Rust: How to tackle it, and at what cost?

[acme15]

Hi guys, I have seen various ways to repair rust, ranging from the outright lazy and quite probably short lived solutions, to the out-and-out 'cut it away and replace the metal' method (which I have no doubt is the best way as it will prevent the rust from spreading).

Should all rust be treated by removing it altogether and replacing a section of metal, or are there other ways which may be appropriate in some situations?

I have seen all kinds of rust 'prevention' and 'curing' products such as Por15, Corrosion block, through to 'electronic rust prevention' and 'cold galvanizing rust curing', but am I not right in thinking that rust is simply a chemical reaction which will spread irrespective of what you slap on it, and that these various putties and sprays will only slow it down?

How much will proper rust repair cost? (i.e. cutting away the affected area, fabricating a replacement section, and welding it in place etc) I'm sure it will depend entirely on the extent of the problem/size of the section and various other factors, but if you had to give me a general estimate? Something like in the M3 sticky thread at the top of this section for example.

I have no physical example of what I mean, this is just pre-purchase talk so I can get a general idea of the cost involved in repairing the rust on an E30 if and when I come to purchase one, and what kind of rust should make me shake my head at it and walk away.

Thanks all once again

*edit* oh and also, what is the best way of preventing new rust damage once the existing rust is all but gone?

[Speedtouch]

Check out some Zoners restoration threads to get an idea of what's involved:

http://www.e30zone.net/e30zonewiki/inde ... storations

As for repair methods, it all depends on what standard you want to get the car to, e.g., for an everyday 'hack', a fibreglass repair may well be perfectly acceptable in the rear inner arches, for instance, where structural strength is not of primary concern. It may well be frowned upon by purists as a bodge, but if it keeps the water out of the car then it does the job.

Best way to prevent rust is to keep the car clean and well ventilated and the drain holes clear, and use a rust preventative such as Dinitrol or Waxoyl every couple of years or so.

If you spot some rust developing, get it repaired asap to prevent it spreading.

[Rich320I]

way to many variables to make an estimate mate,

factually i can say i had a new inner arch, and a repair to the jacking point at the front, and that cost £100, including seam sealing and repainting the inner.

[Grrrmachine]

Rust occurs on a molecular level. It eats through the crystaline layers of iron, and once it's begun you can't stop it. Treatments like POR-15 and other epoxies work by converting the surface rust to a stable compound, and then seal the area so that no more oxygen can get in. But it's not a permanent solution - as soon as the tiniest microscopic split happens in the epoxy layer, oxygen gets in and the rust starts anew. Brushable/sprayable coats only delay rust - the only guaranteed rust removal method is to cut it out and replace.

On an E30 there are a number of places where rust is pretty much guaranteed. The good part is that most of these are in hidden places; inner wings, floor corners, boot floor and the like. These means that a semi-competent mig welder just needs to chop out the old, weld in a new patch, and then coat the repair in the right chemicals to seal it up. How much is entirely up to the hourly rate of the welder.

But if the rust is on the surface - outer wings, scuttle, roof - then you need a skilled body worker who can do the delicate cuts, fabricate a curved repair section and weld it in without distorting the surrounding metal. Then you need to sand and paint that area to fit. That costs sh!tloads, since bodywork is an art gained over years of practice. The x-works thread is a good example of a master craftsman practicing his art, which is why it's a Sticky. People would easily pay a five-figure sum for the work done in that thread.

[acme15]

People would easily pay a five-figure sum for the work done in that thread.

Say what now?

[maggspower]

Rust in e30s is common, good rust repair is rare If you are in the market for an e30 get the best you can body wise, end of, very very few will be rust free.

No one can estimate for unseen rust repairs, there are various ways to do the jobs. But cutting out and letting in new metal is the propper way. But then it needs to be treated BOTH SIDES, which is the hard bit, if you are doing sills and other enclosed panels.

I am about to try a product which sounds good, Epoxy Mastic 121 from Rustbuster, a 2 part epoxy paint. Aparently the bond is so high between the paint and the metal that if it is stone chipped it will rust at that point but the rust cannot creep under the edges of the paint. There are a few other products simular to this: Jotun, and a few more whos name escapes me. They seem to do very well in independant long term tests.

