Fiberglass over our plastic panels?

-
W

Woodsman341

Well-Known Member
Joined
Oct 28, 2022
Messages
356
Reaction score
114
Location
Columbia, SC
Hi folks,

I searched the forum and didn't find exactly what I was looking for, so here I am with the first of two questions.

First, the Dart Sport I picked up actually has all it's plastic panels, and are mostly good with the exception of one cracked sail panel. All plastic parts, though, like the pillars and kick panels, have divots and nicks and such...you all know the drill. So my first thought is to use fiberglass resin and fabric on the rear of the panels to add a little strength, then use fiberglass resin to cost, rebuild, repair the outer faces. I'm not going for factory correct, more of a "just for me restomod/restoration". My main concern is that the heat released from the fiberglass resin curing may further damage the plastic. Thoughts?

I considered just using Bondo, but I'm really not sure about how well it will adhere to the original plastic.
 
Kendog 170 said:
Something like this?
Plastex Rigid Plastic Repair Kits
Click to expand...
Not exactly, I want to completely cover both sides of the panels with something like fiberglass and then sand, and either paint or cover in vinyl. I can repair the cracks and such with a small kit like that, but I imagine it would only be a matter of time before the un-repaired sections would start crumbling, you know?
 
Use a slow curing epoxy to keep the heat down. Whether fiberglass and resin is a good fix for the panels or not, I don't know. Lots of plastics can be tough to adhere to.
 
If I was going to do that much fiberglass work I would be more inclined to use the original panels to make a mold. Then just make new panels out of fiberglass.

Especially if you’re not worried about them looking original.
 
I thought about that, but before I could get that far I would probably have to go ahead and do what I said above. :)
 
vacuum molded uv resistant pvc/hdpe keep the texture and color
 
jazak5 said:
vacuum molded uv resistant pvc/hdpe keep the texture and color
Click to expand...

Yes, but again, I would still have to repair what I have before doing that, and if I'm not mistaken, vacuum molding wouldn't do well with the mounting posts and such on the backside of certain parts.
 
Woodsman341 said:
Yes, but again, I would still have to repair what I have before doing that, and if I'm not mistaken, vacuum molding wouldn't do well with the mounting posts and such on the backside of certain parts.
Click to expand...
ever try to get those nuts and bolts off of the cardboard???!!!! :rofl:
 
I honestly think you're going to have a hard time getting anything to bond to the OE panels in any long term kind of way.

If you use them to make a mold you can just repair the mold or the fiberglass afterward, both of which would be easier than repairing the surface of the panels.

doug 371 said:
repair the crack and spray them with paintable rocker guard?
Click to expand...

I did that with my A-pillar trim. It makes them look a lot better but I don’t think it’s going to do much or anything at all to keep the trim from deteriorating and cracking further. As a short term fix it works, but in the long run I’ll either need to find other panels or cross my fingers and hope someone reproduces them at some point
 
A few weeks ago i used this to repair a urethane bumper cover tear in the mounting ear. It cures very nicely, very hard yet flexible enough. Worked very well for my application. Supposed to beable to sand and print it. for $7 at your walmart, i'd give it shot. For the crack, I would glue the crack AND a reinforcing gusset on the back side so it doesn't spread any more.

www.jbweld.com

Plastic Bonder Syringe - Black

PlasticBonder™is a quick-setting, two-part, urethane adhesive system that provides strong and lasting repairs and works on thermoset, carbon fiber composites, thermoplastics, coated metals, concrete & more.
www.jbweld.com www.jbweld.com
 
I used fiberglass filler, mar-glass. Duct tape on outside and sanded inside of panel with 40 grit. Duct tape to cover the hole where piece was missing. Suprisingly the adhesive on the tape left a texture similar to what the panel had. Held up til i sold it.
 
Tooljunkie said:
I used fiberglass filler, mar-glass. Duct tape on outside and sanded inside of panel with 40 grit. Duct tape to cover the hole where piece was missing. Suprisingly the adhesive on the tape left a texture similar to what the panel had. Held up til i sold it.
Click to expand...
Nice. I have a spare kick panel in rough shape that should make an interesting experiment piece. Nothing ventured, nothing gained...
 
