Chassis coating/paint/restore/rust remediation & no VOC linseed oil based coatings

94trilocked

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Out of personal DIY curiosity I am interested in paint products (and other auto care products) that have no VOCs, preferably organic, easy application/cleanup and long lasting. Before the modern petrochemical paint systems there were various other oil based systems. I'm not talking about various epoxys or urethanes.

From my personal experience using linseed oil based paints on wood for restoration - it takes a lot longer to apply (days drying between coats) - but I don't worry about it getting on my person or fight with cleanup or PPE, and it's generally OK to go down the drain or in the grass - there's nothing particularly harmful in it. Bottom line is it is forgiving and protects the parts. The benefit on wood is that it is not encapsulating the same way as a latex 'plastic' paint - the wood breathes and does not trap moisture. When latex fails it is because it traps moisture and essentially steams the wood, leading to paint bubbling and rotted wood - think about a F/G boat with a rotted transom.

Bridges used to be primer'd with hematite or red lead carried in linseed oil (similar to red oxide primer the auto industry used to use). I suspect these systems were 'too good', inexpensive and not profitable for modern bridge painting outfits where they finish a bridge in 5 years and it's time to go back to the other side and start sandblasting and painting again. Think old formula Rustoleum Rusty Metal Primer, or the red oxide primer the auto industry used to use.

Typically these more organic type paints are long weathering and don't fail in a spectacular way if periodically maintained.

My 94 FZJ-80 has some significant rust in the rear chassis and axle housing/components. So, the plan is to clean them up and apply one of these linseed oil based primer systems and compatible top coat. I will take a bunch of before/after pictures and keep track of it over time.

The hematite carrying primer ("Iron Oxide Minium") is from a Swedish company called Ottoson, which has a distributor in PA. I already have a couple of linseed oil paints in various colors that are compatible with the primer.

Here is a recent study from Sweden on historical metal structures and the paint formulas they used.

Pretty science-y and I don't pretend to understand most of it, but I get the gist.

If anyone has any requests for me to consider on this project - I'll be your monkey - lemme know!
 

PAToyota

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[...] that have no VOCs, preferably organic [...]

Umm... You do realize that VOCs are volatile organic compounds, right? ;)

Sorry, couldn't resist... I roll my eyes when people talk about using essential oils rather than other items with harmful VOCs.

Although a lot of linseed oils claim zero-VOC, understand that is a legal term and that linseed oil does produce aldehydes and hydrocarbons while drying.

As for a coating breathing, the last thing you want for a metal coating is something that breathes. You do want something that seals the metal. That's why epoxy primer is typically the go-to in harsh conditions.

Having said that, I'm familiar (as an Architect working with restoration and historic works) with the "drying oil" varnish paints (armour paints) and they can be quite durable. The issues that stop most people from using them is the longer drying time, loss of gloss, and yellowing. For chassis components, that is going to be less of an issue.
 

PAToyota

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More often than not for failing undercoating/seam sealer, the underlying issue is that the undercoating or seam sealer failed and moisture has gotten under the undercoating or seam sealer.

It's not that you have to let that moisture out, it is that you shouldn't have let it in in the first place.
 

94trilocked

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On the other hand... I have a couple gallons of West System epoxy I need to use up and might as well use something we know is going to last.
 
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You need to be careful when saying you want to use organic coatings. That term means something very different than you think when it comes to protective coatings. Almost all protective coatings are considered organic.

Red lead primers used on bridges are VERY different than iron oxide primers. They were very effective because of the lead. They’re also no longer used because of the lead. The three-coat system used on most bridges these days lasts way more than 5 years and no DPW/DOT is looking to spend more money than necessary on maintenance projects.

When coating a metal for corrosion control, you want a coating with a very low moisture vapor transmission rate. Breathing isn’t a desired quality of a corrosion control coating.

Good luck trying to paint over the oil-based coatings with a modern, better performing epoxy or urethane coating once the oil based coatings fail.
 

PAToyota

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On the other hand... I have a couple gallons of West System epoxy I need to use up and might as well use something we know is going to last.

I'm not sure I'd use the West System stuff for "painting" something. Typically their coatings are much thicker and may lead to the coating cracking - moreso than an automotive epoxy option.
 

94trilocked

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I emailed with the West System technical department. Basically... get down to clean metal, apply Ospho, let dry. Sand with 80 grit to shiny metal just before applying epoxy in thin coats with a foam roller/brush. Ospho can stay in any pitting and this isn't a problem. When epoxy has cured, hit with a scotchbrite, wash then paint.

Played around with one of those cheap pressure washer sand blasters today - actually works, tested on the factory hitch.
 

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