Author Topic: Repair / strengthen cracked plastic on cluster 68 camaro  (Read 7173 times)

sabino56

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Repair / strengthen cracked plastic on cluster 68 camaro
« on: December 13, 2019, 11:43:50 PM »
68 Camaro speedo/ gas instrument panel

The plastic is cracked around the screw holes at bottom and a crack is starting up towards bezels. 
I’d like to prevent the crack from running and strength around the screw holes.
Wondering if anyone else has been through this and had success.
I was  thinking of trying JB weld on backside bridging crack.
Any suggestions on epoxies or glue for this plastic or suggestions would be appreciated!
Ed

77thor

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Re: Repair / strengthen cracked plastic on cluster 68 camaro
« Reply #1 on: December 14, 2019, 12:31:39 AM »
Hmmmm… I would use fiberglass resin mesh on the backside.
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sabino56

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Re: Repair / strengthen cracked plastic on cluster 68 camaro
« Reply #2 on: December 16, 2019, 02:53:51 PM »
Thanks for suggestion.  Looking at it a bit more, I think I can make a sheet metal backing plate and either epoxy or fiberglass it in.  I’ll post whatever I do and succeed/ fail when I do.
Ed

KurtS

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Re: Repair / strengthen cracked plastic on cluster 68 camaro
« Reply #3 on: December 17, 2019, 04:12:46 AM »
I repaired a lot of 69 dashes including rebuilding screw bosses. I use J-B Weld. If you do anything threaded, coat the screw in oil first and put it in place, then put the epoxy around it. The screw can easily be removed after epoxy sets.
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adjudimo

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Re: Repair / strengthen cracked plastic on cluster 68 camaro
« Reply #4 on: December 17, 2019, 11:24:40 PM »
You should also drill as small of a hole where the crack ends. This will stop the crack from getting longer. Then fill the small hole in when you repair. I would use JB Weld to do this or you could let the fiberglass resin fill it in. Your choice. But definitely drill the hole. It works.

sabino56

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Re: Repair / strengthen cracked plastic on cluster 68 camaro
« Reply #5 on: December 18, 2019, 04:57:32 AM »
Thanks guys for the advice, I appreciate it.
Ed

bcmiller

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Re: Repair / strengthen cracked plastic on cluster 68 camaro
« Reply #6 on: December 18, 2019, 02:39:54 PM »
Let us know how it turns out.
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william

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Re: Repair / strengthen cracked plastic on cluster 68 camaro
« Reply #7 on: December 18, 2019, 09:49:27 PM »
I first attempted a repair on a '69 dash back in '76 when the wiper switch mounting pegs broke off. IMHO repairing them is just kicking the can down the road. No matter how well engineered the repair is, they usually fail again. In particular, the mounting tabs for the cover at the base of the steering column. It's 50 year old plastic. There are excellent repros of the 69 dash cluster and if you're going through the bother of removing it, best to do it only once.

'69 dash pads, same deal. Over time, the pad shrinks and the plastic liner cracks and warps. You can glue them back together but it will be temporary.

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Kelley W King

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Re: Repair / strengthen cracked plastic on cluster 68 camaro
« Reply #8 on: December 18, 2019, 10:16:13 PM »
ditto on that temp dash pad, be there
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ko-lek-tor

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Re: Repair / strengthen cracked plastic on cluster 68 camaro
« Reply #9 on: December 18, 2019, 11:17:49 PM »
I’ve had success with JB Weld and screen door mesh. On contoured areas I use the plastic screen. Have also fixed wiper switch bosses on 69s
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ZLP955

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Re: Repair / strengthen cracked plastic on cluster 68 camaro
« Reply #10 on: December 19, 2019, 05:33:49 AM »
I repaired my '69 console base pretty easily with JB Weld but am going to get a plastic welding kit and try that method out on some old parts that are beyond saving. The kit I've been looking at consists of what resembles an electric soldering iron, and plastic filler rods of different thickness and base plastic type (ABS etc); rods come in black, white and grey.
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joesauer

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Re: Repair / strengthen cracked plastic on cluster 68 camaro
« Reply #11 on: December 19, 2019, 06:00:59 PM »
I repaired mine with JB weld, but over time cracks appeared elsewhere.....just an age think I guess.   Eventually, just replace the housing.  Not that expensive.

sabino56

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Re: Repair / strengthen cracked plastic on cluster 68 camaro
« Reply #12 on: January 05, 2020, 04:37:25 PM »
Just update on what I did.  I decided to try to save the cluster for now until I decide what I do on interior. Interior is not bad & I didn’t want a new shiny cluster with everything else aged.
I formed some 18gage sheet metal pieces to fit the back side of bottom of cluster and JB welded it in place.  I’m not great with metal forming so it was kinda fiddly to get it to fit without stress on plastic but it worked out ok.  The metal backing makes it stiffer and allowed me to mosaic back the broken pieces to reform the screw holes. We’ll see if it lasts or just causes cracking to move elsewhere.