Unconnected crack leg

[Mr Bill]

Sometimes I see combination or starbreak chips which have little unconnected legs which are about 1/8 to 3/8 inches long.The main chip fills ok, but the unconnected legs do not. I have drilled into them and popped a bullseye, but when I inject resin, they only fill partially. These legs are very tight. probing them does not help.
What is the best method for filling them or connecting them to the rest of the chip?

[GlassStarz]

have you tried a crack spreader?

[Mr Bill]

It never occurred to me to use a crack spreader on something so small.

[GlassStarz]

Sometimes a little pressure from inside is all you need to open that obnoxios leg be gentle though dont want to spread it

[screenman]

Is it possible these legs are actually connected but contain some moisture. As water has roughly the same refraction index of glass it is sometimes difficult to see properly. This would also explain why the leg looks like it is partially filling. Most unconnected legs reasonably close to a damage should break into the centre with just a light tap in the correct area. Are you also using a UV shield as premature curing can be a major problem in some places in fact I would say most. Please do not take this reply as a slight on your expertise, I am just trying to come up with a few suggestions.

[Mr Bill]

I did use a UV screen.
I welcome all suggestions. Hopefully more people will offer opinions. Its nice to see how other people would handle the problem.

[SGT]

When I encounter a disconnected leg and cannot get it to join the main void with probing/flexing, then this is one of the rare times I will have to drill using Delta Kits tooling to open the chip and connect it.

[sgailey]

You can try using heat to force the air out of the crack. The DS100 works quite well for this, because it heats a small area, gradually.

I would not recommend attempting this during the pressure cycle. Apply heat close to the glass, about 1/2 in. from the end of the troublesome leg. Continue to apply heat until you see the tip of the crack begin to close. Apply additional heat if necessary to close the crack the rest of the way. If the crack is indeed connected to the rest of the break, trapped air will be forced out of the leg as it closes.

Be sure to let the glass cool down before setting another pressure cycle.

[screenman]

If the leg is unconnected and is very likely to be subsurface then car I think may not help, where will the air go and how will the resin get in? However if the legs is connected and just hard to fill and does not have moisture in as I mentioned earlier then some heat can help. Althoug I prefer flexing and holding. We have guys in for trainig that have been shown to flex a leg by just giving it a quick push, when flexing what you are doing is holding the leg open wider to allow the resin to flow. So when you flex hold the pressure until you see the resin stop flowiing and then release go onto to vacuum for a while and the pressure again if needed.

[tooldini]

I do what Glasstarz does just pushing on the center. I press quick and fairly hard. When desperate I just flex from all angles inside and out. Usually you can get is connected but screenman is right it could be moisture if you didn't dry it out first. Are you talking about drilling at the end of the crack or into the pit on the combo? If have before drilled and popped into the combo pit this has helped connect some funny cracks.