Pictures would be VERY helpful. From what I gather, you have one sail panel with an actual crack, and all the other plastic pieces only have superficial damage. If I am wrong, please correct me, but that is what you stated. First, for the hard plastic parts, body filler will work fine in the scratches, divots and nicks. I have done it a million times. If the scratches, divots and nicks are very bad, you could use 5-minute JB Weld epoxy. Build it up in thin layers. It is a bit harder to sand than filler, so do not put on too much. But body filler will work most of the time. For scratches, divots and nicks in flexible plastic parts, I use a two-part epoxy specially made for plastic. it will fill the damaged areas and flex a bit. With hard or flexible pieces, a light, thin skim of regular filler can be used to get that perfect surface.
I am not familiar with the sail panels in your car. I do not know if they are hard or flexible plastic. Here is a short version of what I do for cracks in plastic:
Hard Plastic: I first drill a 1/16 hole at the end of the crack. This is called 'stop drilling'. It will keep the crack from spreading further. Then I widen the crack a bit and bevel both sides of the crack on the side you will see. Then I strengthen the area by applying a patch on the backside with 5-minute JB Weld epoxy and a little fiberglass cloth. Scuff the repair are with sandpaper first. Once the epoxy cures, you will have a very strong repair that will likely not flex or crack anymore. Now you just need to repair the front side. I'd use more 5-minute JB Weld epoxy like body filler. Make sure to use thin coats. I like to tape around the areas to be filled with cellophane tape (because it is thin) to try and keep the epoxy only in the desired repair area. Then sand the area down and use a light skim of regular filler to make the area perfect. I have been doing this for years with good results.
Flexible Plastics: There are lots of kinds of flexible plastics used on cars, and I would have to see what you are talking about. If the flexible piece is the kind that will melt if touched with a soldering iron, I fix the crack by stop drilling it first. Then I repair the backside of the crack with a soldering iron, and I use a plastic zip tie as filler (like using a filler rod when welding). On the front, I will probably use the epoxy for plastics mentioned above. I sometimes use the soldering iron and zip tie filler rod, but that is only in a bad crack. The soldering iron and zip tie filler rod method on the front is much harder to finish to look nice.
 
harrisonm said:
Pictures would be VERY helpful. From what I gather, you have one sail panel with an actual crack, and all the other plastic pieces only have superficial damage. If I am wrong, please correct me, but that is what you stated. First, for the hard plastic parts, body filler will work fine in the scratches, divots and nicks. I have done it a million times. If the scratches, divots and nicks are very bad, you could use 5-minute JB Weld epoxy. Build it up in thin layers. It is a bit harder to sand than filler, so do not put on too much. But body filler will work most of the time. For scratches, divots and nicks in flexible plastic parts, I use a two-part epoxy specially made for plastic. it will fill the damaged areas and flex a bit. With hard or flexible pieces, a light, thin skim of regular filler can be used to get that perfect surface.
I am not familiar with the sail panels in your car. I do not know if they are hard or flexible plastic. Here is a short version of what I do for cracks in plastic:
Hard Plastic: I first drill a 1/16 hole at the end of the crack. This is called 'stop drilling'. It will keep the crack from spreading further. Then I widen the crack a bit and bevel both sides of the crack on the side you will see. Then I strengthen the area by applying a patch on the backside with 5-minute JB Weld epoxy and a little fiberglass cloth. Scuff the repair are with sandpaper first. Once the epoxy cures, you will have a very strong repair that will likely not flex or crack anymore. Now you just need to repair the front side. I'd use more 5-minute JB Weld epoxy like body filler. Make sure to use thin coats. I like to tape around the areas to be filled with cellophane tape (because it is thin) to try and keep the epoxy only in the desired repair area. Then sand the area down and use a light skim of regular filler to make the area perfect. I have been doing this for years with good results.
Flexible Plastics: There are lots of kinds of flexible plastics used on cars, and I would have to see what you are talking about. If the flexible piece is the kind that will melt if touched with a soldering iron, I fix the crack by stop drilling it first. Then I repair the backside of the crack with a soldering iron, and I use a plastic zip tie as filler (like using a filler rod when welding). On the front, I will probably use the epoxy for plastics mentioned above. I sometimes use the soldering iron and zip tie filler rod, but that is only in a bad crack. The soldering iron and zip tie filler rod method on the front is much harder to finish to look nice.
Click to expand...
I have used the zip tie as filler as well, works slick!
 
