Rust converter

[cubangt]

I just read the rust test sticky above and got some good information. But still a little confused. So we are trying to work on things as we get other things done and something easy for my daughter to do is paint under the bus..

So i was looking for something she can just paint over the rust to convert it or seal it and protect it enough to keep it from rusting further.

I found this on a few searches
Corroseal Water-Based Rust Converter Metal Primer, Rust Converter

I just want to seal the rust and maybe spray paint it a little to clean it up under the bus.

The POR 15 i have used in the past and was ok with it, but required multiple steps which is fine for my 74 Camaro as i was trying to get everything back to bare metal and working my way up, this bus is not getting that level of restoration. Also looking a the eastwood rust encapsulator just looking for brush on and walk away unless we decide to spray can the bottom to look decent. We are just trying to get it road worthy and protected to last her a good time. I don't plan on getting under the bus to wire wheel or grind anything unless its needed. Everything is pretty solid, but plenty of surface rust, no major pitting.

Are those 3 above the better options?
Has anyone used the corroseal product?

[VW_Jimbo]

I use Ospho in a spray bottle, after I wire wheel or wire brush the rusty area. Rinse with copious amounts of water, then let it dry. Wipe the spot with vinegar, allow it to dry and hit it with primer. Rust converted and primed!

Ospho is awesome stuff!
_________________
Jimbo

There is never enough time to do it right the first time, but all the time necessary the second time!

[cubangt]

Is that the stuff that turns the rust black once applied?

[viiking]

[viiking]

Here is a post I posted a while ago re rust converting. For your information the Corroseal Rust Converter is mainly Formic Acid. Formic acid is acid exuded by ants of all things and is like acetic acid but has one less carbon atom. That is, it is in the same "family" of acids as acetic/vinegar.. See the comment below about acetic acid/vinegar.

As I say below, read the link to Ray Greenwoods dissertation on the subject. He has the answers.

Finally in your situation I WOULD go the clean with detergent, convert with acid/phospho and then paint with Master Series or KBS rust paints. These paints have worked for me and will give a "do it once do it right" result even though you say you don't want to get under and do too much cleaning.

From the post: https://www.thesamba.com/vw/forum/viewtopic.php?p=10076407

With rusty steel ANY acid will work. The stronger the acid the faster the reaction but the issue is with the by products and the relative safety of handling the acid. Some are extremely corrosive, some are added to foods we eat to impart "tang" to food.

You can use:

vinegar = acetic acid
citric acid = food acid
muriatic acid = pool acid/concrete etch
CLR= Lactic acid or sometimes sulfamic acid
Ospho = phosphoric acid
Oxalic acid= wood bleach
Tannic acid
etc

My goto acid for nuts and bolts and small parts is citric acid. It is used in industry to passivate stainless steel by adding a new oxide layer to the steel. It is safe to use and as previously stated is added to foods so in small concentrations is not poisonous.

For larger areas I just use phosphoric acid. Any brand. I just buy pure phosphoric acid and water down to the required concentration.

If you look at the ingredients listing or SDS for any proprietary rust converter you will see one or more of these acids. Most are based on phosphoric acid because the resulting phosphate coating is an excellent base for priming.

For a very authoritative discussion read any comments made by Ray Greenwood in the previously linked post. One of my undergraduate degrees is Chemistry, but he really has all the answers.

http://www.thesamba.com/vw/forum/viewtopic.php?t=131753

To the OP, I think cleaning and then treating with any of the rust converter products will be OK. Follow the instructions EXACTLY especially with the rinsing (if any) before painting.
_________________
1968 1500 RHD Lotus White Beetle since birth. In the hospital for major surgery
1966 Lancia Flavia Pininfarina Coupe - in the waiting room
Discharged: 1983 Vanagon, 1974 1800 Microbus,1968 Low Light,1968 Type 3

[MuzzcoVW]

Another vote for Ospho, or SEM Rust Mort ( same thing) I had serious surface rust on the roof of my '75. Using this stuff AS DIRECTED totally transformed what I had to work with and I was able to epoxy a rust free roof when done. It's imperative to know that with most rust these acids must be applied and the area tested over and over before it's ready for topcoat. You apply, let sit and then sand. If it sands off brown (rust) re-apply. Do this until sanding/agitating comes out clean. Then neutralize and top coat. Works awesome! I won't even touch one of those old school rust converters anymore (and personally despise POR!) If you need to use something like that look up Master Series products

[Bulli Klinik]

Here's a thread I recently started on this topic.

https://www.thesamba.com/vw/forum/viewtopic.php?t=787636

Personally, I prefer to have all the rust completely removed prior to phosphoric acid treatment. If you run a piece of sandpaper over a blackened area that has been "converted", you'll likely still find rust underneath.
_________________
I've never met a Bus I didn't like.
Mike K
Bulli Klinik
Colorado Springs

[MuzzcoVW]