Fiberglassing a tonneau cover?

I need a tonneau cover on my truck, and was curious about the difficulty in making it myself.

I was thinking if I made it from some plywood, then rolled out a couple sheets of fiberglass fabric (where would I buy a piece that large?) then remove the plywood "mold".

Is it difficult to get something that large paintably smooth?

How many layers would it take for something like this to be strong enough? 4-5?

Estimated cost of materials? (I am comparing this to just buying one)

As an afterthought, If I installed a pin switch at the tailgate and made it so the tailgate had to be down in order to open the cover, everything in the bed would be protected.

It would be nice if it was waterproof, and hinges with some kind of lift pistons would be needed as well.  Making it smooth might not be the hardest part...

Still interested in your thoughts!

would definatley be easier to just buy one but a lot more fun building it..plus you could make it a custom shape as opposed to just a flat cover..you could make it sligghtly taller in the centre to allow water to shed more easily..etc...

you are going to need atleast 7-12 layers of mat for this...a consistant 1/8th to 3/16's of an inch thick...you may want to consider some how pre building ribs out of fiberglass to mold to the bottom side of it too for a little eatra support..

getting a large surface flat isnt that hard you just have to use a big sanding block...

building in gas shocks etc...is going to take a lot of planning and and positioning...

my best guess at this would be:

25 yards of Mat - Ebay - 75 bucks plus shipping.

2 gallons of resin - 30 bucks a pop

ply wood/ chip board for armature - 20 bucks...or five finger discount from local construction site LOL just kidding

a pile of cheap 2" paint brushes, and mountain of laytex/ vinyl gloves - 30 bucks walmart

couple quarts of kitty hair - 15 a pop

couple quarts of Rage gold filler - 15 a pop

piles of sand paper - 20 bucks

a quart of high build primer/ or about 6 or 8 rattle cans - 50 bucks at Top Shop Auto Body Supplies

and a crap load of time...

your call but store bought will be a gauranteed fit...a piece home made this large could easily warp and not fit..

Answer #1 (from me):  Difficulty making one yourself....on a 10 scale will be a 7-9 depending on which way its built and for what truck, as well as if you want all the bells and whistles(opening struts/locks/ect.).  If your a 9 to 5'er and come home and work until dusk, it could possibly be done in about 1 to....well, it depends on your experience, so Ill leave that open.

Answer #2:  Yes, its easily possible to get something that large paintably smooth.  Again, depending on you.

Answer #3:  CrazyOldCougar is good on the 7-12 layers, but even that is dependant on what you use to build the framework.  (Ill explain)

Answer #4:  Cost depends on your shopping habits.  I have on record here with a build we did for a 95 Ranger.  The build ONLY for the cover without ANY extras was $197.  A local dealer/install shop for the same truck was provided by the owner at the cost of $640+tax.  (Ill explain the build)

This "Custom" bed cover was fabricated with a 3 foot wide, and 1inch raised center that started fore and ended aft.  The edge of the cover was flush fit to the inside of the bed, which would not be to your waterproof expectancy.  The construction consisted of a 1" x 1" angle steel channels welded to build the box edges, also an "X" channel was welded to secure it square.  The steel rectangle's measurement was purposely built 1/4 inch shy of touching the edges of each side.  A thin sheet of masonite panel lays flat and screwed to the frame.  Holes were screwed irratically throughout its surface.  Test-fit!!!  This is the time to figure its articulation on how its going to move via hinges, struts, locks, ect.  After this step, its time to remove it from the truck.  Set it up on stands at a low height.  Or, it can be hung from the cab end and where the tailgate end it toward the ground.  Mix a large amount of resin, apply to the wood, lay FG cloth, roll out the excess resin with roller, immediately apply more resin on top of the FG cloth.  This ensures both sides of the FG cloth is soaked in resin, as well as stuck to the wood for secureness.  Sand top of each layer.  Do this until you have at least completed 5 cured layers.  (Explaination: I agreed to CrazyOldCougar because thats how the mass produced bed covers are in thickness on average - some are nearer of 3/4" thick.) BUT, you have an "X" member in the mass of your cover made of steel.  Now, lets think.....are you going to put alot of weight on this cover?  Why would you put ANYTHING on your nicely painted bedcover?...EVER?  Why make this thing weigh more than 3-freaking-hundred lbs?  You be the judge.  If this thickness is NOT to your liking, resume the operation until satisfied.  Next, as a reminder, each time FG cloth is layed, it should also lay over the edge to build up the sides to fill the gap to flush fitting.  Finally, finish out the surface with a skin layer of body filler, sand prep for paint.....

See, now you have me wondering if this might not be too bad.

Per your explanation, I could do that.

The only thing that comes to mind is aerodynamics.  I have been thinking about it, and thought it would be nice to maybe have three sections, because I do occasionally carry items that are taller than the bed sides.  They would also be easier to move and store if needed.   I'd have to figure a way to secure the pieces to the bed, or I'd be concerned about 3 relatively light sections acquiring some lift at freeway speeds and flying away.  Even if was was something like spring mounted pins latched from underneath where you couldn't see them.  Hmmm...

You are correct, I would never place anything on it, I am crazy about my truck!  It's a Quad Cab Dakota, so the bed is only about 6 feet, so it would only be 3 roughly 2 foot sections, and I have a roll-in bedliner, so I wonder if it wouldn't look better to "paint" it with the same bedliner I did the bed in.  It goes over the rails, so it would be visible with the tonneau installed.  That would mean it wouldn't need to be a PERFECT finish, just really good.

Thanks for posting!  I think I am going to attempt this after all!

As far as being waterproof, if I install aluminum U-channel along the edges and use it to mount the sections, it would double as a gutter of sorts.  Not perfect, but it's pretty unlikely I'd be carrying priceless documents in the bed anyway, right?