What's the best power-drill tip to use for removing rust?

tenby ( snipped-for-privacy@hotmail.co.uk) gurgled happily, sounding much like they were saying :

Angle grinder, wire brush in drill, linisher, that sort of thing.

Filler is not a "rust limitation measure". It merely smooths out an uneven base. If you use it as a "rust limitation measure", it's a hideous bodge.

If the metal's thin or holed, then the only fix is welding new metal in.

Thanks for that info, i'll get a wire brush fitting

I'm sure you are right. My only decision is when to weld. Up til now i've just been brushing off rust and trying to keep it looking nice. But now there are holes all the way through at the very bottom in some places. On a big 4.5 tonne merc the sills reach down at least a foot below the solid chassis bits, so there's a lot of sill there that isn't structurally crucial, So my dilemma is *when* it's best to weld? I suspect the time is now, but I'm not clear if welding can cause some other problems, such as new rust starting at the top of the weld, which might mean I'd be better waiting a little longer...??? (The rust can be seen to affect about two inches of the lower sill in the worst areas, with some holes right through at the bottom)

Is it better to weld a smaller area to prevent future problems, or wait til more needs doing? What would you suggest? Which policy extends the life of the vehicle the longest?

[...]

As it's likely that at some point the welding you do will influence the structural integrity of the vehicle, can I respectfully suggest that you really should take a short course in welding at a local tech college?

This would seem particularly important in view of your self-confessed lack of vehicle maintenance knowledge.

Chris

Welding large lumps of thick steel to each other on a bench is quite simple, welding thin rusty cills upside down under a car is a whole different ball game, and without knowing what you are doing you will make things worse.

Unless you are planning to lean to weld properly, and this can take some time, I would suggest you save some money and have it done professionally.

Yes, on reflection, a slow run up would be a better idea... I'll have to pay someone to this job. I can see the longterm benefits of buying a share in such equipment though. Also, the other geezer has a lot of mechanical and maintenance experience, so I'm likely to learn something there.

I'll probably get taken out and shot at dawn for this but I leave the rust there and soak it in Hydrochloric acid (Spirits of salts).

I've done this for years with excellent results. It kills the rust stone dead by soaking up the Oxygen from the ferrous oxide.

I think you will find that it is the 'active ingredient' in those rust pen remover things.

Cutting disc.

Filling isn't a rust limitation method. It's a method of hiding it for a few months until it comes back through.

As a matter of interest, did you get a quote for diesel conversion and if so how much?

Cheers tox

That should, of course, read LPG conversion...

tox

No, that's Phosphoric acid, which converts the rust to a phosphate.

Hydrochloric acid is pretty nasty stuff, but you are correct in its use for removing rust from iron, for which it is used industrially ("pickling" -

The rustis converted into ferrous chloride solution. It does however need to useup some of the clean iron to complete this process.

Absolutely. I've just effected a medium-term repair (ie one that will get me through another 18 months before I have to take the wing off!) to the door hinge plate on one of my Minis, and even with my experience, it took a great deal of care & skill to avoid blowing holes in it.

However if you are going to keep and maintain an older vehicle, learning to weld is very much worthwhile - I always know that any repair I do will always be done to a high standard - something you can't be sure of with a garage unless you know who is doing the welding!

An angle grinder with a wire brush on it. A proper serious angle grinder, not a £20 special from B&Q, but something with some proper power. It'll rip out everything that's not solid and leave you with a load of holes to fix, but this is a hell of a lot better than painting something that'll rust again soon. If you're getting holes, get the lot chopped out and some new metal welded back in - I'd seriously pay a man to do this as a) the kit's not cheap, b) as others have mentioned, it's not easy and c) you'll have enough on getting it painted.

Grind down the welds and 80 grit the entire panel would be my next course of action, followed by a coat of two pack etch primer (it's not as deadly as two pack paint), or aerosol / 1k etch primer if you really must be a pikey. Then filler primer, rub down and topcoat. Again, this is something you can DIY, but getting a good job will cost cash for tools, and a lot of time, and it's probably as well off to pay a man again. As it's near the ground on a van, the finish doesn't need to be perfect, so it shouldn't cost a mint. And the other thing to do is lather the back side of whatever's rusting with Dinitrol.

An angle grinder with one of those plasticy impregnated brush thingies that Wicks sell. They don't throw off dangerous bits or catch in the same way as a wire brush does. Great for removing paint and rust. They have a higher 'running cost' than some other methods but are the best I've found for home use.

messagenews:qbyDi.28311$ snipped-for-privacy@newsfe3-win.ntli.net...

I haven't - LPG sounds like a very good idea in many circumstances, and I'm surprised more people don't go for it given the facts I've been able to garner in the last 24 hours. However, I quickly realised that LPG will be unsuitable for a mobile home, since my whole reason for having the thing is to spend time in a diversity of different countries, in many of which obtaining fuel would be difficult or impossible. Thanks for an interesting suggestion however !!!

Thanks, I'll print that one out!

Cheers. I reckon it'd be possible to make an alright looking job using a cheap spray gun (circa £15, either suction or gravity feed - I prefer gravity), or even an aerosol (bear in mind that aerosol paint is very heavily thinnned), but you'd really need to borrow a compressor and the breathing gear if you're going to use two pack (aka 2k) - it is possible to get 1k base and clear paints but they don't last as well. You also need to make sure that everything is very clean before you spray, and don't spray it in a dusty old shed. Time spent cleaning will be paid back times over in time saved on correction. Seriously as a DIY proposition, you'll need to be prepared to accept that it isn't going to look stunning cosmetically unless you invest a lot of time into it, and it may still come out wrong.

There are a lot of factors involved (I've just about finished respraying and rebuilding my car some 12 months after I took it off the road) - I ended up building a polythene tent inside my shed, heating it etc. so that the paint would set properly and I've got to say that if I were starting again and I didn't want to learn how to DIY it, I'd have paid someone else. I could have earnt the £3k a respray would have cost times over in the time I've spent on the car.

It may pay more to brush paint it if you've not got the time to DIY it properly or the urge to spend cash on paying someone who knows how. In fact, a lot of yanks are doing this - painting a car with very cheap paint, their equivalent of hammerite AFAIK, then rubbing the whole car down and polishing it. It can give surprisingly good results from what I've seen on the web. And of course if you can get hold of Stephen Hull on this group, he knows a hell of a lot about Coach painting and paint, which obviously requires far less kit than for spraying.