How to deal with corrosion on aluminium ??

[Supersprint1988]

How to deal with corrosion on aluminium?

My car is suffering from bubbles under the paint on the aluminium side skins.

It seems that the standard answer to this question is to send the car to Arch for a re-skin.

Is there any one who has tried with glass/sand blasting + a good filler and re-spray, or perhaps another methode. Will it last for reasonable period of time, or is it just a waste of time ?

When searching the archives, it seems that some cars can be suffering from corrosion on the side skins as soon as 3 - 4 years after a re-skin, and in that case one could think that the easy repair might last allmost as long.

Any one who has done this ,- is it or

 

Cheers

Carsten

[Sheds Moderator]

You can fix it by abrasion, removing the rot and filling/painting, just as with steel. Just as with steel though, once it takes hold you need to be utterly ruthless with treatment or accept that it will recur. Once you have repaired it, slather the whole thing in Waxoyl or similar wax, and keep the grot traps clean.

 

The big problem is where ally touches steel so you need to slather those joints in Waxoyl, thin it with a bit of paraffin/white spirit to get it to flow in the joints and keep the moisture and salt out.

[myothercarsa2cv]

Put a sticker over it

[BBL]

Quoting batteredoldsupersport: 

The big problem is where ally touches steel...

...and where ally touches c/f as well.

[The Pikey]

I see aluminium corrosion all the time at work (caravans) I'd say you are wasting your time unless you want a fix for a few months tops. Aluminium corrosion seems to start on the unprotected/unpainted side so I think the corrosion would be worse on the inside.The only real cure will start with a phone call to Arch....

 

Jason

[rj]

And then get powder-coated side panels whilst you are at it.

[The Pikey]

Yep, mine are Aerial Atom silver as that's what was in the gun at the time

 

Jason

 

Edited by - Jason Fletcher on 28 May 2011 17:03:01

[Fil M]

Have a look at ACF 50 spray Carsten. It is a fluid that tracks into and holds corrosion where its at. If you can get the nnozzle near the inner source of corrosion you will find it will stop it progressing. In this warm weather it will penetrate well. I used it to protect the entire underside of my car including a few ally bubble spots and its unchanged after the winter. You can get it on E bay and find out more about it on google. Its useful for a number of things and when a rag dampened with it is rubbed on the suspension arms they come up a treat and repel the crud too!

 

Motorcyclists rave about it ... it costs a few quid but goes a very long way.

 

Fil

[Michael G]

Another vote for ACF 50.

Great stuff. Very easy to apply, minimal mess. Has kept my Defender in great shape for the last several years, so I now use it on my Seven.

Michael

[Supersprint1988]

Jason I hear what you say about repairs, but perhaps there is a difference between Caravans living their life out there in the rain, and a car that are stored dry and protected and only driven when dry ( unfortunately mine hasn't always been that well cared for ) and then again, perhaps the enviroment is not that important when the first damage to the aluminium is all ready there.

 

I am afraid the ACF 50 won't be able to deal with my corroded aluminium

Is there really no one who has tried the grid blasting / filler option ???

 

Edited to correct at least some of my incorrect spelling !!

 

 

 

 

 

Edited by - Supersprint1988 on 29 May 2011 21:03:13

[dalongbloke]

Having done loads of work on mine over the winter... The problem I think with ally repairs on sevens is that you are talking thin panels.

,

These would be v difficult to grit blast without damage or distortion, and nI can't see how you would use filler on such thin panels. Possible if over lying steel I suppose.. but movement and cracking would happen soon I fear.

 

I also LOVE acf 50.. fantastic product for sevens.

[jmalcol1]

ACF50 excellent product. I use it to wipe suspension parts, anti roll bars etc.

[I reply to every thread]

Waste of time trying to repair unless your natural inclination is to bodge

[Sheds Moderator]

Is there really no one who has tried the grid blasting / filler option ???

Like I said:

You can fix it by abrasion, removing the rot and filling/painting, just as with steel. Just as with steel though, once it takes hold you need to be utterly ruthless with treatment or accept that it will recur. Once you have repaired it, slather the whole thing in Waxoyl or similar wax, and keep the grot traps clean.

