finishing trouble

[Mike Ballard]

Hi -

On some unfinished cherry I applied three or four coats (in steps) of pure tung oil cut with turpentine and let the last sit for about 5-6 weeks. I thought I'd try satin wipe-on poly (Minwax's) so followed the can's instructions and applied three light coats over three nights. Then in searching about the wiping marks I kept ending up with I followed someone's tip in applying a light coat, let sit an hour and apply another coat for overnight. Sand with #400 and repeat. I wanted 5-7 coats anyway before applying wax.

My problem is that the wiping marks are gone but there is an uneven sheen which I seem to be stuck with. The difference is like if you apply brush-on poly, let it sit overnight then scuff it - it's usually mostly non-reflective and you can see areas you missed since they reflect more. That's what I have now. It's only noticeable with backlighting.

On the last one-two (tip from above) I wiped on circularly then a minute or two later I wiped all the poly off. I did that a couple times. It looked great and I let it sit overnight. But when I tip the piece in the light now I see the uneven sheen I described. I don't know how to fix it but if it can't be fixed, will waxing even out the sheen or just make the difference more pronounced? I don't want to get into stripping off wax if it won't so am asking first.

Mike

[Gerry]

[B a r r y]

Use only gloss finishes to build a finish. Apply the satin or semi-gloss stuff as only the last coat or two, or simply rub the gloss finish down to the sheen you prefer with steel wool and a wool lube.

Non-gloss finishes contain a flattening agent that creates the duller look. This flattening agent can also cloud the finish if used as early coats in a build. ALWAYS completely stir a non-gloss finish, making sure all of the stuff from the bottom of the can is in suspension before using.

Try wiping on another coat of completely stirred satin or rubbing the finish out with 0000 steel wool and a lubricant, such as Behlens Wool Lube, or Murphy's Oil Soap (non-spray version!)

Barry

[Gerry]

About the "gloss only" to build, IMHO, that's a matter of degree and not a rule. One of those cases where you really need to know where you're going before heading there. If he were building many thick coats that'd be different. But for a few light coats over oil, I wouldn't go buy a 2nd can of gloss. For the case given here, I don't believe you'd be any to detect any difference.

On Mike's issue, I'll guess that steel wool suggestion below will do it, and that Mike's paper is just passing over those spots. Iff the spots are very small, just lightly buffing with the wool alone may be enough. If that fixes it but makes it uneven, then add some lubricant and do the entire item.

GerryG

[Mike Ballard]

Poly can was vigorously shaken (upside down) before use per instructions. I used #000 steel wool for the three coats where I followed the can's instructions. I used #0000 for the last 2-3 coats (dealing with the wipe marks repeatedly) except prior to the last coat (just before posting here) I used #400 w/d paper and mineral spirits instead. I used the wool as it comes out of the package (it's folded over a couple times) and did not bear down on it.

This is about a 7" x 10" piece where a 1.5" or so wide chamfer was created by planing down many degrees around all four top 'edges'. I studied the sheen more carefully and it looks as if it is mostly concentrated along these chamfers, such as would happen when sanding carefully across the top but not so carefully once you hit the chamfer and head down to the edge. These wouldn't bother me too much but there's a relatively large patch right on the top I have to fix.

If the sheen problem (which I didn't notice earlier or created at the latter application(s) of poly) is underneath the final coat or two, do I need to sand those away - is this something wax will not 'hide'/even out? (this is where I didn't want to do a trial waxing only to have to figure out how to strip it off if it didn't work).

I can't get any of the suggested lubes today (and would like to finish it if possible) so could I substitute MS instead?

Mike

[Gerry]

Firstly, the sheen should be entirely on the surface. If the poly is cured enough, the wool and spirits should do it. Actually, 400 w/d paper with spirits and using fingers to carefully guide the pressure should also work, and that could also be used with water and a little mild soap. Sounds like you're dealing with an uneven surface. Only issue would be if the spots are actually a collection of small dots in depressions your abrasive doesn't reach. In that case, pumice and a rag would work better.

I keep menti>