If you can't reach the back side of a repair then, it needs to be coated with some form of cavity wax, or it will be a short fix.

Prevention is much better than repair. Clean out wheel arches, and other rust traps(battery tray/rear valance, factory chassis supports etc) localy treat the rust, and get the repairs covered then get some wax on it. A nice hot day is best as the wax flows best, but a heat gun will help. Its best to do any welded repairs and paint before the wax, it makes good fuel in a welding fire And when fresh will ruin new paint.

[daimlerman]

Unless you are a competent welder,or are married to one ,the above advice regarding buying the best,rust free car has to apply.

Spec is un-important,oily bits can be swapped with ease to get the E30 you aspire to...

I have tried to build the 'perfect' E30 twice,so far,('er indoors has banned further try's) but they are still not,quite right!

[Grrrmachine]

People would easily pay a five-figure sum for the work done in that thread.

Say what now?

Read the thread. Entire roof skin off, body shell completely stripped and taken back to bare metal, only New OEM BMW replacement panels used, whole car set on a jig, then sealed, filled, painted and undersealed back to factory condition.

What you end up with is a factory-fresh as-new straight-as-an-arrow bodyshell of one of the most iconic sporting saloons ever made, which should last another 25 years. How much is that worth?

Even the simplest jobs cost something. My neighbour knew I had a MIG welder and asked me to fix a cracked seat mount on his VW Sharan. I told him I'd want around 50 quid. "But it's only 5 minutes welding!" he cried.

"yeah, and I've got to get under the car to scrape of the underseal so your car doesn't catch fire. Then cut out the broken metal. Then cut a new piece, hammer and trim it to shape to millimetre precision, weld on a nut, line it up properly, then get under your car and melt steel to 6000 degrees C about six inches from the tip of my nose without it dripping on me. Then rub it all down, spray it and coat it so it doesn't rust. And I've lost half my Saturday".

Welding isn't just zap-zap-done - if it was we'd all be doing it.

[acme15]

People would easily pay a five-figure sum for the work done in that thread.

Say what now?

Read the thread. Entire roof skin off, body shell completely stripped and taken back to bare metal, only New OEM BMW replacement panels used, whole car set on a jig, then sealed, filled, painted and undersealed back to factory condition.

Well when you put it like that...

Christ, I almost had a heart attack.

[polsta]

Each area/senario need a different solution , some have to be cut-new metal fabricated , some a new panel is best, and in cases a whole new panel is cheaper /easier /better than a load of man hotex messing about trying to cut out and repair, most/all e30s will have done sort of rust and often hidden and un found if say the owner has never had the dash and carpets out

Different quality if welder/areas of the country will have varied labour rates too, you need to have an idea of what rust areas need sorting to get an idea of costs and also factor in paint costs afterwards if its things like wings and rear panel or rear arches

[acme15]

Cheers for all the info so far guys

What do we think of this? http://www.e30zone.net/modules.php?name ... highlight=

[snakebrain]

Cheers for all the info so far guys

What do we think of this? http://www.e30zone.net/modules.php?name ... highlight=

Grrrr speaks the truth.

That one for sale is almost certainly going to need lots of bodywork. It's tatty at best, and the arches he mentions will be the tip of the rusty iceberg. Always, always cheaper to buy a clean, sorted car and keep it that way than to try to bring one like that back from the dead...

[polsta]

its a 316 not the most desirable of e30s, but still a red 2 door chromie quite rare, but you should be able to find a cleaner 316, ideally- if your going to fix a lot of rust and expense, its better to do it to a niceer more desirable e30, or buy the best you can in the 1st place, sadly these days a massive percentage of e30s (bar the very best) for sale have rear arch issues

[Willeh]

I thought it would b easier to post in here than start a new thread, I've started to tackle some of the rust on my car and to be honest there isn't much that I've found so far after a reasonably thorough going-over. The front of the o/s/f inner arch has completely rotted through (the seam where the arch meets the flat section, under the washer bottle) which I'll fix myself when more practiced at welding (in the process of being cut out and primed etc. at the moment) but something I recently spotted was a small patch at the base of the windscreen, near the the n/s bottom corner. It's right against the rubber seal for the screen which is what worries me. It's not too deep or big (oo er) at the moment, roughly 5-6mm diameter semicircle from memory.

