I am a professional I do these dashes, but they will cost you a grand and about three weeks without your dash. If you do it yourself and you do it right maybe 4 or 5 weeks if you're new to this stuff.
You can listen to what everyone else is saying but they are missing a few steps and if you don't want your dash to looked like a bondoed pile of shit then you have a few things to learn. I would recommend you get a second dash from the junkyard unless your a professional with glass cuz if you screw up your not out of your original dash and the air bags will most likely be taken out of the dash already so you won't have to tear up your stock dash. Sell it on EBAY or on this site.
The conditon of the vinyl doesn't matter cause you will remove it first before glassing it. Remove the plastic hardware first, Clock,gauges,vents,etc. Then peel the vinyl off by pulling from one end to the other till it's all off. Use a heat gun to loosen it. Underneath the vinyl there is a thin yellow or white mold foam. Remove this with a metal scraper and a heat gun. When the plastic is pretty much cleaned off, wipe down twice with acetone to remove the glue left by the foam.
{Hint} Wear rubber surgical gloves with acetone; it will get very cold and doesn't feel good in cuts, and when mixing fiberglass resin, it will get hot.
Now you should have a clean plastic dash. Forget cutting up fiber glass and draping it all over you dash it's too messy to lumpy and will be harder than hell to do the finishing work on after it's hardened. Go to a sound shop where they sell and install custom home systems and car stereo systems or even Radio Shack and buy 10 or 15 yards of speaker grill fabric. it comes in alot of different colors but lighter colors (100% polyester light beige or tan is best), seem to make it easier to see imperfections when sanding and filling with bondo. Set your dash up on two saw horses in a well ventilated area free of dust or wind. Cut a piece of grill cloth to be a foot longer and wider on each side of your dash, if it were laying face down.
Next lay a piece of clean cardboard down, it must be large enough to lay the fabric on.
Next lay the dash face down in the middle of the fabric so that you are looking at the back of the dash. Stretch the fabric around the dash from top and bottom and make the two edges meet at the middle of the back of the dash. Start in the middle,pull it tight and staple it a few times with a regular office type stapler. Plastic Clamps from Home Depot work also. You will need about five to ten clamps to keep the fabric tight while glassing. Repeat this task from the center out to each side then you take the flaps on the ends and pull those back and staple and clamp in place. I think I bought some in a pack of 16 for a few bucks.
When you flip the dash over make sure, most if not, all of the wrinkles are stretched out and re-stapled and clamped. Wrinkles = more work sanding and filling with bondo and sanding some more.
Now set the dash carefully onto the saw horses with out bumping the clamps or you'll have to do that step again.
When mixing resin you don't want to follow the directions on the can cuz they are repairing boats not building a dash. You want the fiberglass to set up fast so it has less time to collect stray hair, dirt, dust, and everybody's curious fingerprints. Keep in mind the faster it sets up the faster you have to work and it also gets hot faster so pay attention to detail or you'll be buying double in supplies. For real!
If you get one tube of hardener with a pint of resin or two tubes with a gallon of resin you'll want to buy about six to ten more tubes. To mix resin hot you need to use more than three or four drops. You'll need to stick a thumb tack or pin in the end of the tube to get a good 2-3 second stream for every 1-1.5 cups of resin. If your just learning resin don't mix more than this at a time because if you put too much hardener in you'll kill your brush and what ever you used to mix it in. Not to mention you'll waste a lot of resin.
You will need about 5 or 6 natural hair paint brushes. Home Depot has them for like a buck or two a piece. you also need about four painters cups (clear plastic)
to measure resin and one for cleaning your brushes in the acetone. Blue paper shop towels, more durable and lint free for absorbing the acetone out of the brush after each cleaning so it can dry.
Wear the gloves.
When you add the hardener to the resin mix it with a stainless steel wisk from the kitchen, not your moms though, she'll hurt you; but any way find one. When you mix it it will turn a dark red or green color depending on the amount of hardener.
If it does not change to this color after about 1 or 2 minutes you didn't mix it hot enough. Starting out if it is not that color it won't matter cuz your just learning so it will give you a bigger window to work painting the resin on to the dash.
Only glass one section at a time and when the resin you mixed has ran out or starts to gel up stop brushing it on and get that brush into a cup of acetone(the sooner the better) before it gets hard. Then wearing gloves slosh the brush up and down in the acetone to remove and break down the resin then seperate the hairs of the brush with your fingers in the acetone. Then use the paper towel to absorb and dry the brush. Set this brush off to the side to dry, and discard the gloves.
At this point if you want you can take a break and wait for the glass to harden so you know what your finish will look like with that mixture. If the drying time is too much for you add a little more hardener on the next batch. If it turns dark green or red at the 1 minute point after mixing you only have about a 5-8 min. before it is too hard to brush on.
Put on some fresh gloves and repeat the resin mix with a fresh cup , and a fresh brush. Once you have brushed on a thick layer 1/8 inch over the whole dash let the resin cure over night. REASON: Fiberglass resin shrinks.
Next day remove the clamps and cut the excess cloth from the back of the dash and trim the edges of the dash. Then use a palm sander or a dual action sander with 60-80 grit sand paper to take off any globs or high spots or fringe around the edges of the dash. Once it is pretty smooth it will still have some imperfections, but it is also a little thin, so take it easy sanding so you don't burn through to the plastic.
Now you have to go back and repeat this whole process at least one more time to make the glass dash thick enough that it won't crack and ruin your paint job. You have to make sure that the next layer doesn't have any air pockets between the two layers when glassing it. After sanding and trimming the dash for the second time with 60-80 grit paper then move up to 150 grit for a once over.
Do not forget to let it cure overnight once again.
Now you are ready for the bondo. I'm going to assume you know how to use bondo, and if you don't you can read the can on this one. Using the plastic type
spreaders mix a portion large enough to give a thin layer over the whole dash.
You can mix a little at a time if you don't feel comfortable with the curing time. After about 10-15 minutes you can start too shape the bondo with a cheesegrater (found at auto body supply store) and block it down with 80 grit sand paper. Repeat bondo application as needed. Then block it down again.Till all Pits and dents are filled. Then block it down with 150 grit.Then primer and block with 150 grit. Primer again and block down with 180 grit then move to 220 grit wet sanding.
After this point you should be pretty close.
As far as painting goes I would have a paint shop spray your dash at the same time they shoot your car so the blend is exactly the same, especially if your doing a custom mixed color or a pearl.
Holla if you have a question. B)
