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Air bubbles around bullseye edges.
Posted: June 15th, 2021, 8:49 pm
by HBCC
So I have been repairing chips for 7 years now and lately I have been experiencing at about 80% of the time the following.
This is specific to bulls eyes only.
I pressurize and vacuum cycle as I have always done but once I release the bridge from the windscreen tiny air pockets will appear around the outside of the bulls eye.
At first I thought it was due to too much pressure on the glass itself from the bridge and the glass flexing back to its original position.
I have reduced bridge pressure and also tried to push resin into the chip as I am unwinding the piston from the glass.
No matter what I do this is continuing to happen.
Could this just be a batch of resin which is not viscous enough ? I am at a loss.
Regards
Paul.
Re: Air bubbles around bullseye edges.
Posted: June 17th, 2021, 4:53 pm
by Brent Deines
Hi Paul,
As always there are a number of possibilities, but one thing you said makes something jump immediately to my mind. Are you unwinding the "piston" from the cylinder before removing the bridge from the glass? Assuming you are using a Delta Kits bridge, this would be a mistake. The injector and/or complete bridge should always be removed while the injector is in the pressure position.
Please clarify, are you unwinding the piston from the cylinder, or the entire cylinder from the bridge before applying pit filler and a curing tab? The former can cause the problem you are describing. The latter is the correct procedure.
Personally I loosen the adjustment knob in the center of the bridge and swivel it out of the way before applying pit filler and a curing tab. That way if I do see any air bubbles that were not visible while the bridge is in place, I can swivel it right back over the damage to run another pressure/vacuum cycle or two.
It's unlikely bad resin in my opinion. Even if for some reason the resin is bad, you should still be able to fill the damage and remove the air.
HBCC wrote: ↑June 15th, 2021, 8:49 pm
So I have been repairing chips for 7 years now and lately I have been experiencing at about 80% of the time the following.
This is specific to bulls eyes only.
I pressurize and vacuum cycle as I have always done but once I release the bridge from the windscreen tiny air pockets will appear around the outside of the bulls eye.
At first I thought it was due to too much pressure on the glass itself from the bridge and the glass flexing back to its original position.
I have reduced bridge pressure and also tried to push resin into the chip as I am unwinding the piston from the glass.
No matter what I do this is continuing to happen.
Could this just be a batch of resin which is not viscous enough ? I am at a loss.
Regards
Paul.
Re: Air bubbles around bullseye edges.
Posted: June 18th, 2021, 3:36 pm
by DRAMIREZ.1
I have had the same thing happen to me too. When pulling the vacuum I have noticed the resin pulling in on edges of the bulls eye. I unscrew the injector while it is still under pressure. This has cleared
up the problem.
Re: Air bubbles around bullseye edges.
Posted: June 23rd, 2021, 11:51 am
by kennycrane
I know that this is not protocol but when I see that air is remaining on a vacuum cycle and I cannot get it out, I do not hesitate to cure under pressure, works every time.
Re: Air bubbles around bullseye edges.
Posted: June 25th, 2021, 2:11 pm
by HBCC
Hi Brent,
I normally release the entire bridge, I was unscrewing to try and find a work around.
Brent Deines wrote: ↑June 17th, 2021, 4:53 pm
Hi Paul,
As always there are a number of possibilities, but one thing you said makes something jump immediately to my mind. Are you unwinding the "piston" from the cylinder before removing the bridge from the glass? Assuming you are using a Delta Kits bridge, this would be a mistake. The injector and/or complete bridge should always be removed while the injector is in the pressure position.
Please clarify, are you unwinding the piston from the cylinder, or the entire cylinder from the bridge before applying pit filler and a curing tab? The former can cause the problem you are describing. The latter is the correct procedure.
Personally I loosen the adjustment knob in the center of the bridge and swivel it out of the way before applying pit filler and a curing tab. That way if I do see any air bubbles that were not visible while the bridge is in place, I can swivel it right back over the damage to run another pressure/vacuum cycle or two.
It's unlikely bad resin in my opinion. Even if for some reason the resin is bad, you should still be able to fill the damage and remove the air.
HBCC wrote: ↑June 15th, 2021, 8:49 pm
So I have been repairing chips for 7 years now and lately I have been experiencing at about 80% of the time the following.
This is specific to bulls eyes only.
I pressurize and vacuum cycle as I have always done but once I release the bridge from the windscreen tiny air pockets will appear around the outside of the bulls eye.
At first I thought it was due to too much pressure on the glass itself from the bridge and the glass flexing back to its original position.
I have reduced bridge pressure and also tried to push resin into the chip as I am unwinding the piston from the glass.
No matter what I do this is continuing to happen.
Could this just be a batch of resin which is not viscous enough ? I am at a loss.
Regards
Paul.
Re: Air bubbles around bullseye edges.
Posted: June 25th, 2021, 2:13 pm
by HBCC
This is my current work around also.
I would like to add that the air bubbles I am experiencing are not visible until the bridge is removed.
kennycrane wrote: ↑June 23rd, 2021, 11:51 am
I know that this is not protocol but when I see that air is remaining on a vacuum cycle and I cannot get it out, I do not hesitate to cure under pressure, works every time.
Re: Air bubbles around bullseye edges.
Posted: June 28th, 2021, 5:43 pm
by Brent Deines
Gotcha. I'm not opposed to trying to cure under pressure if nothing else works, but if it is happening frequently something else is going on, especially with a bullseye. I can't tell you how many people I've talked with over the years who have said that after months or years of repairing windshields they started having this problem, only to realize something in their process changed. Sometimes they figure it out on their own, sometimes I have been able to help them over the telephone, and sometimes they discover something in a training class that helps them. I know Korey has helped a lot of people by video call as well. Often we can identify something just by watching someone do a repair. Let us know if you want to schedule a call or video call to see if we can help. That definitely should not be a recurring problem when filling bullseyes.