Plastic Fix?

[bushwesl]

I was riding all last weekend at Silver Lake and had a blast, although when I came home I noticed that my rear Fullbore plastic developed cracks on each side in between the actual fender and just before the seat (the little valley area in between). I assume they broke from riding on the trailer? Anyway, I was wondering if there were any safe ways to fix them without having to stitch them up, etc? Thanks in advance!

[RichM1983]

I'm not sure what kind of cracks your talking about, lots of spider cracks, or just a few bigger cracks, but if there isn't a lot of cracks then you could take a small drill bit and drill a hole at the end of the crack to stop it from spreading any further. But if you have a bunch of small cracks that look like a spider web or broken glass then I don't know a good fix other than maybe reinforcing the plastic under the area that is cracked with some sort of adhesive or something.

Hope this helps.

[bushwesl]

Yea, it's cracked all the way through. Broke pretty good. What kind of adhesive would you recommend to use to try and glue them together. They're just cracked, but not all the way to any edges. Hope that makes things a little clearer.

[Creech52]

I dunno any other ways to fix a crack thats gonna hold up other then stitching with zip ties, or using a peice of thin sheet metal on the underside of the crack and drilling/riveting it to the plastic

[troybilt]

I've heard of welding plastic, :confused: don't know how well it works though. I was actually going to try this on a set of stock plastic that I have that is good shape otherwise, except for a small crack. I heard using a heat source like a small butane or propane torch, maybe even a lighter. I have one with an open flame for a soldering iron. (can get one at home depot for 10 bucks). Heating both sides pretty well to join them together, and hold until it cools.

Then once it is joined need to sand the joint with 180grit all the way to 2400 grit or more sand paper, to get an extremely smooth surface.

The next part sounds a little strange too, but using a hair dryer on high setting go over the area that is sanded smooth to make shiny again, like new.

I did a search on this and found this and some other info that the superbike boys do to fix their plastic. Just and idea. If you come up with a method let us know how it works. I'll try and find that article I read.

3M has some stuff on there site too: http://solutions.3m.com/wps/portal/3M/en_US/3MAutomotive/Aftermarket/Solutions/Mobile_Repair/Plastic_Repair/Bumper/

[RichM1983]

You can weld the plastic but it looks bad. I have never seen a plastic weld that looks good. You may be able to with time but I dont know.

What I would do is since they are big cracks I would drill really small holes with a drill bit at the end of every crack so they cant spread. Then I would use some bondo or fiberglass form Advance Auto. I can't remember which it is. One of the them will bond to the plastic. Really and truthfully though the only thing you can do is stop the cracks from spreading with the holes and then just be satisfied with cracked plastic till you can get some more.

[wilkin250r]

I've welded plastic many times, with success. None have ever cracked again. But like Rich said, it's ugly, I've never been able to get it to look anywhere close to "new". Heck, I can even get it to look decent, but it holds.

I used a cheap ATV fender welding kit (http://www.urethanesupply.com/storeatv.php) to do the repair. It's not much more than a soldering iron with a fancy tip on it.

The only issue is, you'll have to find out exactly what type of plastic you are welding. I think most OEM fender are polyethylene (PE). I know for a fact the old dull-style Maier were polyethylene, but the new shiny Maiers are polypropylene (PP).

The ATV fender kit comes with PE rods, but they won't stick to PP plastic, you would need to get some filler material that is the same type of plastic. Often, what I would do when making repairs on an unknown type of plastic, I would just cut small strips from some hidden area. Because it's from the same piece, I KNOW it's the exact same type of plastic, and the color matches exactly.

[C-LEIGH RACING]

What about if when your welding it, you had a piece of aluminum cut to the same shape as the outside of the area where its cracked & then some way to hold it in place while the plastics being welded.
If the aluminum piece was polished, wouldnt it provide a smooth outside finish after the welding is complete.
Just thinking :confused:
Neil

[bushwesl]

Thanks for all of replies guys. I'll have to see what I can do to fix it, but like mentioned before the only thing I can do is fix it for the time being until I get new plastics. After looking at it again it's actually broke worse than I had remembered before. I've never had a problem with them until now. I think what did it was the addition of an OMF seat latch. Before the fenders were able to flop around a little more with the OEM latch, but the OMF tightened things right up and perhaps made it too rigid, thus the cracking/breaking of my fenders.

[wilkin250r]

Originally posted by C-LEIGH RACING
What about if when your welding it, you had a piece of aluminum cut to the same shape as the outside of the area where its cracked & then some way to hold it in place while the plastics being welded.
If the aluminum piece was polished, wouldnt it provide a smooth outside finish after the welding is complete.
Just thinking :confused:
Neil

I don't think that's feasible, and I also don't think it would provide any better finish than simply sanding and polishing the plastic.

The main problem is that most fenders have a thin, protective film on them to provide a shiny finish. Even if you sand and polish a welded area, you'll never match the rest of the finish because you don't have that protective film.

[C-LEIGH RACING]

Yeah, now that film stuff is crazy.
I seen on tv how atv fenders are made with the camo print on them.
A bunch of spray nozzles on a long bar spray the colors & pattern on to a pool of smooth flowing water & then a flat sheet of plastic comes up from the bottom up through the water & the pattern is envoloped onto the sheet of plastic. It them goes to a heat dryer to set the camo print then cooled. Once that process is done, the sheet is heated again & placed over a vacume mold & sucked down onto the mold to make the shape it needs to be for what ever atv it is o fit. Weard to say the least how they get that camo design to stay in place on the water & then it all comming out locking right.
Of course though, them ol jap boys is tuff, aint much they cant do.
Neil

[BigBore24]

i think your right about the omf seat latch. mine came with that latch on it along with the same kinda cracks you are describing on the rear. i had a heck of a time getting the thing back on after taking it off once too. what a PITA