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Fiberglass on plastic

4K views 6 replies 3 participants last post by  udtoy 
#1 ·
I am considering a custom dash project using the original dash pad stripped down to its plastic core as the starting point. I've only done fiberglass over wood, so I'm a little concerned about the ability of the resin to adhere to the plastic and that it might vibrate apart or separate over time in the vehicle. Any tips or experience with fiberglass on plastic will be greatly appreciated.
 
#2 ·
To do this right your going to need to remove the dash pad.

Now you are going to make a mold using the dash pad. Lets get this out of the way right now. This is going to destroy your dash pad. If not destroy make look like hell afterward. But the fiberglass result will be worth it.

Remove your dash pad and insert metal braces to retain the shape in the radio hole, instrument cluster, glove box, vents, etc. You want these braces around a inch deep. Lots of time spent here will be worth it later. These inserts can not move so don't be afraid to do things like using epoxy to hold them in place.

If you want the stuff to fit back stock you need to make the dash pad holes bigger. You would think that you could just cut out the fiberglass. But that is not always the case. Any curved areas will need to be opened up the thickness of the fiberglass. Some will and some wont depending on the design it is hard to describe in text. It is a trial and error thing that varies with each vehicle.

To make the mold you are going to take your smooth surface dash and lather it up with a layer of release before laying a single even layer of mat down. Remove any creases, cutting and tucking so that that single layer of mat fits snug. You want enough material so you can put a pin in it from the backside to hold it taunt. I find practicing with a bed sheet first eliminates much of the guess work. The areas where you have your braces filled with flat sheets of aluminum will have gaps. Don't worry about them.

Now that your large expensive sheet is laid down and tight with no gaps the fun begins. Get out your brush and resin laying down your 2" x 20"(or so) strips. You want to layer these. The pattern does not matter. Those gaps for the inserts I told you not to worry about start laying the material in those first. You want the strips to fill the voided area before you layer over them. Then just keep layering the rest cross hatching until the entire dash is at least 1/8" thick. Now I like to leave it for 2 days at this point letting everything cure properly. Separating a mold early is the easiest way to ruin it. I don't know your environment so 2 days should be more then enough. I would wait the 2 days to be safe.

2 days later you come back and you need to remove your dash. Remember I said your going to destroy your dash? This is where that happens. You want to pry at the corners a little gently. Little by little pry around the exterior gently. I cant stress gently enough. It will take time. You can speed it by pouring water/release mix into the gap. But dont go overboard prying or you will break the mold in two then need to start over. There will come a point where the thing will pop. Now you If your lucky you can weasel your dash pad out in one piece. If not you simply cut it out and set it aside. Even if you get it out the surface will be full of gunk and the inserts held in place by screws.

Now you have your mold. Look it over removing any creases or additional gunk. If you want to add a logo or reversed text now is the time.

Once the mold is clean and pretty get your new bed sheet and find the best way to cut and lay the stuff. You cant wrap this one so it may take a few sheets before you find what works best. Once you have a plan go liberal with the release and lay down the full layer. Grab that brush and apply a even layer of resin. Now lay down your strip around your insert bulges edges. You are going to reinforce the heck out of these edges because if it cracks it will be here. Focus on any curved areas of the dash laying more material here. Cross hatch your pattern and just go thin on the middle of the inserts as you will be cutting them out.

2 days later come back and pry the corners enough to get your resin/water mix inside. Let that sit, prying a bit, insert more water, pry and such slowly until the dash breaks free. If you needed to cut out your old dash then you have no real choice here you need to destroy the mold. It is a extreme case where you can not get the dash out. If you need to destroy the mold separate the dash first then cut the dash out of the mold using a dremel.


Look over your dash. If has lines or such don't worry you can fix those later. Right now you need to fit it against your car and make sure it did not shrink to much. You are not removing the inserts right now. But if you need to remove any slag to fit it do so. Once your sure the fit is good your going to go back to your old dash and piece it together. What you are after is the hardware if there is any. You are going to reuse this hardware carefully placing it and reinforcing it using resin and strips on the inside of you new dash. If you have holes measure those holes perfectly before drilling out a larger area inserting a steel gromet(or nut) and layering fiberglass around the gromet. Once it is dried you drill out the interior of the gromet and you have a insert that wont crack. You want these grommets inset 1/16 or so and using a washer on front of the dash will let you layer the back. Once the back is dry you will remove the washer from the front.
Once the back is dry you come back and insert pieces over the front to encase the grommet. You will sand these down later so don't go nuts.

