doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com The quest for wisdom- Slacum and Red Oil

Gentlemen,

These are my first posts on the forum, and it will be ones of slight �archaeological character�- and probably a quite long ones too.

I found this forum on my quest for the ultimate recipe of Slacum oil, and I found there is (was?) quite a few people with extensive knowledge and love for the long wanderings of a stock finisher on his quest for gloss and glory.

As for my self, I have finished some stocks on both shotguns-and god forbid- quite a few single shot and repeating rifles. My work and methods is by no standard professional, but more those of trial and error, which can be a good way to gain knowledge since You don�t have to pay bills with the results.

I have mostly been working with traditional methods including varieties of linseed oil, turpentine and CCL Red Oil. For end finish I have used CCL gunstock conditioning oil and polishing compound, which combined with sweat, tears and sore palms (and the occasional presence of foul language) have produced decent results. I found that patience, attention to detail and time is essentials when applying a traditional stock finish.

Modern methods such as true oil, tung oil and polymers is not my �cup of tea� and when I tried �tinctures� like these the result has more often ended up in the extensive use of profanity and the accumulation of grey hair.

Regardless of me repeating a lot of what has already been covered there is a slight hope that some of the people who have been active in discussions regarding Slacum mixtures, Red oil, Alkanet and other questions regarding stock finishing will be interested to once more go into the breech and share their accumulated wisdom.

In others words: Dig, Salopian, Yogi, Crossedchisels- if You are still around- I will highly appreciate Your input in these matters. Off course that applies all You other members with experience and knowledge or just curiosity. Please feel free to discuss, share and criticize what is to come.

The purpose of this thread is to �round up� the information that I have found here and on other places, share my own experiences, put the spotlight on some details which I feel have not been properly answered or covered before.

The debate will at some points have the character of reversed engineering and the understanding of how the different parts of a Slacum works together and their individual purpose.

It will be quite thorough in more than one way, so please bear with me and the abundance of questions to come.

I would like to start my elaborations with a link to a documentary (one of the best I have seen so far) about the making of Purdeys and the history about Purdey.
If I am breaking any rule by linking to other sites and such, please advise and accept my sincere apologies for this. By the way I do not have any personal affiliations with Purdey although I wish that were the case.

https://www.youtube.com/watch?v=fac892fHBME

I will relate the discussions to what have been demonstrated in this video regarding stock finishing. Most of the things in the video confirms my own findings and others raise new questions that hopefully will be answered in due time.

Altogether I personally think the video brings up a lot of the questions related to preparing and finishing wood.

Erland

Cleansing of the wood

At 1:21:50 In the Purdey movie linked above the finisher mentions that they use a �mild acid� solution combined with a hot-air gun to both clean the wood and raise the grain prior to wet sanding of the wood and applying the finish.

Sounds like a smart thing to start with. To my experience if you cut corners in the basic work the end result will be compromised. Yet I have not used this method myself. I usually start sanding the wood or use some paint strippers or ammonia to get rid of old finish and grit before applying the new finish.

Do someone ha any idea what sort of a �mild acid solution� might be? I am thinking Vinegar (diluted?) or as mentioned by an American gun maker-oxalic acid..

Any ideas regarding the strength and usage for cleaning purposes? The reason I am wondering about the strength is that I don�t want to �hurt� the bare wood with a to strong acidic solution.

I might guess that You repeat the process a couple of times with sanding in between until You wont get any �stains� on a clean cloth. Any thoughts on the need to neutralize the acid using alcohol, spirits or such before moving on?

Boiled VS Raw Linseed oil

This is a question that I have been pondering about for quite some time, and that I have found to be quite a �hot-topic� on other internet forums and by stockers I spoke to.

My findings start with the quality of the oil regardless of it being �boiled� or raw.

At he beginning I was not that peculiar of what oil I used. I just went to the hard wear store and picked up whatever that was in the shelf. Nowadays I am more picky with what I choose. Today I only buy high quality cold pressed linseed oil from artist stores and such since I have found that the quality is superior of the cheap stuff. Mostly due to less �crap� that what You get in the cheaper �bulk� products.

After some reading up and contacts with producers of linseed oil and practical applications I have come to the following �conclusions�.

