Plastic and crack repair

[triketrash]

[attachment=0]IMG_20160502_121429127 I came out yesterday morning to find a crack in the upper portion of the faux tank plastic on the right- there is also some bubbling in the paint- culprit? Brake fluid from a recent front brake job that must have burped out of the reservoir. The weird thing is that it went several days before it did this. The only other variable is that the ambient temp went up about 40 degrees over those days- anyway, to fix a crack like you see, should I just use ABS glue alone, or should I mix up a slurry?

[MikeB]

There are many ways to fix that crack but it may never look exactly like new. That said, read through these two articles on this board:

viewtopic.php?t=22655

and

viewtopic.php?f=16&t=31409.

I have used the Plastaid http://www.plast-aid.com/ and Plastex http://www.plastex.net/ materials myself and like them quite a bit. You can also use the ABS glue slurry to do the repair. I have done that too but it is time consuming. The Plastaid and Plastex methods are a lot faster.

There is also a Loctite® Epoxy Plastic Bonder http://www.loctiteproducts.com/p/epxy_p ... Bonder.htm that I have heard works very well.

You know of course, the best way to make it look presentable is to repair it from the inside out which means removing the right fairing faux tank. It is not that hard to remove and reinstall the results will be well worth the effort.

Good luck.

[WingAdmin]

I've repaired several stress cracks like that, and I'm getting quite good at it. I always do it from the back side, so the repair is invisible.

I will first scrape the paint away (if any, it's usually overspray) from the back of the panel around the crack. I'll then cut a slight "v" along the crack on the back side, to give it more surface area to bond to.

I then put ABS glue along that "V" and clamp it together. Some ABS glue will squeeze out the front of the crack, I wipe that up quickly.

After it's cured, I'll then add reinforcement so that it doesn't occur again. If the crack is in a really oddly shaped area, I'll mix up slurry and slop it around the crack and the surrounding area, building it up to at least 2-3 times the original thickness. Sometimes this takes two or even three applications, letting each one cure before adding the next.

If it's flat or only slightly curved, I will take a small piece of ABS, cut it to fit, and if curved, I'll heat it and bend it to fit the back of the panel. I'll then apply glue to the back of the panel as well as to the piece of ABS, and clamp it in place. This adds a ton of strength, and I haven't had a single crack reoccur after using either method.

If done well, the crack closes right up, and can only be seen under very close inspection.

[triketrash]

OK- got it- thank you- The V is a great idea- wouldn't have thought to do that. I'll let you know how it goes. Vince