I'm trying to improve the panel gaps on a 1974 Lotus Europa - the English were not too good at it back then. Question is - what is a suitable panel gap for a fiberglass car and what kind of radius do you put on - for instance - the edge of the bonnet (hood) with the thought that paint would not stick well to a sharp 90 degree edge around the bonnet.

Tom

Welcome, Tom,
Always liked Europa's, but alas they didn't like me (6 foot 1, 250 lb. even as a teenager, ha, ha.) Easiest thing to use as a spacer is a simple paint stir stick. Make the spacing tighter than that with some fiberglas and you can get enough wind resistance at speed to sometimes hit glas on glas. Make them much bigger than that and it doesn't look very "production." This was a kit car that I built where the average door gaps from the factory were a horrendous 1/2 inch or more. You can follow along there and see how I reduced them down to that paint stir stick standard....
viewtopic.php?f=12&t=7938&p=48940&hilit=Darrelk+fiberglass+kit+build#p48940
If I were doing your car the best way to establish those panel radius areas is to pull up as many pic.s of Europas as you can on the net. Next I would try and go look at a few in person and take my own pics. If you can see them in person you might ask the owner if you could lay some paper over those areas and take tracing and mark their locations on each tracing.
You are absolutely correct about that 90 degree thing. You always want to avoid any type of sharp corners on an car. If you spray a sharp area the paints "thin" away from that area as you shoot leaving sub par thickness. I've seen guys cut through even with hand buffing/polishing near an edge because they didn't "soften" those edges.

Darrel,

Can you give me an idea of the amount of 'softening' - 1/8" radius, 3/16", 1/4"? Looking at other Lotus bodies will probably not give me any useful data - they aren't too many around and all panel gaps and fits are usually the same - not good. I've read other sources that suggest a 4 to 5 mm panel gap, the paint stick you suggested measures 5 mm. After adding primer and color coat, the 5 mm will probably become 4 - 4.5 mm. I guess I'll aim to that.

Tom

This is just an educated guess but based on what I've seen of Lotus bodies when I was younger I would think 1/8th to 3/16 would be okay. Yes, that is correct about the paint stir stick thickness. I've used that method building and rebuilding about 10 fiberglas cars and trucks or so and it has always served me well. The only exception I ever made to that rule was a large tilt nose I did on a truck. I spaced that out at more like 7 mm just to be safe using a piece of plastic sign material. I was always concerned about the wind possibly grabbing the nose and slamming it back as I put it down.

To raise the level of the bonnet to match the surrounding body shell, I have Evercoat Everglass Short Strand Fiberglass Reinforced body filler and Eastwood Contour Premium body filler. Some of the panel fitting problems will probably require 1/8" or more of filler to level the bonnet to the surrounding body shell. Are there any guide lines as to how thick each material can be and still have strength? Stress cracks have been a legacy with the Lotus body shells. I would think the Everglass could be applied thicker than the Eastwood product. I plan on roughing up the areas to be filled with 80 grit.

Yes, your reasoning is sound there using the short strand stuff to achieve your thickness then "cream out" with the other type filler for establishing flatness of the panel. Honestly good quality fiberglas filler can go up to 1/4 inch with little problems as long as the panel is fairly stiff. Regular bondo type body fillers I prefer to work at 1/8 inch thick at most. If something is going to require more surface filling than that I would go back to a fiberglas filler or if it was really bad, build up fiberglas/resin/mat. Just remember on stress cracks..... you have to get down to the root of the problem by grinding open in a v shape down to the bottom of the crack. You can also drill "stop" holes at each end of the crack which will stop it from continuing to run in either direction over time.

I am building a factory five kit car and have had the same questions. Depending on the part of the body I either used the paint stir stick with sandpaper on one side to set the gap..or I set it for 3/16" using this method

https://www.youtube.com/watch?v=gms-PS2GcOE

I have gotten the panel gaps to where I want them and am filling with Evercoat Everglass to get adjoining panels in the same plane. In doing the sanding and contouring, the edges of each panel are a sharp 90 degrees. What is a proper radius at the edge of each panel - 1/16", 1/8", 3/16" - anyone have any recommendations? There needs to be a radius to eliminate thin paint at the panel edge. And, how can the radius be applied accurately?

Tom

find a drill bit the a size you want your gap and use the non drilling end, tape up the drilling end so it wont cut your fingers.
as for the radius, i would make the line as sharp as possible as its easier to tell if its straight and where you want it when its sharp, then do the raduis on it, lol, unfortunately i ahve no idea on how to get an accurate and achieve a consistant raduis
with a piece of timber you would use a router, do they make something for bodywork??
krem

I was thinking of routing a piece of wood with an inside radius, then using 180 grit adhesive backed sandpaper formed to the inside radius and sanding the panel edge with that - anyone tried this? For the panel gap, I made a 'gap gauge' from a 1/4" wide piece I cut from a tapered wooden door shim (you can buy them at the hardware store), then marked it with 3, 3-1/2, 4, 4-1/2, 5 mm pencil marks.

Tom