How much rust to remove

[tufd24]

Hi all,

 

Restoring a D-24.  My 3rd classic restore ('67 Mustang and 50 Jeepster) and as I'm learing I'm trying to get more and more hands on.  With the previous cars it was send to the paint man and check in every few days/weeks to make sure the job looks good.  None of these are off-frame so not everything can be cleaned and prepped perfectly.  My usual check-in's saw a lot of sanded areas and the parts with the worst rust removed and replace.  All other areas were brushed and treated with an anti-rust coating (whose adhesiveness was variable).

 

On the D-24 I'm removing as many panels and parts as practical without doing a full off-frame restore. I'm doing much of the work myself.

 

Question is, as I clean the various parts (panels, bars, etc.) how much rust is acceptable. I can take a wire wheel and easily get rid of the surface rust, or I can really have at it and get the metal pretty close to bare polished. The latter obviously takes significantly longer.

 

What's appropriate, the right balance?  I may take some of the larger panels to be blasted, although the forum seems to advise against as it may cause warping disfiguring of the metal.

 

Help and advice is appreciated.  Thanks!

[chopt50wgn]

When I replace any sheet metal I always cut out the rust. If the metal is intact, by that I mean if you tap it with a screwdriver and it's solid, then you have a good piece to weld to.

If you have some spots that have minor pitting and you can get the rust out of the pits and it's also solid you are good there too.

   As far as blasting goes, they are correct in the warping factor that can happen. I would just take the time and either sand the paint off or use a chemical stripper. Either way you save money and the chance of warping a panel you may not be able to replace.

[desoto1939]

for some metal that has pitting and you have wire brushed the metal but the rust is still in the pitted area Eastwood sold a chemical that you could brush on and then it would go into the small areas where the rust was still visable and then remove the rust back to clean metal.

 

i do not remember what the product was called but if you contact them or even go on theri web page would should beable to find it.

 

 

Rich Hartung

Desoto1939@aol.com

[Robert Horne]

I have been using a chemical from Advance autoparts made by "Purple Power",

for rust treatment. After using a wire brush, chemical stripper, blasting,

or what ever, I apply the Purple Power Rust Treatment with a spray bottle.

After drying for a day, I wire brush the treated area again, and apply the

treatment again. Depends on how bad the metal was at the start, on how

many times I do this, sometimes one treatment is enough. After cleaning

with paint thinner, it is ready for primer.....

[Dave72dt]

MSDS for Purple Power Deruster indicates it's primary component is phosphoric acid, same as every other rust converter, doesn't say it's concentration level

[Plymouthy Adams]

phosphoric is the only acid that targets only rust and not the base metal..levels of concentration can go as high as 85% but at 85% it is not good to let the agent dry..turns very brittle almost as much trouble to remove as the rust..Ihave found that 55% is the strongest solution that I care to mess with its cost at 55% is extremely cheap..this solution is the only one that I know of that when it dries will actually self flake from the surface.  Keep from nonferrous material though...will not harm glass or stainless.  This solution also mixes well with other products for duo purpose applications.  Use in ventilated area especially if accelerating with flame..

[greg g]

body shop supply houses sell a product called Ospho.  You spray it on work it with a scratch pad.  When left to dry it leaves a primable finish and will protect bare metal from further runst for up to a year or so.  It is basically phosphoric acid with a zinc component.  Muriatic acid works, but best done outside on a surface you don;t care about.  Both Phosphoric and muriatic will etch concrete so not food for garage floors.

[Eneto-55]

I have been using a chemical from Advance autoparts made by "Purple Power",

for rust treatment. After using a wire brush, chemical stripper, blasting,

or what ever, I apply the Purple Power Rust Treatment with a spray bottle.

After drying for a day, I wire brush the treated area again, and apply the

treatment again. Depends on how bad the metal was at the start, on how

many times I do this, sometimes one treatment is enough. After cleaning

with paint thinner, it is ready for primer.....

Since Dave gives the information that this solution is Phosphoric Acid, be careful about the dust you create when you wire brush it after it has dried.  As I understand, its acidic characteristics are restored when it gets wet, like on sweaty skin or in the eyes.

[Old Ray]

I buy a five gallon pail of some form of Phosphoric Acid for smaller parts, the first pail was some kind of truck frame acid wash and the second one was for cleaning steam cleaner coils. I soak the parts overnight or longer, works great………. (unless you forget the sons gas door over the winter  ).

 

This is some seat belt shoulder harness brackets made out of scrap on my last project, untreated horizontal, treated vertical.

 

[Joe Flanagan]

Another vote for phosphoric acid here. I've been using it (diluted with water as Tim says) for a long time. I'm very happy with the results.  

[Don Coatney]

As Kirk said, "Too much LDS back in the 60's"

[Robert Horne]

Since Dave gives the information that this solution is Phosphoric Acid, be careful about the dust you create when you wire brush it after it has dried.  As I understand, its acidic characteristics are restored when it gets wet, like on sweaty skin or in the eyes.

Thanks, I am very careful with this stuff. I always work with it on the outside of my shop, and have the wind

at my back.