gelcoat polyester headliner

Hello everybody,
Just discovered this forum that looks like a goldmine. I am curently restoring an old Triton. I want to make polyester panels for the headliners, that is on the roof and hull, on top of isolation foam. I got a big laminated panel and want to put wax then gelcoat then mat. First I need to order the material and I am not sure of what I need. Foam, which type is the best and which thikness? Then wax, is one layer enough, how does it work? Gelcoat: one or more layers? Mat what thikness? As you see this is a bit of an adventure for me but I hope I can manage with a few test trials.
I would be glad for any advices, I found this thread but it didn´t answer all my questions. http://www.boatdesign.net/forums/materials/beginner-needs-help-fiberglass-panel-making-30599.html
Thank you very much to take time to give me some advice and sorry for my english...
Jules from France

 

Headliners are panels on the under part of a deck or roof. There usually is an air gap in between them. Their purpose is decorative only. When you say "on top" do you mean under the foam and covering it?

 

Thank you for your answer. I plan to make headliners on the roof with no foam as the construction is already made with PU foam. But the surface is terrible with gaps and no paint so the other solution would be epoxy filler and paint, long and expensive work. But most importantly I want to make these panels to cover the hull in the aft cabin and on some part of the main cabin where there is no isolation and there I want to put foam covered by these panels. I hope it is clearer.

 

Panels are fairly easy to make, though you'll need sort sort of form to cast them on or over, so they fit the locations. This means you'll make them twice, once for the molds and once again for the final piece pulled from them.

For flat areas, you could just cast some pieces on a work bench, say with a Formica top. When cured cut to size and glue in place. The curved or other wise pieces that require some level of conformation to the hull/overhead will be the areas that'll make you cuss.

On the curved and compound areas, I'd cover these with spray adhesive and press plastic sheeting over it, working out wrinkles and folds as you go. Apply the fabric and resin of choice to the plastic and let this cure. These can be popped off after it's hardened up and trimmed to fit, then glued in location as desired.

 

You can also search on local building supply companies for pre-made panels.

 

Thank you. I am sorry I just realised I got mixed up I ment the front cabin and not the aft. There the curve is not so important and I was thinking the panels could bend sufficiently to adapt. This is why I wonder how much material I need to make them sufficiently stiff and yet bendable so they adapt smoothly. The rest is flat surfaces. I already got a formica board to work on. The idea is to glue some plywood "sticks" to the hull, and use velcro for fixing the panels on them so I can access the hull quickly if necessary. The foam would not be glued only stand in the sandwich.
But the moulding technique is very interesting thanks for the tips anyway,althought it seems more difficult than working on a flat horizontal support...
If I find these panels here, in a greek island, at an affordable price I will surely go for them but I doubt I will!

 

Just get a good heavy wieght paper to make patterns with. If you were doing a cabin sole it is easy to use inexpensive brown papaer to make a good a good template, but on overheads you have to use something stiff enough to hold itself up while you adjust it and cut with scissors or a utility knife.

 

If they are simply decorative panels, they don't need much fabric, so a layer or two of just about anything you like will get it done. If it was me, I'd lay down a layer of fairly light mat, say 2 ounce, then cover this with 12 ounce cloth, mashing it down with a weighted hunk of plywood, so it make s a uniform, flat panel. When cured, peel this off the work area and cut to fit. Of course, you'll need to protect the counter and any weights on the backer, so the goo doesn't stick.