RP sliding roof detail

[Hugh Barnes]

on the Archive drawing - https://archive.a7ca.org/collections/tec...em/TD0190/? - Detail 'B' shows a cross section of the rear of the sliding panel, where one can see a metal strip that was used to hold everything in place, presumably both the roof covering and the rubber sealing strip. Remarkably, I still have this piece. However, the making of the triangular 'fillet' that goes across the panel that the panel covering and rubber strip are afixed to has been a fraught affair (taking best part of two days and 3 prototypes) to get right and I am trying to keep its depth down to an absolute minimum at this point, mainly as it is a bugger to get over the very rear of the roof that is curved whereas the roof forward of that is flat.

Does the Team think:

a) that the rail is truly necessary and 

b) are there loads of cars running round where this metal strip doesn't exist?

This image shows a trial section installed without the metal strip...

   

Am I fretting too much?

[Chris KC]

Hugh, 
I think it makes no great odds when the sunroof is open. 

The danger I guess is that if the car is left parked outside in the rain, worse still pointing downhill, water may enter the interior through the gap at the back of the roof. Eddies being what they are, it just might dribble when driving in rain too.

I should have thought though as long as you have that broad rubber sealing strip pressed gently down onto the rear deck by some means, it will make little difference what structure is around it/ supporting it i.e. A larger gap but steeper seal angle would be as effective. It might graunch a bit when sliding back the panel.

As you well know I have no experience to back any of that up! But I haven't seen many RP sunroofs with any kind of rear seal arrangement. Perhaps they don't go out in the rain much.

[Hugh Barnes]

Thanks Chris...

The reason a number of prototypes were made was to get to the 'ideal' angle of the triangular fillet to get to the point where the rubber seal would press down on the rear part of the roof. It looks a little flat in the photo, but that maybe becuase I have made the tail a little too long and I need to shorten it a little. It does seem to remain in contact with the roof as I slide the panel back and forth so I may be over-thinking this. But , as is always the case, at this point it is as easy to get it right as wrong.

[Hugh Barnes]

Having had one or two chats on the side and thought a bit more about this overnight, I have decided not to fit the metal rail. My rationale is this; In 1933 construction processes were limited witht he option of metal tacks or slow acting adhesives. The option of a metal rail, quickly screwed into place solved the need for an efficient process. Today, with staple guns and contact adhesives, our options are different. So, I have decided I wil staple the vinyl into place, having wrapped it round the rear of the panel and across the face of the fillet, then will use contact adhesive to affix the rubber sealing strip - which will have the additional quality of covering up all the staple heads eliminating the potential for (further) paint damage to the rear of the roof as I slide the panel onto the rails for the final fit...

[Denis Sweeney]

A word of caution, I have found the “high temperature” contact adhesives have not been as good as advertised nor as I would have hoped for, in summer time the roof and interior gets extremely hot and I have found the adhesives wanting.
It is a bugger of a job trying to remove the failed adhesive.

[Colin Morgan]

I am not sure how an RP sunroof differs from a Ruby sunroof, but the large fixed metal sunroof frame on a Ruby that carries the sunroof panel and allows it to slide, and which also has a sealed down flanged lip that stretches across the rear of the aperture, seems to stop rain getting in along the back edge. 

Some water used to find its way in this way (often dripping down the neck of driver and passenger), but not since I removed the rubber strip that was fastened to the back of the sunroof (probably not original/possibly a poor copy).  This appeared to be helping the water to find a way in.

The metal strip that used to trap the rubber strip in place is still there, but hidden by the overhang of the roof panel - and it must be the combination of the 'step' provided by the frame sealed and screwed onto the roof plus the overhang of the sunroof panel that keeps the rain out.

[Hugh Barnes]

A word of caution, I have found the “high temperature” contact adhesives have not been as good as advertised nor as I would have hoped for

MY chosen form of adhesive for such an application would always be 'Evostik' and I dont think it would suffer in the way you describe, Denis?

I am not sure how an RP sunroof differs from a Ruby sunroof, but the large fixed metal sunroof frame on a Ruby that carries the sunroof panel and allows it to slide, and which also has a sealed down flanged lip that stretches across the rear of the aperture, seems to stop rain getting in along the back edge. 

Some water used to find its way in this way (often dripping down the neck of driver and passenger), but not since I removed the rubber strip that was fastened to the back of the sunroof (probably not original/possibly a poor copy).  This appeared to be helping the water to find a way in.

The metal strip that used to trap the rubber strip in place is still there, but hidden by the overhang of the roof panel - and it must be the combination of the 'step' provided by the frame sealed and screwed onto the roof plus the overhang of the sunroof panel that keeps the rain out.

Colin, I too am not sure how they differ. I know they are different, though that may be by dimensions only and the broad prinicple remains the same. On my car I have set the rail assembly (including the transverse rail to the rear of the opening) on a thin bed of mastic, so that should be sealed against water ingress. Similarly, on the rails themselves, just to the rear of the transverse portion, there should be drain holes that let any water that gets that far run away. I cant imagine a situation where the addition of the rubber trip would actually make things worse? Unless there was some 'capillary action' that caused the water to travel up the underside of the rubber and then drip off?

Maybe?

At the moment I am summoning up the courage to add the vinyl to the panel having put the hessian and thin layer of wadding in place. It is the cutting of the corners that frightens me...

   

   

[Chris KC]

FWIW, I'm pretty sure the basic design of the Ruby metal track set is the same as the RP, it's merely a little smaller.

I too have some experience of contact adhesive softening in warm conditions. It's hard to find anything which sticks rubber permanently. A possibility which comes to mind is the adhesive which comes in tyre puncture repair kits? It will certainly bond rubber well (if scuffed and solvent-wiped), though I can't say how it will stick to the substrate (vinyl?) without some experiments.

[Colin Morgan]

I removed the rubber strip to see what difference it made - and then have never had cause to put it back.  Have no rational explanation as to how it worked, sorry.  (It is possible the rubber provided an internal lip from which water dripped, after somehow finding its way there, perhaps from the ends?)

Not ever having tackled recovering the panel - the cover on my roof being well over 50 years old and very brittle - I am not sure about the cutting of the corners.  However, on my roof panel, whoever did the job last just folded the material over in both directions - didn't cut it at all!  This does seem to have worked.

[Denis Sweeney]

Folded the vinyl at the corners on Ruby, wouldn’t cut them.
Have you seen the papers I posted on this forum on recovering a sliding roof, it shows how you pad out the vinyl to give a nice smooth finish. Just search sliding roof

Edit, sorry Ruby Sunroof, follow the thread and you will see the papers I followed and the pics taken at the time