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Thread: seeking basic finish wisdom/advice

  1. #1
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    seeking basic finish wisdom/advice

    I'm just a short few steps away from gluing up my cherry cabinet. It's built in a Shaker style, as a frame with panels. I'm planning to finish it with just oil of some kind. I was thinking Tung oil, but I'm not here to open up the BLO/Tung oil debate!

    What I'm wondering is a real noobie question: should I oil the parts before glue-up or assemble everything and then oil? Ideally I'd like a finished interior, so that calls for oil first. Also, as you can see from the photo there are lots of tiny corners, and I wonder if those are places where oil would build up too heavily. Oiling first enables me to rub out the wet oil before glue-up, and then have rubbed, dry panels to assemble that will need no further finish.

    The photo shows the back's three rails and two panels (22" w x 41" h), and one side (11" w) with only its frame, to show how this piece will come together. You can see the grooves into which the panels will fit. Panels are double-layer 1/4" cherry ply made from MDF. By doubling them I have the cherry veneer both inside and out.

    pre-glue-up.jpgAttachment 419129

    I know if I oil first I need to keep oil off the tenons and out of the mortises, so I was thinking of blue-taping them first, and avoiding the tenon shoulders altogether as well.

    I'm leaning toward oiling before assembly. Any advice to the contrary?
    Last edited by Bob Jones 5443; 11-08-2019 at 1:19 AM.

  2. #2
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    I do tend to pre-finish as much as possible before glue up for all the reasons you state. I use blue tape to cover glue areas and stuff mortises with backer rod.

    A few things to consider, however. Assuming by oil you mean BLO or Watco or the like, I donít use any of these on interior areas...inside cabinets, drawers, boxes, etc, because the oil can smell for a lifetime. I tend to stick with shellac for interior spaces.

    Also, oil finishes on cherry can cause major blotching. Some like it, some donít. If Iím looking for as much of a blotch free finish as possible, I first apply a thinned seal coat of shellac...maybe even a couple of coats. This doesnít guarantee blotch free, but seems to minimize it. As with any finishing, test a few scrap pieces all the way through to the final coat.

  3. #3
    You might consider an oil-varnish blend like Watco Danish Oil. These products are applied just as pure oil: wipe on, wipe off. This adds more protection and a more lasting sheen that pure oil won't always achieve.

    Pre-finishing is good because any glue squeeze out will be removed easier than if you glue first. Prefinishing an oil or OV finish doesn't really require masking because you can wipe up to the edge of the mortise or tenon pretty easily.

    Pre-finishing is not good if you anticipate having to sand the frames flush after assembly.

  4. #4
    Quote Originally Posted by Bob Jones 5443 View Post
    I'm just a short few steps away from gluing up my cherry cabinet. It's built in a Shaker style, as a frame with panels. I'm planning to finish it with just oil of some kind. I was thinking Tung oil, but I'm not here to open up the BLO/Tung oil debate!

    What I'm wondering is a real noobie question: should I oil the parts before glue-up or assemble everything and then oil? Ideally I'd like a finished interior, so that calls for oil first. Also, as you can see from the photo there are lots of tiny corners, and I wonder if those are places where oil would build up too heavily. Oiling first enables me to rub out the wet oil before glue-up, and then have rubbed, dry panels to assemble that will need no further finish.

    The photo shows the back's three rails and two panels (22" w x 41" h), and one side (11" w) with only its frame, to show how this piece will come together. You can see the grooves into which the panels will fit. Panels are double-layer 1/4" cherry ply made from MDF. By doubling them I have the cherry veneer both inside and out.

    pre-glue-up.jpgAttachment 419129

    I know if I oil first I need to keep oil off the tenons and out of the mortises, so I was thinking of blue-taping them first, and avoiding the tenon shoulders altogether as well.

    I'm leaning toward oiling before assembly. Any advice to the contrary?
    I don't believe you could keep an oil out of the joints without skipping the area altogether. Then when you assemble you end up getting a little glue squeeze out that should be wiped off with water. That would raise the grain so you would have to sand it and the color could end up a little different. Keep in mind that cherry is very sensitive to light. You can sand it and sit it in the sun for 15 minutes and sand just part of the board and where you sanded will be lighter. I saw a guy lay a saw blade on a sheet of cherry plywood for 30 minutes once while he ate lunch. After he picked up the blade there was a clear image of the saw blade with the arbor hole and you could count how many teeth the blade had.

