If anyone has had any experience with fiberglass then you could probly answer some question i have about it.

I'm thinking of making my own tonneau cover, i would like to point that out first.

can you apply fiber glass, let it dry and then slap on another wet coat of it, will it stick good or will it split? aren't you supposed to do a bunch of thin layers?

also, do you think i should be okay if i just have the fiber glass holding itself up, meaning no metal framing or anything like that. will it hold on it's own once it's dry? could i layer the fiber glass around a metal mesh for reinforcement, what about temperature change, will it want to separate from the metal?

as for a molding, i'm planning on making a wooden tonneau cover first, then layering the fiber glass over top of it, then once the fiber glass is dry then i can separate it from the wooden mold. i think it would use a multi purpose grease to have it separate nicely. I'm also taking into account that the wooden mold will have to be about an 1/8 of an inch smaller on the sides and top to compensate for the thickness of the fiber glass....also you guys don't have to warn me about the sanding, i've been sanding and preping things to paint all summer so it's no biggie for me to spend alot of time sanding. by the way though, what kind of sand paper should i use? 200 grit to sand out the really rough stuff at the begining and then finsh with maybe 400 grit?

I'm going to say that without a proper mold or a lot of fiberglass experience you will probably be spending more in the long run to try and build it yourself than to buy one. And I am usually all for building something yourself.

Unless you have had some experience with making "structural" fibreglass parts, I'd forget about it. Making a mold out of wood then expecting to seperate the dried fibreglass from it is a dream. The use of grease with the resin wouldn't work to well. It will soften the resin. You need to have a very smooth surface and apply PCV which is a release agent between the paint (gelcoat) and the mold. Using matt fibreglass alone will leave a pretty rough surface where you can see the grain of the matt. You need to use a chopper gun to apply the glass and resin too.

Do yourself a favour, go down to the local Leer topper dealer and buy one

I don't know...I'd have a crack at it...but that's just me
I've done quite a bit of fibreglassing in the past and I don't think it's that difficult.
I do think though it will cost you more in the long run and won't be as good a finish as a bought item.
To get a good finish on the outside (the bit you can see) you'll need to make a wooden cover (as you said) and it will need to be a perfect..really, really perfect version of the finished product you want. Next you'll need to coat it in releasing agent (as Rob said)....grease won't work. The releasing agent dries and forms a plastic layer like cling wrap. Then you'll need to paint on gel coat (any colour....doesn't matter at this stage...you'll see why). Next you lay your glass matt over it and use a special roller to push all the air out. then, you'll have to install some kind of frame work...just roughly glass it to the glass you've already laid.
It will need to be integrated into the glass as it will stop the MOLD from twisting.
That's right...now you've made the 'mold'.
Pop the timber plug out and then do it all again (minus the ribbing/bracing) internally to make your finished tonneau! I would however recommend inserting steel or better Aluminium into the tonneau where you intend fixing your latches/struts etc to it.
The glass resin will stick to ANYTHING really well. You won't have to worry about it separating as long as it's clean!
Lot of work huh?!
I used to make radio control boats

Howard

Howard:

An old RC nut, eh! I actually still fly RC. Currently have a Dave Patrick Bi-Plane (4 Stroke Engine), Spread Spectrum Radio, etc. The kids love to watch RC flying; one club member flies scale helicopters in competition. These helicopters manuever like dragon flies, it's unreal to watch. It's hard to believe the things don't just fly apart from all the "G" loading.

I can understand the desire for a fiberglass bed cover, but having owned one, I can say I'll not have another one. If you use your truck like a truck the fiberglass cover will always be in the way, and they are also very heavy. If you build one you'll need to take this into account and have a way to mount assist struts on.

The covers I like and hope to get one of soon is a semisolid cover made up of foldable sections. You can fold back some or all of the sections depending on the load you need to haul, or just remove it completely, fold it up and set it in the back of the truck alongside the load. Some of them can also fold up against the back glass like a headache rack when you need the whole bed, so you don't have to completely remove it or take any bed space for the cover. These covers have the solid effect of a hard cover with the utility of a soft cover.

Well. Id say thats about a $200 project easy. in this case, it would be cheaper to buy one.

and that quote doesnt include any tools....

In theory it'd go something like this : make a perfect piece. wood.. sand, bondo, sand, sand, epoxy paint, sand, bondo. get it mirror polished and perfect. the better it is, the better the other part.

Then you use a mold release and spray it down on the part, creating the female mould. .. it dries you reinforce the backside with wood stringers and glass over them...dry.. separate ( or try to. )

then you inspect the female side, fix anything if need be.. polish..

clean, spray with mould release ( this can go two ways, IF you want gelcoat or just regular glass, i'll assume glass.)
You should spray down a layer of resin.. dry, then next hand lay in a sanding veil ( 100% absortion and allows you to sand and you cant see it. ) after a few of these, then you can work up to your structural. Id suggest kyntex or a biaxial weave. you can get into triaxial and higher but all these are expensive but very, very strong they incorporate biax weaves + mat backing. boats are made of biaxial.

few layers of all this and literally you dry it..trim the edges and remove from the mould. I'm sure there are spots i left out and i didnt mention the gel coat because that DOES require PVA to be added - it seals the resin so it can cure otherwise it'll never cure. ( polyester)

As far as cost, forget epoxy. unless you want to invest.

polyester is cheapest, then vinylester. and vinylester is the good one its a mixture of epoxy and polyester. for cost reasons I'd ditch the gel coat and just paint it or wrap with some sort of material.

check out some of the big fiberglass suppliers.. they have how tos. like us composite.

okay, I kinda thought it would get a bit comlicated so i think i'll try something smaller first to test out the process.

...now i don't know if this would apply to the tonneau cover, but i've seen costom subwoofer boxes made out of fiberglass and all they do is make a basic frame, wrap it with a wire mesh or even clothe and then "paint on" the fiber glass, when it dries then they sand, paint and polish it. ...it's rather easy but i guess you can get away with that when doing sub boxes.

Here's a ricer S10 site that has a nice little primer on how to fiberglass. Impressive looking stuff in there. I can appreciate the detail and quality of the work even if the overall effect of most of the finished products are nauseatingly fast and furious. At any rate, this link goes step by tiny feets step in how to fiberglass, what's needed, ect.

I have one of the hard fold up covers. It has 4 pieces and is really nice when you want to haul something.

Here's and idea since you have to make a really perfect piece of wood anyway why not make a tonneau cover out of wood. I think that would look really nice all varnished up like a wooden boat

Time to go fiberglass everything plastic.