Another Thread About...

[James_m 0]

Well ive been having ago with my rust issues today, with varying success, so i thought id post my results and seek advice from the 205 collective....

Pretty average rust for a 205 i reckon, ive certainly seen worse

 

After i had spent ages with a drill with wire attachment, rust does'nt seem to want to come off!

link

 

Here especially, seemingly no amount of grinding removes it, just makes it go dark and smooth's it a bit

link

So far ive been using the as mentioned wire attachment in a drill, and the purple disc from frosts automotive made especially for the job, but i couldnt fit that squarely enough so it span out of balance if that makes sense, rendering it useless, not sure what to do now as nothing seems to take it off Anyone got any advice?

 

Lastly i have a warning.....the usual places for rust on 205's mine wasnt too bad - inner wings etc(or within repair anyway) But there was 2 that i havent seen mentioned before that are possibly more serious, and in my case are.

link

This is below the master cylinder where chassis rail meets the bulkhead, and the rail continues down the car, what seems to have happened is, a small hole has been made by a stone or whatever, allowing the elements under the thick sealent type stuff covering this area and the floor pan(?) and just rotted the inside, thing is with it, its not at all obvious if the engine was in the car and you was looking at it, i only noticed because i felt the paint was slightly soft on the rail, and then further inspection revealed that it wasnt actually attached solidly to any metal any more. my passenger side is no where near as bad, though looks as if its about to go the same way if left untreated

 

 

Here's another piclinkI think i may have got any with it, few more years and i think it would have rot right through the chassis leg

 

So in summary, what shall i do to remove the rust?

Edited June 1, 2006 by James_m

[hengti 2]

you need to use fairly big washers either side of the Frost disc to clamp it properly

 

make it work - as they're absolutely fantastic at removing rust - you won't believe how good they are compared to wire brush attachements!!

[James_m 0]

Yeah, i guess i could have persevered with it a bit more, i just thought the wire brush would do a better job, obviously not....

 

Cheers mate.

[newdean0 0]

That rust on the chassis leg is fairly common. I helped out on an engine swap last weekend where it had gone right through and there have been a few posts around a while back with some pretty scary pictures of rust there.

[Miles 331 1 Cars]

All normal points, Seen a few with rust on the inner wing wheel arch of where the passenger would stick there left leg on, Which again gets hidden by the sealent until its tooo late

[B1ack_Mi16 67]

My experience with rust is that sandblasting is the only method that'll remove it properly.. or of course, change the panels.

 

But the drill attachment tools just don't seem to work.

 

I blasted the whole underside of my car...

 

From this:

http://cortex.fa-s.ntnu.no/~kristian/205gt...05/CIMG0753.jpg

 

To this:

http://cortex.fa-s.ntnu.no/~kristian/205gt...05/CIMG0853.jpg

 

There was some rust left in the biggest pores where it was at it's worst, but I treated it with some phosphate acid thingy and I hope it'll last for a while before it comes back now

[johno_78 2]

you dont actually need to remove all of the rust, just the big loose bits. then all you need to do is to apply a rust converter to the infected areas before repainting.

 

an old customer of mine has a company with produsts exactly for this problem. this is his website rust link.

[Banjo 1]

You need to buy a grinder and do it properly with a sanding disc, there not that much and are very handy..

[ALEX 98 1 Cars]

That rust preventer is good stuff.

I've used it on a few places on mine. it doesn't even need painting over when applied. Ideal for the chassie VIN number, which usually gose rusty.

About £4 a bottle AFAIK.

[James_m 0]

Bit of an update....

i ended up persevering with the frost disc, which in the end worked really well, getting rid of 90%

of the rust! all was looking good, i applied the metal ready which seemed to dissolve parts of the rust in places, but kept running off the front panels below each headlight, nevermind i thought i kept applying it as per instuctions and hoped all would be well.

 

Then got onto spraying, 2 coats of etch primer then a further 2 of white paint from an aerosol can and i was pretty pleased with the result

 

However.... i went out today to find its rusting from underneath and obviously bringing the paint up with it i wasnt expecting a life time solution, but 2 weeks!

 

Anywho i cant leave it like this, so whats the solution? my feeling is the metal ready was just too impractical and as per Beastie's threads, the metal still wants to be rust

 

So can anyone recommend a decent rust inhibitor which is thick enough that it wont run straight off the panel?

Also, i have a feeling maybe etch primer wasnt right for the application, is their anything i could try that might give a longer lasting finish?

 

Thanks James.

[ALEX 98 1 Cars]

did you shake the bottle first?

[paul205mi16 4]

i would like to see how u solve this too,as i have no sandblaster and would be doing the job in a simular fashion.

my rust is also identical.

