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post #1 of 6 Old 03-11-2012, 12:41 PM Thread Starter
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Finishing carved maple

Folks;

I am doing some gouge carving work, making designs in 5/16" (ish) maple. The steps are these:

1) Sand to 600 grit
2) Carve cool design
3) Use 1/2 Shelak & 1/2 Denatured Alcohol to apply a wash coat
4) Use a mixture of a small amount of cocoa and mineral oil to highlight the carved portion
5) Use mineral oil to remove excess highlighting
6) Apply a 2nd washcoat to seal the piece
7) Apply a wipe on polyurethane

I find that after step 5 and before step 6, this tends to warp the wood with the grain (giving a bent piece). I want to use this technique to make coasters, and a warped coaster is no good to anyone. Any recommendations on finishing this maple a different way in order to reduce or minimize warping?

Keith
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post #2 of 6 Old 03-11-2012, 02:45 PM
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Quote:
Originally Posted by keithp View Post
Folks;

I am doing some gouge carving work, making designs in 5/16" (ish) maple. The steps are these:

1) Sand to 600 grit
2) Carve cool design
3) Use 1/2 Shelak & 1/2 Denatured Alcohol to apply a wash coat
4) Use a mixture of a small amount of cocoa and mineral oil to highlight the carved portion
5) Use mineral oil to remove excess highlighting
6) Apply a 2nd washcoat to seal the piece
7) Apply a wipe on polyurethane

I find that after step 5 and before step 6, this tends to warp the wood with the grain (giving a bent piece). I want to use this technique to make coasters, and a warped coaster is no good to anyone. Any recommendations on finishing this maple a different way in order to reduce or minimize warping?

Keith
First off, are you treating both sides of the wood the same way? in other words the same steps on the back as the front? Secondly, post a pic so we can see what it is your trying to achieve ok.

Thirdly, if these are going to be used for drink coasters the shellac will not hold up well if daily or oft used for alcoholic drinks and or a lot if water is used often and left to set for long times.

I'm sure you will hear what else will work better from others, but they to will be looking for more details!!

Last edited by chemmy; 03-11-2012 at 02:50 PM.
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post #3 of 6 Old 03-11-2012, 04:28 PM
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As a woodcarver I would say it is unnecessary to sand finer than 220 grit to put an emulision coating on wood. If you were using an oil finish 400 grit would be good. The shellac you are using for a wood conditioner should be de-waxed if you are finishing with polyurethane. Zinsser makes a product called Seal Coat that is compatable with polyurethane. I wouldn't use mineral oil at all. I would use an oil stain and use mineral spirits to wipe off the excess and let dry throughly before topcoating. Chemmy is correct in that whatever finish you do to one side of a board you should do to the back. If the back side doesn't show you should also carve out the back if possible. If you have ever noticed on wide solid wood molding the back side is kerfed. Cutting out the back reduces warping.
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post #4 of 6 Old 03-12-2012, 09:37 AM Thread Starter
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Treat both sides

Okay, so I should treat both sides the same, that's good advice. And I should also use some sort of sealer instead of polyurethane? Here are some photos as well. What do you mean when you say the shellac should be de-waxed?

When you say to use an oil stain instead of mineral oil, I'm not sure what you mean. I use the combination of mineral oil + cocoa powder to fill the voids. My understanding is the thinned shellac blocks that cocoa mixture from entering the wood. I could also use some sort of wood filler to accent the carving instead of the cocoa stuff, I would think and then use a putty knife to scrape off the excess. You can see it is still a bit warped (though not as much as it was since I treated the back side with mineral oil). The side view has the carving on the top, with the back towards the bottom. The carving itself takes very little actual wood out of the piece.
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Last edited by keithp; 03-12-2012 at 09:41 AM. Reason: added more information.
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post #5 of 6 Old 03-12-2012, 11:22 AM
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Treat both sides
Okay, so I should treat both sides the same, that's good advice. And I should also use some sort of sealer instead of polyurethane? Here are some photos as well. What do you mean when you say the shellac should be de-waxed? Polyurethane is not compatable with standard shellac. The wax in the shellac will create adhesion problems with topcoating with polyurethane. Polyurethane is a fine product, you just need a different sealer. For some reason you can use standard varnish over shellac because in the old days people had a lot of knotty pine paneling and the painters used shelac over the knots to keep them from ozzing and then finished with varnish. You can also use lacquer over standard shellac. I often use the orange shellac when replacing a part on a antique to give the finish the yellow cast that the rest of the furniture has.
When you say to use an oil stain instead of mineral oil, I'm not sure what you mean. I use the combination of mineral oil + cocoa powder to fill the voids. If your intent is to fill the carvings like putty, I would use putty. A mixture of mineral oil and cocoa powder will eventually fall out. You can mix tinting color with bondo and then hardener you can fill the voids and it will stay forever. My understanding is the thinned shellac blocks that cocoa mixture from entering the wood. I could also use some sort of wood filler to accent the carving instead of the cocoa stuff, I would think and then use a putty knife to scrape off the excess. You can see it is still a bit warped (though not as much as it was since I treated the back side with mineral oil). The side view has the carving on the top, with the back towards the bottom. The carving itself takes very little actual wood out of the piece. Any amount you carve on one side of a board will weaken it to where it will cause it to warp and the more you cut into it the more it will warp. The pictures are of a carving I did probably 25 years ago that go almost through the board. You can see how much it has warped. Both sides were finished but cutting that deep into the wood I should have put it in a frame to help keep it straight.

I just don't like the idea of playing chemist with finishes. At one time I had a furniture refinishing shop and have nearly always had problems when stains were improvised. Over the years I had a couple of guys that never used packaged stain. I had to supply them with linseed oil and tinting color for them to make their own. Then we kept having chemical reactions between the stain and topcoat and some of furniture was coming back as warranty work. I finally put my foot down and insisted on using bought stains. After that we had no more problems.
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post #6 of 6 Old 03-12-2012, 12:52 PM
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I agree that shop made stains can be harmful if you don't understand the chemistry as well as how to apply and use them. My family and me made our own traditional stains for several decades without problems using only BLO, mineral spirits, and colorants, mostly industrial colors in linseed oil or japan colors with no problems EVER!! Though we normally dyed with water dyes and would apply the glaze over the sealed wood, or at times directly on the wood, depending on the samples we had to match, it was in knowing what you could and couldn't do with the stain/glaze to turn out a hassle free end product. To many who still use such stain/glazes still don't understand this and contiinue to mess up job after job especially when doing glazed painted finishes.
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