Ceiling rivets are 5/32", exterior rivets are 3/16" Blind rivets were used either side of the front destination frame, front U/S waist rail rivets were filled with seelastik.
Anyone who has refurbed RML will see why LT didn't use rivets below the waist, if you drill through a 3/16" rivet and it spins it makes the holes bigger each time then you have to use those soft ugly big head ones!

My bus number (if any): RTL 960, RMC 1458, RM 1585 and several RTs

Thanks for that insight Brian. One of the good features of the Gesipa rivets is that the shank(?)spreads to cope with any enlargement of the hole and grips very well

My bus number (if any): RML2302

Somewhere a few years back now there is either on this site or on the 'other channel' a long explanation of how to deal with the oxidisation problem caused by rivets and the alloy it was fastening.

It is the magnesium content of some brands of rivet that cause the white powdering corrosion that can often be seen.

This causes a cathode/anode reaction between the differing alloys used in the RM ceilings. The Beading is a soft alloy and the roof panels a sheet alloy of different alloy compositions.

When the RM was designed and the specifications were being made, less was known about corrosion and fatigue with alloy metals being used for stressed structures.
You may recall that running concurrent with the RM development was the D H Comet project and that the first accidents occurred in 1953 and it was 1954 when stress alloy failures were being identified but not confirmed.

Whilst the RM is not a pressurised bus traveling at High altitude, consideration was given to protecting against fatigue and corrosion and by 1959 when mass production commenced, much had been learned.

The RM was not cobbled together with raw metal ( even though alloys were considered corrosion resistant hence RM 664. But they were prudent. Almost every body component was stove enamelled and sealed and both sides of all panels and beading, as well as a mastic type sealer applied in strips not from a gun.

Had the RM been just put together as originally envisaged, intended to save weight to the maximum, it would have probably dissolved within a decade.
Although there were a few later issues, popping rivets and screws and some corrosion caused by chaffing from body flexing, most of the RM under the skin is as good as new when all the decades of dirt is cleaned away.

This prudence of belt and braces is very much part of the longevity of the RM body given the years of damp, salty roads and heavy duty service endured.

Borne out too by some of the short cut restorations and refurbishments which fitted bare metal panels with no etch primer, not stove enamel primer and the corrosion along the panel joints is there in just a few years.

So for a long term preserved bus, it's a slow process. Protecting against damp and condensation which affects a rarely used vehicle far more than a daily used vehicle for obvious reasons, needs to be more thorough than when built or passing through Aldenham. It's unlikely that any owner wants to give a body off full Aldenham job every 7 years and probably won't be wanting to repaint their bus every 7 years either.

With the ceilings, I know of a method that seems to have worked and lasted.

All the parts are etch primed with a zinc primer, then, if possible, stove enamelled or primed with special attention to the jointing faces / edges. Then a thin 3M felt tape is bonded to the frame and each hole re opened with a braddle or pointed punch, so the hole is partly lined. This stops the chaffing when the body flexes. The quality of rivets is imperative as this will help.
I cannot remember which rivets were found to not react but someone knows, as much was written before with brands etc. Each rivet is given a fine smear of modern sealer before being fitted. This minimises the chances of movement and chaffing and resists the penetration of condensation . When fitted, a high zinc anti corrosion primer is applied over the lot and then the normal painting.

The rivets are expensive and the process a bit laborious. But it should result in a ceiling that should be pretty good and corrosion free for a much longer time. The soft felt tape ( which is no thicker than a sheet of gasket paper) also reduces creaking and cracking noise as it is in effect a gasket.

Hey Mark,
I know what you mean about the problems with the paint on the lower deck ceilings in regards to the rivets. The only thing is in regards to your bus which I have been fortunate to travel on many times, it represents a good 'every day bus' that hasn't been over restored just taken good care of. So the only thing is if you start repainting the lower deck ceiling before you know you may end up restoring the whole interior, but its up to you and if you need any help you know where I am.

I will at some point have to tackle this problem with 2460. I had roughly the same idea in mind as mentioned by Jack earlier by given the ceiling frame work, panels and beading a good rub down and clean. Then to apply a couple of coats of etch primer and primer etc and then sealing everything up with sealant. The ceilings may be coming down in the near future as last week I was discussing with an electrician 2460's rewiring project.

I used this method when I repaneled 2463 about 7 years ago and separated any steel work away from any contact with Ali by using etch primer and primer, applying a thin gasket and sealant, using etch primer on both sides of the panels and beading, so far no sign of corrosion on the panels and that's with my bus living outside.

I have heard of another trick a few years ago from a fellow bus owner who has been in this game many years, and that's to cover the rivet in insulation tape before fitting it to the ceiling.

Best Regards,
Peter.

My bus number (if any): RML 2463 & RML 2460

No sealant was used or should be necessary in the interior of a Routemaster. Lighting panels and all mouldings should be fitted "dry".

My bus number (if any): RTL 960, RMC 1458, RM 1585 and several RTs