Windshield Repair Forum

I would say most of our tech support calls for stars not filling have to do with too much pressure on the glass, not enough pressure in the injector, not enough resin in the seal, or improper bridge setup, in that order. Not removing the moisture and not using the UV shield are less common as we try to beat that into every customer's mind. We do look at their purchase record however to see if they have purchased a moisture evaporator and a UV shield, and we do go over the proper usage of those tools along with proper warming methods when we are diagnosing problems. This time of year improper warming methods rises closer to the top of the list.

The funny thing is we don't get all that many tech support calls, which is part of the problem in my opinion. Instead of technicians going to the manufacture to discuss proper usage of the tools they sell, they tend to search the Internet, which is sometimes helpful, but often times ends up causing bad habits and habitually poor repair quality. I'm not sure why someone would take the advice of someone they know nothing about and who’s repairs they have never seen before consulting someone who developed the tools and techniques that work best with those tools, but that is the way things seem to go these days.

Often we see posts from new technicians on the forum who have never contacted us for technical support. When asked to outline the procedure they are using we find they are not even following the most basic of setup instructions. It's an interesting and sometimes frustrating phenomenon that has come with the vast amount of information available on the Internet and the lack of technical support that many companies provide these days. I have to admit that when I am having a computer problem I don't typically bother calling the hardware or software manufacturer, but search the Internet in hope of finding there. However, I would call the manufacturer if I could actually talk to someone and it did not cost me an arm and a leg to do so. With that in mind I would again encourage Delta Kits users to utilize the FREE technical support that we offer. It's rare that you will not be able to speak with a technician immediately and in most cases we can resolve technical support issues quickly.

We do try to answer questions on the forum so others can benefit from the dialog, but that fact is that eventually the thread gets buried and the same questions get asked over and over again. It's also far more time consuming to answer questions on the forum and technicians often get confused when they hear conflicting opinions from a number of sources. Don't get me wrong, there is a lot of very good information on the windshield repair forum, but there is also some misinformation from well intentioned technicians who may not know what they are doing.

This post is not directed toward screenman, mrchips, or any other specific windshield repair forum member, but just my perspective based on many years of providing technical support for Delta Kits products.

I think I am going to pop a star with my punch on my practice glass and try a few of the suggestions u made Brent. After that and if I am still not satisfied I am going to make another star and call delta for some technical expertise.

I had a 1/4 inch bulls eye to repair near the center bottom portion of a windshield. The glass was 84.6 dgs. It was sunny and th car was facing away from the sun. The outdoor temp was 63 dgs. The crack was 3 plus months old. We had a heavy frost early in the morning, and it was now just after 1pm. The car had not been driven all day. I used the evaporator for 20 seconds over the break. I mounted the bridge and added the resin. As soon as I released the plunger to the pressure mode a crack developed from the bulls eye toward the passenger side of the vehicle (horizontal) about 4.5 inches and stopped. I am trying to get a understanding of how or why the windshield cracks when doing breaks. I kept my kit in my house over night and put it in my vehicle when I went to make that repair. I did not check the temp of the resin thinking it would be slightly higher or equal to the windsheld temp. The plunger when I released it went all the way down, and I remembered to pull up and reset it, if that occured. It was a moment or two after that that I noticed the crack. The crack started filling with resin. I dded more resin to the windshield surface when I saw it had stopped about half way across the crack. I added a little heat from the windshield with my lighter and the crack disappeared.
a few moments later the crack reappeared but only at the end about 1/4 inch and in the center of the crack about 1/2 inch. I used the film curing tape to cover the resin as I applied more to prevent air from getting in. I talked to Delta 3 times reference this while doing the repair. The end cleared up and only the center portion of the crack 1/2 inch could be seen. When I looked at the crack from inside the vehicle it appeared completely clear. from a straight on look from outside the vehicle I could not see the crack or the bulls eye. When I looked from an angle I could see the 1/2 inch crack again. I am thinking I was looking at a filled crack and I was maybe seeing the headon angle. I had to look for the bulls eye to put the pit resin on. After it was cured & polished the owner could not find it. However the 1/4 inch crack could be seen if you looked at it from a certain angle. The cause of the crack, possible pressure cold resin, or I didn't wait long enough for the ws to cool after I used the evaporator. My question! When a crack like that happens do we need to drill at the end if the crack fills with resin. My thought was I caused the crack to extend and I filled it. If I had initially found the break with a short crack more than 3 inches, I would have probalby drilled and made the crack run to the hole, then used my slide hammer to creat a small bullseye and filled it. Did I do this correctly or should I go back and locate the end of that crack and drill. When I had a chance to sit back and think of what happen during that repair, that question poped up. I want to be able to do good quality work and the best way I know how is through experience and understanding of how the chemicals, heat, pressure react with the glass. Cold weather is here and I am getting an arsenal of things such as a blow dryer, lighters, etc... and practicing on my office WS to see what works best. I sat in class Friday and I read all the books I have pertaining to cracks, yet sometimes the answer is not obvious at the time Iam looking at it. I read several post last night on this site and I see others have similar problems. Brent and his staff are worth their weight when you are at a job site and you need to consult someone then. I have yet, to recieve a bill from them for their advice and guidance. I simply purchased their product and I inherited a gold mine of information and solutions.
My wife owns a tax office and she has clients that will call all hours of the day and night with their concerns. She replies and seldom charges for her time. Most CPA's today keep a stop clock near and they charge by the fraction of the hour. You never get to talk to a person after business hours or weekend. That may be why my wife has loyal clients that extend from one generation to the next. Her clients are like family and she keeps her prices low. We want to make a living, not a killing. We are all involved in the same struggles of life and Delta Kits reflect that same attitude that my wife has toward her clients. Sorry about that! I got off track for a second, while thinking about some of the post I read tonight. If someone can answer my question, I would appreciate the advice. Candyman

The first thing to remember is that sometimes things happen that we have no control over. I've done a lot of repairs and have had a very small percentage crack out, either while I was working on them, or after the fact. Those times that I have had crack outs while working on the vehicle, typically something I did or did not do was the problem, however I have seen cracks move for no apparent reason. What I'm trying to say is that even if you do everything correctly, a crack can run. That said, you have already mentioned the things that I think are the most common reasons for crack outs.

