How Do I Get Rid Of These Brush Marks/Blotchy Finish Aberrations?

[Bob Hoover Ross]

The story thus far:
- first coat of Minwax water-based Helmsman Spar varnish, applied with a synthetic bristle brush; let dry 72 hours
- sand lightly with 220 and 320 grit pads
- second coat of Minwax water-based Helmsman Spar varnish, wiped on with fine cotton rag; let dry 72 hours
- sand lightly with 220 and 320 grit pads

There are a number of areas on the guitar body with finish aberrations such as can be seen in these photos:

Not sure if these are brush marks from the first coat that didn't get sanded out, or (more likely since I didn't notice them the first time around) wipe marks from the second coat that didn't get sanded out.

But is that all it is? and hence the solution is to simply Sand Some More?

iow, do these look like the sort of marks that will sand out with 220 or 320 grit? Or do I need to take a different approach to finishing this body?

(Not looking for glossy, the goal is a satin finish, as close to natural wood texture as possible. I'm only applying any finish -- and specifically, Helmsman Spar -- for its UV blocking.)

Any suggestions on what I need to do to get this smoother, less blotchy?  Thanks.

 

[PhilHill]

Possibly something to do with it being water based, that can sometimes cause milky blotches. There's also the fact that padauk can be a bear to finish somtimes. You could try 400 grit or 600.

 

[Bob Hoover Ross]

A follow-up to my OP -- which, yes, was from three-and-a-half years ago, and Full Confession: I have not done anything to the instrument since then. Those finish aberrations are still there, haven't successfully sanded them off, haven't applied any additional coats of Helmsman Spar, haven't installed the electronics or hardware, it's just been sitting as-is in a case for 40-something months, untouched.

And my question now is: Having waited for so long, is it going to be easier or harder to remove those marks when I finally get around to resuming work on this project?

Have I mentioned how much I suck at finishing work? (in every sense of that word!)

 

[mayfly]

It would be the same effort. BTW, looks to me like to you just have to level sand some more then more buffing. Especially on that spot on the horn.

 

[Spud]

I would sand it with some steel wool, (Stratamania likes 3M scotch brite pads) then buff it out. In fact, it could be ever so slightly easier than months ago as it is fully cured now. Get moving, this isn't some kind of parlor game.

 

[stratamania]

It looks to me like those marks could be below the surface of the finish, so sanding with your abrasive of choice until they go would be in order. Then build the finish from there.