Boiled Linseed Oil vs Tru Oil

[Frank/Pa]

Check out Mike Brook's rifle building tutorial under member resources.

 

[Stophel]

I won't get into what is "best", but will tell you about the use of linseed oil. First off, you CANNOT slop the stuff on the stock, let it soak in, and ever expect it to dry. EVER. It is NOT a "flood and soak" finish. No matter what anyone has told you. It has to be applied in exceedingly thin applications. The first few applications can be thinned with turpentine to aid absorption into the wood, but still, do not put in on heavily. With each application, wipe it on thin, and yes, let it soak in, and then wipe off all the excess from the surface of the wood. Now, whether it's "boiled" or raw, or really boiled with lead carbonate, it HAS to have sunlight to dry. Period. No if's, and's or but's about it. It can sit in a warm dry room FOREVER and not dry. Real boiled oil with dryers can dry in a few hours. Raw oil can take a couple of days (all day in the sun) to dry, but it WILL dry if put on thin enough.

When linseed oil is dry, it takes on a gummy consistency. It will be dry, but it will never be hard. When you start getting the grain filled with the oil, and you get close to the surface, you need to apply the oil (still as lightly as possible) and let it stand on the surface of the wood and get dry or nearly so, and it will be gummy. You then "cut off" the oil from the surface with burlap, making sure to get it out of all the nooks and crannies. Do this until the grain is completely filled. With a true oil finish, nothing is left on the surface of the stock.

Linseed oil was actually not used a lot in the 18th century as a stand-alone finish. It WAS done on the most plain arms sometimes, and then, probably only a few applications without bothering to get the grain completely filled. Linseed oil based varnishes were used, generally over top of a shellac or seedlac based grain filler. MUCH quicker and easier to do than any oil-filled finish, with the added advantage of the shellac and oil varnish complimenting each other as a finish. Shellac is supposed to be good for stopping (or rather, slowing) water vapor, whereas the oil varnish works more with liquid water. The stock will still "breathe", but water transpiration is slowed to a point that the stock wood can easily handle it.

Water may pass through linseed oil, but it can also easily pass back out again, which is an advantage to my way of thinking. Linseed oil (when fully dry) is also virtually indestructible and water has no effect upon it whatsoever. People who complain about their boiled linseed oil finish washing out in the rain simply did not apply it correctly, nor did they allow it to dry thoroughly.

A good, ready source of good quality pure linseed oil is from Wal Mart. Go to the "arts and crafts" area, where they sell paint and ribbons, and things like that, and they should have small glass bottles of "Daler-Rowney purified linseed oil". This is good, artist grade oil, clear and light in color. (WalMart sells the oil, but doesn't sell the pigments to go in it....go figure.) I haven't used this on a gun yet, but I have tested some paint I made with it once, and it dried surprisingly quickly (again, in the sun). It is much better stuff than the hardware store linseed oil. I have had others tell me that they love the stuff for doing oil finishes, since it is so much nicer than the typical "boiled linseed oil" that you buy in the gallon cans.

Tried and True "Varnish oil" is actually pretty good stuff, containing only pure linseed oil and rosin as the resin. It works best as a top coat only. It dries relatively hard, and filling the grain with it is more troublesome, since you can't "cut it off" with burlap, and you must use steel wool or something to scrub it off the surface (I am desperately trying to wean myself from the use of steel wool...the bane of sharp corners and stain). It works best with a shellac grain filler, and again, it must be put on THIN.

I've had mixed results with Tru-oil. Sometimes it works alright, but sometimes the surface is very brittle and flakes off. Because of this inconsistency, I have quit using it entirely. Tru oil is a varnish, with resins in it. I don't know what type of oil(s) it contains, nor the resins used. It does hav an attractive, almost coconut-like aroma, though!

 

[matt denison]

Yeah, what Mad Monk said. There's some confusion between an "oil" finish and a "TruOil" finish. I use a lot of TruOil. It is a varnish with "phonetic resins" and a dryer added. It works very well on open grain wood like walnut to fill the grain and achieve a glassy-smooth finish. Five thin coats will fill most grain if you remember to take most of it off between coats with steel wool, or 600 sand paper. (I think steel wool is faster, use a tack cloth to get the tiny steel flecks off.) I thin it 50-50 for the first two coats and then less and less as I aproach the final coat. I always cut it a little bit even for the last coat. I let it dry 24 hours between coats. If the steel wool/sand paper loads up quickly then let it dry longer until the sanding material cuts cleanly on the finish and makes dust. I apply it with my fingers so there are no fibers or brush strokes. Also you can controll it better. take your time and rub, rub it on evenly. After the last coat drys completely I take it down one more time with the steel wool, carefully dulling it as evenly as I can. It is important to remove ALL of the dust from the stock with a tack cloth or slightly damp rag. Now I apply paste wax to fill the minute scratches from sanding. After assembling the gun I like to wax it again, really smearing it on , gushing it around to squeeze into any gaps and specifically along the barrel channel where water can sit and build up. Now it is a strong, durable, waterproof varnish finish with a satin sheen.

