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I turned a mesquite bowl to near final dimensions on my lathe, then filled some defects with epoxy. The defects were in end grain areas. After turning it flush and removing enough wood that there are no visible epoxy stains outside of the inlays, it looks like there may be areas of end grain where the wood pores have been filled with epoxy (only visible when looking very close). Will the wood still absorb polymerized linseed oil evenly, or should I use another finish, like shellac? I used tape dams, so most of the bowl was spared from being unnecessarily coated in epoxy, but not all.

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Will the wood still absorb polymerized linseed oil evenly

This is very firmly a maybe.

Sometimes visible filled grain/pores do indicate that if you oil (or use a finish that acts similarly to 'wet' the wood) you will get a very noticeable pale area, which is obviously what you want to avoid.

The good news is you don't need to try it and see with oil, you can use anything that will wet the wood as it will give you a preview of the effect. This of course includes water, but you'll probably want to use something that won't raise the grain so instead denatured alcohol (UK: meths), mineral spirits (UK: white spirit) or acetone/lacquer thinner are the usual alternatives, in very approximate order of frequency of use1.

If you see the dreaded pale area then just wait for the solvent to evaporate and go with shellac if that's your preferred alternative finish to polymerised linseed. FWIW the final effect may not be that different2.

1 Although not in order of preference. Unless you're planning on using a water-bourne final finish I don't believe there really is any practical reason to prefer one over another except in drying time; and unless you're terminally impatient :-) this is really only a factor on large areas that you want to assess all at once.

2 Nerdy finishing geek-out: while oil will frequently give the absolute maximum 'pop' to grain, maximising contrast and chatoyance, shellac is no slouch in this department. And with some wood oiling before applying film finishes like shellac, varnish or nitro lacquer doesn't do much, certainly not enough to warrant the extra step and its associated 'drying' time.

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  • Thanks! Would raising the grain matter if I haven't sanded yet?
    – Brian McCutchon
    Oct 15, 2022 at 15:28
  • Very much not, I just assumed that you were ready for finish right now and would therefore prefer not to have to sand off raised grain. But if you are going to sand, even sand what by your standards is lightly, do the wetting test afterwards since any amount of wood removed from the surface might take off what's been affected by epoxy penetration. Penetration (from any sort of finishing oil or liquid finish) can be quite astonishingly shallow, so even "a normal amount" of sanding might reveal unaffected wood. Obviously this applies less to end grain, which is noticeably more absorbent.
    – Graphus
    Oct 15, 2022 at 17:55

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