Raw:
Better penetration into wood since the molecular size is 100 times smaller than in Boiled Linseed oil- ca: 0,000005 � 0,000001mm = 5 -1 nm. The low viscosities allow the oil penetrate deep into the wood- hence giving it a deeper finish?

Drying/hardening/polymerization is very long without additives and therefore You need driers like turpentine or other additives to stabilize it. I have found that if You use pure raw oil, the wood can start too �bleed� after You applied it-specially in high temperatures. Not very good if You want a �stable� finish.

Polymerization-letting the molecules �bind together� in larger clusters (hence making them more stable?) seems to be a key part to getting a �stable� finish that wont �bleed out of the pores in the wood. I have also seen comments about the raw oil that it can accumulate growth of mold and bacteria due to that it is containing proteins, fat and amino acids, and that is one of the reasons that you put additives into it and heating it up. I will check into this part a bit closer.

There is also what�s labelled as �oxidized raw linseed �oil. This is made by putting raw linseed oil into open air containers which is submitted to sunlight an oxidization for about 6 months. I have not tried this type of oil yet, but its said to have better drying/hardening/polymerization capabilities than Raw linseed oil. I was informed that the process changes the molecular size towards Boiled linseed oil. It is also extremely expensive.

Boiled, which seems to be oil with addition of different chemicals rather than �boiled� or heated in many cases. High quality oil although seems to actually have been heated/boiled.

Larger molecular size than raw oil 0,0001 mm = 100 nm. It extends to about 15% when it dries and clogs therefore well inside the wood. The linseed oil oxidizes rapidly over low heat development or addition of driers. The drying/hardening time is one or two days in comparison to raw oil which might take weeks or months�

So here is the first �divider�- what shall You use as a base for Your Slacum or Red oil?

You want penetration I assume. But how much do you really need?

Raw oil to get the penetration and depth -with some additives to speed up the hardening- or Boiled linseed oil with the benefits of quicker hardening?

Do You really benefit from the deep penetration capabilities of the raw oil or will boiled oil suffice for the grain structure of walnut? The pores in wood is about 0,03 mm.

Both? Start up with raw oil-and additives-and then move over to boiled-and additives?

Mixing them together to get at �two-in one� combined with driers/ additives?

Do the additives change the penetration capabilities of raw linseed oil- do they by aiding the polymerization process increase the molecular structure of the oil and therefore have a negative impact on penetration?

What is Your experience in this field- if You want to share what are Your standpoint regarding raw vs boiled linseed oil?

I have found out that different pieces of wood -I have mainly been working witch European-French walnut- react differently to raw linseed oil and Boiled linseed oil. Usually the really dense and hard stocks need to have some raw oil into the Slacum to get a deep penetration into the grain structure.

Red oil

In the Purdey video the finisher mention that they use Boiled linseed oil as base for the Red oil 1:22:22.

Since the red oil comes on first it should have the best penetrating capabilities if you want �depth�. Any thoughts on why raw linseed oil is not used?

I want to underline that I do no question the methods that used by Purdey (if correctly presented) by any mean- I am just a bit curios regarding the choice of boiled oil in comparison to raw.

So far I have only used CCL red oil and I am about to make my own red oil since I got a big bag of Alkanet root last week.

So the question still lingers- Raw or Boiled linseed oil for the base of Red oil?

Benefits of Raw oil might be to get a deep and even distribution of the colour?

The finisher also mentions-if I understand him correctly- that he start out with a thin coat which he the then burnishes in. After that he applies two heavy coats to soak in. Why this order- why not the heavy coats to start of with?

Slacum

Now to the fun- and labour intensive part of a Slacum finish.

I will not go into my process of preparing the wood more than that I use the same method as Purdey with wet sanding and going to from coarse smaller grain size. I usually end up with 2000 grit. I have now obtained some rotten stone and will try this together with a �chammy� cloth for burnishing. I have tried 0000 steel wool but I found I to be coarser than 2000 grit (visible through a magnifying glass) and it also leaves residue in shape of small metal particles which are almost impossible to get of the wood and that will reappear in the finish as flakes�that seriously ruins Your day.

As for my self I use the sensation of �feel� to check when I am through with sanding and burnishing. When You cant actually feel the wood surface although You are running your fingers over the surface You are getting there. The sensation is almost a bit eerie. You can se Your fingers running across the wood but You cant really feel the wood.