My question is, would something like this be suitable for a wire brush, fill, paint, etc. job? Would it likely have spread under the windscreen seal? is replacing the seal a windscreen-out job? I'm just trying to assess whether it's a quick fix or a choppy weldy kind of fix that'll eat my cash. I'm competent when it comes to mechanical stuffs and structural bodywork but not too great on the stuff that needs to look nice, especially when its in such a shitty place that will definitely cause problems down the line. I can get pictures, probably Friday, possible tomorrow.

Something else I forgot to ask, I'm taking off both front wings as I'm stripping the front down to check it all over while its off the road, and was wondering about the seam sealer at the back corner near the scuttle;
a. does it really need replacing? will it make much odds?
b. where is the cheapest place to get it?
c. (this will sound the bodgiest, but bear with me) is there anything around the house that could be used as a replacement, like silicon sealant? I know you can get an inert one and one that has an acid in it or something and apparently the inert one is okay to use on paint, but is this confirmed?

Cheers.

[G-Bear]

Say what now?

Read the thread. Entire roof skin off, body shell completely stripped and taken back to bare metal, only New OEM BMW replacement panels used, whole car set on a jig, then sealed, filled, painted and undersealed back to factory condition.

Well when you put it like that...

Christ, I almost had a heart attack.

He also got the shell dipped which cost over a grand I think and it came back with a couple of dents (which is quite common)... More labor fixing the fixed.

[Grrrmachine]

Willeh, check out my resto thread (link in sig) - it covers all those repairs and more.

You'll want the windscreen out to assess the true extent of the scuttle rust, but I just sanded mine down and gave it a few zaps with the mig to put fresh metal in the pinholes - no need to cut out the old stuff.

As for the seam sealer, you can get Tiger Seal on ebay for a few quid. Yes, it's needed and no, normal silicone sealer won't work. It will contaminate the paint.

[initial_g]

One clear answer, cut out and replace, and lead the welded areas rather than fill. These rust neutralisers and miracle cures dont work do not work generally when the inner arch has gone to go it properly I remover the rear quarter panel, unstitch the inner arch and spot weld a new one inplace paint it all and seal it then paint the inside or the quarter panel then fit the new quarter panel I spot weld where all the orgional welds were BUT dont spot weld the inner and outter arch lips (as this causes a corrosion hot spot) I use panel bond like most manufacturers do. Then seam weld the panels together and lead load it using a very very thin amount of filler just to get the finished shape.

[Willeh]

Cheers man, just gave that a look, sterling effort . Really hoping mine isn't as bad as yours was, but judging from the rest of the car it should be sound, most of the usual places are pretty spotless so far.

Thing is, I'm in a bit of a shit situation at the minute with the car as it's stuck in a council garage miles from my house, with no power (thus no lighting...) and no storage so I don't really have the means to strip it, grind it, weld it, etc. right now. I'm also jobless at the moment which means a, I don't have a ton of cash to throw at this right now and b, the car needs to stay in a condition where it can be on daily duties at the drop of a hat. It's not too bad at the moment as the front it is completely off, and soon the rear too, but it can all be back together within an hour if I need it to be, but that would not be the case if I took the screen out. Need money for resto, need job for money, need car for job, etc. so i can't have it hanging round in a million pieces, especially in a garage where I can't fix it anyway. I'll just do what I can with a wire wheel and some paint at the moment, we'r actually in the process of sorting a half decent unit at the moment, but that couold be a few weeks away, or up to a year .

[Grrrmachine]

With a ten-quid tool from ebay, the windscreen can be in and out in half an hour. I've had mine off the car three times - it's a piece of cake. If you take the windscreen out and find that the scuttle has rusted behind the dashboard, you won't want to bother doing any other work to the car anyway.

[initial_g]

Windscreen can be out for free ;)

[Willeh]

I can have the windscreen out no problem, but I can't afford to replace it if it gets smashed (pretty likely as I have nowhere to keep it) and I've never put one back in, so I'd most likely have to pay someone or risk fucking the job up and forking out for a new one anyway. Is there a guide anywhere? (I've read the Wiki guide, but I'd like to see some pictures etc. as I like to be 150% prepared for a job if I can help it!).

[Grrrmachine]

Windscreen can be out for free ;)

Yes, but getting it back in without the tool is a PITA. Took me at LEAST 25 mins last time...

