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Mastic rear wings
Posted: Wed Aug 11, 2021 11:11 am
by cleverusername
Just had to repair the near-side rear arch and the big issue I am having is the outer panel and inner wing seem to be stuck together with some kind of black goo, it is almost like roadtar. The has made welding it up a real pain, as it is really difficult to remove completely. Still after a few small fires I have got it done.
Is this something Triumph did or is it a PO's repair which has caused this problem?
Re: Mastic rear wings
Posted: Wed Aug 11, 2021 12:14 pm
by Awaiting Repair
cleverusername wrote: ↑Wed Aug 11, 2021 11:11 am
Is this something Triumph did or is it a PO's repair which has caused this problem?
I remember reading a while back about this, apparently it was done at the factory in an attempt to stop the arches rusting at the spot welded seams....
Cheers
Keith
Re: Mastic rear wings
Posted: Wed Aug 11, 2021 1:54 pm
by new to this
I didnt have this problem,as my inner arches theres no lip left 
Dave
Re: Mastic rear wings
Posted: Wed Aug 11, 2021 5:39 pm
by captain_70s
I suspect it's a large quantity of the same sort of bitumen tar type stuff they put on the floors under the carpets.
I knocked mine off with a hammer... Well, sort of. The metal it was sitting on disintegrated.
Re: Mastic rear wings
Posted: Wed Aug 11, 2021 6:56 pm
by TrustNo1
petrol gets it off, its messy but it works
Re: Mastic rear wings
Posted: Wed Aug 11, 2021 7:21 pm
by cleverusername
captain_70s wrote: ↑Wed Aug 11, 2021 5:39 pm
I suspect it's a large quantity of the same sort of bitumen tar type stuff they put on the floors under the carpets.
I knocked mine off with a hammer... Well, sort of. The metal it was sitting on disintegrated.
To be fair to Triumph, I was a bit surprised how effective the tar was as a rust suppressor. The edge of the lip had gone but it didn't make it beyond there into the main panel.
Different story in the footwells, that sound deadening will fool you. I had to remove it all before I found all the holes.
Re: Mastic rear wings
Posted: Thu Aug 12, 2021 6:32 pm
by captain_70s
I had no such luck sadly! Whether or not the tar runs down to the lower edges I don't know, it was certainly present along the top edge.
On the flipside the footwells were solid!
The worst example I've found is my Volvo 740. It has thick pads on the footwells and an equally thick factory underseal. I didn't realise how rusty my floor was until I started flailing about at it with a hammer, even then it was bouncing off the tar despite there being no metal left!
Re: Mastic rear wings
Posted: Thu Aug 12, 2021 11:32 pm
by cleverusername
captain_70s wrote: ↑Thu Aug 12, 2021 6:32 pm
I had no such luck sadly! Whether or not the tar runs down to the lower edges I don't know, it was certainly present along the top edge.
On the flipside the footwells were solid!
The worst example I've found is my Volvo 740. It has thick pads on the footwells and an equally thick factory underseal. I didn't realise how rusty my floor was until I started flailing about at it with a hammer, even then it was bouncing off the tar despite there being no metal left!
Wow that is poor, basically the paint was holding it together.