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Thread: staining pine window frames with Osmo

  1. #1

    staining pine window frames with Osmo

    Hi all,
    I've been asked to finish the wooden frames of a rather large contemporary house. The frames are pressure treated pine and the owner wants to use the Osmo product line.
    I did some test runs on a few pine trim pieces with the Osmo colored woodwax. But I'm seeing a lot of blotching, as expected with pine. The blotching is very intense in some areas and I'd like to avoid it. So I'm reaching out to get some advice. I should add that I'm a newbie to finishing. So any help is much appreciated. Here are a couple of questions:

    1- I haven't tested on pressure treated pine. The test piece that I used wasn't pressure treated. Is there any relationship between pressure treating and blotching. Will it intensify it or reduce it?

    2. I know that I can use a sealer like shellac prior to the application of the Osmo to prevent blotching. But right now, even without the sealer the stain is not penetrating much and I'm afraid that the shellac might intensify this issue. Any suggestions?

    3- The owner wants the Osmo because of its low VOC and its natural-looking matte finsih. From my point of view, the extra good thing is that you just do two quotes and you don't need to sand in between. Are there any other products with a similar profile (matte, low VOC, easy to apply)? I know Rubio has one. But that seems too expensive to me.

    By the way, I just joined the forum and am looking forward to being a member of this amazing community!

    Thanks again!

    F.
    Last edited by Jim Becker; 09-06-2021 at 4:34 PM. Reason: Text defaulted so it's readable on large monitors.

  2. #2
    Join Date
    Apr 2017
    Location
    Michigan
    Posts
    2,754
    Welcome to the forum, I'm sure you will get good advice here.

  3. #3
    Thank you Tom!

  4. #4
    Join Date
    Jan 2008
    Location
    Whidbey Island, WA
    Posts
    442
    What you're experiencing is due to the nature of pine. Birch, maple, and some others also blotch easily when stained. There's some tricks to try. You want to open up the pores, either mechanically by raising the grain, or with a product, such as a washcoat of thinned shellac. I'd start by raising the grain with water, applying the stain, then your final grit of sanding. If that doesn't work, move onto the shellac.

    https://www.finewoodworking.com/2008...-blotchy-stain

    Others may have other methods!
    JonathanJungDesign.com

  5. #5
    Join Date
    Mar 2003
    Location
    SE PA - Central Bucks County
    Posts
    65,638
    I'm going to add one more thing to this conversation...unless that PT is the special kiln dried variety, it may have a much higher moisture content than "regular" construction pine. That can affect the finishing process for sure. Even for a more common exterior opaque stain product, PT usually has to be allowed to dry for some period of time before attempting finish if one wants the finish to last a reasonable amount of time.
    --

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

  6. #6
    Quote Originally Posted by Jonathan Jung View Post
    What you're experiencing is due to the nature of pine. Birch, maple, and some others also blotch easily when stained. There's some tricks to try. You want to open up the pores, either mechanically by raising the grain, or with a product, such as a washcoat of thinned shellac. I'd start by raising the grain with water, applying the stain, then your final grit of sanding. If that doesn't work, move onto the shellac.
    Thanksfor the responses. I tried a wood conditioner before applying the stain and I got good results. I'll try the water method next.
    Last edited by Jim Becker; 09-08-2021 at 5:13 PM. Reason: fixed quote tagging

  7. #7
    Good point Jim. I guess I have to check the water content with a meter.

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