9 replies to this topic

[eebee]

My ‘64 850 has suffered bodgery in the distant past. Areas such as the boot floor seem to be sound but covered in thick tar-like underseal. Should I use heat & a scraper or is there a better way ?

[Maccmike8]

Ive used heat and a scraper very successfully in the past - but others may suggest better ways.

[Tupers]

Hot air gun and scraper is about the best was to get the bulk.

You can wipe away the excess with a rag soaked in paint thinners, get yourself a mask though it gets very stinky.

[eebee]

Sounds like a rainy day job...
Thanks.

[TXCollector]

Before you have a go with the heat gun just try it with a scraper first, a lot of underseals dry-out and come off quite easily with a scraper and wire brush, as soon as you put heat near it it'll just soften and become a right royal pain in the ass to get off!

Wear good eye protection too as those little chips of underseal are a bugger.

It's a damn messy job whichever way it goes - good luck!

[GraemeC]

I've not tried it (yet) but one that has been suggested to me in the past is to get some of the pipe-freeze spray that plumbers use, which makes the underseal brittle so it just chips off easily.

[RooBoonix]

As said above, some underseals go almost brittle over time so you can chip them off with a hammer and scraper in quite big chunks. I used an MBX tool on mine which is like a rotary wire brush/bristle tool which worked well on the underseal on my car which was still quite rubbery and was a nightmare to get off with a scraper. The tool made light work of it, but it made a right mess.

 

My car/shell is on a rollover jig though, I'm not sure I'd want to be laying under a car with an MBX tool spinning at couple of thousand RPM...

[cal844]

For the tar like bitumen in the car I used an old wood chisel that I'd resharpened and used with a hammer, it's effective but use caution not to punch holes in the floor.

For the underseal I used thinners and a paintbrush to spread it out, then hold a rag against it to burn the underseal off.

Alternatively use a wire wheel on the grinder

Edited by cal844, 24 May 2021 - 09:24 AM.

[eebee]

Thanks all. It’s worst in the boot area but seems to either chip off with a paint scraper or stay tar-like, which does eventually clean off with white spirit. The underside of the new floor pans has all been coated in it too; a horrible job to be done piecemeal as my sanity allows ! Am finding areas of filler under it though...

[MatthewsDad]

It's a soul destroying job, whichever technique. A little at a time and a cuppa in between is the best option.