Stubborn Legs

[FIX A CHIP AUST]

My last couple of jobs have been stars with tight legs and I'm having problems filling them right to the end, any ideas why?

[screenman]

We really need some more insight. Could be and most often is premature curing of the resin, moisture in the legs, legs not connected, legs open to surface and many more. Although I would point to the first 2 too be the most likely. Proper preparation is everything.

[FIX A CHIP AUST]

I have searched some previous posts on similar subjects and I agree as we have had a lot of rain lately however the last two days have been very hot with high a uv index I beleive it is combo moisture and premature curing. I should have search the forum before posting. Thanks for the info.

[Glassdoc]

One of the most common over looked cures missed when filling a star break is too much injector head pressure. (the injector is too tight against the glass). This force actually pushes down on the star causing the legs to close themselves off so they won't fill.. The proper amount of pressure is just enough so the injector does not leak.. Too often, even I when coming out of winter mode to summer find myself using too much pressure.. Just a thought.

[splitpit]

I don't really follow the premature curing issue. If you are taking the proper care during your repair, how are you getting premature curing? I agree with glasdoc that injector pressure can be an issue and certainly moisture could be the culprit. If in doubt, dry it out.

[jayjacque]

I had a couple yesterday that were just bears. Other ones I did went fine. But those couple gave me fits. Maybe it was that I didn't dry them out. The day was sunny and they just looked like normal stars, one with 3 legs, the other with 4 or 5. Tried popping. tried heating on the vacuum cycle, tried just waiting. But that's a question I have: If you heat on the vacuum cycle on starbreaks can you give it time to fill after that and/or can you do another vacuum cycle or two? In other words, after heating, when it starts to cool back down, does the break then close off so it's hard to fill say 5 or more minutes later?

[screenman]

To those of you that might not understand what I mean by premature curing, it is when you let some UV from whatever source direct or indirect get to the resin before it flows to the end of the legs. This causes the resin to thicken and to cease to flow. Now we might have different water over here than other parts of the world but we find that 2 dry days would not mean that moisture was not present. Whilst I agree increased injector head pressure can cause some flow restriction, in tests we have carried out this tends to apply more to combinations than starbreaks.
Now I have posted this before but you can try this very easy test, on the shady side of the car maybe even a side window place a small drop of pit fill on the glass and cover it, wait a minute and even in the shade you will find it has cured. Proof if any is needed of the need for a UV shield at all times.

Now when we flex a star with a probe the legs open ,so if we increase the injector head pressure does not the same happen, it did when I just tried it on our practise screen. Make an upside down V shape now this is the shape of most damage place it on a surface and push down and it opens up, pull up and it closes. This is an example of what happens when we flex starbreak.

Splitpit I am not asking you to do these excersise as I know you are already very succesful but these are some of the thing we get guys to do in our training classes. It works great for getting the message across.

Hey who pinched my if in doubt dry it out line. I have copyright on that one. LOL

[splitpit]

I know what premature curing is. I'm just saying that it shouldn't happen if proper care is being taken during the repair.

[GlassStarz]

There are many reasons for legs not to fill here are a few I have run across and my solution
1.Legs open to surface resulting in loss of pressure keeping them from getting resin to end of leg/ I often put a cure tab on the leg if the leg goes to the surface you will see a little resin seeping putting a cure tab on it seems to plug the loss and after a little time leg fills
2. too much head pressure flexs it enough to close the leg/Just back off on the head a little
3.Non connected legs/ Flex them a little this often works or in worst case break out the evil drill

As we all know the star or spider is the hardest to fill I often will use a match on the inside when injector in vac mode then put into pressure mode as the glass cools it will pull resin into the end

[screenman]

Whilst I agree with legs to the surface which I mentioned on an earlier post, we find with the correct preperation stars fill far easier than some other style breaks. Such as combinations, bat wings etc. But on the whole with the correct method nothing is much of a probelm. I have just retried the head pressure test and we can still see the legs open. The trainee looking over my shoulder reading this is enjoying the banter. Legs not connected is obviously part of the perperation process before we apply the bridge.