The yellow dash plastic in my 90 GXL has disintegrated to the point that the cluster surround and idiot cluster trim can no longer be mounted. I picked up another dash from a 91 with the same yellow brittle plastic and practically every mounting tab is either cracked or missing. I have tried using a urethane repair compound (3M #4240 Duramix) as an adhesive and as a reinforcing material, prepping the plastic by rough sanding and following up with brake cleaner, to no avail. Nothing seems to stick to this shitty plastic.

Does anyone know what type of plastic this is and a possible semi-rigid adhesive that will stick? I have noticed that many of the s4 dashes use a black colored plastic that appears to be less brittle am I correct? If need be I can source an s4 dash and re-spray the vinyl part black.

 

Maybe try mechanical means. Perhaps predrilling small SHALLOW holes (you don't want to hit something important) then threading short screws in to provide something for the urethane compound to bond around. Or skipping the compound and using straps or some other fabricated pieces.

I'd be hesitant to spray paint the vinyl. I've seen it flake off on other vehicles before, it could look like TOTAL ***.

 

I may try the hole drilling method with screws as a final attempt. This plastic is so brittle that the drilling/ screwing alone will likely shatter it, let alone trying straps. It's ridiculous. As for the vinyl paint, I too have seen other's attempts at color change, most of them used Krylon paint for plastics, which will pop off at the slightest provocation. It's junk. It's all about the surface prep and paint used. I've used SEM vinyl paint extensively with excellent results, as it's a flexible coating and they make vinyl prep chemicals for help with adhesion.

 

You might want to try fiberglass. I have some mounts in my dash that need fixing and or reinforcement and a friend suggested fiberglass. It seems like it just might work. They probably cheaped out on the S5 dashes and now after so many years, the heat has just baked them to a brittle mess.

 

maybe try a methacrylate adhesive product, such as the system from weld mount, we use these on boats. Perhaps you can take a donor piece of plastic such as abs or other maybe acrylic, fiberglass, and use the adhesive to bond pieces to strengthen the current dash. I can tell you personally that the holding power of the adhesive is tenacious http://www.weldmountsystem.com/index.htm

 

if you fiberglass such as jerry has suggested you will definitely require epoxy resin not polyester or vinylester- regardless of the resin the other issue is you must grind or sand what you are glassing and if its that brittle it will most definitely break

 

Good point. It may not be possible to scuff the surface all that much due to the brittleness. The idea of that weld mount system sounds pretty good.

 

I like the weld mount idea. With the urethane that I tried, it adhered better to areas that I had scuffed and also to areas where there were voids, corners, pockets etc. If I were to use the weld mount tabs I could possibly use them as "anchors" to flow the urethane around or adjacent to a crack, and rely on the "skin effect" of the urethane. I've never done fiberglass work and can't get real excited about it on this project. Most of the cracks are in areas where there's no room to lay the glass. I'll post a few pics of the areas in need of repair. I'm probably one of many who have been in this situation.

 

if its a crack you can use one of the weld mount tabs as a brace or gusset so to speak and leave it like that to strengthen the area

 

I'm with ya on that Rob thanks for your ideas

 

If you prep the surface with prep all or acetone and use duplicolor fabric and vinyl paint it will hold up. Im 2 years into it with daily driving and parking in the sun. No flakes yet

 

if you need any of that stuff I have local sources for it, I thought I had a tube left over from another project but I guess I didnt

 

I also have a plastic welder at work that has various types of plastic rods. Once I determine what type of plastic it is I can zero in on the right material. I'm going to look for any stampings in the plastic that might indicate the type used. My luck such stamping would be hidden by the top vinyl lol. Doesn't appear to be ABS, possibly a type of polyolefin or polypropylene. I'm no plastics expert though.

 

polypropylene you can get glue sticks designed for them, you find them at better glue stick suppliers

they used to sell glue sticks designed for battery case repairs, not sure if auto parts stores still carry them as I imagine liability these days makes it not worth it. And if it is polypropylene you can use any plastic stamped with a "2" under it for recycling such as a gallon water/milk container for donor material

 

Excellent. Thank you sir for checking in on this thread. On something like this it helps to put two or more heads together. Once I come up with a solution I might start a How To thread as I'm sure many others are as frustrated with their broken tabs and such.

 

your my guinea pig, I did a carpet swap and didnt want to remove the dash for fear of tabs breaking, one day I may have to do a heater core or need it out so you will learn for me, lol