no-paint door fitment - Plastic?

[Oppenheimer]

So we hear that Jim's design uses a floating fender gap to door to hide the trimmed door panel. Trim to fit door panel would be trimmed at front only, gap would hide raw glass edge.

What if the door panels were injection molded plastic instead? I'm imagining this would be easier to control the panel dimensions (is the whole trim to fit issue due to controlling door panel tolerences or door opening tolerances?) If so, that could eliminate this design imposition.

There would need to be a sturdier door frame underpinning it, but I don't think that would add much weight (and it might add safety?)

Perhaps other small body components could be plastic as well. I'm thinking mainly of trim pieces, like the black door gap grills on the Rodney design.

[crackedcornish]

when FFR first made mention of "no paint" panels this is the first thing I thought of. Works great on some of the complex curves of motorcycle and atv panels, so why not on cars too.

...now that I think of it, the front fenders and doors on my 4th gen.camaro are some type of plastic..of course they're not "no paint" but it shouldn't be to hard to make colored plastic doors

[BipDBo]

I have doubts that plastic would be a good idea for the doors. From what I've heard, the problem with the paintless doors is that you can't trim them. I'm not sure why trimming would be needed if you have some leeway fastening the body panels. I think that trimming plastic panels wouldn't yield good results either. It's also much more difficult to make injection mold plastic pieces precisely. They tend to come out warped. Also, I think that it may be very difficult to match the color between plastic and fiberglass pieces. I think that plastic body panels like those on the good old Saturns were painted, so that they could be glossy.

[Psay]

Other than cost I don't see why an accurate Gel coat GRP door cannot be made.

The Ultima GTR has such a door and it fits beautifully. If you look at the pictures below it not only has to fit fore and aft but also into the roof. I personally have never worked on such a door, however, they must be a lot more difficult to make fit than a regular car door.

61896190

[riptide motorsport]

The cost of the die's to make the Panels would be astronomical!

[JRL]

Other than cost I don't see why an accurate Gel coat GRP door cannot be made.

The Ultima GTR has such a door and it fits beautifully. If you look at the pictures below it not only has to fit fore and aft but also into the roof. I personally have never worked on such a door, however, they must be a lot more difficult to make fit than a regular car door.

61896190

You nailed it - COST.

[dclin]

Ok, this particular topic has been in the back of my mind, because I really don't get what the problem is; is the problem that, the panels being hand finished/trimmed fiberglass, F5 is worried about that the each individual panel may have variance? It bugs me, because quite a bit of the styling is being dictated by this 'problem'.

Why don't they simply mold the ends with a 90 degree lip/turn - that way the edges are pointing inward (and therefore unseen), and let the mold define the edge and panel gap?

[olpro]

You nailed it dclin. The panels can be trimmed on the lip part where the raw edge is no problem. It still may need a little dressing to protect it but that is all out of sight and out of easy reach. There is no need for extreme design approaches where the door has to be offset from the fender or body.
The early test parts will prove the fit and if there is some issue, the tools must simply be slightly modified. It will be important to mold all the close fitting parts with consistent control, at the same time and same place, same materials, etc.
An injection mold tool is many many thousands of dollars, even for a small size one so fiberglass is the way to go.

[Someday I Suppose]

I might also point out that I dont believe Jim has said anywhere that the reason he left the back of the fender open was to hide the door edge. It may very well be the reason he did it, but he made have done it for other reasons as well.

[Oppenheimer]

I might also point out that I dont believe Jim has said anywhere that the reason he left the back of the fender open was to hide the door edge. It may very well be the reason he did it, but he made have done it for other reasons as well.

It wasn't said on the forum, it was said by Jim in person to one of the forum members (BeerBaron?), who relayed it on here.

[Arrowhead]

I'm thinking it might also have to do with the exactness of the frame. Having perfectly pre cut panels makes the precision of the frame even more critical. If the frame is off 1/8" it would throw the body fit off unless there was a system of shims and adjustments to fit the panels. We can tolerate that with the current fiberglass bodys, but preformed panels won't be so forgiving.

[PhyrraM]

I'm thinking it might also have to do with the exactness of the frame. Having perfectly pre cut panels makes the precision of the frame even more critical. If the frame is off 1/8" it would throw the body fit off unless there was a system of shims and adjustments to fit the panels. We can tolerate that with the current fiberglass bodys, but preformed panels won't be so forgiving.

Good thought. Sounds very likely.

[crackedcornish]

a body that is made up of several smaller pieces will be less sensitive to the "exactness of the frame"...you will be able to spread any imperfections in panel fit out through several body gaps, so it's not as obvious as it would be on a car that uses fewer, larger pieces.

[PhyrraM]

a body that is made up of several smaller pieces will be less sensitive to the "exactness of the frame"...you will be able to spread any imperfections in panel fit out through several body gaps, so it's not as obvious as it would be on a car that uses fewer, larger pieces.

Only as long as the adjustment is great enough.

With a one piece body, it's pretty much "center on frame and bolt down". I would think you could hide alot of variation this way.

However if each panel is mounted seperately you could end up with a progressive situation where the misalignment grows as you progress from front to back. When the amount of misalignment is more than the available adjustment, your screwed.

It's likely all moot anyways. I'm sure FFR won't let that happen regardless of how the body is designed or mounted.

[olpro]

The panel offset (as on model #4) is a reasonable way to deal with body tolerances. However, it is only one way to address this issue and does have its drawbacks, notably how it limits the design.
There are other well known approaches, each of which has its advantages and disadvantages. Remember, ALL production cars (in steel) have this same tolerance problem and find a way...