Question - using pigments

I have found some old pigment powder (blue and turquoise spinel) I want to use to colour a swamp ash tele body (completely raw right now). I want the final finish to be quite translucent (or even transparent). This (and other forums) have really overloaded my poor brain with information, and I have very little experience with wood finishing so I could use some feedback on my plan:

1: sand, raise grain, sand to 240 or 320 grit.
2: mix linseed and some other drying oils with some siccatives (or just buy ready made product) and add pigment powder (find the right amount for the tint/translucency by using trial pieces)
3: put the 'oil paint' on the body and leave to cure
4: add more coats of clear oil until the pores etc are filled enough.

Should I sand with finer grain before applying the oil?
Should I prefer dyes for coloration?
Should I (partially) fill the pores?
Should I apply one (diluted) coat of clear oil before applying the coloured oil?
Might the resulting surface look anything like (look more like dye to my untrained eyes):
http://www.warwick.de/tools/load.php?imgid=47533&max_height=350&max_width=450&sharpen=true&bg=15151A&quality=85

Does this seem to be a sensible approach and would the result be able to withstand the daily life of a guitar? I have found little information on using pigment powders&oil, most people seem to use dyes or other (water based) products for coloration before using tru-oil/other drying oils.

Does this seem to be a sensible approach and would the result be able to withstand the daily life of a guitar? I have found little information on using pigment powders&oil, most people seem to use dyes or other (water based) products for coloration before using tru-oil/other drying oils.

To answer the question, no.

And the reason you have found little information is that it requires knowledge, training and skills in both the making and application of "craft paint" that were in the past taught through apprenticeship for several years (or decades) in order to become a "journeyman" qualified to make "oil paint", properly prepare surfaces for its application and actually apply such coatings.

This is the type of system that is (from a practical standpoint) outdated and available off-the-shelf as "oil stains" in semi-transparent forms and "oil based enamels" in opaque forms.

But there are FAR more ingredients involved in making a workable finish than in your simplified description (most websites don't include the other items - blends of solvents, Japan Drier, percentage by weight of raw and boiled oils and what specific oil blends to use, chemicals that help the material flow...because the practice of modern painting dosn't require the basic "formula" you want to work from.

And what you are lacking in your "formula" are three essential ingredients: 1) driers, whether drying oils or metallic-based drying solutions, 2) UV inhibitors ( your color will fade to a washed-out blue as the yellow pigments - most susceptble to UV rays - quickly fades to nothing, and 3) protection from physical damage; you have no resin system, and as you noted, just basically a dye with some small amount of oil that may or may not dry hard.

Old pigments are also not stable. They have a limited shelf life (especially anything with reds or yellows in them) Both reds and yellows may also contain lead, so you'd want to be REAL cautious about using them unless you can find formulation data if they are old (since if tey are truly old they will have been made in pre-MSDS days).

Most prefessionals who work with faux-finishes (the type of work that deals with aged-pigmentation look) would have disposed of the pigments as hazardous waste, as there are off the shelf good that will acheive the same affect that are far more convenient, safe, and stable. But even those require topcoating for physical and UV protection.

This type of work is not something for the untrained individual, and even reading a dozen books on the subject won't get you the working experience needed to ensure good results.

In other words - I think you're in WAY over your head here. If the photo posted is the look you want then investigate wated-based dyes, but realize the surface will scratch easily without a coating system over it (lacquer, urethane, polyester etc). There are threads on this forum (posted by Colt) that deal with basic lacquer finishing that would be a good place to start - then get some scrap wood and start practicing. With no experience I suggest a minimum practice/test area of at least 2-3 times as much as the actual surface you want to coat, following all procedures. You will likely run into trouble and that much practice will help you learn how to deal with the inevitable problems that will crop up.

^^^^^ This.

Thank you for your extensive reply Silverface.

My thoughts on the issues you pointed out to me:

1 - on ingredients: you are absolutely right that only drying oils would probably take forever to cure, so I would add driers/siccatives to the oils of course, and some resins as well. But it would probably be much smarter to skip this step and buy ready-made drying oil product that would seem suitable (like Tru-Oil for example). I would then add the pigment powder to that (and find out the right amount by using trial pieces). Most oil-based products will yellow a bit over time of course, but I could live with the guitar turning greenish a bit.

2 - on pigment: The pigments I found in my cupboard and want to use are powdered blue and turquise spinel, these mineral particles should be incredibly stable, UV-light should not have any noticable effect.

3 - top coat: I would probably use the drying oil I had used for the pigment in clear form to build up a protective layer. Many people seem to be satisfied with a (Tru/Danish/...)oil finish, and as might be expected it would not be as hard or resistive to abrasion (and very probably not as shiny) as a modern professional finish, but it would be easy to touch up if necessary. The appearance I am after would be a satin oiled gloss anyway.

I will probably just do some (or a lot of) trials, will try to remember to make pictures/documentation of the process and post details here. It might take some time though. The thing is I will probably have just one shot to get it right on the guitar body without blotching... as I understand it I would be very difficult to correct any errors once I have applied the pigmented oil.

I will appreciate/consider any suggestions/remarks at any time of course!