Cracked Plexi Front Windshield

[interstateflyer]

I have a rock fracture in my right front plexi window shield. 1 1/2 inch.

Is there a way to repair the fracture?

Will it grow in size and eventually fail if not repaired or replaced?

[kswelsh]

I have one just like it. I ordered a Pink Flamingo vinyl decal on Amazon and placed it over the crack. Looks great

[dwightdi]

Plastic fabricators use a thin solvent based acrylic adhesive to glue Plexiglass together for products made from of sheet stock. I have never tried it, but, low viscosity epoxy used to fix rock chipped auto windshields might be able to wick in and fix it.

[dznf0g]

That crack means it did its job! Glass cracked is a much more expensive and complicated problem. I have several like that. When the time comes for replacement, I will go with polycarbonite instead of plexi. My understanding is that poly can make the bends (out of flat stock) without heating or buying OEM parts.

Mine have not grown from their original size in 3 years (oldest one)

[spclkaz]

Not sure what type of TV you have, but I have used some removeable mud flaps similar to these on my PU TV and have never had any thrown rock problems...

[dznf0g]

Ummm, I have rock tamers. Flying rocks from oncoming traffic is my probable cause when considering the location of my cracks.

BTW, Rock Tamers DO reduce the majority of body and window protector damages. Never hook up without them.

[Cadillac4275]

While we're on the topic: I lost my entire plexi guard-frame & all from wind while in the storage facility. (Let's not discuss the details, ok?) I have the frame...can a replacement plexi be done or do I have to buy the whole thing??

[dznf0g]

626, (BTW, welcome) use the search feature for rock guard or plexiglass, or window cover. Somewhere around here there are some older threads on this topic. As I recall, Plexiglass can't be bent around the curve of the side units without cracking unless it can be heated in a large oven. That obviously presents problems. IIRC, polycarbonite can.

I have never seen just the curved plexi available alone and an entire guard segment would have to be purchased.

Flat stock poly and plexi can be purchased locally...just google it.

[StreamDog]

To answer your question, the fracture I have hasn't grown in two years.

[interstateflyer]

Thanks everyone for your suggestions.

I'm pretty certain that the fracture was caused by a damaged right side mud flap not providing complete protection.

I'll try applying helicopter tape on either side of the fracture to help stem it's possible spread.

BTW: The mudflap most likely saved the new Michelin tire from damage when I backed into a hidden piece of rebar. Installing a replacement flap today.

[dwightdi]

Polycarbonate (Tradename- Lexan) must be baked (to remove the moisture) before it is heated to 350 to be bent to match the curve. It will resist stones much better. Plexiglass is acrylic and has very little elongation before it cracks. When hit by a stone it cracks. It is cheaper than Lexan.

[dznf0g]

Hmmm, I gotta find that old thread. I thought it was polycarbonate that could bend (at least enough to make the curve of our AS rock guards). I can't even remember whose post it was.

[dznf0g]

dwight, I think you're right and I have it backwards. I still can't find the particular thread I was looking for, but some others dance around it. A bunch of references to the "cyclops" guard and Lexan bending cold into the frame...but they don't have a radical curve. Several references of Plexi working for cold fitting into the wrap arounds. I just can't find the thread about Lexan used for wrap arounds.

[guskmg]

I have used Rock Tamers for years including a trip to Alaska and back to Fort Worth. No cracks or dents on the stainless steel rock guards or plexiglass ever. On the cracks, try to stop drill just beyond the end of the crack with a plastic drill bit. It will keep the crack from spreading. I'm not sure if epoxy based fillers will work on plexiglas like wind shield glass.
guskmg

[dwightdi]

Ultra Guard is what I have on my truck.

[Gearheart]

As a retired plastic fabricator I can tell you this. Polycarbonate i.e. Lexan, can be bent cold if the thickness is 1/8" or preferably even less. .080-.100 I will not relax into the curve but has to be held under tension. This will eventually result in hairline stress cracks. It absorbs water from the air and as mentioned above it must be slowly heated to drive the moisture out before heating it up to 350 where it can be moulded over a jig. This is complicated voodoo and we refused to even attempt such jobs at our shop. It also explains why Harley D windshields are so expensive. It is a lot easier to hot mould acrylic so that is what the stone guads are made of.

[dznf0g]

Can Plexi be installed cold in our AS wrap around window guards?

[nwclassic]

Consider stopdrilling to resist further cracking. Common strategy used in non pressurized aircraft window repair. A small hole is drilled at the leading end of a crack (which distributes stress across a larger area). A clear filler can then be used to seal it.
Method works equally well for metal cracks.

[frankrightbrain]

Here is a good laugh that will also answer the question about lexan's flexibility. I have a good deal of experience with plexiglass in helicopters. The fix we used in crack repairs was to "stop drill" the extreme ends of all cracks, thus stopping their radiation(growing). On longer cracks after stop drilling we used 18 gage(phone line size) copper wire to lace the crack much like shoe laces after Drilling equidistant holes along both sides of the crack and the ends. Not pretty but functional and met flight safety to exceed 100 knots airspeed. Maybe I'll do mine and post picks.
Another important thing to know about plexiglass or lexan's is to not use any cleaners that have ammonia. It will degrade the polymers and cause chemical induced crazing and eventual failure.

https://m.youtube.com/watch?v=XjuMFfRvuMs&autoplay=1

[thesignlady]

Go with Lexan for your rock guards it is more suitable. Above Gearheart states which thickness to safely use. Lexan cold forms to the compound curve just fine. I replaced a busted wing window where the PO had previously put in plexi. The plexi was in awful condition with full length breaks as well as being super yellowed and hazy, it obviously did not weather well.