Cracked Plexi Rock Guard

[Roadtech]

I have an crack on my curb side plexiglass curved rock guard. The L shaped crack is about 1 inch horizontal and 4 inch vertical crack. Should I replace the rock guard now or wait until I have more cracks? I wonder if another rock hits the cracked area, whether it will go through.

[A W Warn]

I have a few cracks in mine, from three different rocks on the Excella and one on the Safari. I have no plans to replace them.

[dznf0g]

I have several, when it gets bad enough, I'll replace with polycarbonate.

[Morgan guy]

One thing you might try to delay replacing the rock guard is to obtain some liquid acrylic (or acrylic cement) and slowly squeeze it into the lines of the crack. It will seal the crack and minimize problems if you are hit with another rock.

[mandolindave]

You could put a cool sticker over the crack. It might slow down the spread of the crack if you drilled small holes at the ends of the crack.

[SKP46015]

Is it just me that has aluminum rock guards on my old Excella...? when did Airstream move to a pexiglass (?) rock guard... was that a cost-saving move for them?

[dznf0g]

Originally Posted by SKP46015

Is it just me that has aluminum rock guards on my old Excella...? when did Airstream move to a pexiglass (?) rock guard... was that a cost-saving move for them?

We're talking about the window guards, not the corner protectors.

[dames7]

We just return from a 6000 mile trip to the Northwest and thank GOD I got a
ROCK TAMER MUD Flaps on my TV and did not see one ding on the AS or crack window guard. Well with the $200+

I camp next to another AS in Montana and he had all 3 windows guards broken from rocks on the road over the last 2 years.

[dznf0g]

Yeah I have rocktamers. They don't help with stones thrown form passing or oncoming vehicles.

[GammaDog]

I took a rock to one of my plexi wraps on i90 in SD in July. Went right through leaving a hole the size of a dollar bill. It saved the glass underneath. That part new from airstream will set you back almost $500. You can install it in 10 min with minimal effort. The window underneath is almost $1,000 and must be rerivited.

I'd live with cracks for $500 but replaced mine given the hole and a personal belief that sometimes lightning does strike twice.

[dznf0g]

Gamma, I assume you replaced frame and all? You can, with some cutting and riveting get plexi (or polycarbonate) stock and replace the plastic only. I understand, however, that plexi has to be heated to make the curve of the side guards....could be tricky.

[dwightdi]

To have the best strength Plexi window guards need to be formed by what is called slump molding. You have a wood male form mold and then heat the plexi up to the point that it droops over the form to make the curve. This results in no molded in stress and the window guard is best at resisting stones. If you cold bend plexi you have a high stress and it will crack if impacted with a small stone. Poly carbonate (Lexan) is somewhat subject to the similar limitations. It must be heated slowly to dry it out and not cause bubbles to form.

[dznf0g]

Originally Posted by dwightdi

To have the best strength Plexi window guards need to be formed by what is called slump molding. You have a wood male form mold and then heat the plexi up to the point that it droops over the form to make the curve. This results in no molded in stress and the window guard is best at resisting stones. If you cold bend plexi you have a high stress and it will crack if impacted with a small stone. Poly carbonate (Lexan) is somewhat subject to the similar limitations. It must be heated slowly to dry it out and not cause bubbles to form.

Dwight, I keep getting mixed info on the poly. Some say that with thicker sheets, heating is necessary but not thinner sheets. I don't remember thicknesses mentioned, nor what is OE in our plexi guards. Thinner and more crack resistant may be better than thicker plexi????? If it is thinner, I'd just have to find extra thick spline material (they already use special order thick spline with the OE setup.

Can you shed light on the thickness debate?

[amaier7771]

Subscribing, this is interesting....