Adding to the ABS repair topic are a few of the latest items repaired from a 2004 T1950, one of my project campers. In this case, cracked fender skirts and a fridge door panel retainer.
Using the same process described in the first post above is how I repaired the cracked wheel well fenders. The screw hole areas had many cracks, and one fender cracked into two pieces. Start with cleaning all the dirt off. LA's Totally Awesome works well or other spray cleaners. At this stage, you want to get all the dirt off.
I needed some extra ABS plastic to reinforce the separation between the two halves of one of the fenders. I saved what fender parts were leftover from my T310SR tire blowout. I cut up the parts into two small strips to span the crack.
Here is a picture to show how the strips will span the crack joint.
Next is to grind out a good portion of the crack's depth or chamfer the spliced fender joint's edges. I used a cutter on a Dremel to do this. Ideally, you can grind out part of the plastic from both sides to allow the solvent weld mixture to weld deep into the plastic. Here are some pics of that grinding/prep process.
A view showing the grinding out of cracks and the chamfering of the butt joint ends. Chamfer both sides.
Once you have completed grinding out the cracks, clean both sides with a high flash cleaner to remove any leftover dust/grim. I used Naphtha, but lacquer thinner or denatured alcohol does not melt the plastic but clean it.
In my case, one side of the cracked fender was warped and would not butt up even to the other broken half. I had to put weights on the two parts to force them flat and create a tight butt joint, straight in line with where I wanted it to end up.
I found a better cutter to make ABS chips. It is a more coarse rotary rasp I use on a pneumatic die grinder and chip away at an ABS plastic pipe coupling.
I have not yet mastered how to create the chips and not make such a mess. More on that as time goes on.
Create the ABS cement mixture as listed in the first part of this thread. Seal the jar of the mixture while you do a final cleaning. Wipe Acetone on all cracks and the split joint area to be solvent welded as described in the first post.
First, apply the weld cement mixture to the fender cracks on the outside of the cracked fender. Do not use any cement on the outside joint between the two split halves at this time.
Turn the fender over so the backside is up and place it on blocks. Position one block to be under the split line of the two halves of the fender as support.
Set the joint to be welded in alignment and clamp in place with weight or another clamp method. Apply weld cement to the split line from the backside. You can also apply cement to the screw holes areas on the backside at the same time while you let the first coat of cement firm up.
After 45 to 60 minutes, check the joint if the cement has firmed up. It needs to be firm enough to remove the weights and not separate. Do not lift and turn over yet. Place the two reinforcing strips over the top of the joint. Grind any high spots in the joint cement to allow the strips to lay flat.
Apply a coat of weld cement over the area the strips will contact the fender. Press the strips into the wet cement.
After both strips are in place, coat the outer perimeter of both strips with weld cement.
Let the strips cure for about an hour. Test with your finger the cement is no longer wet. Then remove weights/clamps, flip the fender over, and apply the first coat to the fender outside split joint. Let the entire fender cure overnight.
Repeat adding a second coat of weld cement the next day and let it cure to both sides. Repeat a third coat the next day and let it cure for 24 hours. This is a three-coat, three-day process to get the full bond strength to hold long term. After the third coat has cured, file or grind off any bumps/drips of cement that will not allow the fender to bolt up to the side of the camper flush.
After any grinding, sanding, or filing of the rough edges, clean the entire fender with a high flash cleaner to remove and dust, etc. You are prepping the fenders for painting.
I have tweaked the plastic painting process a little since the first post. I start with Krylon Fusion white glass paint. Since this paint is very thin, it needs to be applied in thin coats, or the paint will run without issue. The black weld cement on a white fender allows us to see the thinness of the coats.
Below is a picture of the first thin coat over the entire outside of the fender. I did not paint the inside. This first coat is almost a dusting of paint. You do not want 100% coverage at this stage, or it will start running.
After one to two minutes, apply the second coat as thin as the first over the entire outside fender. The can states recoat within one minute, but I had a barn temp of 55F, so I waited a little longer. The first coat should not be wet any longer; a light finger touch and not much if any paint will be on your finger.
Wait the same period before applying a third thin coat as the first over the entire outside fender.
After the third coat, I let the fender dry for approximately 3 to 5 minutes and then switched to Rust-Oleum stops rust standard gloss white paint. The standard oil paint is not fast-drying paint, and you do not want fast-drying Rust-Oleum paint. The Fusion paint was the only fast-drying paint I used.
Apply a topcoat with the Rust-Oleum. It should cover now.
Apply a second coat if needed after a full 48-hour cure. I did not have to do the second coat as I have total coverage, and the fenders look great.
You may have to drill out the screw holes with overflowed cement before mounting. I recommend "not" to use bevel head or flat head screws which seat into the fender holes when mounting. The angle of the screw creates high-pressure points and can promote cracking. I use flat stainless washers and stainless screws. The flat washer clamps on the fender's outer surface, not into the countersunk holes trying to wedge the plastic apart.
I mentioned repairing the ABS plastic strip for a refrigerator panel; here are pics of the process. You use the same techniques as listed above. Since the plastic strip was black, I did not have to paint this piece after solvent welding.
Warm with a heat gun and squeeze the split plastic back into shape. And in this case, make the angle back to 90 degrees of the part.
The cracked plastic strip.
Heat and form the splits back in line and create the 90-degree angle once again.
Grind out cracks just like on the fenders.
For a complete repair, you need to apply three coats with a full 24 hour cure between coats with the ABS solvent cement mixture.
For fenders where the screw holes have blown out the plastic hole totally, I have placed a stainless flat washer with the screw size hole I need over the large blown-out hole. Then apply cement to the flat washer and the fender. Layer up three times, and it works great for fixing blown-out fender mounting holes.
I hope this helps,
For more pics on this ABS repair, see my Flickr page. https://www.flickr.com/photos/camper...57718295191002