Help: cracked fenders ideas how to repair?

[Troyg25]

Fixing up some fenders on my 250sx project. The cracks are in areas that don't look to bad but not sure how to approach it with out wreaking my fenders?

In small hair line cracked areas does JB Weld work? I've read the soldiering iron v-grove trick but does the weld work just as good?

Looking for thoughts and ideas.

Thanks in advance

[honda4h]

sand the back of the crack/ruff it up buy some automotive goop at Canadian tire. i have used it for years it is rubberized so it flexes try it out i use it on all kinds of stuff. Canada rules in hockey gold baby.

[fabiodriven]

JB Weld is not going to work in this application. I'm not familiar with the stuff honda4h is suggesting, but I can add one tip. Drill some small holes right at the points where the crack begins. That way you're preventing it from getting bigger.

[effort=results]

https://www.youtube.com/watch?v=yhQy3UFqz2M


This is how i do it hope it helps

[barnett468]

Hello;


Are you trying to do a cosmetic or structural repair?

if you are doing a structural repair you can do the following.

1. buy some panel bonding adhesive and extra nozzles from an auto paint supply store and store it in the fridge or cool place at around 60 degrees until use. if it gets warm, your working time will be GREATLY reduced. if it gets colder than around 60 degrees it will be very thick and come out extremely slowly.

http://3mcollision.com/3m-panel-bond...ive-38315.html

2. buy a thin piece of flat 12"x12" metal from the heating/ac duct dept at the hardware store.

3. cut it 1 1/2" longer and 2" wider than crack.

4. sand metal and plastic with 180.

5. shape metal to conform with area needing repair.

6. cut around 1/4 - 1/3rd off plastic applicator or adhesive will come out too slowly. Don't use the first 2" of adhesive that comes out of the nozzle because it will not be mixed well enough.

7. put thick lines of adhesive around 1/4" - 3/16" apart.

8. press metal lightly into adhesive. you do not want to squish it all out.

9. if necessary hold pieces in place for around 5 minutes until adhesive sets.

10. place in warm place at least 60 degrees and it will be fully cured after 1 hour. you can spped up the process by warming it SLIGHTLY with a blow dryer on LOW.


The adhesive gets moderately hard and is sort if sandable kinda, lol.

[aldochina]

if your not looking for perfection, just stitch em up. I like to use 18gauge solid copper wire with red insulation(for hondas). its thin yet strong, dont have to drill huge holes for stitching, and it blends well. I have free acsess to such things, so it works for me. Sheet metal and rivets make a strong repair also. I have had no luck with the soldering iron and a piece of old plastic. Its always recracks after some good riding.

[kb0nly]

Plastic welding is the way to go unless you don't care what it looks like, in that case drill and stitch works fine. Using a soldering iron and a piece of plastic only works on spots that won't flex or take any abuse, its a surface repair at the best. Grooving it and using a plastic welder with the right rods makes a permanent repair as it thoroughly melts in and bonds it. I have done a few repairs that once they were shaved down and sanded and buffed you couldn't even tell it was there.

[NeverLift]

I just did this to my ATC70 fenders using a hot air plastic welder. It is a very strong fix I can bend and flex it with no signs of it breaking again.



This week I'm going to be fixing some LT-4WD fenders that are in horrible condition. I plan on making some video of it and will post it up here for anyone that is courious.

[Troyg25]

Thanks for all the info. I picked up a 250sx with a nice clarke rear fender. It has a small crack in the back maybe a few inches

I will post some pics tonight and see what you think. Thinking plastic weld is the way to go. But that brings me to my next question lol. You think if I took some old fenders and melted them into clarke fender it will bond? Not sure if it will and I might make a mess.

[aldochina]

how much are the plastic welding kits? never looked into them. That looks like a sweet little unit neverlift!!

[trike savior]

everyone please stop the zip stitching and the metal with pop rivets. Plastic weld or fiberglass. i like fiberglass on the back side the best. i do not understand what was going on in the you tube video with the screen and then fiberglass resin with no fiberglass cloth. but to each their own.

just my opinion fiberglass is cheaper than buying all the tooling and having to practice or running the chance of overheating and distorting the plastic.

duct tape your parts together on the top side, trying to keep your cracks as tight as possible. flip the fender over to the back side and sand the area with 60 grit. wipe it down with some kind of cleaner, (starting fluid, paint thinner) the cleaner the better. use fiberglass mat, not the woven cloth kind. get some $.99 paint brushes from walmart and nitrile gloves. the gloves are worth it, it sucks getting it on your hands. applying the matting is like applying layers of duct tape, start small and get bigger.

paint the area with resin then stick your first layer of matting. about 1" wide as long as the crack is a good start. from then on you will only dab (push) with the brush, adding more resin as necessary. trying to paint the matt drags or spreads it out. full saturation is key to it being strong, the matting will no longer look white, but the color of the resin. dab it until it is saturated, then apply the next piece of matting, about 2 1/2" wide and longer than the crack (unless going to an edge). repeat again until saturated and apply next piece about 4" and longer than the 2" piece. Saturate it again. be generous with the resin now and make sure to get the matting laying nice and flat or you will have some sanding work to do. take off the gloves and wait for it to harden.

remove the tape after it is completely dry/ hard. dry time depends on the amount of hardener used. when you remove the tape you may find some resin bled through the cracks, some scratching with your fingernail should remove it.

[NeverLift]

I got it from amazon.

http://www.amazon.com/Kendal-REWORK-...dering+station

I lucked out my work bought it.

[afdfirefighter]

I just did this to my ATC70 fenders using a hot air plastic welder. It is a very strong fix I can bend and flex it with no signs of it breaking again.



This week I'm going to be fixing some LT-4WD fenders that are in horrible condition. I plan on making some video of it and will post it up here for anyone that is courious.

I also use a plastic welder. Where did you get the red welding rod?

[NeverLift]

At work I have a bunch of HDPE storage tubs that I weld. When one is beyond repair I cut it up into little strips and use those. I ordered some welding rod from ebay and it didn't work at all. It just balled up and didn't mix with the fenders. They had it listed as HDPE but I don't believe it is.

[afdfirefighter]

Would you be interested in selling a little bit of that stuff? Right now I am trying to use the existing plastic and blend it as nice as I can. Doesn't look too bad but yours definitely looks better.