Can anyone recommend a good sealant for body panels?

I need to remove/replace some panels/aluminium strips and possibly rearranging some windows.

cheers

My bus number (if any): RMF2771 (RCN 701)

TEX body sealant in strip rolls.
It's similar to the original stuff, stays slightly flexible and watertight can be trimmed and is not messy. Also Fire resistant.

They also do a brush on version, much cheaper but requires a deft hand to keep even watertight layers and avoid mess.

Remember all faces need some sealant applied to avoid 'spiders' forming under the paint and water ingress corrosion between alloys.

The superstructure, the panel, the strapping

Personally I use silicon sealant in a tube, just make sure to get the surplus off the outside as paint doesn't always stick to it!

My bus number (if any): RML2532,GS67,MLL721,MLL738 and an RT.

I assume Matt means sealant for mouldings and strap plates, panels don't have any sealant behind them.

Never heard of strips being used on LT buses,on RMs we use aluminium strip horizontally on the upper deck under and over panels.
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It really depends on whether you envisage having to change the panels or not.
At LT we used Seelastic,now called Seamseal CV, applied to the moulding strap plate. It's a non-drying bedding sealant it's flexible and doesn't dry and harden, so ideal for strap plates and mouldings that need to be taken off in the future.

If you are not intending to change them just use a clear silicone sealer as we now do, and make sure you clean it off well, check the day after use for small amounts leaking from behind mouldings etc. Problem with that stuff is getting if off again if you need to.

My bus number (if any): RTL 960, RM 1585, RMC 1486 and several RTs

Tex Sealant is more or less the same stuff as sealastic without the toxic content.

One advantage as I mentioned is it comes in a roll ( like double sided tape ) and is rather like blu tack in consistency,
pliable and a doddle to use along straight edges like side panels. It's grey in colour and does not dry out or weep oil which some versions of sealastic used to.

A modern version of Sealastic Seamseal CV is also available, The Tex one is a fraction of the price though.

I've used it for at least 18 years and use it with a rolling pin to thin and stretch it a little.

I have to say that every panel I have removed and fitted on every RM has had a thin layer of sealer on the framework and the back face of the removed panel as well as a thicker layer on the strap plates. Some still had Park Royal Labels on the backs of the panels so were completely original. Amazing after several overhauls and 30 plus years London service that some panels were never touched or damaged.

When I was doing my apprenticeship we were told that no external panel must ever have metal to metal contact.
So sealastic was applied to the framework, the panel fit fastened, and then the outer strapping also given sealastic.
"Like double jam sandwich" was the instructed description

That ensured no chaffing and water ingress.And no cross reaction from differing alloys.

Every panel removed from 531 had grey sealer between panel and frame, and panel and strapping and beading.You can get a good sealer on a roll from Teroson, its like a thin bead of Dumdum, excellent stuff.

My bus number (if any): RM531

Well Park Royal didn't do it and Aldenham didn't do it and the garages didn't do it either. That was because the panels were stove enamelled primered. Only bits of an RM that had any sealant behind were the front route destination frame and the window pans as they don't have an external moulding. If you put sealant all over the place you'll never get the mouldings to bed down and water will get in!
On the upper saloon there should be a thin strip of aluminium under the panel above and over the lower advert level panels, the upper saloon waist mouldings have a small lip to allow for this.

Maybe these sealants were used instead of that after sale by LT. Park Royal applied a bitumen like sealer between the stress panels and the pillars, but nothing on the removable panels,except as stated above. What you may have seen was "leakage" from the sealant applied to the mouldings (horizontal) and strap plates (vertical).

My bus number (if any): RTL 960, RM 1585, RMC 1486 and several RTs

I would have thought that any more than an absolute trace of sealant behind the panels would stop them laying completely flush to the framework and end up looking like a right dog' s breakfast, especially when the light reflects off them. In theory if all the gaps between the panels are sealed under the strapping no water should ingress ? And it's not dissimilar metals that are touching so there should be no reaction problem.

My bus number (if any): RML2747

Following on from Graham's post,I have a recollection ( it's a long time ago now!) that behind the strap plates on either side of the front route indicator panel,(and rear advert panels?) Park Royal put a thin green canvas tape. It was never replaced if removed.
In addition, blind waterproof pop rivets (these had no hole at the bottom) were used on these strap plates and across the top of the cab. The mandrel holes in the rivets were also filled up with seelastik,

My bus number (if any): RTL 960, RM 1585, RMC 1486 and several RTs

One point I have noticed from various modern sealer data sheets is that the expected useful life once applied is stated as around 10 years before it starts to fail. I have found this to be the case on some of our older vehicles especially where the glass is held in place with sealant and are subject to a lot of UV light. Amazing that the original RM sealer is still functioning after all the decades. In common with other materials the modern equivalent has probably had the useful ingredient removed by order of the powers that be in Brussels ! Saying that what is the expected life of a modern vehicle anyway ?

My bus number (if any): RML2747

Graham

There are many different sealant/adhesive products out there nowadays used in the construction industry that perform brilliantly and could be used on any vehicle body for sealant purposes if required. I am not talking about the products generally available from the do it yourself stores, one that we have used is a Geocel product called 'The Works'. Naturally if overpainting then the specification or data for the product should be checked beforehand.

Hi Ed we also use 'the works' great stuff works on wet or dry but can be a bit tough if you want to remove it - as I say not sure how long before it starts to degrade long term. It's usually the presence of silicone that causes over painting problems. I use a product from ideal sealants called 'Automarine on my own buses which can be over painted and is not too runny.

My bus number (if any): RML2747