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Hi Everyone,

I applied a black colored grain filler on my acoustic prior to using sanding sealer.
Afterwards I put about 3 coats of sanding sealer on, and now I've noticed not all the grains were filled.
What's the best way to handle this? Should I sand back a bit/level sand, fill the grain again and then re-apply sanding sealer?
Can I just grainfill now without sanding back?
Thanks!

You can go ahead and grain fill again if you want to. I fill after sealer. I guess it depends on your filler and sealer/finish. I don't think you want to sand before filling if you're doing it after sealer, the filler will go into your sanding scratches and I don't think you want that.

Adhesion is important here.... need more info about products being used to give any usable advice.

_________________
Brian

You never know what you are capable of until you actually try.

https://www.howardguitarsdelaware.com/

I'm using all stewmac products. Colortone powdered grain filler and then Nitro Sanding Sealer.

FWIW I have always found any water based grain fill to be problematic. It shrinks more than most other fillers when it dries so it requires usually twice the coats to get the same fill. Adhesion over sealers etc can also be difficult as most finish products are water resistant and will readily bead water without thorough prep. Stew Macs info seems to suggest this as well as they say to apply to wood..... not sealed surface.

To move on sand back so at least all the gloss is gone before applying more filler. Back to bare wood would likely be best. Alternately you could switch fill materials to something like an epoxy and finish the fill over what you have.

_________________
Brian

You never know what you are capable of until you actually try.

https://www.howardguitarsdelaware.com/

If the - black - grain filler you originally used is not evenly distributed you may want to sand back completely to wood and reapply the filler. Too heavy of a build up of sanding sealer can affect adhesion of the top coat and clarity of the final finish, so be careful with that.