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I have about a 1 inch crack in my windscreen where it attaches to the screws, I was wondering if there is something I could do to keep it from spreading ? it is a clearview windscreen with vents.
 

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Drill a small hole at the end of it... If you are brave enough

Don't use a brand new drill bit, a slightly worn one is best, do not twist or bend the drill, be while it is in the hole.

Some people put sticky tape on the surface first to prevent slipping or scratching while getting started

Do not push hard and be careful as it brakes through - you can avoid chipping by switching to the other side once the centre has broken through and finish from the new side.
 

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Just make sure you get all the way to the end of the crack. It's better to be a little past the end than not to the end. If you don't get far enough out the crack will continue to spread.
 

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I have spend a lot of years as a private pilot and have seen and fixed a lot of cracked canopies.

Here's a pdf file showing some of the common ways to fix cracks. In aviation, we used to stop-drill the end of the crack, then drill a series of very small holes along each side of the crack and then lace the crack with either brass wire or stainless steel wire. This removes further pressure from propagating the crack.

http://www.glapinc.com/instructions/pdf/AC43.131BChapter3.pdf

Hopefully some of this will help solve your problem.
 

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Good point Buffalo
Better to be ahead of the crack tip than behind it (and it might be slightly further on than it looks to the eye)

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Boring tech alert

If "common sense" tells any readers that you can't strengthen something by removing material-

The hole is made to blunt the crack.
In simplified terms the crack needs a sharp point in order to grow (propagate).
This focuses all the stress into a tiny area.
It also means that the bonds holding the material are broken at the tip of the crack, so the next bond is supported by its neighbours except in that one area, the area where all the stress is concentrated - so it is also likely to fail.
Blunting the crack spreads out the stress and takes away and prevents the bonds being broken one at a time (this is down at molecular levels)

You can easily see something similar with plastic food packaging. With a perfect flat edge it takes a lot of effort to tear open. If there is a zig zag or a snip in the edge it is very easy to tear. This is also why you scratch glass or bricks before you try to split them.

Composite materials (fibreglass, carbon fibre) gain strength by building this idea into their structure. The cracks hit the interface between the fibres and the resin and split/change direction or circle the fibre; weakening the crack like the hole does but leaving the intact fibre caught up in the matrix to support the area.

This isn't a new discovery, for thousands of years people have mixed hair into baked mud and impurities in metal because they discovered it made it stronger
 

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Good point Buffalo
Better to be ahead of the crack tip than behind it (and it might be slightly further on than it looks to the eye)
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This isn't a new discovery, for thousands of years people have mixed hair into baked mud and impurities in metal because they discovered it made it stronger
To add on to Mr Fly's comment; Property I used to own had plaster and lath walls. Plaster is made with horse hair for that extra strength.

And to add another point, a drill bit for acrylic or plastic is often sold at craft stores. They are at a 60 degree angle point, not the same bit as wood/metal bits. Cost is minimal >$5.
 
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