Advice For Slight Rust On Seams Underneath The Headlights
Posted 19 July 2012 - 06:42 PM
So Arthur has had a little bit of rust, barely really noticeable from any distance, on the seams underneath his headlights ever since I owned him, offside slightly worse than nearside.
Looks like previous owner has touched up paint in that area before, but don't know what he did before doing that to treat the rust. I have been painting waxoyl on the paintwork to try to keep it at bay ever since I've owned Arthur (a few years) and this seems to have stopped it getting noticeably worse.
I could leave it and hope regularly applied waxoyl will stop it developing too badly. My worry is that there will be more rust going on in places I cannot see that will end up in me having to have a new front end.
So I could get the rust ground back and treated, but I'm not sure if this is the best thing to do or not? I'm uncertain because:
i) I have metallic paint work so a colour match would be difficult and it would be likely to be slightly darker than the original paintwork and maybe more noticeable than already repainted slightly waxy rusty bit!
ii) When you grind back the rust what would replace the space where the rust was? Is this what filler gets used for?!
Excuse my lack of knowledge about how body work repairs work, but if anyone has any advice / recommendations I'd appreciate it!
Posted 19 July 2012 - 07:05 PM
That's one of those nasty places as chances are it's come from behind so will go back through the seam.
Your best bet would be to get one of those spot blasting guns which comes with rubber nozzles and recirculats the grit and hire a compressor for the weekend and slowly blast the seam clean. Then when clean paint with por15 rust prevention paint which is really good stuff, then touch up with a touch up paint stick. As for filler I would use a marine corking in black as this stay flexible unlike filler which goes hard and cracks over time and most can take paint to stop it being seen. The tricky job is going to be cleaning the back of the seam, but with the spot blasting gun they come with various rubber nozzles, so you could just cut a slot in one so the seam runs inside the nozzle and blast it clean that way. Then paint with por15 paint then when dry waxoil it.
If you don't want to go the shot blasting way a dremel with straight bristle steel wire brush and remove the rust that way then paint and seal the same.
Posted 19 July 2012 - 09:24 PM
Spot blasting would help but its keeping it down to a small enough area so i think the dremel is the way forward. You can buy good quality non silicone based automotive sealants which will allow you to over paint without any reaction. Putting filler over rusty areas is asking for trouble but if you treat the area first with a rust treatment of your choice followed by a very fine skim of filler or if the damage is minimal you may get away with some filler primer. Flat back then prime flat back topcoat and then lacquer.
No matter what you do though in time the rust will come back, it just depends on how long you can keep going until its time to replace the panels.I would try and treat the back of the seam as well and then seam seal it to prevent any more moisture ingress. Follow that with some waxoyl.
Posted 19 July 2012 - 10:41 PM
Posted 20 July 2012 - 03:02 AM
You could if necessary make an improved stiffner by butt welding the panels and then adding a stiffner cut from a single thickness of 1.8mm instead of the original two of 0.9mm. Seam welded (not structurally necessary but avoids water ingress), it would mean that the equivalent amount of metal was in the right place, but with no gap between to invite water and corrosion. I think that a similar process is used on certain seams when deseamong the shell, i.e. a false flange made of one piece oif metal is welded on the inside to replace the seam lost on the outside. (Never deseamed a shell, I think it spoils the looks.)
Oh, and something I often wonder about. It would be possible to cut out the overlaps and butt weld the joints in the wing itself where it is shaped around the headlight. Some minor hammer and dolly work to get the metal flush. I think that those particular seams are ugly. Yours, the vertical one, is rusty, and that particular seam is only so the wing could be manufactured, as without it the steel would not be sufficiently stretchable in the press. They are not flanged and do not stiffen anything.
Posted 20 July 2012 - 06:51 AM
It is annoying that it is in such an awkward place - and if I remember rightly getting to the back of that area to treat anything is not all that easy either.
Anyway, Arthur is going to have some work done on the front and rear valences soon (I think it's the valence, hidden panels behind/ underneath the numberplates - when you run your hand along them bits of rust have started flaking off) so I will add the seams to the list for my car restoring miniman to do. Definitely want to put off the front end replacement as long as possible - even though I suspect it's inevitable at some point.
Posted 20 July 2012 - 05:00 PM
I know some people look like you just shot their granny when you mention lead, but wear a proper mask and it's fine, and the best bit is the tallow used on the wooden tools smells like burgers cooking, so makes you hungry as well.
Posted 20 July 2012 - 05:06 PM
Not easy to acquire admittedly but easier than lead loading and somewhat safer. Still would like to give lead loading a go but that's for another day.
Posted 23 July 2012 - 04:57 PM
One benefit of being lead-free is that you can use power tools (sanders etc) without poisoning yourself.
However, lead or its modern substitute, mostly tin, do tend to encourage dissimilar metal corrosion if the joint is exposed to moisture.
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