Right up front please to not take the following as evidence that I am being contrary to some of the advice provided here. I am completely new to this 'period specific' wood finishing using shellac. I appreciate the time spent to reply to my inquiries. Now to my current thoughts and questions.
I am about to begin the processes of putting an orange shellac finish on my 1893 Parker G forend. My goal is to create a finish that is close to the original as I am able to accomplish. An added demand is that this finish come close to matching the original untouched finish on the stock. To this end I have accomplished the following. Mixed my own shellac from flakes in the these cuts and colors: 1# Plantina, 2# Blonde, 1# Orange, 1# Garnet. These are ready to be used if needed. I have BLO available, but not raw LO. I have Japan Dryer available if needed. I have caster oil available if needed.
After extensive reading I have decided that the shellac application technique of french polish is not required to apply the shellac. I will use a pad as in the french polish technique but will not be building up a gloss finish. Also, I will not be filling the pores in the walnut. I examined the wood on the stock and the forend before starting the project and I see no evidence that filling the pores was part of the original wood finish process.
I have read the two articles by Austin Hogan (thanks to Mike McKinney for getting the Parker Pages USB to me in a timely manner) and I have consulted my gunstock finishing library works by Newell, Dunlap, Mills and Barnes, Howe, and modern texts by Flexner, Jewitt, Dresdner and Allan and the excellent collected work by Woodreaux (over on the DoubleGun forum). This is what I have gleaned to date.
Newell recommends the addition of caster oil (non-drying oil) as a plasticizer to the shellac. Note. There is a thread on the Wood Web discussing Shellac and Linseed Oil wherein one contributor suggests that using a drying oil such as Linseed as an additive (other than a padding lubricant) is not to be recommended.
https://www.woodweb.com/knowledge_ba..._Finishes.html
Mills and Barnes recommend the one-time application of raw linseed to the stock prior to the application of shellac. I see no evidence that the wood was colored with linseed oil prior to application of shellac.
Dunlap gives his favorite technique of applying BLO to the wood following by shellac immediately and the use of the hand rather than a pad. I do not think this to be applicable either.
Howe has a strong distaste for "that orange shellac, colorless, dreadful, frightful looking, ... disfiguring looking finish" In a word awful, do not use.
Flexner, Dresdner, Jewitt each recommend mineral oil as a lubricant. None recommends a direct mixing of linseed oil, raw or boiled, in any proportion with the shellac.
As a last bit of information I have watched Brian Dudley's work on his FB page and these videos show fantastic finish work on Parker and Lefever wood. However this high level of grain filled finish is not what is called for on my project. Brian does state that he prefers to apply the finish to the wood prior to recutting the checkering.
If you have direct experience with using shellac as a finish on a Parker or any other makers wood and not building up to a french polish technique finish and could provide a photo or two of the Parker wood I would be appreciative. Reaction and thoughts on what I have posted here are welcome. Thanks to CHE and Quigley97 (Parker forend photos) for advice similar to Dunlap but without the mixing of BLO and shellac.