filling grain in walnut for shellac

[mickthetree]

Hi All
I'm getting some great results with shellac on some walnut and maple, but I think the walnut needs some sort of grain filler. I've got a few coats down now (all on test pieces). Can I rub this and use the resulting dust to fill the pores? I see pumice powder used to be used, but Liberon dont seem to sell this any more.

Cheers

 

[MIGNAL]

You can fill the pores with your finish but you will be at it a long, long time.
Pumice is available on Ebay. I never really mastered the technique using Pumice. Some people use joint compound - (the stuff used on plasterboard) and dye it to match the wood.
I now use my own concoction of Gypsum ( used in Brewing - Ebay again), egg white (a binder) and liquid Fish glue. You could probably get away without the glue and just use the egg white. You will have to use a water based dye - probably Black or a very dark Brown for Walnut. Always darker than the wood you are using it on, otherwise the pores start to jump out at you. Just mix the Gypsum, Dye and Egg white so that it forms a paste. Apply the paste (across the grain) using an old plastic credit card. It doesn't matter if you leave an excess sitting on the wood. It will sand off relatively easy the next day. Allow a couple of days for it to shrink and harden. You will probably have to do a second application - over time most pore fillers shrink back.
Always do a test piece first, just to make sure that the colour is right.
Here's a link to my method (also Walnut):

http://www.classicalguitardelcamp.com/v ... hilit=pore

. . . and the final result:

 

[heatherw]

There is a possibilty here http://http://www.jpennyltd.co.uk/shopping/pgm-more_information.php?id=142 ,<i like the Mylands ones myself but they come in 4kg sizes, whereas these are smaller and cheaper, and look to be very similar. See what you think........

 

[mickthetree]

Thanks for your suggestions guys.

As I have time on my side I'm going to try an option I've read in an old book about filling with Shellac. Add a 2 pound cut of shellac to the surface which should fill the pores. Sand back the surface then check all pores remain filled. Then finish coating as normal. It might take a couple of goes apparently but I'll give it a go and report back.

 

[MIGNAL]

Try it. I've done it many times. If you can do it in 2 goes you are a much better man than me. Don't forget to look at it 3 months later though when it's all sunk back!

 

[mickthetree]

ah! I dont like the sound of that :-( I'll do some tests and see how I get on.

 

[Sgian Dubh]

Try it. I've done it many times. If you can do it in 2 goes you are a much better man than me. Don't forget to look at it 3 months later though when it's all sunk back!

Sinking down into the open pores of the wood is a characteristic of filling grain with polish. Generally speaking grain filling is usually most satisfactorily achieved with either proprietary grain fillers out of a can, or from home made grain filler using, for example, Plaster of Paris coloured with one or the other of appropriate pigments or water soluble powder paint. At least this is the case if sinking is to be either avoided or minimised. Using Plaster of Paris is a very old technique and it's quite hard work compared to modern grain fillers, but you can create your own colours for the filler, such as a slightly darker blending colour, or even a contrast to the general background colour, including vibrantly bright if you wish. Slainte.

 

[mickthetree]

Hi Richard

Many thanks for your input. Do you have any can style grain fillers you would recommend?

 

[MIGNAL]

Mickthetree. I have, for the cost of the postage you can have them! All oil based thixotropic fillers.
I simply can't agree with Richard. Plaster of Paris is the easiest filler that I've used, ever. I've tried virtually everyone available. Pumice method, Glue, Finish, Epoxy, CA, Thixotropic. Every single one is a pain. Just that the gypsum one is much less so and it doesn't have the health issues like some of them.

Here is a tutorial using a similar method to mine but using dry wall compound. He makes a big deal about the excess and the speed of drying. Not much of an issue with my method because the excess can be removed with a damp cloth, minimising the amount of sanding that is required. :

http://www.youtube.com/watch?v=Zhk6rZ2UI1Y

 

[mrpercysnodgrass]

Plaster of Paris is an easy to use grain filler, however it does have a big drawer back. If you add pigment to it, that pigment will blow out leaving you with a yellowy white grain. How fast the pigment blows out will depend on how much daylight the piece is exposed to, so it may take anything from three to twenty years, but one thing you can be sure of , it will blow out. French Polishers in the UK used Plaster of Paris extensively from about 1900 to 1920, they stopped using it when it became clear it did not hold the colour, If you look in your local Antique shop, you will see lots of Edwardian furniture with the yellowy white plaster in the grain. Of all the methods of grain filling that have been mentioned, using shellac, thixotropic and pumice are all good and easy to use, I have used them all over the last thirty years and my favorite is pumice, so here is my method, which works well and takes very little time and effort to master. I hope it is of use to you.
The pumice must be fine '000' or '0000'. In the past you could buy pumice in the same grading system as wire wool but now the different suppliers dont tell you what grade it is. The only one on the market I know of that is the right grade is Mylands. If you have some from Fiddes or Jenkins you can put it through a fine sieve but that is laborious. You can also make yourself a pounce but I find that some of the larger grains tend to get through and then it gets scratchy. When you have your pumice put it in a jar or tin and drill some 3mm holes in the lid to make it into a shaker.
The next bit of kit you will need is a dish cloth, just an ordinary cotton dish cloth edged with a coloured stitching, the type you get in the 'pound' shop in a bundle of ten for, oddly enough, a pound.
Get a washing up liquid bottle and a marker pen and place marks on the bottle to divide it into ten equal parts, ( by eye is good enough ) Place one part shellac to nine parts meths ( finishing spirit if you are using this on fine antiques )
Method.
Shake a fine sprinkling of pumice over the surface.
Shape the dish cloth into a bundle with a flat crease free surface like a rubber and charge it up with your shellac/meths mix.
Apply the 'rubber' in interlocking circular motions all over the surface until the pumice has disappeared into the grain, then straighten out with the grain just like French polishing. It will look as though nothing has happened, repeat several times depending on how deep the grain is, again it will look as though nothing is happening, but then you will see the grain begin to fill, when you see this happening make your mix a little dryer and then all of a sudden you will see a sheen appear on the the surface, at this point leave it to rest over night. Next day flick it back with 400 grit then if the grain is still a little open carry on with some more pumice, other wise finish as normal. it will give you a good hard base that will not sink.