LaffinDog

 

[Vaino]

Seeing you delve into the history of the LR, what did most original gunmakers use for a stock finish? Some say some form of quicker drying varnish was mostly used and common sense would lead one to believe that from an economical standpoint, these "oldtime" gunmakers couldn't afford to apply a finish over months at a time. Stroking, petting and "sun bathing" Old Betsy when applying a slow drying finish {if it completely dries at all} sure might be pleasurable, but hardly seems what they might have done, seeing they were in business to make money for the support of their families. The use of varnishes just seems more logical?.....Fred

 

[Stophel]

The consensus seems to be that, for the most part, guns would be finished by filling the grain with a seedlac/shellac type spirit varnish (a "spit coat" in furniture making vernacular). Dries quickly, doesn't muddy the appearance of the grain. On top of that (on the surface of the wood) they did one of two things. Use a spirit varnish as the top coat (which are generally not too durable, as they are inherently brittle...which can be offset by using something like spike lavender oil in the mixture...something I have not experimented with), or use a linseed oil based varnish as the top coat (boiled with lead carbonate or some other drier added). Resins used would be rosin, mastic (the two that are easy to obtain and melt and fuse easily into the oil, and is what I use), sandarac, copal, etc. There are also turpentine based varnishes, with which I am not familiar, but they were used and are reportedly rather more durable than a spirit varnish. Guns would be finished rather similarly to furniture and musical instruments.

 

[Va.Manuf.06]

Herr Deutscher, that is one of the best short disertations about period correct finishing I have read yet, thanks for posting it. :bow:

 

[Stophel]

I'm merely reporting. I give much thanks to others who have done most of the research! :bow:

 

I've seen a few recomendations to apply TO by the drop with the fingers. This is the most common application method and the one I used to always use as well when useing TO. However, talking with Ken Hurst awhile back, the subject of stock finishing came up and he suggested applying TO with a folded up piece of "Bounty" paper towel :youcrazy: . He said use ONLY "bounty" and fold it into a pad with all edges folded into the center. Well considering the source, and since I had a gun in need of a refinish I decided to try it. My own opinion is based purely on this one experience BUT, no more sticky fingers for me. Paper towel is easier, cleaner and produces a BETTER finish IMO. It's difficult (read impossible) to get a representative view of a finish in a photo on the net ('specialy when I'm takeing the pics) but, here's the result of the refinish.

 

[Stophel]

I wonder how gunsmiths survived before the advent of paper towels!!! I go through an IMMENSE amount of paper towels. Rubbing on oil, varnish, gun oil, grease, wax, stain, water, shellac, alcohol, turpentine, etc. I use paper towels for everything. Have to use good quality ones with no lint.

Tung oil is something completely different from linseed oil. It is widely regarded as a "better" oil than linseed oil. It is supposed to dry reasonably hard (I have seen it reported that it can even be downright brittle). It is also supposed to be quicker and more thorough in drying. I have never used the stuff, myself, so can't comment directly on it. I do know that some people are violently allergic to it, so before you go slopping it on your stock, test out a drop or two on your arm or something to make sure you don't react to it. :winking:

 

[BEP]

Deutscher,

Excellent post. But can we agree that perhaps "cure" might be a better word than "dry" when it comes to linseed oil finishes?

And, with respect, I will disagree with one point - linseed oil does not need sunlight or UV to cure. I have a collection (hoard?)of MilSurp rifles and use boiled linseed oil to restore and maintain their finishes. Just finished my yearly maintenance of several and the thin coat of BLO that I applied and rubbed in was done in a basement shop and then put back into storage and never saw sunlight at all. The oil cured perfectly in a day or so. I would certainly agree that putting them in sunlight hastens the process, but it is not a vital componant.

Once again, thanks for the great post. :hatsoff:

sneezy

 

[Stophel]

You must have magic oil! :grin:

If the oil is soaking into the wood with none left on the surface, there is no oil for you to feel, so it can easily feel dry, even when it is not.