Longer Cracks

[scrubs147]

I got a call today for a crack in the windshield. The crack started from the driver's center view and went under the seal of the windshield's side bar (about 12" in length); the crack was "S" shaped. From what I understand, a crack should not be repaired if it disappears underneath the seal. Yesterday I saw a "Safelite" tech (my next door neighbor) remove the bottom molding under the wiper. He then filled a small crack all the way to the windshield's edge. My question is, if you can get to where you can see the edge of the windshield, is it OK to fill the crack?

[puka pau]

The short answer is "yes". The somewhat longer answer is that you should ensure that the section of the crack that extends under the molding to the edge is both clean and dry. If the molding is flexible you can wedge it open above the glass surface so that the edge of the glass and hence the termination of the crack is exposed. If there is residual moisture under the molding, extra care is required to make sure that the first few inches of the crack remain dry. Moisture has a tendency to "wick" or travel by capillary action along the length of a crack. You may think you have dried the crack completely only to discover that the first few inches close to the edge have mysteriously accumulated more moisture. I've repaired literally thousands of cracks extending to the edge of the glass with consistently favorable results. So your question begs a question in response: Who told you that it was not proper technique to repair a crack extending to the edge?

Cheers;

Puka Pau

[screenman]

If I cannot get under the moulding I drill and pop close to it, this gives the glass a new edge so to speak. I use an airline to dry out all long breaks and blow the water out of the seals.

[scrubs147]

If I recall correctly, during DeltaKit's training, we were advised to stay away from any cracks that travel under the seal's edge. I believe that the reason they gave us for this was because you could not see if any of the resin filled the entire crack, so as long as you are not able to see your repair there is no way of knowing that your repair was successful. Now I understand that Delta's training only touches on the basics and they cannot cover every scenario that could happen which is why we post our question here. So, to answer the question, "who told me I couldn't fill a crack to the edge?" No one did. It is only an answer to a question that I am looking for so I can further my experience to get closer to perfection... eventually.

Also, Delta's training gave me the confidence I was looking that I couldn't do on my own... thanks.

[Brent Deines]

I will review our training materials and discuss this point with our trainers. I don't tell technicians that they cannot repair edge cracks and agree with screenman on procedure if you cannot get to the edge of the crack because of a non-removable molding. I've also removed moldings and cowlings when applicable to repair an edge crack. I'm sorry if we gave you the impression that an edge crack could not be done. That is simply not the case.

Delta Kits does train to the ROLAGS standard which lists "Edge crack(s) that intersect more than one edge" as a repair limitation where replacement is recommended. Keep in mind that ROLAGS is a work in progress so that certainly does not mean that a qualified windshield repair technician cannot successfully repair damage that is listed as a "limitation" by ROLAGS. Every technician will have to determine if they want to adhere to the standard or not, but I feel it's a good idea to know what the standard is and write to the ROLAGS committee if you think something should be changed.

[paulrsf]

What I recall hearing during the Delta Kits training was that new technicians might want to steer away from attempting repairs where the damage extends into the seal until they have more experience and confidence making repairs. It made sense to me since new technicians have a lot to absorb and these types of repairs can be more involved. I still often turn down making these types of repairs if I sense there is any significant instability in the glass or if the conditions present make it hard to determine if I can get to the entire damaged area. Personally, I'd be more inclined not to repair an especially long crack than I would be worried about attempting a repair that extends under the seal.

[puka pau]

In my experience I've found that commercial compressed air sources ('shop' air) are suspect from contamination by either moisture or compressor lubricant (oil). Either of these contaminants will negatively affect the quality of the repair. You could use a commercially available can of compressed air, build an attachment consisting of a moisture and oil filter with the requisite fittings to plug into the shop air line or (as I did) build your own unit. I bought a 12 volt oilless compressor that fits into a small tool box just slightly smaller than the Delta box fit a moisture filter to it and wired a battery and a female accessory plug for my Drystar moisture evaporator and UV cure light. This unit allows me to be self-contained and work on site without having to rely on a shop for either compressed air or 12 volt power.
Also, I've found that even if it's impractical or impossible to cure the last inch or so of the crack that disappears under the molding it rarely if ever affects either the initial quality or the longevity of the repair.
And lastly, I find it curious that after all this time the ROLAGS specifications (such as they may be) remain a 'work in progress'. If nothing else, this just indicates to me continual politicking nitpicking and turf defending between the repair tool vendors, the glass replacement guys and the insurance companies - all at the expense of the technicians in the field. In my long and somewhat varied professional life I've been a member of several professional associations and trade unions and I have to say that this WSR business is sometimes both a curious and odiferous kettle of fish indeed.

Cheers;

Puka Pau

[screenman]

I have not found a problem at any of my customers with contaminated air, if I did I would just fit a filter behind my blow gun. What pressure and volume of air do you get from your 12v machine?

[puka pau]

Screenman;

My self-contained oilless compressor (which also can be used in vacuum mode) is rated at 100 psi and 1.7 cfm. These are the nominal specs at the compressor outlet at full power without attachments like a hose or nozzle. I use a needle tip nozzle the orifice of which is about the size of a mechanical pencil lead (smaller than a wood pencil lead) which increases the psi but probably slightly impedes the cfm.
I was made aware of the potential for contaminated air by the instructor that taught me long crack repair techniques more than twenty years ago and that potential was confirmed by more than one fleet/truck/bus service manager. You probably won't ever see a mist of either water vapor or lube oil spewing from the air nozzle but this doesn't necessarily mean that contamination isn't present. In fact, even a brand new oil-lubed compressor will pass enough lubricant around the piston ring(s) to significantly (for the purposes of WSR) contaminate the air flow. So if you use shop air chances are the air is contaminated by either moisture or oil. As I've found through experience that effective long crack repair is excessively dependent on environmental factors my strategy has always been to be safe rather than sorry. A question for you: if you use shop air exclusively, how do you dry out long cracks on site prior to repair? Or do you not repair long cracks on site?

Cheers;

Puka Pau

[screenman]

All my repairs are carried out at the fleet companies base, without exception they all get vehicles inside for me if I ask them. Like you I have been doing long crack repair for over 20 years, well 23 to be exact I am more than happy with my success ratio. However this does not mean I will not look for the equipment you talk about, as I am sure that it will help the guys that come through me for training.

Most companies over here use a screw type compressor, this lets out far less contaminates than a normal compressor, they also have many filters and moisture removers along the line.