1. Wash the part with soap and water, then just water, use an air hose to find the ends of any cracks. Stop drill the ends of the cracks, I would use a 1/8" bradpoint bit.
2. Scuff the back side of the panel with scotch brite where you are going to do the repairs, do a larger area than the size of the reinforcement patches.
3. Pre cut your glass patches and test fit them. I would use a 6 oz cloth and 1.5 oz cloth. The 1.5 oz cloth patches should be larger and be placed last, I would recommend you buy some pinking shears rather than borrowing your wife's. This is not to save you the fight, but rather an opportunity to win points AND buy more tools at the same time.
4. Use green or blue 3M masking tape on the visible side of the panel. This will prevent resin from getting through the crack and stop drilled holes and onto the outside/visible side.
5. Mix resin and apply to the inside surface in an area larger than the patch.
6. Lay the 6oz glass patch in place and stipple with brush to pull the resin through the cloth. Make sure that the glass is completely wetted. Then lay the larger 1.5 oz glass on top and use brush in the same way. Lay the peel ply cloth on top and stipple it as well. Make sure there is extra cloth sticking out past the edge of the part so you can grab it and peel it off after the resin is cured.
7. Let cure. You can make a curing box, don't go over 150* F.
8. Lightly sand with 120 to remove any glass spikes. Not needed if you use a peel ply cloth.

Tools and materials:
6 oz fiberglass cloth
1.5 oz fiberglass cloth
Peel ply cloth
1" paint brushes (trim to about 1" - 1 1/2" length for stiffer bristles for stippling)
Mixing cups and sticks
2" 3M masking tape
1/8" bradpoint drillbit
Pinking shears
Drill set to slow speed
Resin and hardener
West System, expensive
Generic stuff, cheap
 
Last edited:
Ottmundr said:
1. Wash the part with soap and water, then just water, use an air hose to find the ends of any cracks. Stop drill the ends of the cracks, I would use a 1/8" bradpoint bit.
2. Scuff the back side of the panel with scotch brite where you are going to do the repairs, do a larger area than the size of the reinforcement patches.
3. Pre cut your glass patches and test fit them. I would use a 6oz cloth and 1oz cloth. The 1oz cloth patches should be larger and be placed last, I would recommend you buy some pinking shears rather than borrowing your wife's. This is not to save you the fight, but rather an opportunity to win points AND buy more tools at the same time.
4. Use green or blue 3M masking tape on the visible side of the panel. This will prevent resin from getting through the crack and stop drilled holes and onto the outside/visible side.
5. Mix resin and apply to the inside surface in an area larger than the patch.
6. Lay the 6oz glass patch in place and stipple with brush to pull the resin through the cloth. Make sure that the glass is completely wetted. Then lay the 1.5 oz glass on top and use brush in the same way. Lay deeply cloth on top and stipple it as well. Make sure there is extra cloth sticking out past the edge of the part so you can grab it and peel it off after the resin is cured.
7. Let cure. Lightly sand with 120 to remove any glass spikes. Not needed if you use a peel ply cloth.

Tools and materials:
6 oz fiberglass cloth
1.5 oz fiberglass cloth
Peel ply cloth
1" paint brushes (trim to about 1" - 1 1/2" length for stiffer bristles for stippling)
Mixing cups and sticks
2" 3M masking tape
1/8" bradpoint drillbit
Pinking shears
Drill set to slow speed
Resin and hardener
West System, expensive
Generic stuff, cheap
Click to expand...

Fantastic information! I especially liked the part about buying my own pinking shears (I actually DO need them for another future project). Thanks again!
 
Woodsman341 said:
Fantastic information! I especially liked the part about buying my own pinking shears (I actually DO need them for another future project). Thanks again!
Click to expand...
Glad to help.

Just curious, what would you pay for these parts made of carbon? They would not save a lot of weight, just look cool.
 
Ottmundr said:
Glad to help.

Just curious, what would you pay for these parts made of carbon? They would not save a lot of weight, just look cool.
Click to expand...

Honestly, I have no idea. I briefly considered trying my hand at it, but I didn't want to invest in the extra equipment and supplies. :) I messaged you, so if you have a price on mind, or examples, feel free to let me know.
 
Woodsman341 said:
Honestly, I have no idea. I briefly considered trying my hand at it, but I didn't want to invest in the extra equipment and supplies. :) I messaged you, so if you have a price on mind, or examples, feel free to let me know.
Click to expand...
I would have to buy good parts, make the molds and then do some layups. Then I would need to test fit to make sure the molds are the proper shape.
I cant figure out how to clear out my inbox on this tablet, I will when I can sit down at my desktop.
 
You must log in or register to reply here.
-

Back
Top