Undersealing - a tiny bit of extra info.

[Trouble at t'Mill]

Yes, it's very like a coating of candle wax when 'dry', which is why it doesn't 'chip' when hit by stones, etc.

[Trouble at t'Mill]

Job finished, and I'm pretty confident it's a thorough one! Waxoyl looks superb the next day once it's dried off - everything has a beautiful (well, you know what I mean...) even, satin finish.

Thanks to Dandy for his tip; I removed the rear light units (two screws on the inner black flange visible when the rear hatch is opened, and then 'tap' the light units sideways outwards - they should unclip from slot-type holders), and then gently prised the large cable grommet out from the panel behind. As you gently pull the cable a couple of inches out from this hole, you'll come across an in-line multiplug; squeeze the clip on the side and pull apart - this allows you to fully remove the light unit. The resulting hole gives you excellent access to the inside seam where the inner and outer wings are joined at the arch - SPRAY! SPRAY! SPRAY!

(I'd already removed the rear oddment/ashtray holders and sprayed down in there, so between doing that and spraying in from behind the lights I'm pretty sure the whole inner rear wing seams are nicely protected.)

Hmm, I wonder what'd happen if I removed the front side lights too?! These are even easier to take off; one screw at the top - just slacken it - and the unit pulls straight forwards. Yippee - again, terrific access to the space between the inner and outer wing panels.

Ok, even if your car has been 'undersealed', unless these 'internal' areas have also been targeted, then I strongly recommend you do so. Can you still get Waxoyl in aerosol cans? If so, that would do the job nicely.

Reading threads on this forum - and from my own experiences with cars in the distant past - it seems that the most common areas for rust to break through are the wing arches and the front bonnet edge. The problem with the arch 'lip' is that the damage is caused by very small amounts of water - and damp - getting into the seam where the two (inner and outer) panels join along the inside of the arch. The damp settles in these tight seams - even gets drawn in by capillary action - and starts to eat away... Unfortunately, undersealing the wheel arches doesn't necessarily prevent this damage as the edge of this seam is often still exposed - if rust breaks through your outer arch, it's come from immediately behind this panel (ie: from the hidden internal area) and not from under the actual wheel arch.

I used one of these cheap 'airless' electric sprayers for the job - worked superbly. You probably know about keeping the Waxoyl indoors on cold days so's it flows more easily, but you can also thin it slightly using White Spirits. I kept it as thick as possible for the main undersealing, but thinned it quite considerably (ok, don't shoot me - I used petrol 'cos it was readily to hand and also evaporates very quickly...) for doing inside these panels because the thinner fluid produced a much finer mist which travelled further and got drawn into every little crack, seam and join. (When I did inside the sill sections - removing a couple of plastic bungs for the job - it was gratifying to see the 'mist' coming out of the other holes further along the sill as I blasted the nozzle inside!) Rather than take off the door trim panels, I again fired this thinner mix up though the drain holes - not ideal, but again I could see 'mist' coming out the other holes so I'm pretty sure the whole inner edge has been covered!

Rust is a soul-destroying problem (ok, it ain't good for the pocket either) so I really feel it's worth the effort of tackling these vulnerable areas. Messy, but very satisfying

[Simon Jones]

Can you still get Waxoyl in aerosol cans? If so, that would do the job nicely.

Brought one Friday - it was under £7 from Halfords. Some good tips there which I'll be making use of over the next few weeks.

What I'm planning to do to keep the tin of Waxoyl runny is to modify a 12V coolboox that has a warming facility. It needs some silicone sealant round the join (as it says its not suitable for liquids) & then I'll fill it with hot water & put the tin in. The heating element kicks out a lot of heat, so should keep the water pretty warm.

I've currently got the radiator out, so I've got good access to the front cross-member for spraying before I refit it. I can't decide whether to use clear or black on these areas. The clear stuff is thinner so better for injecting into holes, whereas the black wax is better for the underside.

I've also taken the plastic wheel arch liners out so there is bags of room to get inside the front wings. The other place to do is the rear of the front headlamp mounting panel & under the slam panel. I'll post some pics soon, but the paint there is very thin there & you will find rust under the paint which tends to make it flake off.