For me the purpose of a oil finish is dual- protecting the wood against moist and giving it pleasant looks.

Then there is the magic concoction of the Slacum�. For my self I have used a bit of everything from pure boiled linseed oil and raw linseed oil- these to mixed in different proportions and added balsamic turpentine. Do not ask me for measurements since I only mixed these by feel (no heating involved) and I have no clue what so ever what�s in my bottles right now. I have used these mixtures both for grain filling and penetration and used the CCL Gunstock conditioning oil for the end finish. I do not use any grain filler more than sanding in dust in the pores when sanding. I have not yet put any �filler� into my Slacums.

Well time to get a bit more methodical in my approach and I found the to recipes from Dig and Salopian which I shortly recite below.

Dig�s

Boiled linseed oil 16 oz
Spirits of turpentine 2 oz
Carnauba wax 200 gr
Venice turpentine - 2 teaspoonfuls

Salopian

1/2 pint of Raw Linseed Oil
2 ozs of Plaster of Paris (Dental Quality)
1/2 fluid oz of Butter of antimony
1/2 Gill Spirits of Wine
2 teaspoons of Vinegar
1 teaspoon of Venice Turps.

Salopian on Manton

Cold drawn linseed oil 1 quart
Gum Arabic (dissolved in warm water) 1/2 ounce
Alkanet root 2 ounces
Rose pink 1/2 ounce
Vinegar 1/2 pint
Boil these together and then let stand for 1 or 2 days.


For starters we can se that the recopies are quite alike in quite a few parts, but they also differ. I don�t say that one of them are more �correct� than the other- there is many ways to skin the proverbial cat..

The �oily-part� is covered above so I will focus mainly on the additives and their function in the Slacum.

There are a couple of the additives that reoccur in the slacums (oil excluded) and that is balsamic turpentine and Venetian turpentine.

What do these contribute with to the Slacum?

To my understanding the balsamic turpentine have to effects. It lovers the viscosity of the Slacum- hence supporting the penetration and pushing the oil deeper into the wood, BUT I also understand when it evaporates it can push the oil out towards the surface again which should be counterproductive? Any comments on this thesis?

I have also read that the balsamic turpentine aids the Drying/hardening/polymerization, but I have not seen any good explanation to this �chemistry�. Does anyone have a bit deeper information regarding this.

Venetian turpentine. For me a mystery so far. Got a bottle the other day from an art store. Thick and smells a bit less then regular turp. Expensive to say the least�.
Aids the Drying/hardening/polymerization process? A substitute for Gum Arabic as in Manton�s recipe?

Gill spirits? Lovers the viscosity? Aids the Drying/hardening/polymerization process?

Vinegar? Aids the Drying/hardening/polymerization process?

Butter of antimony? Yet another mystery. Aids the Drying/hardening/polymerization process?

And as a last note for now.. Have You experienced that your Slacums deteriorate over time if exposed to sunlight and air? I have found that some of my mixtures have clogged up when left in a bottle for a year or so. When that happens I usually put some balsamic turpentine in the mix to dilute it. Sometimes it works and sometimes it doesn�t.

If You have managed to plough through this ordeal of information I am more than grateful and I hope there will be some interesting debate-once again- over this fascinating subject!

I wish You all a Merry Christmas and a happy new Year!

