Oil over Shellac?

I'm just finishing up the first piece of furniture I've built since my high-school wood shop days (20 or so years ago). It's an arts-and-crafts inspired full-length mirror frame, meant as a Christmas present for my wife. I built the frame from a plank of very tight-grained vertical grain fir that I found in the barn when I moved into our current place. The frame uses through mortise and tenon joints with mahogany pegs. The mortises are embellished with a bit of carving as well. Anyway, the project has come out better than I could have hoped, and I don't want to screw it up at this point with a poor finish. I've done some experimenting on scraps from the same plank and this is my plan. I intend to first fume the piece in an ammonia tent for four hours to add just a touch of brown to the color of the fir. I want to tone down the bright mango orange look that fir tends to take on with most "clear" finishes. My experiments with fuming the fir worked great and four hours gave just the right amount of color for my taste. Eight hours had the fir looking too brown, so four it is. It's what to do after this that has me puzzled. I want to use Daly's SeaFin, a locally made tung oil based "teak" oil. I've used this on various household projects over the years with very good results. I plan to follow up the first coats of teak oil with a mixture of the SeaFin and beeswax. I got this idea from the archives of this list and my experiments so far have been outstanding. The beeswax mixture gives a deep natural satiny finish with good scratch resistance as well. I probably wouldn't use this for a table top but for something that will hang on the wall it seems like a good choice. I also like the idea of a finish that can be dressed up later with a minimum of fuss. The only thing I don't like is tendency for the teak oil to exaggerate the contrast between the light and dark growth rings (early and late wood?). I got a much more even tone when I preceded the teak oil with a single coat of orange shellac. When I used the shellac, followed by two coats of oil and two coats of oil + beeswax I got just the deep warm amber tone I'd been looking for. I'm really nervous however about putting teak oil over shellac. I can't find any reference to anyone doing this so I'm unsure of the pitfalls. I'd hate for some chemical reaction to occur causing the shellac to peal, turn dark, or gum up after time. Even though I like the look much better when I use the shellac, I'm leaning toward leaving it out of the mix to avoid potential problems. Any relevant experience here would be much appreciated.
Richard Johnson Camano Island, WA
P.S. I tried straight orange shellac, but I didn't care for the overly shiny finish. I wanted something that let the nature of the wood show through a bit more.
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If you are using a 1 lb cut of shellac and only put on one coat to seal the wood to even out oil absorption you should not have a problem. If you are actually building a finish with the shellac then you are going to have problems. Not with the shellac but with the oil.
Teak, danish, tung, linseed, oils are not surface finishes and are meant to soak into the wood and cure not sit on top of a hard finish.
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Mike G.
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