Removing Underseal From The Underside Of The Chassis (Part Three)

Well, a lot of progress in the last three weeks. I managed to......

......strip the underseal from the boot area.

At the moment I have decided not to strip and repaint the chassis around the rear suspension area. I might do that later this year, but was saving it as a winter 2023 job. 

 

With the underise stripped of the leathery underseal, I then went over the whole area (except the engine bay area) with a wire wheel to remove the sticky residue. 

A bare surface at last

A downside of using a high speed wire disc is that it polishes the surface meaning that any paint may have trouble adhering. Last year I'd bought a cheap 'Parkside' brand variable speed angle grinder from Lidl. At the time I just shoved it in the back of a cupboard and forgot about it. Now it came into it's own. I ran a flap disc at very low speed all over the underside. The low speed meant that the flap disc gently scratched the surface to roughen it, without the risk of the disc cutting deeply. I similarly used a mini flap disc on an air tool to get into awkward corners.

 

I vacuumed the surface to remove any clinging dust, degreased and treated any remaining surface rust with dilute phosphoric acid. It's the active ingredient in potions such as Jenolite. Nasty stuff when working upside down! Goggles and gloves are essential - and even then you need to be particularly careful.

The rust treatment converts and turns rust black

Before rust treatment

After rust treatment

I degreased  and vacuumed again and (having plugged all the threaded holes), applied a first coat of two part epoxy primer. I bought a 'winter grade' of epoxy, for use at lower temperatures. I applied it with a roller, but also used a small brush to work it into joins and corners. Brushes and rollers need to be considered as 'sacrificial' as it's not worth the effort in trying to clean them for re-use. I also bought roller tray liners and white 'paper' disposable overalls.

That's better!

Although a roller produces a stippled effect, as it's the underside and will be covered in a waterproof underseal, I wasn't too concerned. Once the first coat was dry, I then applied seam sealer over all the joins.

Seam sealer  over the joins - it 'skins' very quickly

More seam sealer....

The seam sealer is messy, sticky stuff and 'skins' very quickly. Although I used a brush to apply it, it soon began to dry and clog the bristles. Again, I'm not to bothered about neatness here as it's the underside.

 

Once the seam-sealer was dry I applied a second coat of epoxy and am thinking about a third! Phew! Not bad going considering it's winter.