 

[MIGNAL]

I don't quite know exactly what you mean by 'blow out'. I assume that the Pigment that they were using was rather fugitive. In which case the solution is easy: use something that isn't or at least one that will last a lot longer than 30 years. Many of the high quality drawing inks are archival.

 

[Sgian Dubh]

I don't quite know exactly what you mean by 'blow out'. I assume that the Pigment that they were using was rather fugitive. In which case the solution is easy: use something that isn't or at least one that will last a lot longer than 30 years. Many of the high quality drawing inks are archival.

I too have found the whiteness of the Plaster of Paris used in work from the early 1900s, or thereabouts, has a tendency to show through, but not every piece I've looked at where the grain was filled this way has shown that effect. I haven't found it to be the case in the grain I've filled using it, but it's also true that I've only been intermittently using it as a grain filler since the early 1970s, so perhaps it's just a matter of time before that happens. It's a possibility I suppose that the colourants I've used have meant I've not received reports of the whiteness showing through. In my case I have mostly used water soluble powder paint to achieve the colour.

When I said it's more difficult to fill grain with Plaster of Paris, what I meant is that I find more effort is required to do the job properly compared to proprietary ready mixed fillers, but that may be due to the way I do the job-- I can't say for sure. Slainte.

 

[MIGNAL]

You sometimes see the same effect with Pumice if you don't 'clear' it first. A technique that is commonly applied when filling Rosewood Guitars is to do a few spit coats of Shellac. Pumice is then applied to the fad and then 'cleared' with a few drops of Shellac, quite often a finger is used to mix the pumice and shellac together. It is only then that the fad is used on the actual wood, the circular action mixes the Shellac, wood particles and Pumice forcing it into the pores.. This supposedly ensures that the pumice does not show through. It works but can be a little laborious. Some people have real trouble with this technique though.
The same applies to Gypsum. The finish will 'clear' it. In fact a technique used to fill in very small dings is to 'french polish' with a mix of Shellac and Gypsum - no dyes or pigments.
With my mix of gypsum, glue and egg white I decided to add a pigment - one that is considered to be permanent. Perhaps when they were filling grain using Plaster of Paris they didn't use any pigment at all. I've certainly come across references to Plaster of Paris mixed with Linseed oil - no dye or pigment.
The actual 'filler' though probably matters not. I could easily substitute the Gypsum for Pumice. I'm sure that would work too.
Certainly my method proved to be one of the easiest to use. I don't know if that is the result of the mix. Perhaps the addition of the glue and egg white gave a little more working time. I do know that it dries very hard, as you would expect.

 

[Sgian Dubh]

You sometimes see the same effect with Pumice if you don't 'clear' it first...

... The same applies to Gypsum. The finish will 'clear' it. In fact a technique used to fill in very small dings is to 'french polish' with a mix of Shellac and Gypsum - no dyes or pigments...

... Perhaps when they were filling grain using Plaster of Paris they didn't use any pigment at all. I've certainly come across references to Plaster of Paris mixed with Linseed oil - no dye or pigment.

I think you may be right. I've seen white glaring through after gypsum, pumice, and Plaster of Paris were used as grain fillers. I suspect that in many of those cases there was nothing used to colour the filler.

If I use Plaster of Paris the only addition to the mix is a pigment or water soluble powder paint. The technique doesn't involve linseed oil. The mix is Plaster of Paris plus the colourant in a bucket or pot. Application is via the use of a small wad of cloth dipped into some water to wet it, followed by dipping into the Plaster of Paris mix and then forcing the wetted powder into the grain with a roughly elliptical motion. This requires several wettings of the cloth, dipping into the dry powder mix and working into the grain followed by scouring off with hessian before the powder dries too hard in the open grain to burnish off. I usually work on an area of about one square foot at a time in the application and burnishing off sequence. There is a description of the methodolgy I use here: http://www.richardjonesfurniture.com/Ar ... table.html Slainte.