Linseed Oil Rust Proofing. Hazards?

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I'm planning to use linseed oil as an all natural rust proofing spray on my vehicles. There's alot of talk of people having sucessfully used this as a DIY.

One of my concerns is that linseed oil is known to self ignite (soaked rags left out to dry):

https://en.m.wikipedia.org/wiki/Linseed_oil

Is this a concern as an underbody spray? Eg if some of the oil gets on the exhaust components?

I would also like to spray down some of the brake components (drum, calliper, lines), but would be concerned if the oil has any adverse affect on braking incase it gets on the pads.

Has anyone used linseed oil as rust proofing and can share you experiences?
 
I've never heard of anyone using linseed oil for rust proofing, do you have links?

I am aware of linseed oil and fires with rags, so I would avoid trying this.
 
Linseed oil self-oxidizes when exposed to air and releases heat- that's how it 'cures' and why it is well-regarded as a wood finish. Its generally only a problem when the heat can't escape, for example wadded-up oil soaked rags. It doesn't burst into flame when you wipe down a cedar beam ceiling with it (was an annual maintenance ritual in the house my folks restored back in the 60s). So that in itself shouldn't be a problem under a car.

It is flammable, so obviously if you soak and exhaust system and then fire it up before the oil cures, that would be a problem just like coating your exhaust with any other oil would be.

Sounds like a huge mess, to me, but then I don't have to fight the salt monster with my cars, either.
 
There are two types of Linseed oil, boiled and raw. Raw Linseed oil can take several weeks to dry, boiled dries faster. They also cut it with turpentine for rustproofing, it is not used straight. I would read up on it before using it, there's some info about using it for rustproofing on the web. One problem I've noticed with using linseed oil, it is a great environment for mildew growth. I never used it as a car rustproofing, there are better choices.
 
Did a bunch of reading and it seems people have used both boiled and raw linseed oil. I figure I'd stick with boiled because it's more readily available at the hardware store. The lower viscosity also helps because I built my own sprayer and the nozzle won't pump thick oils very well.
 
I have used and am using boiled linseed oil (BLO) for chassis rustproofing and it works for me.

BLO has been injected for years in airplane and helicopter tubing to rust-proof steel tubing. Because of rapid changes in pressure and elevation water can condensate in airplane tubing causing rust. Once cured BLO stays put and is pretty imprevious to temperature and pressure changes and also fairly lightweight when application is controlled so it's very attractive for the aerospace industry.

I use BLO for rustproof undercoating because I have not found it to dissolve the factory undercoating present on hte chassis of my truck; I have however read reports on BITOOG of other rustproof undercoating being too caustic and dissolving factory undercoating.


So far BLO has held up good. It doesn't melt during the hot season and stays put. Water beads on it. I have not found a convenient way to spray BLO because of its high viscosity so I apply it with a paintbrush. If you have a triuck to spray it I'm all ears!

As far as BLO being not popular, I put this on the account of being readily available and cheap and not secret. There's no profit to be had in peddling BLO as a rustproof undercoating, no "secret formula". A gallon costs a few bucks. So there's no marketing budget spent on publicizing it.
 
Originally Posted By: DrRoughneck
I have used and am using boiled linseed oil (BLO) for chassis rustproofing and it works for me.

BLO has been injected for years in airplane and helicopter tubing to rust-proof steel tubing. Because of rapid changes in pressure and elevation water can condensate in airplane tubing causing rust. Once cured BLO stays put and is pretty imprevious to temperature and pressure changes and also fairly lightweight when application is controlled so it's very attractive for the aerospace industry.

I use BLO for rustproof undercoating because I have not found it to dissolve the factory undercoating present on hte chassis of my truck; I have however read reports on BITOOG of other rustproof undercoating being too caustic and dissolving factory undercoating.


So far BLO has held up good. It doesn't melt during the hot season and stays put. Water beads on it. I have not found a convenient way to spray BLO because of its high viscosity so I apply it with a paintbrush. If you have a triuck to spray it I'm all ears!

As far as BLO being not popular, I put this on the account of being readily available and cheap and not secret. There's no profit to be had in peddling BLO as a rustproof undercoating, no "secret formula". A gallon costs a few bucks. So there's no marketing budget spent on publicizing it.



Do you use it straight up or cut it with turpentine? Have you tried HVLP, or airless spray to apply it? Both will work well. I would think something along the lines of a Wagner Power Painter will work well too.
 
Originally Posted By: DrRoughneck
I have not found a convenient way to spray BLO because of its high viscosity so I apply it with a paintbrush. If you have a triuck to spray it I'm all ears!


Does anyone know if BLO works with spray guns? I don't yet have an air compressor setup (waiting for a good deal), but the high viscosity is a problem for spraying.

Right now I've just rigged up an old fire extinguiser with some 3/8" tubing, a long steel brake line, and a spray nozzle from a Rust Check can attached to the end. Pressuring it up to 80 psi with a junk tire compressor. Works ok and the long line means I can get inside the frame. Only problem is it's a small tank so I have to refill often.
 
I use these babies to spray the thick stuff. I also have another extension that sprays downward. BTW: BLO is a 10% component in my homemade rust preventative oil. It helps it set up and draw O2 from the metal. NAPA or Sure Shot branded sprayers have to most attachments for them. You are not mixing air and material with these sprayers. It is material only which cuts down on the mist which saves your product and your health even with a respirator. They are rated for 100 PSI.


100_644802_zpsexhzmgce.jpg
 
Can you provide more detail on which spray nozzle you are using for your BLO application? How well does it mist?
 
Originally Posted By: gomes512
Does BLO cure into a hard/semi-hard film? Curious about the long-term, will it stiffen over time and then trap moisture?

It is hard but not brittle. Here it's the fall and leaf debris slightly stick to it even when dry because of the slight rubbery texture.
 
linseed oil was what "linoleum" was made out of, it polymerises in air...and that's what the ignition risk is.

Drape your rags over a horizontal chair back until dried, don't wad them up.

Linseed is fine...fish oil was always my go to, and it reeks.
 
Originally Posted By: DrRoughneck
One thing I've thought about regarding BLO is using a gravity-fed sprayer. It's cheap ($16 at harbor freight) http://www.harborfreight.com/20-oz-high-volume-low-pressure-gravity-feed-spray-gun-47016.html

image_21036.jpg

Do you guys think it would work with BLO? I don't want to cut it with toluene or turpentine because I don't want to dissolve any pre-existing coating.


The only problem you might encounter with that gun is you're really going to have to cut the product, a lot. And if you're shooting the bottom laying on your back, a gravity feed is not your friend.
 
I haven't sprayed linseed oil in maybe >>20 years now (wood use at the time), but I certainly don't remember it being a problem. Its a heck of a lot thinner than latex paint. Seems like pretty much anything that could spray paint could spray linseed oil.
 
I've used it as a binder when abrading rust with aluminium (by hand or power-drill). This produces a sort of metallic primer "paint", which lasts quite well.

I've also used it as an ingredient in a rust-inhibiting spray, cut with diesel and motor oil. I've so far only used a hand plant-sprayer and have been on the lookout for an old fire extinguisher to make a better sprayer, which might double as a tyre inflator, but havn't seen one yet.

Mostly I use sunflower oil for spraying, though, since I can't get linseed here, and I have a lot of sunflower oil.

I don't necessarily want a fast-setting oil in this application, so I think un-boiled linseed might be better, but I don't have any real evidence for this.

I don't think spontaneous combustion is likely but any vegetable oil used in enclosed spaces (especially un-cut) is likely to grow mould. This may not matter outside the car but within, say, the door skins, it could be a respiratory hazard.
 
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