Cracked front fiver cap - solutions?
 

All,
Came out to my 2006 Coachmen a couple weeks ago and noticed a crack about 16" long coming down from the top of the front ABS plastic. Did a little research and guess it is not totally uncommon. Happens during freeze / thaw cycles and that part of the RV faces the eastern sun.

I have drilled the end of the crack hoping that stops it from progressing, but I need to repair it. Insurance won't pay since it's not CAUSED by something external (wind, hail, rock, vandal, etc) and I have a $1K deduct anyway.

Especially looking for actual experience / advice. I've heard whatever I use has to continue to allow movement. I, obviously, wish it minimize making it look worse. I've heard of Sikaflex - but they have dozens of products - not sure which one is best.

After sealing it, I'm wondering about covering it up with something that looks like it should be there - another decal, etc.

Any and all ideas welcome. Thanks!

sikaflex is some strong stuff, but I dont know how you would be able to apply it without it standing out (stuff I have always used was like a super duper silicone)

As far as covering it up, I would go with having a vinyl shop make up a new decal for the front that will also go over the crack. If you go that route then you can design pretty much anything that you want with the only determining factor being it has to cover the crack/repair.

good luck with the repair..

Josh,
Do you remember the number on the sikaflex tube you used? Sounds flexible and strong- just what I am looking for. That is one of my big questions... Getting the right product.

And I like the custom decal idea. I would think they could match colors.

I don't remember off the top of my head what it was we used but after a quick search, Sickaflex 291i sounds like what it would have been. With this you can apply it and sand it smooth to help hide the repair. I will call a buddy tomorrow and ask him because he still uses the stuff.

Yeah any vinyl shop will be able to take a new/existing design and match the colors pretty close. This way the front will still match the designs on the rest of the trailer and wont look out of place.

Below is a link for it so you can read up on it and make a better decision.

http://www.bosunbobs.com/en/Sika-Sik...n=UnitedStates

I repair ABS with ABS. You can use ABS solvent cement, which is usually dyed black but can be had in clear. You can also dissolve some scrap ABS in MEK. Just be sure it isn't filled or the result will be gritty. I've had good luck with junk computer parts.

Reinforce with fiberglass cloth. Sand and paint when done.

It is normally not that difficult to gain access to the rear of the cap from the inside. This would give you the opportunity to reinforce the back side of the crack with cloth and do it right. Then, do a normal glass repair from the front. This should prevent this occurring again. I am assumming this is a wood framed unit - - this is not unusual especially if you might have had a small leak causing a bit of rot or settling in the framing. Lots of twisting and flexing going on in there rolling down the road. Amazing they don't crack more.
Bob

I have a 1985 Alpenlite that's had some water intrusion issues, as evidenced by curly paneling. After sealing, though, no more water. The superstructure frame is aluminum.

I'm toying with the idea of finding another one that didn't get resealed in time, shelling it out down to frame, and start over with a custom rig. The front cap on them is a fiberglass hump dome that is unique, slippery air flow wise, and roomy inside where needed.

I haven't had good luck with fiberglass-epoxy or fiberglass - polyester repairs on ABS. Fiberglass cloth and ABS in solvent works pretty well.

ME BAD. Didn't read original post close enough. Did not notice ABS. DUH. Forget what I said other than the possiblity of access from the inside for additional reinforcement. (note to self - new glasses, Bob) [duhhh]

Bob

Actually, a couple of layers of glass bedded in ABS solvent cement (you can use the black plumbing stuff inside out of sight) works very well for a repair. Then use 1 layer of light cloth on the outside bedded in cement, and a coat or 2 over the top after dry for sanding and finishing.

The trouble with ABS is that it is not originally reinforced, and with age it gets brittle and cracks, so any repair is temporary.

If I rebuilt an old fiver with an ABS cap, I'll use the original to make a splash mold and make a new one out of fiberglass-polyester.

Yep, and even they crack sometimes. I have a very small crack in my rear cap luckily on the bottom corner. Easily repaired and has not re-appeared. Hey, it's an RV - - always some little thing to do on one. Mine needs a good buff out right now. Man that thing is long and tall after about 3 hours.

Thanks for the input guys. I don't think inside access is very easy - I don't have a closet or something, just paneling and a shelf that may not go back together as nice. I also currently don't see any water damage (it is a wood frame unit) yet. Crossing fingers.

If I sand out the abs plastic over a patch of some sort (as you've described above) won't it leave the ABS flat looking while the rest of the cap is shiny white? It's not painted so I don't want to have to repaint the whole thing because I sanded a patch and it stuck out like a sore thumb.

I am planning some sort of small decal and a matched piece on the opposite side to look normal and cover the crack repair, but was hoping not to need a decal more than a couple inches wide. I'm guessing the repair you all are talking about above would be several inches wide after sanding especially.

Go to your local boat shop and get some gelcoat. add white colour past to suit and apply over the crack. wet sand to make the lines disappear. BTDT

I don't think he'd have much luck with polyester resin over ABS.

The goop I made by dissolving white computer parts in MEK is quite shiny. If you want smooth, sand it. If you want shiny, don't sand it. If you want it to be right, sand it and paint the whole cap. (with a plastic paint of course)

Is it a separated crack or just a crack (are you trying to fill a void or just "glue it back together"). I've used this stuff in making custom RC bodies and it seems to bond almost any plastic (including PVC etc..) and it works on ABS. Once this stuff cures it isn't coming apart. I've tested it and ripped the plastic before the joint would give.

I know it's not an automotive product but it's worth looking at..

http://www.hobbylinc.com/htm/pls/plsbond-2.htm

It's just a crack - not separated. That stuff you linked to sounds like it would do what others above have suggested - melting the ABS back to itself And if it works as good as you say - then I'm going to get some. That's just the type of solution I was looking for. Thanks VERY much for giving your input.

After the weather is warmer I'll try this and report back with the short-term results.