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Thread: Raised grain issues

  1. #1

    Raised grain issues

    We just finished hours of hand sanding raised panels made of MDF after priming them with a water based primer. Once assembled, the stiles and rails, made of hard maple, will need the same attention. My question is how do we avoid the raising of the grain? How do the professional cabinet makers do it? I am sure they do not hand sand. The decorative edging is hard to sand. Any ideas?

    Thanks
    John
    Hello, My name is John and I am a toolaholic

  2. #2
    Not sure I understand all of what's happening. But there has to be a target to draw fire ...or you will just get a lot of
    quiet ! On mdf panels you need to know by experience or trial and error fitting how to know the added thickness of
    primer will not make fit too tight. If "decorative edge " means the wooden moulding at edges of stiles and rails, most
    don't sand them at all except for places with fuzz . Some mdf panels will get cut smooth enough to need very little
    sanding before the priming. When using mdf for panels it's pays to buy a brand that leaves less fuzz; we used to use
    True Pan Ultralight. But there might be something better now.

  3. #3
    Join Date
    Mar 2003
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    John, it's not unusual to have to do a quick once-over with some 320 or 400 after the first coat of a water borne product on solid wood to get rid of any nibs. Any pro finisher would do just that if it was required. You could also seal with a quick, light coat of de-waxed shellac, but even there, the first coat of anything may need a quick hit with a pad or abrasive paper to insure it's smooth followed by cleaning and then laying down the coats. Many production shops are still using solvent based products, however, where grain raise is less of an issue.
    --

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

  4. #4
    Join Date
    Dec 2010
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    WNY
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    The simple answer is don't use WB primer on MDF. I use BIN shellac based white pigmented primer under nearly everything thing I paint. Wonderful stuff. Easy to spray, great hiding power, and minimal sanding required afterwards.

    John

  5. #5
    Quote Originally Posted by John Gregory View Post
    We just finished hours of hand sanding raised panels made of MDF after priming them with a water based primer. Once assembled, the stiles and rails, made of hard maple, will need the same attention. My question is how do we avoid the raising of the grain? How do the professional cabinet makers do it? I am sure they do not hand sand. The decorative edging is hard to sand. Any ideas?

    Thanks
    John
    With paint you could use a shellac based primer instead. A clear finish you could use Sealcoat. The only way to keep from raising the grain with a waterborne finish is to start with a solvent coating. Just a single coat of these shellac products will seal the wood where the waterborne finish will adhere but not raise the grain.

  6. #6
    Quote Originally Posted by John TenEyck View Post
    The simple answer is don't use WB primer on MDF. I use BIN shellac based white pigmented primer under nearly everything thing I paint. Wonderful stuff. Easy to spray, great hiding power, and minimal sanding required afterwards.

    John
    +1
    You still have to sand it, tho.

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