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Continuing the post, some work below filling pores with rottenstone, trying a method that various chaps have suggested when doing the English style linseed finish. This method helps avoid a lot of wet sanding to fill the pores.

The offcuts below were prepared last year by dry sanding to 1500g, with the grain raised often with filtered water. The very fine sanding to 1500g or beyond, with high quality paper, helps bring out the best in figured walnut. It helps bring more depth and clarity to the finish.

When raising the grain between grits check very carefully for any larger scratch’s left by the previous grit. The dry sanding needs to be as good as possible when trying to achieve the best finish.

Then red linseed is applied. The amount required will vary from blank to blank. When applying the red oil check again very carefully for any missed scratch’s. The oil will show them up. To remove any scratch’s wet sand the area with the oil and the last grit paper used for the dry sanding. Then wipe off all the slurry. Of course it all takes a lot more time and on a stock all the sanding has to be co-ordinated very carefully with the metal edges.

I then let the red oil cure about 2 weeks then I started applying my first amber mixture with rottenstone and French chalk.

Now continuing the pore filling with my second mixture with extra amber varnish and rottenstone. I have added a few drops of svalos thinners and 2 drops driers to ¼ teaspoon finish. Not sure I like the French chalk so I’ll avoid that for now. A coat of finish is applied then after about 1/2hr I rubbed in rottenstone. Keep rubbing and the rottenstone is forced into the pores.

The correct amount of rottenstone will “disappear” into the pores and the general wood surface will become clear. You don’t want a slight grey haze over the wood surface. I can just manage this type of rubbing with my weaker hands & arms. Trying to do a complete stock now would be a nightmare.

The rottenstone needs to mix with the previously applied oil so that it darkens and bonds to the wood. I could have waited longer before rubbing in the r’stone. Using too much r’stone will leave the wood surface and pores too grey. If that happens dab a bit of finish on the wood and keep rubbing, perhaps wipe off a bit of the excess and keep rubbing till the wood clears and it looks smooth. If your palm gets too sticky to rub smoothly wipe the skin with the thinners then keep rubbing.

Then wipe the surface with a white napkin, to remove any tiny bit of grey stone residue or trace of oil. I started this bit of work about 5.45 pm one evening. After about I hr when I finished rubbing the offcuts I checked the bit of finish mix left over and it applied easily to the bit of dowel below. I rubbed the surfaces lightly after about 5 hrs and they seemed dry. I then left them overnight. With the current mixture a quick worker could do 2 applications on a stock each day. I think this second mixture would stay workable enough to rub a complete stock before gelling up too much.

Multiple applications of a small amount of finish and rottenstone gradually fills the pores. Rubbing the wood off smoothly after each application should minimize the need for any further sanding, but very fine sanding at some stage may help sometimes.

Then the next day about midday I rubbed the offcuts firmly across the grain with tissue and the surfaces felt quite dry, no smudging, and the dowel sanded lightly ok but didn’t sand to a powder yet.

So this second mixture with 1 part amber varnish to 1 part total linseed, with the driers, is drying quite well. I will continue building up the finish on these offcuts then when all are cured hard enough I will retest with water and report back the results.

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This first attempt at this method of filling has turned out reasonable. In the hand I think the filler so far is still a little grey so i'll keep practicing. Very fine ebony dust made with fine sandpaper may help darken the rottenstone a bit more.

I think I also prefer this method of palming in the rottenstone filler, compared to wet sanding the filler into the wood.

I have a couple more things to add to the post soon.

Below another test of 2 different types of gum turps, smeared on some glass. Both leave a slight residue, hard to see here, after 1 day they felt the same, after a few days the Lukas turps felt harder. the Lukas website is very hard to research, they have different versions, but I did see somewhere that this one is double distilled and it is their best turps I believe. It's available from Senior Art Supplies here in Oz.

The Diamond G turps is single distilled but from rosin tapped from the best type of pine for gum turps. Google the name for their website. They also sell the raw pine rosin from which the turps can be distilled. A link here to distilling turps on the Groves website. http://www.jamescgroves.com/PINE.HTM

I am looking into which turps is the best as I am not sure if the citrus type thinners is the best for the amber varnish. I got something settling out in my first mixture of amber varnish and linseed that included some svalos thinners.

Dictum Germany has a double distilled turpentine oil they claim evaporates without leaving residue but they won't ship overseas as it is Haz goods.

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Another point about the amber varnish, it's an expensive product, even though the Groves amber was the best value I could find in an amber varnish, so no doubt I will try other resins at some stage.

An alternative would be to use an old style marine spar varnish mixed with the linseed, one made without polyurethane. One of the best I believe is the Epifanes brand.

Another option is to add a bit of pure tung oil to the mix, to see if that improves the water resistance. I will also try a commercial tung and resin product such as the Rustins and see how that works with the linseed and the English style method of pore filling.

In the image below I also have another amber mix that I have not tried yet, with 3/4oz amber to 1/2oz linseed. I mixed it to use the last of the amber in that bottle, adding the linseed will stop the smaller amount of amber varnish thickening too soon.
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Edited by GABE93 (20/04/17 06:24 PM)

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