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B Jake Moran

Deep Surface Rust Restoration

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Posted (edited)

If this is in the wrong area, moderators please relocate but not sure where to get a conversation on this topic.   I have long been curious how to remove deep surface rust from restoration projects.  I offer the following only as an example:

 

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So - if you use a sander and 200 or so grit and go to town on that trunk and rear quarter  area a person would eventually get down to shiny bare metal BUT the surface, especially if viewed under a microscope would look like the Rocky Mountains.  I am wondering if - even if you sequentially get to a "polishing" level of sandpaper, what? - like 600 to 800, do you ever get a surface that can be sprayed with primer and then your color choice of paint?  Or is the metal so damaged by the rust that it needs a smooth coat of body filler?  

 

It seems this high level of surface rust almost preserves the original shape and surface but also makes it difficult to remove and make right again. So I sometimes avoid these cars for restoration.  What am I missing?

Edited by B Jake Moran (see edit history)

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Posted (edited)

You get the car sandblasted, epoxy primed, and go from there. That is Mid West rust, it doesn't come close to east coast rust.  Bob 

Edited by 1937hd45 (see edit history)
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Sandblasting is the quickest, but you could sand it as well.  Start with 80 grit or possibly 60 grit and finish with 180 grit. Primer adheres best to a 180 grit finished metal.   Then start your finishing for paint in primer.  Sandblasting leaves about the same finish as 180 sandpaper.

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Sand or other media blasting will get the rust out of the deeper pits. Sanding won't. The metal will hold paint best if it has a good "tooth" such as from sand blasting or a coarse sandpaper. Sand blasting poses the problem of panel warpage. That's been discussed here several times before..............Bob

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2 hours ago, 1937hd45 said:

You get the car sandblasted, epoxy primed, and go from there. That is Mid West rust, it doesn't come close to east coast rust.  Bob 

Blasting is the most economical way. There is also a dipping process that is a bit pricey. 

As for Midwest rust  not being as bad: In my younger days I had for a winter beater a 7 year old Minnesota  Chevy 4 dr the front seat sat on 2X4s and the head lights were wired in place with bent coat hangers.

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Wow interesting.   So with sandblasting and / or aggressive sanding as I am not sure I can sandblast in my garage - the surface is left like 180 grit level.  Is it my understanding that primer "flows" for lack of a better word -into the "valleys" and what you get is something that can be painted to look like it was from the factory? 


I see a couple of restoration cars in my future and both have thick 1920's metal but are rusted like the above Buick.  I didn't want to end up with some pok marked metal that did not look correct.   Thanks everyone.

 

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Jake, I bought car a few years ago that had been stripped to bare metal and then left in a storage unit. Even here in SoCal cars will rust under the right circumstances. The car was solid but covered in rust. I considered all options and I was wary of media blasting because of the potential for damage and distortion as noted above. Dipping sounded like the best idea but was not an option for me. I decided to go the acid route. Commonly known as wheel acid. I always have some around here to disolve rust off of small parts. It is a combination of sufuric acid, hydrocloric acid and phosphoric acid. I bought a couple of gallons and a good spray bottle. Worked one panel at a time, best done in nice weather. Let the acid sit for 15 to 30 minutes, flushed off with the garden hose and had bare shiny clean metal. Only thing is, it has to be primed right away so you don't run the risk of new rust starting on the bare metal. I am in the California desert so humidity is very low, which certainly helped. I was done in one day and happy that I had been able to do the job myself.

20190331_175342.jpg

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Greg

As I got up this morning I had the same general idea.  Blasting is not necessarily a do it in the garage option.  I would have to remove the body, place on a trailer and take it to a professional and reverse to bring it home and as you note, you would have to get some primer on it pretty quick, especially here in Iowa.

 

What I was wondering in my original thoughts revolved the good old fashioned garage restoration options, and I should have stated that. 

 

What I was thinking this morning had to do with sanding it down - no fun but a certain garage option - but then as you and others note you need to get something on it pretty quick.  I often work in 2 to 4 hour bursts as my time is so limited.  That would likely lead to surface rust which would need removed and I believe I remember products with acid in it to "convert" rust or such and thank you for a photo of your product. 

 

It's good to know these rusted cars CAN be saved by one method or another.

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The specific car this refers to is a rare 1924 Peerless which has been untouched for decades and would need that rust removed.  I am "pretty" sure the metal is good n thick, and was in Montana or California for a great part of it's life, and yes the wood needs restored but that metal!  I kept wondering how to address it.

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You can also use 3M's "Scotch Bight Pads" disks, they make quite a bit of dust.

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Agree with 28 Chrysler about the 3M disks. For quick protection, I just use a mist-bottle for an application of Ospho. I know that there's other stuff out there, but I've been using Ospho for over forty years with satisfactory results. In addition I have used a Scotchbrite pad, dipped in Ospho, for a scrub of the panels, or in hard to reach areas.

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 Sanding will not remove the rust from the pits. The paint WILL have a problem 3 or 4 years down the road.

 I have sandblasted rust (very carefully) and that worked out well.

 On parts that can be removed, a dip for 3 or 4 weeks in Molasses and water will remove every single bit of rust and give you a perfect metal to paint.

 

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I have successfully removed all rust from similar surfaces by first using a power wire brush in an angle grinder to remove all paint and surface rust, then applying many coats of one of the phosphoric acid type metal preparations to clean out the rust pits.   The wire brush does not get down into the pits and neither will any other form of abrasive.  The acid will eventually remove all pitted rust but both the wire brushing and the acid are very slow, it would take days to prepare a car like the one in the photo.  I considered  using hydrochloric acid to speed up the process but I was informed by a chemist that it can continue to react even after it is washed off and painted,  I was strongly advised against that . 

Molasses mixed about 10: 1 water is excellent for smaller parts that can be dipped but it needs a big tank and it needs to be positioned somewhere where the smell is not offensive.  It can take a long time but it will remove all rust from the pits and does not affect the steel.

As has been said above, whatever method is used all rust must be removed .

 

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