Any experience with linseed oil as alternative to high temp paint?

[charcoalwilly]

Greetings all - I've seen a few examples of people using boiled linseed oil to protect exterior of smoker instead of high-temp paint. My limited understanding is that the linseed oil hardens into a protective shell when heat is applied and doesn't get tacky like most oils would on a smoker.

The advantage seems to be two-fold. The oil highlights the patina of unpainted steel and secondly, it can be re-applied more easily than paint, for example, at the end of a cook.

The guys at Workhorse Pits created a how-to video on the subject.

https://www.youtube.com/watch?v=LFp9j28mxKc

Couple of questions for those of you who have experience with linseed oil on their smoker.

* How durable is the coating? Would you recommend it over paint?

* How often do you have to re-apply and how difficult/easy is it to do? Can you simply wipe down smoker at end of a cook? Or do you have to use a weed burner to pre-heat the steel to 425 degrees like in the video?

* How do you dispose of the oily rags to deal with the spontaneous combustion risk? It's the real deal.

 

[toys4dlr]

I don't know the answer, but am looking forward to the discussion if people the raw finish. I just put my deposit down for a 250 gallon Moberg on a trailer. I hope when my time comes there is a cool raw tank available, as I like that look and it is going to live outside exposed here in AZ.

 

[16Adams]

Honestly came close with my Oklahoma Joe Highland. They’re notorious for quick peeling of firebox paint. I went with high temp paint. interesting stuff with the raw steel treated like cast iron from the beginning

 

[charcoalwilly]

I don't know the answer, but am looking forward to the discussion if people the raw finish. I just put my deposit down for a 250 gallon Moberg on a trailer. I hope when my time comes there is a cool raw tank available, as I like that look and it is going to live outside exposed here in AZ.

You're going to love that one. Does Moberg give any instructions or tips on maintaining the raw linseed finish?

Honestly came close with my Oklahoma Joe Highland. They’re notorious for quick peeling of firebox paint. I went with high temp paint. interesting stuff with the raw steel treated like cast iron from the beginning

I saw one guy who used the linseed oil only on the firebox (not the cook chamber) exactly for the reason you mention - that on some smokers the paint on the firebox is going to burn off on a regular basis no matter what you do.

 

[gcs]

It's like seasoning a steel cooking pan, light , very light coat of oil, heat up to smoke point and let cool, repeat as necessary. You can wipe it down with fresh oil anytime, see above....

As for the rags, leave them outside and exposed to dry, or put in airtight container. you can keep using the rag if you want as long as it's dried or protected from oxygen

You want a very thin coating at a time so it doesn't get sticky.

 

[charcoalwilly]

It's like seasoning a steel cooking pan, light , very light coat of oil, heat up to smoke point and let cool, repeat as necessary. You can wipe it down with fresh oil anytime, see above....

As for the rags, leave them outside and exposed to dry, or put in airtight container. you can keep using the rag if you want as long as it's dried or protected from oxygen

You want a very thin coating at a time so it doesn't get sticky.

Thanks gcs - In the video above, they pre-heat the steel with a weed burner. Why not just crank up the smoker to pre-heat the steel? Is it because you cannot get the temp high enough on an offset? He mentions 400-425 as the target surface temp on the steel.

Of course, the legs and base of smoker might be a different story...

 

[rque]

This is interesting as I have a Workhorse raw finish on order. I have seen both JD’s and Jeremy Yoder’s YouTube videos on coating with linseed and Pam respectively. In both videos you need high heat to properly polymerize the oil and form that sturdy barrier. JD goes the weed burner route while Jeremy goes the ultra high heat fire route. I think they both accomplish the task, but it’s what you want to do. Do you want to get it done (relatively) quickly (weed burner) or do you want to get it done easily (coat the whole smoker in oil and let’er rip for a few hours). From the videos it seems maybe the weed burner route is more even as you can move the heat around as you work while the high heat fire is always going to be hotter at the firebox.

My plan is to coat the firebox and rusty areas after each cook and if that doesn’t keep up then I’ll do a full weed burner on a clean up day. Of course this is a plan so we’ll see what actually happens, lots of these Texas style pits are always covered in rust it seems, and the steel is pretty thick…

On rag storage, usual shop rules apply, make sure oil soaked rags have no oxygen exposure in storage, fire safe container, no washing machine.

NFPA advice: https://www.nfpa.org/-/media/Files/...ces/Safety-tip-sheets/OilyRagsSafetyTips.ashx

 

[ttkt57]

A good high temp paint doesn't smoke until it reaches over 1000°F. Polymerized linseed (flaxseed) oil will smoke at a much lower temp. I can see using linseed on a cook chamber that will never get above, say, 300°F, but it will burn off a fire box in minutes, so it's kind of pointless there.

