Rock Guard Cracked on bottom

DEvans1 · 04-23-2018, 03:22 PM

Our Rock Guard on the front of our 2013 trailer has a small crack about 1 in on the bottom section that curves in toward the trailer. I've been thinking of gluing in a long and very light piece of plastic or wood across the bottom on the inside of the guard to reinforce the area and keep the crack from moving to the facing of the rock guard. Has anyone done this before? Any advice on glue and/or material to reinforce the crack. The rock guard is plastic so something that will bond well but be light enough to not create additional stress.

**Bill** · 04-23-2018, 06:06 PM

First, see if you can switch the front and rear stone guards. On some TM's you could do this - on others they are a different size. If you can switch them, it will prevent any future stress on the repaired guard. BTW, the guards are surprisingly easy to remove. Don't remove any screws!

When mine cracked, I got a piece of aluminum strap (any hardware store), I think 1/16 inch thick and about 4 inches long. I positioned this inside bottom flat part of the stone guard, as you suggest, then pulled the crack closed and drilled two holes on each side of the crack so I could pop rivet it into position. You may be able to buy white rivets, or you may have to paint them yourself. Use aluminum rivets - they are easy to pull.

After riveting, I used a wet finger to push a bit of white caulk into the crack from outside, just to hide the crack.

Mine has lasted quite well.

Bill

HoMiPa · 04-24-2018, 06:10 AM

Another option might be to use moldable plastic pellets, on the inside of the rock guard. Several brands out there - Polly Plastics, ThermoMorph, InstaMorph, Moldamer - a search on Amazon for moldable plastic pellets will take you to them, small to large quantities.

**Bill** · 04-24-2018, 10:21 AM

Holly -

I never heard of these, so I am glad to know about them. Do you think it would be wise for the OP to drill a few 1/8" holes, maybe two on each side of the crack, and put an aluminum pop rivet through each hole? The rivets themselves would contribute no strength, but the extended lumpy backside of the rivet would give the moldable plastic something to grip.

One thing we all forgot to mention is that the first step in the repair should be to drill a hole through the very end of the crack. This will prevent the crack from continuing to propagate further into the rock guard.

Bill

HoMiPa · 04-24-2018, 10:34 AM

Quote:

Originally Posted by Bill

Holly -

I never heard of these, so I am glad to know about them. Do you think it would be wise for the OP to drill a few 1/8" holes, maybe two on each side of the crack, and put an aluminum pop rivet through each hole? The rivets themselves would contribute no strength, but the extended lumpy backside of the rivet would give the moldable plastic something to grip.

One thing we all forgot to mention is that the first step in the repair should be to drill a hole through the very end of the crack. This will prevent the crack from continuing to propagate further into the rock guard.

Bill

I wonder if perhaps just drilling a couple of small holes, and molding the plastic into them, along with over the back side of the crack, would work just as easy, without the pop rivets? This stuff molds really easy, into cracks, etc.

I only know of this stuff because my daughter is a theatre props master, so she uses this stuff to mold things sometimes. It's fun stuff. LOL But reading the reviews, a lot of people have used it to mend plastic things, with great success. I've played with it, never mended anything, but it seems like it would work. Certainly worth a try, and WAY cheaper than a new rock guard. You can paint it as well, which is a plus.

**Michael-Rhonda** · 04-24-2018, 08:34 PM

I am facing the same situation. Has anyone tried FiberFix patch? A review says that "FiberFix uses resin as an adhesive. Once you dip it in water, it becomes as strong as steel. That is the significant advantage over tape. When it hardens, there is nothing that can go through it." (https://fiberfixreview.review). FiberFix website is: "https://www.fiberfix.com/about-us". I saw FiberFix at Home Depot. Thanks. Michael

**Michael-Rhonda** · 05-02-2018, 11:36 AM

Answered my own question about FiberFix (previous post) - it did not work. Although drying strong, it did not adhere to the plastic. Will invest in a pop-rivet gun. Michael

ThePair · 05-02-2018, 01:41 PM

Although I've not used it personally, I'd think Sugru might work here as well?

**Bill** · 05-02-2018, 04:13 PM

Yup, I looked at the literature for the stuff, and you've confirmed what I saw there. The stuff is strong, meaning it won't break. But that doesn't mean it is sticky. The rock guard has an extremely slick surface. I'm not sure what that surface is, but I can't imagine how anything that isn't solvent-based would stick to it. And I don't know which solvent.

Some sort of glue or moldable material might stick if you could kill the gloss on the surface. My immediate thought, of course, was coarse sandpaper. But the rock guard material is so thin that I worried about making it weaker, to the point where it would be easy to break. So I did not use that approach. As I mentioned, I riveted a piece of aluminum onto the inside of the rock cover, using two rivets on each side of the crack.This seems to be working, and they were not too obnoxious-looking after I painted them with a high-gloss spray paint. I didn't do a wonderful job of matching the color, so you may want to mask to confine the spray paint to a very small area.

I believe (but I don't know) that two or three aluminum rivets on each side of the crack, and a blob of almost anything moldable, formed over the backside of the rivets, would work.

Do not forget to drill a stop hole at the end of the crack!

Bill

klpauba · 05-03-2018, 06:37 AM

My front rock guard had a crack from the top hinge to a point past the center. I drilled an 1/8" hole at the point near the center to stop crack propagation. I put painter's tape on the outside and used West's two-part epoxy along with woven fiberglas mat on the inside (after a thorough light sanding an cleaning of the inside problem area). There is a bit of discoloration on the outside where the resin made it past the painter's tape but it's been holding up well for the last three years.