 

Waste of time trying to repair unless your natural inclination is to bodge

Nope. See above. Of course, if you DO bodge it, the problem will recur, maybe less than a year down the line. If you are ruthless in treatment and subsequent maintenance (rustproofing wax of whatever type you choose, etc) then the repair will last several years. By that time the metalworm may have chewed its way through a few other bits or the whole car may be in need of a rebuild, in which case your repair has done its job.

 

 

[I reply to every thread]

Quoting batteredoldsupersport: 

Is there really no one who has tried the grid blasting / filler option ???

Like I said:

You can fix it by abrasion, removing the rot and filling/painting, just as with steel. Just as with steel though, once it takes hold you need to be utterly ruthless with treatment or accept that it will recur. Once you have repaired it, slather the whole thing in Waxoyl or similar wax, and keep the grot traps clean.

 

Waste of time trying to repair unless your natural inclination is to bodge

Nope. See above. Of course, if you DO bodge it, the problem will recur, maybe less than a year down the line. If you are ruthless in treatment and subsequent maintenance (rustproofing wax of whatever type you choose, etc) then the repair will last several years. By that time the metalworm may have chewed its way through a few other bits or the whole car may be in need of a rebuild, in which case your repair has done its job.

 

 

I'm sorry but the chances of carrying out an effective repair in the areas that a 7 corrodes are SWA unless you are an ali welding expert. So you are going to peel the sideskin off the lower chassis tube, cut ot the electrolytic corrosion, "Repair" the holes, prevent any spread and then fold the skin back? Or just blast it and whack some pug in? If it's the fomer then the individual probably isn't going to be daunted by fitting new sideskins themselves.

 

If you do it right with new skins they'll certainly last a long time - Mine are 12 years old

[Sheds Moderator]

An alternative: in areas of moderately extensive corrosion, cut out the corroded ally, clean up and repaint the steel underneath. Make up a repair panel that you fit on the inside of the original skin, epoxy the two together, make the outer surface good with filler, paint. In areas of less extensive corrosion, yes, blast it and stick some catty on it. Paint and rustproof as reqd. Come back in 2 years if necessary and tidy it up. A perfect repair? No, but an adequate one. On both 7s and tintops I have held corrosion at bay for years by using these kind of techniques, it's the difference between a bit of work every year or two and a big hole after 3 years if you ignore it. The definitive repair is to replace the panel, sure, but that's an expensive approach whether it's steel or ally. I'll stick with repairing what I have until it really does need replacing. Bodging? Hardly. One of my semi-permanent 7 bodywork repairs is still rolling in the hands of Fishy Dave 6 years after I did it. That wasn't even one of my most thorough jobs. Had I not bothered he would have been in for a partial reskin before now.

[SLR No.77]

Carston, the corrosion is usually caused by electrolytic action between the steel and the aluminium - accelerated by the presence of moisture. You'll actually find that if you have bubbles in the paint and you carefully prick them, they'll often be full of water! A re-skin isn't always necessary to suitable hold back the corrosion, and as an alternative repairs can be done.

However, to do a reasonable job you'll really need to remove internal panels to get to the back, or source of the corrosion. From then it's possible to flat out the corrosion, or even remove as much alluminium as is necessary to leave only good metal. Separate in your mind corrosion prevention and bodywork appearance.

If you now have holes, as BOSS says these can repaired by gluing on pieces of alluminium sheet to the inside. Importantly the whole of the inside area must be clean and DRY - this is why the grot-traps are a major problem area, because they collect dirt which then holds moisture. When you've repaired the inside spray on as much Dinitrol or Waxoyl as you can, then replace the interior panels.

The outside is now purely cosmetic and can be filled and painted just as you would any other small repair - the added aluminium will support anything you add.

If you check the pages of my website (www.superse7ens.co.uk)there's some pictures showing just how bad the grot-trap areas can be.

 

Stu.

 

Edited by - sforshaw on 1 Jun 2011 15:16:07