If you did not allow the glass to cool down enough the difference in resin and glass temperatures could cause a crack out. This has happened to me.

Too much pressure on the glass could be the problem; however since you just attended a training class I doubt that is the case in this instance.

Since the system you are using does not use air pressure, you are injecting under very low pressure, so although it is possible that started the crack running, there really is very little you can do about that other than immediately releasing the pressure which I believe you said you did. Putting too much pressure on the plunger could cause the problem but only if you are not holding the injector like a syringe as instructed in the training class, so I doubt that is the problem either.

Here are some things that bother me about what you reported.

You said the plunger when all the way down when in the pressure cycle. Unless you are using a "very" worn out seal I can't imagine how that could happen. The opening in the seal is considerably smaller than the diameter of the plunger, so even if there were no resin in the seal it should require a considerable amount of pressure to make that happen. Maybe I am just misunderstanding. What do you mean by all the way down?

You said you heated the crack and it disappeared. First, I would not heat a crack that is over 1" long if the glass temp is already at 84+ degrees, and certainly not a crack that is already on the move. If it disappeared when you heated it my first thought is that the glass expanded and closed the crack rather than the resin filled the crack. When the crack reappeared you saw air at the end and in the middle. Again, this sounds more like a crack that did not get filled, but was only temporarily closed due to heating to me. It is not unusual for cracks to be open in some spots and closed in other spots. When the job was complete you could still see a 1/2" of "the crack" in the center from certain angles, but everything else looks great. Are you seeing air, or just the outline of the crack? There is a difference and it is important to know what you are looking at. It is not unusual to see part or the entire crack from certain angles even when completely and perfectly filled with resin, but you should not see any air.

When filling the crack you should have seen the resin flowing from the point of injection to the end. If the resin stopped in the middle and did not fill, it also did not fill the end, unless of course you applied resin to the surface ahead of where the resin stopped in the crack which we do not recommend. You should always be pushing the resin through the crack, not just allowing it to seep in from the surface. That means that if you need to apply resin to the surface, you only do it at the point the resin stops or behind that point, never in front of that point. Did you see the resin flow to the end of the crack? If so, the only other possibility of air getting in the center would be if the crack was flexed which could bring air in from the surface. As the crack is filled you can apply curing film to keep air from entering from the surface, but I do not recommend covering any section of the crack that has not yet filled with resin.

A crack expander could be used on the inside of the glass to help open up a crack a little, but I recommend drilling the end prior to using that tool in order to minimize the chance of pulling air from the surface into the crack. If you do use a crack expander it is best to apply prior to filling the crack rather than 1/2 way through the process, but sometimes a technician makes the decision not to use a crack expander and they finds it necessary. In that case you have no choice.

Long story short, it sounds to me like you are not sure if what you see in the center of the crack is air or just reflection. There is no way for me to know that either without seeing it, but with some practice you will be able to tell the difference when you see it. If it is air, you could try filling from the surface, but you will likely need to drill and fill it. If the end is filled with resin and holding I would not drill the end at this point, but it may be something to consider in the future. Sometimes when the resin reaches the end of a crack it will push the crack out even further, so drilling creates a good termination point to stop that from happening.

There are different schools of thought on drilling cracks, but I typically drill anything over 3" long and would definitely drill a crack that is as volatile as the one you were working on. Drilling provides stability and often opens up the crack so the resin flows in easier.

As stated above I would not have heated the crack. In cold weather you should still warm up the windshield, but I don't recommend spot heating except to remove moisture, and then only after warming the glass around the crack prior to moisture removal.

One other thing that is possible is that the crack was already there but was closed when you started the job, however if that was the case using the moisture evaporator would most likely have opened the crack prior to mounting the injector, so I don't think that is way happened in this case.

Based on your post I fear we may have contributed to your confusion yesterday when you called for technical support. I apologize if that is the case. Diagnosing a problem like this without seeing it is very difficult. In reading over my response to you I think it may also be confusing. It's a little easier on the telephone, but the only good way to diagnose a problem like this is to demonstrate in person which is not possible in most cases. Please shoot me an e-mail when you get a chance to evaluate your tech support calls yesterday. We discuss such evaluations in our team meetings in an ongoing effort to improve our technical support.

Quality crack repair takes a lot of practice and we don't spend much time on long cracks in our training class due to time constraints, but we have been considering adding an extra day just for advanced techniques which would include crack repair. We have been holding off because we don't find many technicians who are willing to pay extra for the extra day of training. What is your opinion on this? There is no question in my mind that it would have been beneficial to you, but would you have paid an extra $100 for it and took another day out of your busy schedule for it?

I'm glad you reminded me about charging for our technical support. We bill quarterly and your bill is up to $4500. Do you want us to put that on your card or do you want to send cash?

Just kidding folks. Tech support at Delta Kits has always been free and we have no plans to change that anytime soon.