  5. #5
    Join Date
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    I would not use tung oil or BLO as the only finish. It does give a nice color to some woods, but it doesn't really build up a sheen unless you put on dozens of coats over weeks/months. At a minimum you can add a few coats of paste wax over the oil.

    You can add some oil based varnish to the BLO to make a wiping varnish- basically that's what Watco Danish oil is. After 3-5 coats you get a nice satin sheen. Application is similar to straight BLO, except you need to wipe off the excess within 5-10 minutes or esle it starts to get sticky.

    On my current project I am going to try OSMO Polyx. It's a mixture of oils and waxes that I've heard good things about, and seems to be more substantial/durable than most oil finishes as it was developed for hardwood floors. Application seems similar to oil/varnish blend- wipe on/wipe off. Kind of pricey, we'll see how it goes.



    I like to prefinish when I use film finishes like varnish or shellac. I find it very difficult to apply them neatly into interior corners, and sanding between coats into a bunch of interior corners is a pain. But as Prashun said, you need to have the assemblies dead on and not needing post-assembly work if you are going to prefinish. Sometimes you can do those tweaks during a dry fit. Another approach is to only pre-finish the inside surfaces, glue up, then do whatever work you need to do to the outside and then finish the outside. With no inside corners the outside is usually easy to finish as an assembly. This works well with padded shellac, have not tried with varnish.

    However, if I'm doing an oil finish I will just go ahead and glue up and then finish as a completed assembly. Oil finishes are easy, there's hardly any time pressure and as long as you make sure to wipe off all of the excess you aren't going to get any flaws in the finish. Oil will try to pool up at the inside corners but it isn't difficult to remove that excess in my experience. My current project is a crib with over a hundred parts- while padded shellac is my favorite finish I do not want to deal with prefinishing all of those parts. So I decided early on I would do some type of oil finish.


    Phil brought up some good points. One about oil emphasizing the figure or blotch in Cherry. You may like this or may not, but you need to do some test pieces. The type of surface prep will affect it- hand planed vs sanded at various grits. Generally, sanding to higher grits like 400 will de-emphasize the figure/blotch, as will applying a wash coat of 1/2# shellac prior to the oil. And the other point about the interior smell- shellac is definitely the answer here. Other finishes can seem to off gas forever in an interior space. However, the OSMO is supposed to be very low VOC, so it might be ok.

  6. #6
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    Bay of Plenty, New Zealand
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    For my workbench I used 100% pure Tung oil from Liberon - it takes forever to dry on European beech and is quite blotchy. On some other European beech I used Liberon Finishing oil. If you oil with Tung oil first then I'm afraid you'll have trouble with glueing. Color is different between the two, the Tung oil gave it more a reddish sheen where the Finishing oil kept more the typical beech color and did not make it blotchy. Son finished a walnut desk with Liberon Finishing Oil and complained after a while that the top got tacky from where his sweaty palms were all the time. A table he finished with Danish Oil was also unsatisfactory.

    Before constructing anything first experiment with some pieces of the timber with whatever you want to use.

  7. #7
    If I am using solid wood panels that will be stained, I usually stain and finish them before assembly. The main reason is that, due to the extremes in climate here, the panel will change size between summer and winter, and if I stain after assembly and the panel shrinks, it can expose unstained wood. In this instance though, I specifically don't want any adhesion between the panel and frame, so having a finish probably helps that.

  8. #8
    I used Watco Danish oil inside and out on this entertainment center for my son and his wife.
    20130905_1848.jpg20130905_1851.jpg

    It has darkened up nicely and has no residual odor.
    Lee Schierer
    USNA- '71
    Captain USN(Ret)

    My advice, comments and suggestions are free, but it costs money to run the site. If you found something of value here please give a little something back by becoming a contributor! Please Contribute

  9. I'm a bit of a newb, but have had good luck with BLO, followed by a few coats paste wax on one furniture project, and lots of tool handles. Light coats dry faster, and actually allow you to get the same results faster than if you douse the wood in the oil - it will keep soaking in, but the more saturated the wood is, the longer it takes for the oil to polymerize and harden as it needs exposure to O2 in the atmosphere for that to happen.