[BERTMAN 40 1 Cars]

what paul205mi16 said...

Edited July 4, 2006 by BERTMAN

[Banjo 1]

You need a GRINDER! Grind the rust back so that its fresh shiny metal, if there are any rot holes cut them out and weld them up, then just paint as normal, etch primer will be fine or just a zinc primer on bare metal.

Ben

[Beastie 1]

etch primer was designed to etch through the layer of oxide which forms rapidly on non ferrous metals and which seals the pure metal beneath itself. It was soon found that etch primer has advantages for clean, new steel panels and for some plastics. What is really needed for steel which has at some point oxidised is a sacrificial primer. Etch primers make relatively poor sacrificial primers. Happily freshly abraded steel doesn't really need an etch primer so we can use something else instead which does make a good sacrificial primer: Either Zinc phosphate (look for at least 80% Zinc if possible) or Red Oxide. Most red oxide available to the DIY trade is pants nowadays but I do rather like International oil based Red Oxide (from Homebase and others) when thinned with a little white spirit and then sprayed on. Allow to dry for 24 hours and then spray primer over the top. Treating the metal with a phosphate based anti - rust treatment is essential unless it is a brand new panel. Most anti rust treatment available over the counter is so weak that it won't do a fat lot. The only industrial strength one which is readily available is Frost's metal ready. I've posted loads on this subject in the past so there's not much point going back over it all again - I'm sure a search will turn most of it up if it is of any use.

[B1ack_Mi16 67]

I've found out after using zink phosphate primer is not always so good.

It has really bad adhesion and will often let go of the metal if you overpaint it with some thicker layer of for example stone-chip protection. When the stonechip protection dries it gets internal stresses and the zink will often let go of the metal. (This has happened several times now, and I'm not going to use zink anymore ).

 

Will now just use a phosphate acid threatment and then clean the surface and seal it with an epoxy-primer.

This seem to have much better adhesion.

[Beastie 1]

I've found out after using zink phosphate primer is not always so good.

 

 

Will now just use a phosphate acid threatment and then clean the surface and seal it with an epoxy-primer.

This seem to have much better adhesion.

 

 

It depends which Zinc Phosphate you are using. As with all paints some are absolutely awful and certainly don't do what they say on the tin. It's the same with most Red Oxides which are also complete crap, although "proper" Red Oxide has excellent results. I have just been serviceing a Morris 1000 which I restored 10 years ago and I'm really chuffed to find that it is still in the same near concourse condition as it was when it was first done. However rust proofing modern classics is actually harder than older classics because often the steel is more prone to corrosion. It is very hard to protect it as well as the original manufacturer did!

 

Epoxy primers are often excellent so I'd agree with you on that one!

[James_m 0]

I tried using metal ready, but unfortunatly i found it to be so thin it just kept running straight down off the panel(below headlights)

It looked to do its job, dissolving some of the lighter rust, but would seemingly rust back before your very eyes if left, which i thought was the opposite of what its supposed to acheive

is their no metal ready equivalents that come in a thicker, possibly paint on formula?

[B1ack_Mi16 67]

It depends which Zinc Phosphate you are using. As with all paints some are absolutely awful and certainly don't do what they say on the tin. It's the same with most Red Oxides which are also complete crap, although "proper" Red Oxide has excellent results. I have just been serviceing a Morris 1000 which I restored 10 years ago and I'm really chuffed to find that it is still in the same near concourse condition as it was when it was first done. However rust proofing modern classics is actually harder than older classics because often the steel is more prone to corrosion. It is very hard to protect it as well as the original manufacturer did!

 

Epoxy primers are often excellent so I'd agree with you on that one!

 

Yeah, but also in general I've learned zink is not good when it comes to adhesion.

I had a course this spring on university "Surface and paint technology".

 

Mostly about offshore constructions and such where they actually use a lot of zink primer.

Before using a zink primer on such constructions you had to grit-blast the surface to a pretty course roughness to get enough area in the metal to give good enough adhesion. So it seem to be a pretty general rule when it comes to zink. The adhesion is not getting better due to mechanic locking due to the roughness, but because of the added surface area.

[Beastie 1]

The adhesion is not getting better due to mechanic locking due to the roughness, but because of the added surface area.

 

That's interesting - I didn't know that was the reason. It's true that it's folly to try and corrosion - protect very smooth surfaces which is part of the reason why sandblasting is so useful. I always use Red Oxide at work with the exception of where a weld thru primer is required. I often do recommend Zinc to people due to the difficulties in obtaining small quantities of good quality red oxide. Zinc usually gives better results if it is designed to be sprayed rather than brushed but overall I accept you point about its shortcomings.