[Trouble at t'Mill]

Cheers, Simon - all good stuff. If you think that one type is 'thinner' than the other, then I'd use that one for getting into tighter spaces like the inner/outer panels seals, and the thicker one for coating exposed chassis members and wheel arches, etc. Mind you, it all dries very quickly to be like 'candle wax'!


In response to a 'private' enquiry, here's more detail in case it's also of help to anyone else:

Although a 'cheapy', my airless gun came with a short (around 5") extension piece which is flexible- when you bend it, it stays pretty much in shape. The actual nozzles have a cone-shaped flute around the end which makes it wider than I'd like, so on one of them (forever to be used for Waxoyl!) I trimmed this unnecessary part off, leaving just the actual nozzle part which is around 20mm diameter. This allows it to get through smaller holes, but more importantly lets me press the nozzle tight against even very small screw and bung holes, etc and spray directly inside without unwanted stuff going sideways!

To spray the front inner wings sections, I got access from the very front by removing the side light assemblies (if you look 'up' after removing the light, you'll also see that the outer wing at this point is single skinned, so spray up there too!), and from the back of the wings via the large gaps between the inner and outer panels you'll see when you open the front doors. Just press the nozzle up against these gaps and fire away! From under the bonnet you can also see some holes which give access to the inner wing sections - go for it!

Bear in mind that, for these particular parts, I diluted the Waxoyl significantly beyond the recommended amount (they recommend using White Spirits) - I reckoned this would allow it to travel further and in a finer 'mist' which would seep by capillary action into the arch seam joins which was my main target. I believe this worked as the Waxoyl would trickle and 'run' where it landed in a pool whereas normally it wouldn't as it was too thick. I could see that, when I sprayed into these confined spaces, the spray mist would really 'fill' these voids, giving everything - up, down and sideways - a neat coat. Similarly with the sills - I didn't bother removing every bung, just the end ones and one near the middle; when I pressed the nozzle tight against the holes and sprayed inside, Waxoyl mist would come out the other holes - pretty reassuring.

You can always add further thinned coats after a couple of days if you also wanted to build up to the usual thickness.

For the rear inner wings areas, access was gained by removing the very rear oddment trays (one has an ash tray) which are held by one screw each. I bent the nozzle to aim downwards, and fired the spray as far forwards from this point as I could, as well and down and back (this is an excellent access point - you can actually see straight down on to the panel seam that I was trying to target). Then, after removing the rear light assys and easing out the large rubber wire grommet, you can spray the very rear section through here.

Again, because of the thinner, finer spray, it basically covered everything inside the arch!

Oh, and I also sprayed through the drain holes on the front edge of the bonnet, as well as into every hole and gap between the bonnet skin and its additional 'webs' on its underneath - try and get the spray right in to coat the inner - hidden - edge seams of the bonnet. Look at any 'van' over 10 years old (and many cars too!) - you'll almost certainly see rust coming through from behind the front bonnet edge.

Oh, oh, and also up through the door drain holes (it would have been much better to have removed the inner door panels, but past experience has shown me that these can be a bu**er to remove without some clips breaking away from the actual panel (in fact I started on the rear door panel, and this happened to the first one I came across - so I stopped )) I basically removed everything I could remove to gain access to hollow panels sections! Eg: The front doors have rubber bumpers near the bottom which pull away very easily - this provides a perfect little hole to inject through by pressing the nozzle tight against it. The side door has a good gap around the locking mechanism (Don't forget, Waxoyl ain't your usual underseal - I certainly wouldn't have sprayed any type of thick 'paint'-type sealer in these places!)

On that note, I also sprayed all the visible brake pipes and hoses, steering gaiters, all the gear shift and handbrake cables and linkages, all the suspension bushes, nuts and bolts, etc etc etc! Future maintenance will be much easier. (There are many comments on this forum about the front anti-roll bar bush brackets having bolts which tend to shear off - they wouldn't have if protected earlier with Waxoyl!!)

Obviously, you don't allow any to get on to the actual brake discs or pads, but I did spray the backs of the callipers so that the bleed screws and pipe connectors will be protected from rust and easy to remove in the future.