Best Regards Erland

Me thinks you have left out the bats blood eye of Newt, leg of Toad, all mixed on a waxing moon, and may be some other items suggested by those three not so good looking ladies from the �Scottish Play.�
There are as many gun stock finishing mixtures as there where Victorian gun stock finishers, and the problem is not what the magic potion contained but how it was applied to the wood.
The linseed oil you describe is artists �Linseed Stand Oil� expensive and slow drying also it would be far better to use the �Venice Turpentine� used as a treatment for Horses Hoofs you will a lot for your cash buying it that way and it is low cost.
In a nut shell stock finishes consists simply of a form of Lac (Shellac) Gum or Resin, Carrier or solvent, and heavy metal siccative to speed up drying if you are using a slow or non self drying oil as a carrier, then you can add to this grain fillers plaster of Paris finely ground glass and colouring Alkanet is just one of a long line possibly ending with Dragons Blood for the weird and wonderful.
The stock finishes of past times only had the standard artists materials to choose from and the effects of each is well known, also there are numerous books on art Varnishes with some formulations going back hundreds of years. Then there musical instrument Varnishes using various types of Colophony (tree resins) which Venice turpentine and Copal is just one of many going up to the daddy of them all Amber after processing was added to Poppy Linseed or Tung oils and used as a top quality wood finish.
Butter of Antimony darkens woods in the same way as Permanganate of potash does in the end it is down to �All Muck and Magic� and a lot of experimentation, and from the substances I have mentioned you will see they are all natural but now we have man made resins not to mention the vast array of synthetic dyes and colours we can use today, to end with there are the waxes some natural and others man made also used as a constituent of many finishes and as a rule of thumb the harder the wax the higher the lustre. Erland you have just started on a long road of exploration good luck with your quest sadly I gave up the quest for the ultimate gunstock finish because there are too many to choose from.

Several months ago I was doing research into the traditional finishes as well. Much of my information was provided by damascus, but from others as well, including folks on this board, but from other boards devoted to violin and furniture refinishing as well. I was considering experimentation with copal varnishes, but ultimately decided that sourcing and processing of the original ingredients would simply not be either cost effective, or substantially superior to using more modern (and widely available) ingredients. Not to mention the hazards of making copal varnish at home.

Since most of the guns I'm working on are field and mid grade, I've settled on a combination Red (Andy's) Oil and French Polish method that I'll briefly describe here. One exception I'm making is a high grade Thomas Bland & Sons hammer gun, I'm not sure if I'm going to use traditional oil finish methodology on that one yet. French Polish appears to be fairly period-correct, at least for Parkers from around the turn of the century.

Once the stock prep is finished, I use a home-made Alkanet spirit stain. I've made two types, one with grain alcohol, another with a commercial stain base. It's very hard to tell the difference, if anything the commercial stain base appears to penetrate a little better. I then use the Andy's oil recipe from damascus. It is alkanet that has been soaked in 50/50 food grade walnut and linseed oils. Both are raw, and appear to be fairly pure. The raw linseed (flax) oil is considerably less expensive that the artist's grade variety. After staining at least twice over a two day period, and allowing another day to dry, I hand-rub in several applications of the oil, using only a few drops each time, over the course of one day. (once an hour, for a day). Then, after 24 hours, I drop to one application per day for one week. I allow a few days after the last application to insure the oil is dry, Since most of the time I've had to use a solvent soak on the stocks, this is usually long enough. I then French polish using a natural shellac, slightly amber in color. The Zinsser folks informed me that their amber shellac product is essentially the same formula as it was at the turn of the century. I use that straight from the can and cut it with alcohol to to the desired weight. It's a three pound cut in the can, so I cut to two lb. for the initial coats, then to one lb. for the final ones. I do use the guideline of 100 passes for the total application. I use Andy's oil for the lubricant during the French polishing. It really doesn't take that much time once you get used to the methodology. I usually rub with rottenstone to develop the final satin look. Once the finish is done, I paste wax at least three coats, usually four or five. It looks very nice, and I hope what I'm doing is fairly historically accurate.

After reading the previous posts in this thread, I'll experiment with exposing some Andy's Oil to air, and see what develops. I had considered adding some Japan Drier to it, but haven't gotten around to it.

I also use oxalic acid whenever I consider bleaching to be necessary.

Regards
Ken

I pretty much "water pop" any piece of wood that is going to 220 or higher. De-whiskering is a given before staining.

In the H&H video linked in another thread, you can see the stocker sanding in the filler, post de-whiskering.

After a mis placed soda bottle, I watched a man FRENCH POLISH the top of my mothers piano. It was easy to watch, as my mothers polishing of my behind prevented me from sitting down.
Figure 8's, then finished with cigar ash. Amazing depth on that finish.

Lot of interesting and well-written info. I'm going to stay with the best product I've found for stock finishing, TimberLuxe: http://timberluxe.com/
JR

The gentleman's name is Brian Board. He was at the Southern Side X Side shoot with some duck calls that he made and checkered. One had 32 lpi and was fantastic looking. Also had some of his finish with him.
Very nice fellow to talk with.