model t roof

[chimp koose]

Anyone here ever done the wood roof on a t coupe ? I was planning out what to do and have seen a few good posts about it elsewhere but when it comes to putting fabric over the wood structure I have an idea that I would like opinions on .  I am thinking to stretch  and staple canvas over the wood and then maybe use fiberglass resin over it to produce a waterproof hard shell .The top would be upholstered like factory but with a convertible top material like mercedes cloth . Maybe the material could be glued to the fiberglass ? I dont like the look of the original shiny stuff .  I plan on putting rockwool insulation between the roof and headliner to reduce sound/heat transfer. The headliner would likely be snapped or velcro fastened to the underside of the top bows . I was thinking of making the top bows thicker so they are even with the headliner surface to allow for easier headliner fastening . Opinions/suggestions please

[kb426]

If you gave me the task, I would start out with maybe 3/8" ac plywood. I would install t nuts to go where the roof bows are for attachment. I would purchase landau top glue and glue landau top foam to the plywood and then Hartz convertible top fabric to the foam. It would be wrapped around the edges and glued in place or a trim piece stapled on top of the edge. I would use the thin micro cell alum. backed insulation and then if you desired a cloth headliner, I would use the foam backed cloth or vinyl that is readily available. Not having any idea what you want the rest of the interior to be and the theme of your car, I could be as far off as possible.

[rumrumm]

If you try to paint resin over cloth, it will droop. Rather than cloth, you might think about using the waterproof cardboard used on interiors as a base and put a layer of fiberglass matte or cloth over it.

[chimp koose]

stuff to think on .Didn't think of the droop ! I think the problem with plywood is that the roof is curved side to side and front to back , might be tough to put plywood on . Also the roof is just over 4' long and wide so a sheet wouldn't cover in both dimensions . I was thinking fabric of some kind as it will stretch in all directions. If it didn't sag too much  a guy could probably use a light filler to take out the droop?  A lot of restorers use cotton batting and chicken wire to get a smooth contour under the top material . I was hoping to make something waterproof and solid under the vinyl top . Originals do not fasten to anywhere but along the edges . I was hoping to glue this one down at least in a few places as well as edge stapling . The ones I have seen with a metal roof do not look like the original roof line which I really want to keep . They are usually too flat and too thin .

[idrivejunk]

Do you mind if I send you down a rabbit hole? I did not have a response at all, just a couple maybes after reading your wishes. So I scouted a little ways down a couple avenues. Hop on the thought train, woo-woooo

Did my first paint job with Durethane clear. At that time, aircraft fabric was on the list of suitable substrates due to it's flexibility. It was around 1990 and Durethane was PPG's equivalent to DuPont's Imron.

In more recent times and in a car audio context, specifically for the fabrication of kick panels with custom speaker mounts in the early 2000s, my stereo shop wiz brother showed me this fuzzy black and presumably 100% polyester "carpet" which was used on woofer boxes but was also easily stretched and formed over a framework or irregular contours. This could then be wetted with fiberglass resin (which is also just polyester) then bondo'ed to create small shaped enclosures.

Then during the twenty-tens during the emergence of commonplace UV-cured products I caught wind of a product which I cannot name now or describe well enough to find on a web search. But it was presaturated and merely needed to have the liner pulled off and be formed as desired then put in the sun or under a UV lamp to harden into something like a thin fiberglass layer.

Today, at fibreglast.com I found some stuff like that sold for patching the big windmill blades or camper shells and what-not. UV cured. Exited that rabbit hole then, after the Durethane came to mind in the shower and I pursued the painting aircraft fabric hole.

And aha! Yes. Any run of the mill current day automotive 2K acrylic urethane (plain ol body shop paint now) or probably also 2K industrial polyurethanes work. On aircraft. So yeah, T roof no sweat.

Poly-Fiber ( conaircraft.com ) sells systems for aircraft fabric coating. As with anything aircraft, that is probably overkill. But yet another new old wrinkle came to light...

Tautening dopes. Same site as that ^^^. Different coatings for different fabrics, synthetic or organic. After your fabric is glued to framework, applying the (color choices) dope tautens (tightens) the fabric to the desired degree by number of coats applied.

However, polyester fabrics are primarily tautened via heat. 250-350°F was mentioned and using a clothes iron to conform the material to contours was shown.

At work, the satin clear we use is PPG's DSC5250 Satin Clear Kit. Quart each of parts A and B.

Now. If you are picking up what I am laying down, you are thinking of just using a polyester fabric, maybe setting it out in the blazing Canuck summer sun a few days, then painting it like a fender.

That is indeed what I am suggesting. 

[enjenjo]

Several of the stereo shops around here use polyester sweatshirt material to make custom panels, then polyester resin to harden it. I don't see why that wouldn't work for you. The fabric shops carry the material in 54" widths so a couple yards should be enough.

[chimp koose]

lots of options to look at . Thanks for the suggestions . I really like the shape of a stock T roof but it is kind of made for a vehicle with the top speed 20hp can muster. I have heard of soft tops wadding up as they are driven at highway speeds . Would love to keep the stock roof profile with a more durable construction.