Hi ken
As far as I know spar varnish was bought in from specialised varnish manufactures it would not be cost effective to manufacture in small amounts. It is possible to purchase traditional spar varnish today but it will be at a price, though you could possibly find more information regarding spar varnish on the internet. I know this may be heresy to some folks but in its day spar varnish was the finest available so by thinning it made it perfect for applying by rag brush or hand on gun stocks amongst other things, and in our time polyurethane varnish far out performed other varnishes on the market and has been used in exactly the same way as spar varnish and I will put my hand up to doing it!!!!!!!!
The ‘red oil’ has always been manufactured from Alkanet root only, by adding Vandyke brown to the mix you will remove that unique red colour. Quality ‘Vandyke Brown’ pigment used in artist colour is manufactured from Iron Oxide and because of this it is extremely permanent and stable, because of this it is used to colour grain fillers as well as being used as a wood stain in its own right. The linseed oil in Andy’s version of red oil is raw oil that is no drying agent is added though the only difference between boiled and raw linseed oil is the boiled dries much faster.