 

[gtsum]

I ordered my workhorse 1975 with the linseed application so I’ll see here soon enough on the reapplication, etc. I dig the raw look over the painted look


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[charcoalwilly]

I have seen both JD’s and Jeremy Yoder’s YouTube videos on coating with linseed and Pam respectively. In both videos you need high heat to properly polymerize the oil and form that sturdy barrier. JD goes the weed burner route while Jeremy goes the ultra high heat fire route. I think they both accomplish the task, but it’s what you want to do. Do you want to get it done (relatively) quickly (weed burner) or do you want to get it done easily (coat the whole smoker in oil and let’er rip for a few hours).

I was surprised he was able to do the same with Pam which is basically raw canola oil. My limited understanding is that "boiled" linseed oil is normally used because it has been chemically modified to encourage faster drying. Some of you wood working guys would know better than me.

"Boiled linseed oil, often written as BLO, is not as it sounds– there’s no heating or boiling involved (unlike polymerized linseed oil). The difference between raw linseed oil and boiled linseed oil is that there are drying agents (either petroleum-based or heavy metals) added in order to make it a more feasible option for finishing wood furniture.

Some of the petroleum-based siccative compounds that are added to linseed oil to decrease the drying time are naptha, mineral spirits, and dipropylene glycol monomethyl. Cobalt and manganese are the most common metal siccatives found in boiled linseed oil."

==
"Boiled linseed oil” refers to a combination of:

Raw linseed oil
Polymerized oil
Metallic dryers
Industrial solvents"

Why the need of dryers?
Linseed oil is a drying oil so it will naturally harden over time. Most other natural oils are non-drying oils so they will not harden and will continue to be “oily” and are likely to become rancid. The amount of time required for raw linseed oil to cure depends on temperature, humidity, etc but is in the weeks, if not months, time frame. To be a viable finish for furniture, the cure time must be lowered.

There are two ways to speed up the drying time of linseed oil-
Apply heat to linseed oil so it polymerizes [or]
Introduce metallic dryers

The faster, cheaper and easier way for industrial coatings manufacturers is to add metallic dryers. Most often cobalt and manganese salts are the catalysts of choice."

 

[Bob C Cue]

I was surprised he was able to do the same with Pam which is basically raw canola oil. My limited understanding is that "boiled" linseed oil is normally used because it has been chemically modified to encourage faster drying. Some of you wood working guys would know better than me.

"Boiled linseed oil, often written as BLO, is not as it sounds– there’s no heating or boiling involved (unlike polymerized linseed oil). The difference between raw linseed oil and boiled linseed oil is that there are drying agents (either petroleum-based or heavy metals) added in order to make it a more feasible option for finishing wood furniture.

Some of the petroleum-based siccative compounds that are added to linseed oil to decrease the drying time are naptha, mineral spirits, and dipropylene glycol monomethyl. Cobalt and manganese are the most common metal siccatives found in boiled linseed oil."

==
"Boiled linseed oil” refers to a combination of:

Raw linseed oil
Polymerized oil
Metallic dryers
Industrial solvents"

Why the need of dryers?
Linseed oil is a drying oil so it will naturally harden over time. Most other natural oils are non-drying oils so they will not harden and will continue to be “oily” and are likely to become rancid. The amount of time required for raw linseed oil to cure depends on temperature, humidity, etc but is in the weeks, if not months, time frame. To be a viable finish for furniture, the cure time must be lowered.

There are two ways to speed up the drying time of linseed oil-
Apply heat to linseed oil so it polymerizes [or]
Introduce metallic dryers

The faster, cheaper and easier way for industrial coatings manufacturers is to add metallic dryers. Most often cobalt and manganese salts are the catalysts of choice."

Great information! Did you know that linseed oil is also called flaxseed oil as it comes from the flax plant. So not only is it a good finish for wood and metal, your cooker is sure to hit home run after home run. Just ask Barry Bonds!

 

[charcoalwilly]

Just to add to the confusion - In addition to pure/raw linseed oil and "boiled" linseed oil, there is apparently a third option known as polymerized linseed oil. From the little I've read, it sounds like the polymerized oil falls somewhere in between the other two. It dries faster, harder and is more durable than pure linseed oil. Not sure how it performs versus boiled linseed oil, but it does not contain the metallic drying agents or solvents.

"Polymerized Linseed Oil is created by heating raw linseed oil in the absence of oxygen to about 300°C (572°F) over the course of several days. During this process, a polymerization reaction occurs, which increases the oil’s viscosity and decreases the drying time. Both polymerized linseed oil and raw linseed oil contain zero VOCs (volatile organic compounds)."

It would be interesting to run an experiment on bare steel using the three options and a weed burner for pre-heating.

 

[ttkt57]

Just to add to the confusion - In addition to pure/raw linseed oil and "boiled" linseed oil, there is apparently a third option known as polymerized linseed oil. From the little I've read, it sounds like the polymerized oil falls somewhere in between the other two. It dries faster, harder and is more durable than pure linseed oil. Not sure how it performs versus boiled linseed oil, but it does not contain the metallic drying agents or solvents.

