Drilling Philosophy 101

[Brent Deines]

Originally Posted by gt_repair

Blind Squirrel
I drill just deep enough to get into what I call the vain of the chip, that is about 25 - 50% into the first layer of glass. Just deep enough

I also use smaller bits from what DELTA uses. I use bits from GT that are .035 for everyday drilling and .025 for drilling in a crack line when needed.

The bits that DELTA uses average .047, .039 and their smallest is .024.
It is like shoping for cereal, so many kinds. What to buy, what to buy.

I do not like the ball type head style, they tend to want to break off in the hole.... I do not drill bearing straight down. I do peck into the hole so I do not burn the bit.

My holes are hard to see when drilling. So I will say again you can drill without have the hole shown.

If you have to drill to get the break to fill I have no beef with your technique. My point was simply that if you don't have to drill, why would you? We don't have to drill with the Delta Kits system, so we don't.

In anticipation of the next question, "Why do you sell burs then?", let me say this. I did not say I never drill, just that I rarely drill. I do drill at the end of long cracks and I use a .047 bur for that purpose as that size seems to work best for tapping a bullseye. This is another technique that I did not use for years, but was taught by one of my customers a number of years ago. Never too old to learn. I use a .024 to bur to drill a starter hole if there is no surface chip at the impact hole, but that is very rare. Most of our customers prefer the .039 bur for this purpose however, so we included the .039 and the .047 burs in our complete windshield repair systems.

I too used to drill much more often, but subtle advances in the equipment we use have made it unnecessary for the most part. This blows people away at trade shows, especially when repairing small star breaks with tiny surface chips at the impact point.

[SGT]

I do not want to debate the technique anyone else uses. To each there own and I respect that. IMHO though, if you are drilling to speed the process up then you will not be getting the best possible cosmetic outcome. If it is becuse your equipment cannot do structual repairs otherwise then you are forced into a necessary evil which with other equipment(DK) is not necessary.

We use Delta Kits tooling and also only drill when it is required to have a structurally sound repair which is rare on most chips. Cracks, I always drill and anchor for structural purposes. This is not hype, false information or anything else, just a fact of capabilities of the equipment we use coupled with a little skill.

Just something to think about...If you drill every repair at least be willing to consider it may not be needed. Try it without drilling using your equipment. If you can fill without drilling then you have to ask yourself what your reasons for drilling are. If you cannot fill with out drilling then ask yourself why not and be willing to consider that it is possible with other systems.

By all means anyone who is questioning the need to drill or just does not think a repair can be done without drilling should go to DK training and see first hand.

If at the end of the day you do not care and drill every repair, Tom Dick or Harry may not agree but it is your and only your decision to make.

[Layne]

Brent---Thanks for your response, I found it to be very informative. I have 12 years experience and have indeed learned a lot from this forum. I drill less now but do find the need occasionally on old chips .

[gt_repair]

I, We do not have to drill because our system in not as good as DELTA. I drill with a .35 just to speed thing along for myself.... I do not need to drill, and the jobs I did today I did one with and without drilling and customer could not tell the differance as did I. It may just be habit as long as I am cleaning out the break with the drill as one other said I just give it a pilet hole.

To stop a crack, I use the same .035 to stop the crack, (no need to go any bigger than that... More of an eye sore if not filled properly). I do not pop the end like others do. I will flex the crack from out side and inside to stop it and have no problems with that...

I think drilling should be done with the smallest bit possable if you are drilling, and that is why I use .035 and inline cracks with .025 unless and if I forget to switch them out then the .025 is my impact driller also.

To satisfy my self, I sized up my bits and they are on the Machinist mic. they are at .025 and .032.. and I drill .050 deep or less based on the depth looking at the bit.

Again, it is not that our non DELTA system can not inject with out drilling but it is by choice..

[Clarity Glass]

Most chips do not need to be drilled. As a self-professed perfectionist I dislike drilling but probably drill 20% to speed the fill time if my customer is in a hurry or if the chip type has a tendency to be slow in filling. If a customer will give me 45 minutes I will fill from the impact. With a quality fill they will say "that is amazing" or "Wow". And, many of the customers have kept my card and come back when they have gotten another chip because they know the quality I strive to achieve. That said, most customers don't care if you drill or not, what they want is for the chip not to spread. Most of the time chips that have been drilled look like a "bug". Without drilling, the aesthetic or finished quality is much better. I think Brent and Delta are interested in giving the highest quality repair because it serves the industry's best interest the more positive experiences the general public has with our service.

[starstruck]

If you guys keep drilling this debate into my head I'm gonna explode!!!!

[SGT]

Originally Posted by gt_repair

To stop a crack, I use the same .035 to stop the crack, (no need to go any bigger than that... More of an eye sore if not filled properly). I do not pop the end like others do. I will flex the crack from out side and inside to stop it and have no problems with that...