[Willeh]

Right, pictures. Set up a Flickr account just for this.


IMAG0009 by geeteearggh, on Flickr


IMAG0010 by geeteearggh, on Flickr

For scale;


IMAG0011 by geeteearggh, on Flickr


and inner arch...


IMAG0012 by geeteearggh, on Flickr


Not too worried about this, as I'm just going to cut it out and prime it, and find a donor to cut out and stick it in.

[Grrrmachine]

You don't need a donor for that inner arch - any car you find will have the same rot anyway. The washer reservoir bracket will have to come off though - that will have rotted through.

All of that can be redone with 0.8mm plate steel, folded with hammers and wood and shaped with a 1mm slit disc on an angle grinder. An afternoon's work. Just buy an old bonnet to use as donor metal.

[Jos]

I am about to try a product which sounds good, Epoxy Mastic 121 from Rustbuster, a 2 part epoxy paint. Aparently the bond is so high between the paint and the metal that if it is stone chipped it will rust at that point but the rust cannot creep under the edges of the paint. There are a few other products simular to this: Jotun, and a few more whos name escapes me. They seem to do very well in independant long term tests.

Pretty sure the 121 is rebadged Jotamastic 8x of some description. Other than the ratio mixes they are the same, the only epoxies mentioned in relation to No. 17 Thinners are 87, 80 and Rustbuster 121. They are also available in exactly the same colours...

J87 is 1/2 the price of 121

[Willeh]

Cheers for the information, Rich was it? I hate calling people by their usernames haha. I don't know if I trust my metalworking to get it up to standard for going in the car, I'm not fussed about it being concours, just from the factory fresh, but at the same time I don't want it to look like dogshit. I think I'll have a crack at both to be honest, as I would like to improve my skills because it's so handy working on older cars like these but get the panel section if I can't get it right.

[Willeh]

Bump for inner wings;

Much tidier than expected, looking at the touring resto thread put the fear in me, but it turned out alright. (Apologies for the shitty angle, couldn't get further away in my little car hole).

Near side:


IMAG0016 by geeteearggh, on Flickr


IMAG0018 by geeteearggh, on Flickr

Offside was fine, except for;


IMAG0019 by geeteearggh, on Flickr

I think it's a single skin? Should be pretty easy fix for a novice.

[Grrrmachine]

The rust you've got around your brake pipes is exactly detailed in my resto thread. Single skin overlapping the chassis rail, both of which will have failed. And considering the location, I ended up removing that whole brake pipe and redoing it too.

To do a proper job, you also need to cut out a square at the end of that inner wing flitch where it's gone rusty. Drill out the three spot welds, then cut out a square from inside the engine bay (you'll need to remove the coolant expansion tank if its an M20 engine). Then weld a patch in and plug-weld the flitch to it, and paint it all up. Otherwise it will rust like mine did.

[Willeh]

Cheers mate, will give the thread another look when I get a minute. The repairs will need to wait a while until I get somewhere better to work on it, probably a few months or so. Also found a random pad wear wire hanging down. Random. I'll probably make myself a build thread to keep track of all of it too at some point, I'd be grateful if you could give it a gander! And it's an M42 for future reference.

Cheers.

[Grrrmachine]

The pad wear wires are front left and rear right, so not random at all

I'm no expert, but my Touring's probably the rustiest one saved so far, and it taught me to weld. By the end I had a weekend where I thought "fook it" and took the entire sill off on one side. So it really makes you confident with the MIG!

Just get yourself in there. My garage is less than three metres wide and I did a full respray in it. Came out like shit, but still...

[Willeh]

Buying welder and gas supply is literally the top of my list of things to buy when I stop being a tramp! I've saved all sorts of scrap like old bike frames and whatnot to practice on. Like I said earlier, my garage is alright but it's not the size that's the problem, it's the lack of power that cripples me somewhat, (and being in the middle of nowhere means extension cords wont help much) any work I do needs to be done with hand tools.
And it wasn't random that I found it, haha it's that I found it like this;


IMAG0017 by geeteearggh, on Flickr

I've even had the suspension off it back when I was in college and didn't notice. But to be fair, that was mostly at 9p.m. onwards in a garage without lighting.