Boiled Linseed Oil Safe?

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Mr_Flintstone

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I’ve used Boiled Linseed Oil like Klean Strip (with additives as a dryer) in the past, but I’m seeing a lot of chatter about it not being safe on the internet. Has anyone heard this or know what the deal is? The MSDS doesn’t mention any “bad” reactions.
 
Definitely not safe, doesn't taste good either.

On the other hand, we've been finishing butcher blocks, kitchen table tops, knife blocks, and cutting boards with BLO since time immemorable.
 
Direct copy from one Googled resource

Is Linseed Oil Toxic?
February 1, 2016 | BY MAIA JAMES
This post may contain affiliate links. Please read our disclosure page.



Written by Maia, Founder & President
We’ve written before about the toxins household furniture releases into our homes (When Furniture Attacks), but mostly have focused on upholstered furniture (check our Safe Sofa Guide for Good Stuff brands).

Toxins in Wooden Furniture
Finding nontoxic wooden furniture can actually be just as challenging as finding a nontoxic sofa, even though you don’t have to worry about flame retardants. Choosing only solid wood pieces is a great start (lots of “wooden” furniture is really made of particle board or plywood which is glued together with formaldehyde-releasing adhesives), but the finishes can be another big problem.

One area of confusion for lots of folks is around linseed oil. Is this truly a nontoxic wood finish, or just Sneaky Stuff?

Here’s the deal with linseed:

Based on our research, we feel that pure, 100% linseed oil poses little, if any, toxic threat to human health, even though it does emit an odor as it dries. Material Data Safety Sheets (MSDS) on linseed oil tell us that it is non-toxic, and various other sources confirm this.


Beware of “boiled linseed oil.”
The confusion around linseed oil arrives when with “boiled linseed oil,” which is what’s found in most stores/home-centers is confused with 100% linseed oil.

Basically, there are three types of linseed oil, two of which are non-toxic.

1) Raw linseed oil is, in fact, flax seed oil. It takes a long time to dry but is entirely non-toxic.

2) The polymerized version is true “boiled” linseed oil, sometimes called “stand oil”. Stand oil is generated by heating linseed oil near 300 °C for a few days in the complete absence of air. Under these conditions, a is highly viscous product results, which provides exceptionally uniform coatings that “dry” to more elastic coatings than linseed oil itself. It also dries much more quickly (although still more slowly than toxic, commonly-used polyurethanes.) This true boiled linseed oil is also non-toxic.

3) The “boiled linseed oil” you can buy in most stores is actually mostly raw linseed oil, but with plasticizers, hardeners, and heavy metals added to make it act like true boiled oil, without the time and effort it takes to actually boil it; in other words, it’s cheap. Folks who are concerned about the toxicity of linseed oil are likely thinking of this type.

We’ve identified two sources for good linseed oil: Heritage Natural Finishes and Earthpaint.

Stay sane,
 
According to the MSDS on the Klean Strip (which is the only kind carried in my town) the only known reactions is mild respiratory reactions to the fumes and mild skin irritation. I’ve used it plenty, and it’s never bothered me. I was just wondering if there was something else that others had heard. If that’s the extent of it, I’m good. I’d use raw linseed, but I’ve heard that it takes years to dry and harden.
 
Yes and I have for decades used bare hands to rub it into gun stocks using the heat and pressure from the hands to apply. :what: I’m starting to exhibit some strange behaviors thought, like forgetting what It was I was looking for, wondering why I came into the room, repeating my self, forgetting the wife’s birthday and our anniversary. Oh wait that’s because Im older than dirt. :rofl:
 
Raw linseed oil smokes around 220ºF; in days of old, it was common for woodworkers to have a pot on a woodburning stove melting down beeswax; that concoction was traditionally known as "boiled linseed oil." The wax buffs to some incredible sheen when done right.
 
Several years ago Hoppe's sold small bottles of boiled linseed oil and I have used it to finish walnut stocks and as a yearly treatment for previously finished walnut stocks. It is great stuff and gives one of the prettiest finishes that I have ever seen on a rifle stock. It takes hours of hand rubbing to get the finish but the reward is great for the time spent. I would rub a stock with the palm of my hand until my hand was hot with friction and that was when the natural shine would improve. I wish it was still available as my supply is getting low. Once the seal is broken on a bottle it will form a dried skim on the top making the bottle hard to use because the skim has to be broken each time it is used and the liquid portion keeps getting smaller.
 
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Most of the commercial BLO has heavy metal drying agents in it so that it does not take forever to dry. Cobalt is commonly used. So, use gloves and do not use it for anything you are serving or eating food off of.

@whughett has it right above. The true polymerized stuff can be used for food products such as serving dishes etc. Any of the stuff with chemical dryers which is what the mass merchants sell, use ventilation and gloves in application. The flaxseed oil can be obtained at a healthfood store or art supply (usually higher).

The untold danger is that if you pile up rags with the stuff, it can spontaneously combust if the mix and temperature is right. Dispose of any linseed contaminated rags, etc. via thorough dousing with water immediately after use. I actually store the rags, brushes, etc. outside after dousing until disposal but then again, I am a worry wart.

