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This is a very interesting series of posts, a real treat for me, especially it coming from Gabe who has so much talent, and who clearly has a good deal of time and effort invested in his excellent techniques. There is a certain amount of enjoyment and satisfaction from knowing exactly what is in the finish being used rather needing a chemistry degree to determine what is actually in the can of store bought gloop. Not that the store bought gloop is all bad!

A trick I use after "washing"/filtering the mucilage from the cold pressed linseed oil with Psyllium husk, is to sun bleach the oil before any further steps. I expect Gabe will know of it, and may have tried it. Horses for courses - it works for me but is by no means essential or necessary. I just feel it improves my own gloop. Others might find the opposite?

Sun bleaching, it is said, drops out much of the yellow tinge of linseed oil films. This is true, but I find it a temporary effect as it does darken back up in time - perhaps a shade or two less than other linseed oils. It also has the effect of making the oil harden quicker, but not as quick as the metallic driers. Sun bleaching only seems to work on cold pressed oil, at least for me and I have read it is so. It also thickens the oil slightly. The longer it is bleached in sunlight, the thicker it becomes. I stop at a few months depending on the weather.There is more to it, but the info is out there for folk interested in trying it for themselves.

The least yellowing linseed finish is Stand Oil, which needs cutting with solvent and some sort of driers added. It's a little more difficult to work with, but it's worth knowing about it, and also how is interacts with stains/dyes/alkanet.

Here are just a couple of links to some basic info:

https://firesciencereviews.springeropen.com/articles/10.1186/2193-0414-1-3

http://www.justpaint.org/weighing-in-on-the-drying-of-oils/

Walnut oil is also interesting to me, especially if it is sun bleached to make it dry quicker. It is a very clear oil and might be worthy of some experimentation for some on here. It has a long history in oil painting, and some excellent properties I have found good in stock finishes when the oil is treated suitably. Cold pressed stuff only, with no additives like vitamin E or whatever. I'm baffled why it is not more use in stock finishes.

Pure cold pressed, unwashed oils with no additives go rancid pretty quick. They need cool storage and nil exposure to air to slow this, and require processing as quickly as possible. I store mine in a fridge in dark glass bottles until processed. Cold pressed linseed takes longer to go rancid than most drying oils, but it can still go rancid.

The main two things I have found with alkanet are that it is very sensitive to pH and that it is not absolutely light fast. I also find that the colour I get from de-barking whole root is more vivid. The ground up root powder I have seen has lots of yellow bits in it, which is the core of the root and I don't want that. Unfortunately the whole root is VERY hard to get in AU nowadays. Experimentation with the pH of the base oil for making red oil gave me some worthwhile results. I think some of the additives and the sometimes practice of bleaching the stock before adding red oil has something to do with pH, more than anything??? I have also found the uptake of alkanet very variable from blank to blank, and perhaps that is another reason why some makers "bleach" their blanks. Our local walnut is the worst I have used in this regard. The experimentation never ends it seems, because each blank, and the wood from each tree, each area, is unique in some way. Walnut is so very variable, not just in looks.

I use a different brew for the red oil, compared to the finishing oil. I find I get better colour with the red oil if it doesn't set up so quick, allowing the wood to be soaked more thoroughly. The finishing oil will harden what is underneath, if done right.

Pure cold pressed tung oil: I find it does not bring out the best colours in walnut, it subdues the contrast slightly and when dried on glass is darker yellow even than linseed. It tends to be dull, too. So if I cut tung oil into a finish it is for it's drying properties more than anything, and fairly low percentages. Most of the so-called tung oil finishes are not really that, they are a manipulated blend of all sorts of goodies. Ditto Danish oil etc. Most folk when they see resins as an ingredient think of natural resins, not phenolic, alkyd or polyurethane resin, etc etc etc. I hope those folk use gloves and don't breathe in the solvents.

I try to use little to no metallic driers, even though they work so well. I just don't like them. With the right blend of oils and natural resins the finish sets up hard, although it takes longer. Application technique becomes much more important. My experience with oil finishes is that the application technique is what is by far the most important aspect - but it pays to use good ingredients, too. I think each person must experiment until they find a system that works for them, hence the variations on the theme.

I am by no means an expert on the subject, but I have long found it interesting. I've added the above in the hope it might be useful to someone. Hope Gabe doesn't mind.

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