open discussion on fiberglass tops

[mightymidget]

I finally purchased a original bugeye top off eBay hopefully it is decent enough to redo.
purchased mostly for looks, but I can see some benifical reasons to have such a part on the bugeye. sidenote..prices are getting crazy for these tops.
I know anything fiberglass is hot, so I would think these tops are hot as well? If so has anyone tried the dynomat to block heat? how about the old style headlinner?
I was thinking of redoing surface with new gelcoat. I have never sprayed jelcoat so enlightened me please if anyone has. Hoping that process would stop future cracking/chipping issues.
any links are advice on redoing the top would be appreciated.
and lastly. why is it a top and not called a Hood as the vinyl counterpart?

please feel free to discuss anything about these tops whether it pertains to anything I mentioned or not

 

[jhorton3]

Fiberglass tops are always expensive. I finally broke down and bought one for my Wrangler, and it makes a world of difference in everyday driving. Adding dynamat could add a lot of weight to the top making it a bit more cumbersome to take on and off the car. My other concern would be keeping it in place under the headliner.

 

[nomad]

I'm in the process of redoing one that probably should have been used for kindling!
I've also had some experience with fiberglass.
Spraying gel-coat has to be done with a pressure pot gun which is rather expensive.
I'm going to grind the cracked areas down to glass and then apply a thin "veil" of glass mat over the top. Then filler to smooth and finish as any other project.
I tryed to cover the whole top with a coat of resin and the cracks came right thru. I've read that if you haven't got too many that you can V them out the fill with resin and I have done that with some. If you have a big "crased" area from an impact I don't think that is possible.

Kurt.

 

[JOeyKnapp]

Kurt, fiberglass resin adds no strength. It will crack very easily. The best way to fiberglass is to use the minimum amount of resin to wet the cloth/mat. Rolling the resin into precut mat/cloth while it is on piece of glass or smooth surface will help you get a very uniform finish. The rolling process breaks down the binding chemicals used to hold the fibers together (for mat) and once rolled out, you can pick the piece up and lay it in place and finish roll it on the piece.

If there were just surface cracks, duraglass might be a good base for filling and strengthening. Then follow up with filler, and maybe even some high build poly primer if the rest of it is a little rough...

 

[nomad]

Thanks for the info, JOey. I figured the resin would cover the crased area's but it did not. I used to make fiberglass parts for flat track motor cycles but never got into trying to repair old parts. We just thru away anything damaged. What is "duraglass"? I will try wetting out the mat before laying it. That should help a lot on getting a smooth surface to work with after its cured.

Kurt.

 

[JOeyKnapp]

Hey Kurt. Duraglass is a filler type of product but it is fiberglass based.

Wetting and rolling it out ahead of time will give you a very smooth surface (comparatively speaking). Just make sure to try and use a minimum amount of resin. Just enough to be able to roll out and wet the whole layer at a time. (so, wet the table lay on mat layer 1, roll it out with a roller and get all of the air out and the resin evenly distributed, lay on layer 2, roll and wet, layer 3, etc until you have all of the layers you need are on the stack. Doing all the layers together helps it to cure faster and saves time.

 

[mightymidget]

are the tops heat generators? mine will be white so that will help.

I also found a perforated glue in Hood liner made by Oscar on the fj40 forums (Toyota landcruiser) that has the 50/60s look.

I discovered gel-coating is a lot of work and will yellow with time.

 

[Guest]

What about that bubble wrp looking insulatgion for metal buildings? It's light and reflects heat well.

 

[nomad]

As of now I'm only planning on laying on one layer of fiberglass "veil" that is only 0.010" thick to cover the "crasing" from various impacts the top has had over the years. Its rough but it has the rear glass window and I picked it up off craigs list for $250 so I can afford to play with it.

As to the heat and insulation I've always wondered how well that bubble wrap insulation really worked. The price is right for it.
I don't expect the top to make the car too hot. There are vents above the rear window and running with the side curtains out should allow quite a bit of air. Wonder if anyone has ever fitted "Old Air" air conditioning to a spridget!??

Kurt.

 

[Billm]

I have no idea why a hardtop could be considered "hot". The Spridget has a lot of heat that wicks thru the firewall and trans tunnel and the hardtop will hold the heat in. The sun beating on a black hardtop will heat it up but nothing compared to the engine heat. Insulation in the top will just keep more of the engine heat in and make it heavy, if it is the right kind it may help the noise but not the heat.
BillM

 

[mightymidget]

don't know that the top is hot, I just know anything fiberglass is hot when the sun beats down on it, the same as metals

 

[nomad]

I have no idea why a hardtop could be considered "hot". The Spridget has a lot of heat that wicks thru the firewall and trans tunnel and the hardtop will hold the heat in. The sun beating on a black hardtop will heat it up but nothing compared to the engine heat. Insulation in the top will just keep more of the engine heat in and make it heavy, if it is the right kind it may help the noise but not the heat.
BillM

Well, Bill, of course it will be hotter than running with the top down under most conditions but I do know that when the sun is really beating down it will feel cooler with the top up.
My top will definetly be white.
In the midwest this year nothing was comfortable but AC!

Kurt.

 

[Billm]

True- what I am saying is that the top doesn't really cause heat (mostly) but just holds it in. Insulation would make it worse.
Bill

 

[nomad]

Agree, Bill. Everything else needs to be insulated. Didn't you and some of the other NW guys use duct insulation from Home Depot??

Kurt.

 

[Billm]

Yes- both Rick and I did. Common stuff from Lowes/Home Depot. Rick got the good stuff with stickum on the back but I accidentally got the non-sticky stuff and had to put it in with spray glue.
Bill

 

[nomad]

Did you notice a difference after the application? I've always thought that the incomeing air from the ventilation system needed to be better insulated to avoid picking up engine compartment heat.

Kurt.

 

[mightymidget]

the heat barrier applied to the inside of the top is applied to stop heat gain from the sun.

The insulation value will not be relevant to the inside heat until the sun sets. during the daytime the insulation would not cause heat gain for the simple fact the top is already present and holding cabin pressure with or without insulation.

if the car is gaining heat from the engine the heat will not be retained simply because top is insulated unless windows are closed and the car is not moving, then if outside temperature is less than inside the car.

then you can factor out the additional heat soak from the top during the day from solar penetration. therefore the interior of car is cooler by eliminating a heat source.

 

[Billm]

Kurt
There was a real difference when I put in the floor insulation but what really made the biggest difference was plugging up ALL of the holes in the tunnel/firewall. Those little blasts of hot air really hurt!
When I insulated the inside of the heater box it made a huge difference too, now the air coming in thru the air system is only warm instead of HOT! (even when the water valve was turned off).
BillM

 

[nomad]

Good points, mightymidget, but I think the heat coming from the engine would be my main concern.
Bill, I have thought about insulating the heater box and will do that along with the floor's. I've plugged all holes already. I also believe that there is insulated flexible ducting available to get the air back to the heater box. Insulation around the plenum that gets the air into the car should be considered as well. I'm talking square cars but my BE was insulated by the PO and I removed most of it around the driver foot area so that I could get more foot room. I'm thinking insulating there needs to be done on the outside.

Kurt.