Houses catching on fire after being painted from crumpled waste rags was a common problem when linseed oil was the basis for most paints.
 
Once the seal is broken on a bottle it will form a dried skim on the top making the bottle hard to use because the skim has to be broken each time it is used and the liquid portion keeps getting smaller.
Store it up side down, prevents air coming in and hard skin formed at the bottom side. I used BLO to finish several stocks this winter and noticed my hands feel itchy after using it for around 2-3 weeks. I did not wear gloves. I buy Formby's Tung Oil Finish in squeeze bottles, squeeze the bottle to force air out before I put the cap on. My BLO from ACE Hardware does not seem need to store up side down, I used the same bottle for 2-3 years still doing fine.
 
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Klean-Strip Boiled Linseed Oil. SAFETY DATA SHEET. 04/13/2006.

RISK OF FIRE FROM SPONTANEOUS COMBUSTION EXISTS WITH THIS
PRODUCT.
Oily rags, waste, and other oily materials can cause spontaneous combustion fires if not
handled properly. Immediately after use, and before disposal or storage, you MUST (1)
Spread out all oily materials outside to dry by flattening them out to their full size in an
airy spot for 24 hours at temperatures above 40 degrees F, or (2) Wash them thoroughly
with water and detergent and rinse. Repeat until you have removed all oil from all
clothes, tools, rags, paper, clothing, mops, and any other materials contacted during use
or as a result of an accidental spill. Make certain all wash and rinse water is disposed of
properly.
 
I usually avoid the risk of spontaneous combustion by taking all the stuff out back to the burn pit and applying a little zippo to the rags. I guess no more bare handing this commercial stuff though.
 
I use BLO also Danish Oils and oil base stains and wiping varnishes in my home basement wood shop. Oily rags are spread flat either on the concrete floor or on top of the cast iron table saw. Spread flat heat produced by the oils oxidation with oxygen is dissipated. No heat no fire.

I know better but using gloves requires forethought. I seem to fore get most of the time. :(
 
Store it up side down, prevents air coming in and hard skin formed at the bottom side. I used BLO to finish several stocks this winter and noticed my hands feel itchy after using it for around 2-3 weeks. I did not wear gloves. I buy Formby's Tung Oil Finish in squeeze bottles, squeeze the bottle to force air out before I put the cap on. My BLO from ACE Hardware does not seem need to store up side down, I used the same bottle for 2-3 years still doing fine.
Formby’s Tung Oil Finish is crap. Read the ingredients, the only thing missing from it is Tung Oil.
 
I usually avoid the risk of spontaneous combustion by taking all the stuff out back to the burn pit and applying a little zippo to the rags. I guess no more bare handing this commercial stuff though.
First off, the dryers in BLO are not good for you or your skin. But like smoking, use at your own risk. I wear gloves.
Oh! And the spontaneous combustion stuff is over rated. I bet there’s maybe one or two on the forum that may have ever witnessed it actually happening. I, myself have tried to get BLO rags to catch fire, without using matches to no avail.
But then, if you’re using BLO on rifle stocks and you are ending up with oil soaked rags, you’re not doing it right.
 
Y'all are hilarious. Dang I miss Saturday morning cartoons!

I've never used BLO on a firearm but I have used to on other things. The finish CapnMac describes is beautiful.

I have seen spontaneous combustion in my neighbor's yard. His philosophy seemed to be out of sight, out of mind. The world is a dangerous place. Just use commen sense.
 
I don't do much with "military wood-stocked" rifles these days and have never used linseed oil on a gun stock. I do prefer a finish that penetrates into the wood surface and will harden up the wood so it will take and allow 24 LPI checkering:

QyEprvkl.jpg

I like to see the older "battle rifles" remain as is, with all the character they've developed while they were in serious use.
 
I don't do much with "military wood-stocked" rifles these days and have never used linseed oil on a gun stock. I do prefer a finish that penetrates into the wood surface and will harden up the wood so it will take and allow 24 LPI checkering:

View attachment 917004

I like to see the older "battle rifles" remain as is, with all the character they've developed while they were in serious use.
I agree, but sometimes they aren’t usable in the condition they were purchased. I needed to use BLO this time to finish a handguard for an M1 Carbine that had a damaged one. Using BLO on the replacement is as close to keeping with originality as I could get.

701F3A62-B851-4B85-BF0C-2ACDF45ECBB6.jpeg 3094FCF5-4AF9-4BB9-8E6C-BCFD1E592662.jpeg F973A79E-8689-45E6-8BB2-87802DC65C82.jpeg
The handguard on the bottom was chipped up and loose on the front lip, and had a lengthwise crack running half-way down. Not a perfect match, but close.
 
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I have used BLO on several wood projects: gun related and non. Last time I used it was on a Mosin that I had pulled from cosmoline. Sometimes I will use gloves, sometimes not. It all depends on how long I want to smell like oil afterward, not for any health reason. Masks fog up my eye glasses so I never use those for BLO either.
 
I have used BLO and regular LO on wood for over 50 years. My Grandpa and my Dad used it longer than that. I still use it on my hickory walking canes and kitchen knife handles. I actually love the smell. It smells like my Grandpa's wood shop.
 
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