Underseal?

[nzchevy]

Is the black coating on the inside of the car, boot & underbonnet simply underseal?
I thought that modern underseal never goes 'hard' and therefore wouldn't be suitable.

Thanks

Roger

[Phil Nottingham]

Underseal was originally a trade name of 3m or what was then the Minnesota Mining & Manufacturing Company (in the US)
Rover used another version which was pitch/bitumen with asbestos fibres in it to strenthen it It was called Bittac. it was used before this on P4's and P3's

It was primarily to provide sound deadening rather than rust proofing which it failed to do very well indeed..

It problem was that it hardened and allowed salt laden moisure to get underneath and stay there. Without it on the floorplan it would be very flimsy and tinny

Old or modern underseals are not a good idea underneath the bonnett as they attract dust and oil/petrol removes them anyway.

I think the best way to simulate the original Rover look is to use spray on stone chip after removing any loose stuff (a hot air gun is best) and treating rust. Prime it before coating with stone chip and then going over it wit satin black spray paint. This will provide a far better surface for keeping clean of grease/dust etc

[Warwick]

Jan 13, 2009 22:24:54 GMT Phil Nottingham said:

3m was then the Minnesota Mining & Manufacturing Company.

I bet there aren't many around now who know (remember) that Phil.

[eisdielenbiker]

This Bittac-Stuff makes me always worrying about lung cancer as my father in law is ill with that (He has never been actively smoking or in contact with asbestos). Is that black paint stuff on the rear parcel shelf Bittac too? Or in any other place in the interior of a P5B from 1971 ? Perhaps the wheel arches in the trunk ? Below the sound deadening carpets und the seats ?
Mark

[Phil Nottingham]

If its not black Bostic - yes it is! However the asbestos fibres are surrounded by pitch and its not dusty. Proided reasonable care is taken there is probably less danger than the average public and some domestic buildings/garages that still have Asbestos Cement sheets in them.

In 1930 Rover sprayed asbestos neat into the doors of most saloons for siund proofing!!

[dorsetflyer]

The whole of the underside of my MK1 1500cc Cortina was coated in that stuff which was a 'bitumen' based product.
Any repair work to it was done using 'Dunlop' underseal.
Funny how its taken over forty years to discover the name of the product.

[Phil Nottingham]

I think there were various manufacturers and not all contained asbestos. The stuff Rover used in the 1930's was also the most dangerous "Blue" asbestos also used in the rail industry.

Very few British manuafactuers even underseald cars from new - its was a dealer applied product. My wife's 1968 Mini Traveller Mk2 has mostly primer underneath on the floor sections as the overspray from painting the sides did not reach underneath very far


BMC did however use Rotadip on it small models from the mid 1950' swhere the bodies were put on a long spit to primer coat all over. Morris Minors, early Mini and A35's had a blanking late in the boot bulkhead to allow the pole to go through.

Was not a lot of use though but P5's are only primered and painted where the gun could reach before the wings/doors were fitted