I had to rebuild the dash in my XJ. Some thoughts:
- I would not flock the dash like lots of the youtube videos. It collects dirt and leaves a yucky finish that you cannot clean without getting crumb sand coating everywhere. It feels awful to the touch.
- Make deep grooves cutting out the material where the cracks are. You want a V shape where the cracks were located. Ideally, you would take off the entire foam part of the dash, get a new piece of foam and heat bend it to shape and then cover it in vinyl/plastic. That is how it should really be done. Most of us don't possess the skills or equipment.
- The expensive dash repair epoxy used in most Youtube videos are not really needed or very useful. I had horrible luck with them and found them to be a waste of money. Don't buy.
- Instead, use a fiberglass mixture called "Rondo".
Rondo
See:
[youtube]
https://youtu.be/qK-CJnDg_yE[/youtube]
Don't use body filler in your Rondo though, use a Bondo product called Fiberglass repair resin. This is like body filler, but designed to be more compatible with fiberglass resin.
The Rondo will self level. You can spread it on the dash and it will spread and lay flat with gravity. So you can work in small sections with the layer you want level to the horizon and then just fill the area and let it level out and set. Much less knife/spreading work. Reposition the dash and do each piece with the edge flat. When done, it won't be perfect. You will have to sand it to level it fully and to go around curves. Of course, fiberglass off-gases and you will want a mask when you sand it. Don't get greedy and push really hard when running the sander or you will pull out the fiberglass in chunks and leave divits and then have to start over. You have to go slow and it takes forever to get it right.
When you are done, if you did a good job sanding you can just paint it-- like I did on the XJ-- or you can cover it. After painting, I covered mine with a dash mat and called it good.
Vinyl Wrap
In a FSJ from 70's or 80's I would vinyl wrap over your work for best results.
See:
[youtube]
https://www.youtube.com/watch?v=IaSm3zoWrAo [/youtube]
Vinyl wrapping also makes the sanding less critical, especially if you had air holes in the pour that popped through during sanding.
It will be much easier to wrap vinyl around the dash than the video showed. The pro in the video used leather. Vinyl stretches in all directions, leather barely stretches in one direction only. You can fasten the vinyl on the back side with some type of mechanical fastener as well. Pay attention to the adhesive you use to attach the vinyl to the dash. You cannot use 3m super 77 or the goofy headliner spray on adhesive from the can. That stuff never works in AZ anyway. Use Weldwood contact adhesive. It is harder to find, but it is the stuff.
I would practice on a junk dash before committing: Lots of artistry/skill involved.