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Thread: Sealing end grain on large parota cross cut slab

  1. #1
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    Sealing end grain on large parota cross cut slab

    Hi all. I have a very large round cross section of parota which is going to be a dining table. 57" in diameter, 2.25" thick, and kiln dried. I've finished a few flat sawn parota slabs and they soak up liquid like crazy, so this end grain will be even thirstier. The final topcoats will be an oil-based varnish, either polyurethane or Waterlox. I think spraying a fast drying seal/base coat or two is going to be my best bet to aid in getting a quick and even build. My two options at the moment are either Zinnser Sealcoat or a vinyl sealer. Can anyone recommend one of these over the other, or any other ideas for my situation? Thanks!

  2. #2
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    As a general principle, choose your top coat and then read its tech data sheet. It will tell you what type of products are suitable to go under it. It sounds like you will need more than a quick sealer to fill the grain. How you do that depends on what look you want. Cheers

  3. #3
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    Vinyl sealer is really for use under the same brand's solvent based lacquers. Since you're intending on using an oil based varnish product for your top coats, you'll want to use something compatible with that. Why not just use a thinned version of your top coat to seal?
    --

    The most expensive tool is the one you buy "cheaply" and often...

  4. #4
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    My thinking is that wiping or brushing on a thinned varnish would soak in even deeper than a full strength. If you've ever brushed or wiped a finish onto a cross cut you know what I mean. I could probably wipe on at least 10 coats of a poly or similar before it starts to build. I'm trying to figure out a way to seal the grain more toward the surface so I can start building the finish more quickly, hence a quick drying spray. I may just try the Zinsser shellac aerosol route. I could also use polyurethane aerosol.
    Last edited by Bennett Ostroff; 05-29-2018 at 10:05 AM.

  5. #5
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    Sanding it to a finer grit will reduce how much finish gets sucked into the pores. When you take walnut up to 600 grit, for example, it starts to build a film on the first or second wiped on coat of varnish. I'm not suggesting you go to 600 grit, but 220 or 320 might make sense if you have only gone to 150 or 180. From there, Sealcoat would be my preference of the two you asked about.

    John

  6. #6
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    What about using a paste wood filler (grain filler) first.
    Steve Jenkins, McKinney, TX. 469 742-9694
    Always use the word "impossible" with extreme caution

  7. #7
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    Thanks for the suggestions. I think I'm going to go with John's suggestion of sanding to a finer grit and using seal coat. If the top coats build unevenly after that, I can always wipe off to avoid random high build areas.

  8. #8
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    There's nothing wrong with what you propose, but Sealcoat has consistency similar to thinned down varnish... Since you're going to use oil based varnish, there's no need to use a separate product for this. Now if you do the paste wood filler, then it has value as a barrier coat to insure adhesion of your varnish, especially if you select anything with "poly" in it. But if not, I'd personally not complicate things with multiple finish products for this.

    BTW, sanding to a higher level is absolutely a great way to handle end grain.
    --

    The most expensive tool is the one you buy "cheaply" and often...

  9. #9
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    Quote Originally Posted by Jim Becker View Post
    There's nothing wrong with what you propose, but Sealcoat has consistency similar to thinned down varnish
    It has a similar consistency but dries WAY faster, which helps seal the wood closer to the surface (at least in my experience) which is what I'm trying to do. I will let you how it all turns out. Thanks for the input!

  10. #10
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    Jim is correct with this. Fast drying does not equal fast building. Fast building requires higher volume solids regardless of drying time. He is also right that you are much better off using the same product all the way through. It's why I use a 2 pack polyurethane clear for this type of application. It is reasonably high volume solids - around 60% - and finishes perfectly off the gun. In your case, pick which top coat to use and go with that. Cheers
    Every construction obeys the laws of physics. Whether we like or understand the result is of no interest to the universe.

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