Now that all your hardware is in place your onto the part that can ruin the dash. Grab the dremel and remove your inserts. I can stress enough that you want to remove as little material as possible checking the fit before removing more. Check the fit over and over until everything fits perfect.

Now then sand down the dash removing any imperfections and grab some very glossy black. Shoot the dash with 3 thin coats and let it dry. You are looking for imperfections, dips, or anything that will just look bad. Take note of these areas. Sand down the dash and insert more fiberglass in dips or such then spray it again and check. Once happy sand the dash all the way down shoot it with primer(meant for fiberglass) and the paint color/clear of your choice. Reinstall your dash and reinstall the inserts.


You have a mold out of this that you can make one or two dashes out of if you mess one up or just need another dash.

Now this is the correct way.


If you are thinking your just going to lay resin on your current dash and not have it crack. Well that could work:nono:. You are going to need to pull it tight around any openings and it will look more like a aftermarket dash pad with the obvious thickness differences and everything being inset deeper. I am not saying it can't be done. But I am going to say that it is not something I would enjoy looking at while driving knowing I could have done it much better.
 
#3 ·
Thank you for the detailed explanation Cerial. I'm going to really have to think long and hard about this one as your process might be a little to far outside of my comfort zone with fiberglass work.
Would making a plug mold from the backside of the dash pad be another approach? It seems that would maintain the proper dash opening sizes without concern for the thickness of the fiberglass, and give all the proper locations for mounting lugs etc.?
Of course I'm just sitting on the couch with a coffee as I try to think through this whole process, so I am sure it is full of problems. :)
 
#4 ·
The other side of the dash pad is shaped totally different then the top.

The only way your going to get all the curvature and fine detail of the original dash is to use a mold. Even then you may loose a bit if your not very careful when making the mold.

Now, for a custom dash. I need to ask just how radical we are talking? If you are not trying to reproduce the original look that opens up so many other options.




If you just want something to work up from you can grab a sheet of 14 gauge aluminum.

Remove the dash pad and toss that thing.

Lay the aluminum down over the steel that the dash pad was attached to.

Grab your shaping tools and massage the aluminum so it fits tight against the steel. If you can add ribbing to stiffen it do so.

Cut/Shape any holes you want for vents etc.

Reuse the mounting clips. You may need to rivet them in place using some epoxy for good merit against the aluminum.

Drill some holes into the aluminum and insert studs so that the threads pass into the steel dash pad mounting locations. Epoxy the aluminum to steel studs so they hold in place and will not pull through. If possible use a washer and shallow nut as backing to prevent them from pulling through.

Remove the dash pad(your going to do this like half a dozen times)

Now the fun part. Grab some 80 grit and rough up the aluminum a bit uniformly.

You want to get some epoxy primer and let it sit over night. Shoot the face and a inch of the backside perimeter .

Grab some 2 part panel bond and lay a skim layer down while very quickly laying your fiberglass mat behind it. Start from the backside and layer over the face then back to the backside. You are wrapping the dash pad in this.

Quickly install the dash pad so the panel bond and fiberglass will retain your shape.

Wait 24 hours or longer and come back.

The panel bond and fiberglass mat will hold a bit of a shape. But, not enough to be moved. Get out our resin and start layering strips from the middle towards the edges. You just want the fiberglass to match the curvature of the aluminum as it is currently pressed against the steel at this point.

Let it dry and add another layer. More and more to the middle until you have a good 1/8 that tapers to less at the edges.

Let that layer dry then you are going to very carefully remove the aluminum "dash pad". Now you are going to build the outer edges thick incorporating the strips so that the edges are 1/8 thick all around. You are doing this fast before the resin dries. Lay out your strips ahead of time. Then carefully install the dash pad adding a thing layer over the middle to attach the outer strips together.

Let that dry and you have your base. From here you can rough up that base and build from it into any kind of shape or radical design you want. Once it is dry it is removable and will not crack.

You get the idea about how to incorporate any vent or other holes that you may have shaped.





This is the more radical side of it if you need a blank canvas for something like 8 gauge pods across the dash or such.
 
#7 ·
Thanks for the encouragement Cerial! I dove in and created a fiberglass dash pad using the old original stripped one as a framework. Used epoxy resin with multiple layers of 5oz. glass. Then did the smoothing and filling with thickened epoxy resin. It turned out really nice with good snug fit all the way around and it uses all of the OEM mounting points.
 

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