Thursday, September 15, 2011

Omega-3 Fatty Acid For Your Cast Iron!

We've been toying around with some finishes for our hand wheels here lately and thought we'd post some of our results for those of you who'd like to give it a try.

We first read about "seasoning" cast iron here and thought it might work nicely for the hand wheels.  Unfortunately flax oil is pricey so we started out by going the more rustic route and rubbing the iron down with a slab of salmon.  That was messy, we ran into a few bones and it made the fish taste funny later.  A small bottle of flax oil can be had for about $10 and will last a LONG time for these purposes.  Raw linseed oil (the non-edible version of flax oil) can be used also but it's a bit harder to find, the boiled variant being more prevalent.

After a couple days we're pretty happy with the results.  We ended up with a patina that's akin to years of use resulting in a warm look that's reminiscent of an old well used piece of iron.  It also has the added benefit of adding a rather robust layer of corrosion resistance.  The resulting finish is an extremely hard polymer that we assume will be very hard wearing.  Those small enameled splatters on the outside of an old frying pan are a testament to this durability.

We also tried a cold gun bluing followed by Minwax Antique Oil Finish that resulted in a similarly nice finish, though noticeably darker and more akin to a powder coat.  We're partial to the flax finish not only because of the look, but also since its natural (you can literally eat the flax oil) --the chemicals in the cold bluing are caustic and smelly. You can also apply the flax oil in your kitchen oven without spousal repercussion.

The flax oil process is simple but takes a while:

1. Clean the iron.  You want all oil and finish removed.  Depending on the item, plain soap and water will work, but you may need to wipe it down with mineral spirits if you've got some residual finsh on there.

2.  Put it in a 200 degree oven for 10 mintes to make sure it's bone dry.

3. Lay on a coat of flax oil with a brush. 

4.  Rub it all off!  The key here is to get an extremely thin coat, very even.  Any thick or uneven areas will cook differently resulting in pooling and possibly a blotchy result.  Watch areas where liquid tends to pool like corners.  

Don't be afraid to get a thin coat on the threads.  We were initially worried that a build up of oil on the threads would cause binding.  Much to our surprise after a few spins on the screws, the polymerized oil actually made the already smooth Moxon wheels spin like greased lightinin'.  We'd probably keep the thread coating light though, 2 coats or so.

5.  Crank the oven to 500 and bake the iron for 1 hour.  

6.  Turn off the oven and leave the iron sit until cooled, about 2 hours. 

7. Repeat five or more times (steps 3-6).  These wheels have 5 treatments.  I've done 6 on a skillet with great results.  The more you do the darker it will get.  The machined wheels seem to stop darkening after the 3rd treatment or so but it probably improves the durability. 

Well there you have it.  We're very pleased with the results.  We won't be offering this as an option on our hardware (don't even ask!) but we think there are probably a few of you who'd like to give it a try.  It makes for a more vintage look with the added bonus of protection.

If you'd like to see these wheels in person, come to WIA where our Moxon demo bench will have one Moxon vise with the cold-blued-and-oiled wheels, and one vise with the baked flax oil wheels. These vises are for sale at a special price at the show ($299), including the specially finished wheels at no extra charge. If you'd like a vise with one of the specially finished wheel sets, include that in your email ("flax oil finish" or "cold blued finish" when you order. )


  1. If I coat my Moxon vise wheels this way, can I also use them as a pick me up snack while working in the shop. I understand that Omega 3 is mighty good for you.

    I will also have my new Moxon vise with me at WIA but this time built into a joinery benchtop. I hope your readers will stop by, ooh and ahh then proceed down the aisle and buy a kit from you.

  2. Do you think this would work for all cast iron items? Would it be a suitable long-term finish to other tools that have lost their original finish?

  3. If you go with the oven and Flax oil, will your Logo button stand up to the heat of the oven? I tried to pop it out, but wasn't able to.


  4. According to a test run by Cooks Illustrated, flaxseed oil plus heat is the best way to season cast iron skillet. Other oils did not provide the same durable coating.

  5. Cast iron is cast iron for the most part regarding woodworking tools and machines. So yes, you can coat any raw cast iron object this way. Be careful if you're unsure of the previous coating (if any). Might want to use an old toaster oven outside.

    Mike, good catch on the logo. Probably wouldn't fare well. We'll look into this.

    Shannon, better stick with the Twinkies. ;-)

  6. I have used flaxseed oil for seasoning (and as the perfect fat for protein shakes).

    Just remember that flaxseed oil is a fat, and therefore should be refridgerated. Otherwise it will go rancid, and that is not good eats - or good seasoning I imagine.

    Jameel - should a solution for logo removal not be found, would it be possible to ship the with the logo and adhesive - to attach post seasoning?

    Finally, after three years I can say, "See you at WIA!"


  7. Jameel - just received my Moxon vice hardware, looks great! I had the same query on the logo (Space Invaders?) standing up to the heat, so if you can try cooking one there first I'll hold off on mine.

    And for those of us outside the continental US, I assume the oven temperatures listed were in Fahrenheit?



  8. Jason,

    Right you are on the volatility of the oil. Flax oil is particularly susceptible to going rancid. Not sure if it would make much difference in this application though.

    As for the logos, we are now shipping the vises with the logo unattached.


    No, the logos won't withstand the heat! You'll have to peel it off and put it back on I'm afraid.

    And yes, Fahrenheit is it.

  9. This may be a place to get bulk flaxseed oil. If you're worried about it going bad, share with other woodworkers/cooks, or eat some:

  10. Jameel,

    Thanks for response - I tried peeling off the logo but it seems solidly stuck on for now. Are there any spare logos available for those early adapters who season their hand wheels and cook their logos?

    And will the Bridge City boys be cooking the (free) crispy bacon with your spare flaxseed oil? Perhaps you can give a demonstration of hand wheel seasoning at WIA..



  11. I realize this is an old post, but I just came across it.

    Do you know if this can be done to non-cast iron metals? I was wondering about coating old planes (planes that have gone through the neglect-->rust-->naval jelly-->recovery cycle). My only concern was if 500 degrees and/or rapid heating might warp the body.

    Does anyone know?

  12. I wish someone would answer your question mwh. I was wondering the same thing. Would paint stick to the metal on the inside of the plane after this process?

  13. Old planes ARE cast iron. Unless they are infills. Obviously you wouldn't want to bake those. I'd keep tools out of the oven if I were you. Use camellia oil, or jojoba oil to ward off rust. But I think you nailed your main cause of rust: neglect. As Don Williams says in his book "Saving Stuff", everything wants to go back to dirt.

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