Don,

I certainly am not saying your way is wrong but I am trying to understand this a little better. Please bear with me if I mis understood. You do not create an anchor but rather just drill a hole correct?. Couple questions pop out at me...Do you drill to the laminate? (trick question here )

Now in aviation, this form of stop drilling you decribe is the only method and has been around long before anyone even thought of windshield repair but the material being drilled does not allow for anything more. I have seen many these types of stop drills fail due to vibration/stress which forces a perminate repair in the end. I personally feel that with this type of pin hole relief there is not enough hole circumfrence area to effectively relieve the stress.

Now with glass we have the luxary of creating a larger diameter anchor than our pilot hole for stress relief. If done properly it also ensures that the reliefe anchor reaches the laminate and the crack will not pass under. I can not say I have seen a crack extend beyond an properly done anchor point. On the other hand I have seen quite a few that progressed byenond just a pilot hole you speak of.

Sorry about that my second question is What made you decide on this method of stop drilling?

It is in my opinion the hardest part of crack repair, getting the crack anchored correctly. Although very simple after you get the hang of it, creating the anchor is usually the biggest fear for techs as they fear not drilling to the correct depth and or taping to hard will cuase a run.

Please do not go on the defensive, I am just trying to get a better understanding of your reasoning and possibly provide additional food for thought as to why anchoring may be more structurally sound.

[SGT]

Originally Posted by gt_repair

To stop a crack, I use the same .035 to stop the crack, (no need to go any bigger than that... More of an eye sore if not filled properly). I do not pop the end like others do. I will flex the crack from out side and inside to stop it and have no problems with that...

Don,

I certainly am not saying your way is wrong but I am trying to understand this a little better. Please bear with me if I mis understood. You do not create an anchor but rather just drill a hole correct?. Couple questions pop out at me...Do you drill to the laminate? (trick question here )

Now in aviation, this form of stop drilling you decribe is the only method and has been around long before anyone even thought of windshield repair but the material being drilled does not allow for anything more. I have seen many these types of stop drills fail due to vibration/stress which forces a perminate repair in the end. I personally feel that with this type of pin hole relief there is not enough hole circumfrence area to effectively relieve the stress.

Now with glass we have the luxary of creating a larger diameter anchor than our pilot hole for stress relief. If done properly it also ensures that the reliefe anchor reaches the laminate and the crack will not pass under. I can not say I have seen a crack extend beyond an properly done anchor point. On the other hand I have seen quite a few that progressed byenond just a pilot hole you speak of.

Sorry about that my second question is What made you decide on this method of stop drilling?

It is in my opinion the hardest part of crack repair, getting the crack anchored correctly. Although very simple after you get the hang of it, creating the anchor is usually the biggest fear for techs as they fear not drilling to the correct depth and or taping to hard will cuase a run.

Please do not go on the defensive, I am just trying to get a better understanding of your reasoning and possibly provide additional food for thought as to why anchoring may be more structurally sound.

[gt_repair]

Brian
What I do is drill about 1/8 - 1/4" in front of the crack. I drill just to the lamination with out really going crazy. I work with two hands and you know you can JUST feel when it is going to break through to the lamination and stop there... I start with a new bit each time to keep the heat down...

I will take the back side of my pribe and tap the glass to walk in to the break(holding breath).

( my method ) The way I came about flexing it, or pushing it from the inside with my back side of my probe was to releive the presure as it if I was puting a crackjack on the inside right on the drill point to open up the crack. That takes the presure off it at that point and I do not have to tighen the jack so hard for that last bit.

FOOT NOTE: Just like some cracks, you can read it all you want and say it will go this way and it will go that way instead. That is why I also use smaller bits. It is a smaller hole to hide.. My customers know the chances I am taking and it does pretty good for me for about 12 or so years. It took a while before I found this method. I will stand behind this 200%. Once you see what I done, you will say, Sh#t, I could do that.

Get an old junk yard car and do it in the car. not a windshield on a rack. It will not be the same... Try it on a friends car with full glass (as a back up) and let them know you need to try a new method.

I will tell you I am just as picky at what I do also. I treat every car with the best respect. It could be a junker to us, but that is all the customer may be able to afford.

I have the used lots calling me in before they have to replace the glass to see if I can stop and hide the cracks...

I hope you try it before slaming me on what I do..... It works.

Good luck.

[SGT]

Don,

Thanks for providing your insight on your method. I was hopeing for more of technical reply on the benifits you thought your method has and to compare the two methods we have.

I certainly am not going to slam you or anyone else. I will have to say that my years of stop drilling in aviation and windshield repair have provided me with the experiences that drilling and anchoring is structurally the best method for me. Your way is the right way for you and that is fine also. So we will have to agree to disagree on this method of crack stop drilling.