Page 1 of 2
Black Tar-Like Substance
Posted: Sat Feb 02, 2013 9:27 am
by Darren65
Can anyone tell me what the black tar-like substance that was brushed over the top of the front struts under the hood actually is? And I suppose more importantly, why this was done?
Something I plan to replicate on my 2.4E and not keen on the look of cars that have just used black paint.
As ever, I appreciate all replies.
Cheers,
Re: Black Tar-Like Substance
Posted: Sat Feb 02, 2013 9:41 am
by johnM
It was to seal the strut top to prevent water ingress.
HTH.
Kind Regards
Re: Black Tar-Like Substance
Posted: Sat Feb 02, 2013 10:03 am
by Darren65
Thanks John,
Was it regular old bitumen though!

Re: Black Tar-Like Substance
Posted: Sat Feb 02, 2013 10:27 am
by johnM
Darren65 wrote:Thanks John,
Was it regular old bitumen though!

I think it was.
Re: Black Tar-Like Substance
Posted: Sun Feb 03, 2013 10:04 pm
by myatt1972
Ive got about 200 litres of International intertuf 16 Darren if you want a brush full, works great on the bottom of a narrowboat.
The brush might be hard after a 250 mile round trip though

Re: Black Tar-Like Substance
Posted: Tue Feb 05, 2013 2:41 pm
by Alan @ CanfordClassics
Still wet here
Those are factory runs! This a bitumen based paint. It does dry more matt than in the pic.
Alan
Re: Black Tar-Like Substance
Posted: Tue Feb 05, 2013 3:20 pm
by Darren65
Very authentic

Re: Black Tar-Like Substance
Posted: Tue Feb 05, 2013 6:47 pm
by myatt1972
Dont forget the splash of red.

Re: Black Tar-Like Substance
Posted: Tue Feb 05, 2013 8:18 pm
by Darren65
Keith, I have way too few pictures of your wonderful, wonderful car
Must bring my camera for a visit soon!

Re: Black Tar-Like Substance
Posted: Sat Jun 15, 2013 7:32 am
by Darren65
I've recently learnt that the product used for this is a 2-pak (epoxy) 'Electrical Potting Compound' which provides a semi-flexible waterproof seal. I've ordered some from RS Compnents.
Messy stuff…I'll let you know how I get on.
Cheers,
Re: Black Tar-Like Substance
Posted: Thu Jun 27, 2013 4:43 pm
by Darren65
The car came in today for a couple of finishing jobs, one being the sealing of the top mounts...
....fortunately I have a good reference source (I love Keith's car

)....
...potting compound ordered from RD Components for about £8....first you need to create a dam to catch it in and make sure you mask the engine bay, extremely runny!

....
....the compound is a two part mix in the bag job which is then carefully poured
into the top mount (not over the top)...
...it takes a couple of hours to start to set, be careful it then becomes firm very quickly, at this point you can brush as required....
...and the end result looks factory authentic AND correct...
I'll stick with the yellow torque paint marks applied by Centre Gravity....of course Keith's red paint marks are only like that because the factory ran out of yellow paint when they built his!
Cheers,
Re: Black Tar-Like Substance
Posted: Sun Jul 07, 2013 12:18 pm
by Rostrenner
Thank you Darren for another great DYI article.

Re: Black Tar-Like Substance
Posted: Thu Apr 16, 2020 12:03 am
by Flat 6
Thanks Darren,
Looks like the stuff you see sometimes in transformers. Makes sense.
I'll give that a go, was going to go for bitumen based paint.
Cheers,
Al.
Re: Black Tar-Like Substance
Posted: Thu Apr 16, 2020 6:03 am
by PeterK
A useful thread resurrection, thanks, and thanks to Darren for the info in the first place.
I guess that I had better wait until I've set my geo first though

Re: Black Tar-Like Substance
Posted: Thu Apr 16, 2020 9:01 am
by Flat 6
It does seem a very agricultural solution for a company like Porsche even back then!
I wonder if it was introduced as a solution some time after initial launch, in response to actual water ingress.
Anyway, in pursuit of originality...
Al.