Drilling repairs

[harrellbenjamin]

J.T Window wrote:
"I liked the post from the guy in Mexico who used an ultrasonic/water bath jewelry cleaner to blast the old resin out of his burrs. The Cheap Tool store in town has one for $30. Anybody else ever used one of these?"

I tried one. I bought it at Circuit City. I didnt notice a lot of difference after I used it.
Its more efficient to just hold the bit over the flame of a gas burner with a pair of pliers and burn off the old resin.

Sounds like a lot of effort to save a few pennys.Why not just put in a new bit every so often?? Unless you drill more often than you need to (I was guilty of this in the beginning) ?? I would think that heating a drill bit would make it more likely to break as the temper is changed at that point after heating?? Just seems like a lot of wasted time to save a few cents........

[Nomad]

If you use the small slightly tapered bits from Brassler, you can use a long nosed plier and simply break the very end off the tip. Gives a new sharp tip to drill with. It will enlarge the hole a little but is still OK for most things until you break it off three or more times. Then I use it to drill holes only in the end of cracks.

My dentist says he does this all the time in the lab.

This will not work with all bits!!

Most of the time you can burn old resin out of the bit by just holding it against the glass and letting it run like you are drilling a hole. It will take a while but will eventually heat up and the resin will burn out of the bit.

I'm not sure but I don't think the carbide end of the bit is affected by heat and doesn't loose temper. At least I haven't noticed that it is affected by heat. Any metallurgists out there?

OOPs, just thought about the times I tried the little ball end bits. Burned up right away the first or second hole. Useless after that. So the above is probably wrong as far as heat and temper are concerned.

[Glass Doctors UK]

although very thin resin may penetrate a repair without drilling, as screen man rightly says drilling is not just for letting resin in, getting water out is just as important too. also anyone who doesnt scurf over a shiny sliver is asking for the pit finish to slide right out in a short time maybe even when it is scraped it will start to lift round the edges. anyone who needs to pop a bullseye is just asking their customer to try someone else who can do it without popping and get a better result.

[quietman]

I drill at end of long cracks and pop a mini-bullseye. I also drill star breaks with stubborn legs that don't fill properly.

[Mr Bill]

Glass Doctors UK
What do you mean by " scurf over"
Do you mean rough up the surface with your drill?

[screenman]

I will answer for him, that is exactly what he means.

As for Nomad burning drills in a couple of uses, he is not using them properly I change drill about every 100 jobs and I use them on most repairs. The answer is to not let them get hot, do not drill into wet resin and if you do hit the laminate burn off the PVB that collects on the drill.

[glassdoctor]

screenman
I know you never mess up and hit the laminate.... what are you talking about? lol

ditto.. I drill most repairs also (as should everyone, ha ha) and bits last long enough I don't keep track. Or maybe I just have chronic short term memory loss syndrome and I just never realized I actually change bits every 3-4 chips.

GD UK:
why does a tapped repair not look good? you seem to think it's really bad to do that.. perhaps you aren't doing it right? lol... I haven't read the whole thread. my apologies if I missed something....

[toab]

Screenman: that can't be just all technique.Those must be damn good bits that u r useing.Care to tell us what brand??
Also heard that some guys use dentist bits.Is that true??

[screenman]

Toab,
The ones I use now are from a dental suppliers, they do not come with a name. I have over the years used drills from many suppliers and have always made them last a long time. We have used Delta drills with no problems whatsoever.

To add to this in training we sometimes show a newbie how not to use a drill and can burn one out on one job, just by overheating. It is suprising how red you can get them to glow.

[ChipperFixer]

You can Google "Dental Suppliers free catalog" and get all kinds of catalogs to order from...I buy burrs in boxes of 100 for .67 a bit. I change out bits about every 5th repair. I also use pit filler for bit lubricant while I drill, it helps them stay sharp and they wont burn up. When I reach the desired depth I wipe off the excess reisen run the dry bit in and out of the hole a few times to dry out the hole and remove the contaminants and there you go....