Steel pitting. Rust convertor or not?

Squidge69

New member
Hi there, I am totally new to this forum but hoping that someone here can give me some advice.

I am currently in the process of restoring a classic 1967 Vespa. I am at the beginning stages and have sanded / polished off most of the rust. As you will see from the pics I am left with some small pitting in some places. Some places worse than others (img_6052, quite deep but no rust). I could go further and polish out most of the pitting but i dont want to thin the metal too much.

You will also see that the underside of the frame is completely rusted. This is surface rust only and its still in a solid condition.

I think that I have got rid of most of the rust everywhere else, but I am wondering if it is worth using a rust converter all over the steel just to make sure that I havnt missed anything?

Also, if I do that, should I remove most of the rust from the underside first? Or can I jsut apply the convertor over that.

Any advice would be very welcome indeed. Thanks in advance
 

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chopolds

Member
Personally, I don't trust rust converter, at least, under my nice paint jobs. There are several ways to get rid of rust in pits, but you need to get rid of them. Rust converters, encapsulators, etc, I leave for undercarriages, floor and trunk pans, or in back of panels that I've replaced, or welded, to seal them up.
OK, blasting with sand (carefully! low pressure), glass bead, crushed glass, etc. Using a rust dissolver, such as Evapo-Rust. Using metal prep. or phosphoric based concrete cleaner...be careful, they are very strong acids, use PPE. For smaller parts, some use molasses soaks, or reverse electrolysis. You can find info on them online.
The important part is to get it all to "white metal", no dark spots, they are rust.
 

Squidge69

New member
Hi there chopolds, cheers for the reply and the indepth answer. Yeah I am totally new to this and even though its my own job I still dont want it to start rusting again after a couple of years.

I guess then I could use the convertor on the underside. I can probably get most of it off anyways. The other stuff on the top side I can certainly sand down a little more and try and remove it all. Its all in the prep as people keep telling me so I will gladly spend more time on that to save problems down the line.

Ive found that Evapo- Rust here in Sweden so ill give that a go. Ill keep away from the strong acids as this is my first attempt, I want to keep all my fingers.

Thanks once again mate, ill post some pics when its on its way.

Matt
 

Squidge69

New member
Hi there again Chopolds, one more question if I may. As the frame is mostle sheet metal, would you suggest literally just painting the Evapo-Rust over the whole frame and let it do its thing. That way to ensure all the rust everywhere has gone?

Cheers
 

chopolds

Member
Well, the Evapo Rust will not work if it is not directly on bare steel. So you are just wasting material if you put it over intact painted metal. I've seen it clean up rusty areas where it didn't look like there was paint under it, but upon removing the rust, you could see there was still paint there. I would just apply it where there is rust.
Couple tips. If it is drying out too fast, before it gets a chance to work, cover it with plastic food wrap, to keep it from evaporating. When finished, follow instructions on neutralizing it. Be very thorough! If you go back over the area with epoxy primer, (and some other type paints), it needs to be super clean. Epoxies do NOT like the acid component in rust removers! The will just peel off of the surface.
Oh, and if using acid, it's really not that bad. The really strong phosphoric in concrete cleaner is, and you might want to dilute it a bit, but I don't. I just use good gloves, and wear splash goggles. I've gotten it on my skin, but it wasn't so bad. Other folks have even used citric acid (used in the food industry) to mix up a solution to soak rust parts in. Even ordinary vinegar will work, but it takes a long time.
 
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