"Polymerized Linseed Oil is created by heating raw linseed oil in the absence of oxygen to about 300°C (572°F) over the course of several days. During this process, a polymerization reaction occurs, which increases the oil’s viscosity and decreases the drying time. Both polymerized linseed oil and raw linseed oil contain zero VOCs (volatile organic compounds)."

It would be interesting to run an experiment on bare steel using the three options and a weed burner for pre-heating.

Polymerized linseed (flaxseed) oil isn't a third kind. It's just what happens over time or by means of moderate heat to the raw or "boiled" varieties. Polymerized basically just means hardened. Harden (polymerize) it a little and you can still apply it to surfaces. Continue hardening (polymerizing) it and it either forms an unusable clump somewhere or a usable coating on something.

 

[ttkt57]

Did you know that linseed oil is also called flaxseed oil

Yes. See post #8.

 

[charcoalwilly]

Polymerized linseed (flaxseed) oil isn't a third kind. It's just what happens over time or by means of moderate heat to the raw or "boiled" varieties. Polymerized basically just means hardened. Harden (polymerize) it a little and you can still apply it to surfaces. Continue hardening (polymerizing) it and it either forms an unusable clump somewhere or a usable coating on something.

Thanks ttkt57 - Does the fact that the manufacturers are heating the oil over the course of several days to such a high temp (572 degrees) make a difference? Or are you saying that you can effectively get to the same place with the raw variety by applying heat via the smoker to polymerize?

I have tried applying flax seed oil to an unpainted steel before, but it just stayed sticky afterwards. Maybe I did not pre-heat to high enough temperature to create the hard shell.

 

[ttkt57]

Thanks ttkt57 - Does the fact that the manufacturers are heating the oil over the course of several days to such a high temp (572 degrees) make a difference? Or are you saying that you can effectively get to the same place with the raw variety by applying heat via the smoker to polymerize?

I have tried applying flax seed oil to an unpainted steel before, but it just stayed sticky afterwards. Maybe I did not pre-heat to high enough temperature to create the hard shell.

Given enough time and/or heat and flaxseed/linseed will harden/polymerize. Trouble is most of us don't want to wait around for weeks or months for the raw stuff to get sufficiently hard to serve as a coating. Hence the various ways of getting the liquid to become a solid faster. Put it on raw and you'll wait almost forever unless you heat the surface you're coating. Heat the oil itself for a while first (polymerize it) and a lot, not all, of the process will be complete before you smear it onto your surface. Add hardeners (that's what today's "boiled" label means) and that will speed things up too.

I can see linseed/flaxseed oil serving well on a steel or iron surface that never gets hot enough to make it smoke/burn off but not on surfaces that get really hot like a fire box.

Put "boiled" or "polymerized" types on your cook chamber and it will greatly speed up the hardening/polymerizing process and form a lasting coating. Put raw on there and it will work too but take forever to harden.

Put any kind of this oil on your fire box and it will just burn off.

 

[charcoalwilly]

I just exchanged with the one of the manufacturers of polymerized linseed oil and they confirmed what you mentioned above.

"Our Danish Oil is 100% pure polymerized linseed oil with none of the toxic drying aids found in the raw (despite the name) boiled linseed oil typically found on hardware store shelves and is already halfway “cooked” so it cures faster and with less smoking than raw flaxoil that many people use.[...]

The “halfway cooked” term means that our oil is polymerized (heat treated under vacuum to above its flashpoint), it cures via an oxidation reaction which can be very slow when working with raw flax oil but since we have partially oxidized it, half of the work is already done. It is faster curing on wood than raw or “boiled” linseed oils and, in this case, on hot metal. With much less oxidation required for it to cure then there is much less smoke and time required for it to complete.

All oxidation reactions generate heat and are sped up by heat, that’s why linseed oil-soaked rags can auto-ignite in the correct conditions – that much surface area of oil on the cloth’s fiber exposed to air can cause a chain reaction leading to a rapid oxidation aka open flames."

Here is the link for their product (there might be other brands out there, but I couldn't find them in quick search).
https://www.triedandtruewoodfinish.com/products/danish-oil/

They said that they mostly sell to woodworkers, but some customers have used to season cast iron pans as well as outdoor steel fire features and bbqs.

Of course, there is only one way to find out. Time for a linseed oil throwdown!

 

[charcoalwilly]

Bumping this thread because I’m nearing decision time on finish for new smoker build.
Any of you new Workhorse Pit owners have experience to share on the linseed oil finish?

 

[gtsum]

Bumping this thread because I’m nearing decision time on finish for new smoker build.
Any of you new Workhorse Pit owners have experience to share on the linseed oil finish?

I like my linseed finish on my WH 1975 and wouldn’t have it any different. Turns the color of a Penny after some use. I have no desire to be using black touch up paint to battle surface rust.


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[charcoalwilly]

I like my linseed finish on my WH 1975 and wouldn’t have it any different. Turns the color of a Penny after some use. I have no desire to be using black touch up paint to battle surface rust.

Many thanks gtsum for the feedback. How often do you have to re-apply the linseed oil? Is your smoker covered from the elements? Would love to see a pic.