    Based on long term observation of some furniture that my dad built and finished with Watco, oil finishes do require maintenance to keep their luster, and I think a bit of wax helps. The wax will get scratches, so it needs re-touching from time to time. My feeling about the oil/wax finish is that it looks great, feels great, and is historically authentic for a lot of furniture, if that's important to you. On the other hand, it needs attention over time, and is less durable than alternatives.

  10. #10
    Join Date
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    I was taught to use Waterlox on Cherry, as Watco has a slight Red tint (which looks good on Walnut).

    If you can reach the back of the assembled cabinet, applying finish after glue up avoids lots of problems.

    Any of these wipe on finishes "off gas" while curing - apply in a well ventilated space that's above 50 degrees.

  11. #11
    Generally we finish furniture after assembly, although finishing parts is occasionally helpful. As examples, sometimes it is helpful to finish mouldings before installing and, as mentioned, we often finish a panel before putting it in a frame. When we make a frame for a cabinet door, we leave the stiles long and trim them flush with the rails after assembly. If we have through tenons, we leave them long and trim after assembly, and if we pin the tenons we trim the pins after assembly. It is also nice to fit the doors and hinges before finishing, but finish the doors before final installation. We often do light chamfering of edges after assembly; hand planed materials have extremely sharp edges. Many other situations would be awkward finishing before assembly.

    The idea that the interior and the back of a cabinet should be finished is an old fashioned 20th century notion. In traditional work, drawers are finished only on the fronts, cabinets are not finished on interior and back surfaces.

  12. #12
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    As I read through these insightful comments, I am reminded that I've learned far more about working the wood and building the piece than finishing it! The pitfalls of the self-taught. It looks like I'm in for working on small samples of the wood for a while until I make a final finish choice and see firsthand how much rubbing out it needs. That's my chief concern: I'm reluctant to set myself up to have to rub out a finish into all the corners of the frames and panels, and I sure don't want any finish buildup in those hard-to-buff areas. It seems like finishing the individual parts would be easier.

    To Warren's points, I have no through tenons or draw bore pins and plan to size the door to finish size before installing it into the knife hinges. Also, I expect to ease all edges the hand will feel before assembly. So, unless I settle on a finish that needs very little rubbing out, I'm leaning toward pre-assembly finish. We'll see. I need to make the door, shelves, and shelf pins first, so I have a little time to decide.

    Also, Warren, thanks for the thoughts on not finishing the interior or back. I'm chewing on that one, but it just doesn't feel right somehow.

  13. #13
    I will normally finish both sides of a panel for stability reasons, but if the inside is not going to be seen, I just do a couple coats of shellac sanding sealer. If I do finish the insides of something (for stability reasons), again it will just be a couple coats of shellac. That is usually enough to even out the moisture exchange to be similar to the outside coat.

    Full disclosure, I'm not a big fan of oil finishes. They stink, take forever to dry & stop feeling oily, and have almost zero moisture resistance. Personally I think cherry looks best with a shellac finish or a varnish over shellac if more protection is needed, but that is just me. I know other folks love oil as a topcoat. That said, Watco is my favorite thing to use as a stain. I just don't like it as the top coat, but it is great under a film finish of shellac or shellac and varnish.

  14. #14
    Join Date
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    In my limited experience with Cherry, it tends to blotch when finished directly with oil. Shellac appears to be better at achieving an even colour.

    Regards from Perth

    Derek

  15. #15
    Quote Originally Posted by Derek Cohen View Post
    In my limited experience with Cherry, it tends to blotch when finished directly with oil. Shellac appears to be better at achieving an even colour.

    Regards from Perth

    Derek
    Agreed. With shellac, you usually get more of a chatoyance effect on cherry rather than a blotch, whereas oil and stains usually blotch on cherry, although I have had some cherry grain be so ornery that even shellac made it blotch.

    For me, most of your blotchy North American woods (cherry, maple, birch) tend to look better unstained and unoiled with a shellac finish or shellac seal coat and a varnish over. Friendly grained woods like oak and ash take stains (especially pigment stains) and oils quite nicely, as they tend to highlight the figure.

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