S1 & S1A Belly Pan Material

[My S1]

MY S1 belly pan uses a grey gel coat.  The upper body used a clear gel coat then primer and top coat. The only other original quality S1A belly pan that I've seen up close used a clear gel coat.  With age the resin had yellowed so it is now a translucent yellow.  What have you folks found on the early cars?  Did they do allot of searching for the best solution or just grab whatever surface coat was available from the vendor?

[SwiftDB4]

By the time I got my S1 I couldn't tell if there even was a gelcoat on the belly pan. Unless you're going to display the car with mirrors underneath any gelcoat should work.

[GavinT]

I've worked on a couple of S2 Europas and an Elan. None of them had a gel coat but they probably all had the grey primer/surfacer.
Is the S1 different?

[Richard48Y]

S2's do have a gelcoat, it is clear and overly thick in the corners.
Tends to shatter over time there and is not being any fun to repair.

[GavinT]

I'm far from convinced about that, Richard, and I've never seen any evidence presented to the point. Perhaps there is some?

If you remove the paint layers with stripper as you're doing and then take a stroke with some sharp 80 grit paper, you'll be immediately into the glass fibres. Gel coat is also noticeably harder to sand than polyester resin.

As we all know, gel coat is intended as the final finish on boats, typically, where it performs a number of roles; cars don't need it. And why would Lotus apply a clear gel coat instead of white or grey? If there's some final correction needed prior to paint, there's no way of knowing if it's been rubbed through. Which brings up another point; how thick is the gel coat on a body that's only supposed to be .093 inches (2.3mm) thick?
Why not just use a coloured gel coat for the final finish, as per boating practice.

The workshop manual is perhaps less than helpful. While it describes the "high quality Polyester" used and even the specific (2.4 oz) weight of the CSM in the original manufacture, nowhere does this section mention gel coat.

There's one mention in the repair section which has to do with the reasons for under-seal under the front wings, but nothing further.
There's one mention in the "Paint Procedure" section where it advises to not use a paint stripper "as this will attack the gel-coat, which MUST of course remain intact" but nowhere in any of that blurb is there anything resembling a procedure for re-establishing said gel coat.
If Lotus presumably considered this important, I'd expect there to be at least some rudimentary info in the repair section.

The workshop manual also talks about "woven tape" used in the original manufacture under the heading of "Stressed Bonds" but I've not seen that, either.

Bah . . I reckon a lot of the text in the manual is rather more conversational than specifics.
As I say, I'm unconvinced but happy enough to be wrong.

But, yes, I've also seen the pools of resin in a couple of corners that ended up cracking. I put it down to the hand layup process and a lesser skilled worker on a Friday afternoon. 

[Nockenwelle]

The S1/S1A underbodies I've seen so far all had the clear gel coat on it. The surface is smooth and not painted. As described above it has yellowed over time. The picture shows the underside of 460478 (once for sale on this site).

[Clifton]

The bottom on my Type 54 S2 is just unpainted fiberglass. The whole bottom looks like the yellow in the S1 pic above.

[My S1]

From what I have been able to deduce, the S1s had a gray gel coat and at some point in time they switched to a clear surface coat.  Here are a couple of pictures of 460202 and 460222.  Another one of those historical bits that makes owning a limited production British car so rewarding.

[My S1]

460222 belly pan

[My S1]

One more question for you long term Europa owners;  why are the corners of the suspension clearance openings on most all S1s always cracked and torn?  I have not yet removed the trailing links or half shafts but I suspect that that is when the belly pan gets ripped up?   Is it possible that it is simply years of flexation?

[Nockenwelle]

It looks like the grey paint has been applied by one of the previous owners. It doesn't looks factory original to me.
The closed belly pan is indeed often cracked or even misses some parts. I know from my own experience that it is easily damaged when removing suspension parts or the whole engine/transmission assembly. Once the engine bay is empty it is often necessary to climb into the bay to do some work. As the space for your feet is very limited it is easy to accidentally step on to the pan and damage it.