Filling Pores in Painted Oak Cabinets

Finishers have suggestions for filling grain and pores before the first coat. But after the paint or coating is on, it's tough. December 6, 2011

I'm refinishing a kitchen with oak doors and frames in a crŤme colored pigmented lacquer (MLC MagnaMax). I'm getting several open pores showing through the finish, and though I suppose that is to be expected I would like to find a way to fill them in without building up too much finish. So far Iíve been spraying and aggressively sanding down, but this doesn't seem to be getting me where I want the finish to be. I talked to my MLC rep and he says he has nothing that will do the job. He says grain filler shouldnít be used over an existing finish. I'm not looking for a full fill - just to get rid of those damned pores! I have a Valspar distributor in town - do they have anything I could use to fill the open grain? I'm looking for something I can spray on and sand off.

Forum Responses
(Finishing Forum)
From contributor J:
Another thing that works for me is using automotive 2K (urethane) primer. It sprays easily and sands better than anything else.

From contributor R:
Did you prime the oak doors with primer first? I would have shot a couple good coats of Clawlock primer or Clawlock high solids primer on first then sanded smooth. That generally allows enough fill in the grain to keep pinholes from happening at open oak pores. Obviously, that does not eliminate the oak grain texture. Or if you want a thinner film appearance on oak, you can shoot a coat or two of Krystal Sealer and sand before spraying a couple coats of MagnaMax pimented color. Or spray two coats of White Vinyl Primer and then MagnaMax pigmented coats over the top. Maybe you have topcoated all of your stuff already and this won't help. You need your sealer or primer to coat the open pores.

From the original questioner:
I talked with my MLC rep about using a vinyl sealer or sanding sealer first and he flat out told me it would be a bad idea to use a sealer over pre-finished doors. "New wood only" he told me - which is why Iím here looking for advice. I was sure a vinyl sealer would do the trick but was surprised by him telling me not to do it.

I'm not familiar with Clawlock primer but will keep that in mind for the next time I come across oak. I may also have to look into other finishing solutions for this type of project since this is the third time Iíve run into this issue and still haven't found a good solution to it when using lacquer other than lots and lots of sanding. I'd hate to have to switch to using a 'paint' for cabinets but when it comes to oak it's just such a pain with all the pores. A urethane primer was another option the rep mentioned, but on further questioning he again said it would be a bad idea over a lacquer finish. I just can't seem to find a good solution.

From contributor R:
MLC White Vinyl Primer probably would have been the most forgiving product to use over a previously coated surface. That is what refinishers typically use to seal out problems. MagnaMax pigmented works great over it, no problem. Try it next time on one of your doors.

From contributor O:
Most people who build doors out of oak prefer to see the pores. It is after all the nature of the oak. If they don't want pores use a wood with as tighter pore structure like maple or cherry. Since you are refinishing perhaps replacement doors would be a better way to go.

From contributor J:
Sherwin-Williams automotive has a filler that comes in a tube. I think it's called Ultra-Fill. It's like thick primer and is made specifically for painted surfaces. I haven't found anything else that works. Also, the grain part of oak is the softest part and it is constantly moving. It's too late now but a grain filler before you start would really help with the holes.

From the original questioner:
Next time I come across oak Iím going to try either the white vinyl primer or the level filler which I am told might do the trick. I'd love to just replace the doors but Iím not there yet. Right now I just do refinishing of existing surfaces, but when I learn how to properly reface and apply veneers to those cabinet boxes Iíll start looking into doing more re-facing with new doors - especially when it comes to kitchens like these. I don't build doors myself but there's a cabinet shop nearby owned by a family friend who builds them. Itís still pretty green when it comes to working with wood (only really got into this about three years ago) so still have lots to learn.

From contributor B:
A thin grain filler prior to the prime job is an ok solution but prone for failure if not allowed proper dry time and topcoat compatibility. I think the problem begins and ends with the coatings viscosity or ability to "flow" into and over the edges of the grain. If you notice water on your car beads up after a wax job as opposed to laying out flat on an unwaxed car, all due to surface tension.

You'd think that a wax job would not bead up water but would allow it to flow off Ė thatís water tension and similar to coatingís tension. Reduce the coatingís tension and this will allow it to flow into cracks and crevices more readily. It'll also up your chances for getting runs and sags. If used wisely a product like Smoothie will reduce the surface tension. Make sure that you clean Equipment and areas after its use though.