Stubborn Repair

[Sneck]

Northidahotim,

For me personally, I drill as a last resort. 90% of my repair jobs (with the exception of long crack repair) are done with out the need of drilling.

But on the occasional "tight star" where there is no "body" to the damage - just a small impact "point" with star like cracks, that's when I drill and pop a mini on a star to connect the legs. I did one just last night exactly like this where I knew looking at it that it would not take resin - so I drilled and popped a mini bull.

Even doing this, it still took about 1/2 hour for the resin to advance to the tips of the star break - partly because It was getting cool outside, and partly because I was taking my time and did not rush anything. I was tempted to use heat to speed it up, but I decided against it and just waited it out. It turned out absolutely perfect.

[northidahotim]

ok. That's what happened today. I went through the vacuum/injection cycle 3 Xs. The legs were not filling. Very small surface hole. I mean to say a couple of the legs weren't filling. When I applied pressure to try to work the resin into the legs the other legs started growing. I worked on it for about 45 minutes. In the case that resin isn't working its way to the very end of the legs just leave in injection cyle? Let it work its way. I was going to market my services to car dealers until this past 2 weeks. I had a star chip spread on me about 2 weeks ago and had a hard time with this one today and am not confident that its going to hold. I use GW so I have good equipment. I don't want to be a hack. This is a long term opportunity for me. All the help is greatly appreciated.

[Sneck]

Northidahotim,

When I applied pressure to try to work the resin into the legs the other legs started growing.

You may have had too much stem pressure, or too much injection pressure (or both).

In the case that resin isn't working its way to the very end of the legs just leave in injection cyle? Let it work its way.

Yes

I was going to market my services to car dealers until this past 2 weeks. I had a star chip spread on me about 2 weeks ago and had a hard time with this one today and am not confident that its going to hold.

Just hang in there and keep practicing. Keep doing it until you can almost do it blind-folded

When I first started years ago, I had the worst trouble getting star breaks to turn out like they should. I found that it boils more down to what you know and learn over what equipment you are using.

My trouble on star breaks years ago was simply using too much injection pressure, and too much stem pressure, using heat, and not allowing enough time.

Rock chip repair requires very little injection pressure, and too much stem pressure (injector against the glass) can actually make it more difficult to fill.

You only need enough stem pressure to keep your injector from leaking.

Sometimes flexing a star leg with the probe on the outside of the glass on a stubborn leg will get the resin flowing.

Sometimes inserting the probe down the throat of your injector and flexing the center of the break will open things up and allow for better resin flow.
If your probe does not fit inside the injector, buy a skinny probe from a hardware store.

I hardly ever use heat. Some techs use it all the time, some never, and some will use it sparingly. The heat actually causes the glass to expand. That means that the cracks will swell shut - closing off the resin supply. That is when a crack will look like it is repaired to a new tech but infact is not repaired yet. What needs to still happen is allow the glass to cool, and as it contracts the resin will be drawn into the crack(s).

Personally, I prefer flexing the legs and allowing for more time over the use of heat.

I use these techniques with more than one type of manufactures equipment and obtain the same great results.

Hope this helps.

[firebob66]

Are you drilling your repairs? I don't often do a great deal of drilling as I have found in my 12 years of repair work that this can actually cause more issues than it's worth. I have found that a good vaccum session and maybe a few cycles of this helps with a little heat under lower pressure makes for a nice repair.

[screenman]

Using heat under pressure I feel is counter productive as the glass expands closing the legs off. The way I prefer is to use heat if I have to is when the damage is under vaccuum, this will in effect shut the damage up and force the air out of the break. Start warming from the outside perimetre of the damage and work your way to the centre ( or should that be center depends which side of the pond ). Once the damage has closed down then one can apply slight pressure so that resin is drawn in to the void as the repair and the surrounding glass returns to its normal size.
Warming under pressure does allow a very small window of time when the repair is made slightly larger but only for second or so whilst the inner glass expands the damage. Also heating under pressure increases the chances of the damage running.


I hope I have explained this properly.

[firebob66]

I'm with you on this, but I think you mean the glass contracts, is this correct? You nailed it when you mentioned a small window of opportunity regarding some limited heat under pressure. I do often add some limited heat during the vaccuum stages. A person needs to be careful when using heat, as too much will make things very interesting in a hurry. I have not experimented with crack repair as of yet.

[screenman]

No the glass expands when heated and contracts when cooled.
This small window of oppertunity as we call it is not sufficient to let resin flow very far. Try viewing repairs under a strong manifying glass you will be amazed at what you will see.

[firebob66]

Thanks for the insite on the heat issue. I understand your point, and will file it for my next difficult repair.

[northidahotim]

Thanks for the input! I had another small star today and with the info i got off the forum last night was pleased with the results. I just let the cycles run long. Long vacuum, Long injection. One confusing thing is that the legs filled but I had a hard time with the area right at the mouth of the injector. It didnt want to fill. I just left it on injection and it took about 4 minutes but finally filled.