks. All goes well until I reach the very end of the crack then the air seems to go in reverse and creates a very skinny, thin, shinny line. In addition some of the air creates micro sized dots in the crack. I have never been properly trained in long crack repair. Currently my method of repair has been to apply the bridge to the impact point, fill the damaged area, then chase the crack with crack resin being carefull not to drop any resin past the filled area of the crack. Any help would be greatly apprieciated. As always Thanks in advance and have a great day.

[Brent Deines]

There are a lot of different methods for crack repair depending on the type of system you use, so I highly recommend you start by talking with your equipment supplier, then if you continue to have problems, try alternate methods offered here on the windshield repair forum. If you're using Delta Kits products I would invite you to give me a call. We can cover more in a 10 minute phone call than we can in days of posting on the windshield repair forum. If you are using a competitor's system I recommend you call them first.

It sounds like you are using the method that Delta Kits prefers, so I will ask a few questions before offering any advice here on the forum.

Are you drilling?

Are you Tapping?

Does the problem occur when you initiate the vacuum cycle or while under pressure?

Have you tried using pressure only?

Are you applying curing film as the crack is filled to make sure no air is being drawn in from the surface, or waiting until the crack is completely filled?

What resin are you using?

What bridge are you using?

How many times has this happened?

How much experience do you have with long cracks?

[StellarChip]

There are a lot of different methods for crack repair depending on the type of system you use, so I highly recommend you start by talking with your equipment supplier, then if you continue to have problems, try alternate methods offered here on the windshield repair forum. If you're using Delta Kits products I would invite you to give me a call. We can cover more in a 10 minute phone call than we can in days of posting on the windshield repair forum. If you are using a competitor's system I recommend you call them first.

It sounds like you are using the method that Delta Kits prefers, so I will ask a few questions before offering any advice here on the forum.

Are you drilling?

Are you Tapping?

Does the problem occur when you initiate the vacuum cycle or while under pressure?

Have you tried using pressure only?

Are you applying curing film as the crack is filled to make sure no air is being drawn in from the surface, or waiting until the crack is completely filled?

What resin are you using?

What bridge are you using?

How many times has this happened?

How much experience do you have with long cracks?

Thanks Brent as always you are always one of the first to reply.

first, no I seldom drill unless I'm having problems with resin flow

I will almost always pop the break, If and only if I drill

the problem occurs only at the very end of the crack, the shiny tip of the crack will shrink to a fine line then move backwards to the point of impact

I have been using diamond clear crack resin for cracks but this last time I was using Magnibond

I am using a Safelite bridge with Novus plastic injectors, similar to a SRP bridge but with the tripod legs surrounding the injector tip

This has happened quite often when attempting to repair long cracks

I do not have much experience with long cracks as I also am in the replacement business so I would usually advise the customer that a replacement is needed

Thanks in advance for your attention to this matter.

[Brent Deines]

Is this happening when you pull a vacuum or removing the bridge?

Is the resin getting all the way to the end of the crack, and then allowing air in, or is it just not getting all the way to the end of the crack?

Although we don't usually advocate curing under pressure, when it comes to long cracks it is sometimes necessary to cure the crack portion under pressure due to the fact that when the pressure is released the crack will draw air from the surface. At the very least I recommend covering the crack as soon as it is filled, making sure to add a little extra resin to the surface so no air can be introduced from the surface.

Unlike bulls eyes, star breaks, and combination breaks, pulling a vacuum will rarely pull air from the tip of a long crack all the way back through the crack and up into the injector, so constant pressure, not to be confused with high pressure, is the key component in properly filling a long crack. We don't normally drill but we do at the end of a long crack (6" or longer) so the air has a place to escape as it is pushed toward the end of the crack. If it is pushed to the end where it is very tight, or even subsurface, the air may not escape to the surface, so as soon as the pressure is released it follows the path of least resistance and migrates back into the crack. Although I have not experienced it myself, depending on the injector used and the length of the crack I suppose this could also happen while under pressure.

Although many technicians like to flex cracks, and or use multiple vacuum cycles, I don't recommend using either of those procedures unless absolutely necessary. I also don't recommend sliding the bridge or using multiple bridges with the Delta Kits system, but as always, I cannot speak for the recommended practices when using other systems.