Repairing Interior Plastics

[MIHELA]

Acetone melts ABS. That's what most of the interior plastics are made of.

 

[kennythewelder]

I have been slowly working on my cracked dash on my 97. Ive been using JB weld, and some aluminum plate, as a backer under the crack for strength. After that dries over night, then I fill the crack with JBWeld, and sand that down flush, and paint to match. The worse spot I had was above the stereo. The crack was about 6 inches long, and because of the curve there, the plastic was uneven. I clamped a small peace of aluminum that I covered ( back buttered) with JBWeld, and let that sit over night. The next day I filled the crack with JBWeld. Then again the next day, I sanded that flush and painted. I will post some pics sone.

 

[kennythewelder]

Acetone melts ABS. That's what most of the interior plastics are made of.

I tried acetone, and it did nothing. Thats when I started using JBWeld and aluminum as a backer plate.

 

[MIHELA]

I need to repair the top of my dash above the cluster and i think I'm going to try something like kevlar fabric and epoxy or dissolved plastic to bond it in.

 

[kennythewelder]

I need to repair the top of my dash above the cluster and i think I'm going to try something like kevlar fabric and epoxy or dissolved plastic to bond it in.

I will post some pics of what I am doing today. It is working very well. It is a slow process though. For a long time, I have seen these trucks at different car shows, and have seen dash boards that were coated with fill primer, sanded smooth and repainted. For some time, I wondered why, or didnt understand why they did that. After repairing some cracks, now I know why. I dont see a way to grain the repair so that it matches the rest of the dash perfectly. That being said, it is hard to tell where the repair is, if its its rite. Also keep in mind that all of these dashes are painted for GM. All of the dash plastic is black under the paint.

 

[kennythewelder]

You can see the aluminum plate I used to reinforce the cracks. There is 1 under the dash, above the stereo, 1 under the dash plastic, next to the defrost vent, and 1 where the glove box latch is. I had a small crack above and below the air bad also, from the glove box door latch. Years of closing the glove box door. As you can see, most of my dash, I have already repaired. With the carpet dash mat, I am in no hurry to finish the repairs, but I will one day. The screws on top of the bezel, ( to hold it in place) I will do away with in time. I have a peace of very thin stainless steel strip that I am going to attach where the plastic used to be, where the bezel latches into, on the top. All of mine broke off, so there is nothing for the bezels keepers to latch to any more.

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[kennythewelder]

A few more pics.

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[kennythewelder]

I have access to metal being a welder, and understand that a lot of people dont. But, an thin metal will work as a backer. An old sign, any old thin metal will work. The peace of metal I am going to use to redo the section that the bezel clips into, comes from a piano henge that was a little to wide for a project at work. Its what was cut off from the henge. About 4 feet long, and about 1/4 inch wide.

 

[MSCustoms]

This is my endeavor for my K5

https://www.gmt400.com/threads/cracked-dashboard-project.21991/

 

[Insert Quarter]

I read the post above about doing the face of the dash, has anyone used fiberglass to reinforce the backside of the dash on a 400 to help prevent future/further cracking? I have an '89 and have the dash off to fix a few water leaks. I've got a good amount of 3M Bondo resin left over from other projects I was thinking about using. It's a polyester resin, from what I've read, that melts ABS, but I haven't found anything about to what extent. Since cosmetics on the backside on the dash aren't an issue, I was curious if the melting is enough to warp the plastic? I don't have any extra interior pieces to try it out and see what happens so I figured I'd ask.