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Thread: MinWax water based, oil modified Poly.... huh?

  1. #1
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    MinWax water based, oil modified Poly.... huh?

    I am using the above finish for some Maple 2" edging that will get lots of wear. I am brush applying the above Poly. I want a glass smooth final surface. A few questions....

    1) for max scuff resistance, was this a good choice?

    2) How many coats for max. scuff resistance? I would guess 5?

    3) How important to sand between coats? If I want 5 coats total, for good solid thick finish, is it OK to apply all coats a few hours apart,.... (dries VERY fast here) then after thoroughly dry, sand from 220/320/600 to get the glass smoothness I desire?

    4) I was planning on sanding with a little distilled water, mainly to reduce the dust... is this acceptable?

    5) I assume always sand with hand block, not power sander such as Festool Rotex set on fine mode?

    5) What the heck is "water based, oil modified"....it says water based, so why the words modified oil?

    Sorry for all the questions :-(
    TYIA

  2. #2
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    1) for max scuff resistance, was this a good choice?

    *** An oil based floor finish will have more scuff resistance.

    2) How many coats for max. scuff resistance? I would guess 5?

    *** Number of coats has little to do with scuff resistance. Instead, it's a factor in how soon the finish will be worn through. For most finishes, 3 to 4 coats is sufficient. Follow the label on the product.

    3) How important to sand between coats? If I want 5 coats total, for good solid thick finish, is it OK to apply all coats a few hours apart,.... (dries VERY fast here) then after thoroughly dry, sand from 220/320/600 to get the glass smoothness I desire?

    *** Depends on the product. If the label says to sand, then sand. With some finishes you can recoat within few hours without sanding but need to sand if you wait longer than 8-12 hours. Have you gone to the Minwax website and looked up the application instructions? You will also reduce the gloss by sanding http://www.minwax.com/wood-products/...yurethane.html.

    *** Finish sanding after application can be problematic on floor finishes. It can make them too smooth and folks are likely to slip. Any sanding needs to wait for the finish to fully cure. This can be 3-4 weeks.

    4) I was planning on sanding with a little distilled water, mainly to reduce the dust... is this acceptable?

    *** No, you don't want to use water as a lubricant on waterborne finishes.
    5) I assume always sand with hand block, not power sander such as Festool Rotex set on fine mode?

    5) What the heck is "water based, oil modified"....it says water based, so why the words modified oil?

    *** Again, go to the Minwax site and look at the info that product.
    Howie.........

  3. #3
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    I know oil base polyurethane that when you applied too many coats, it becomes brittle and tends to crack. But in water base I don't know.

    In Minwax instructions says to use 220 grit, IMO 220 is too rough for between sanding
    I use 320 lightly sanding

    It says let dry for 2 hours between coats.

  4. #4
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    If the product you bought was Minwax Polycrylic then you will not be impressed with its scuff resistance. It is very soft and easily damaged. There are several waterbased polyurethanes that are very hard and wear resistant (equal or better than solvent based products, IMO), but it's a little late for that now unless you strip off what you've put on. But in case you do, or for your next project, you might consider General Finishes Hi Performance Poly. It's very hard by itself, but you can add a catalyst to it that is supposed to increase the hardness even further.

  5. #5
    Quote Originally Posted by Will Blick View Post
    5) What the heck is "water based, oil modified"....it says water based, so why the words modified oil?
    Miracle Whip? MW=MinWax, and MW=Miracle Whip. Can't ignore that, can you?

    Try to find the MSDS and it may help. I've also found the people at Minwax to be very helpful when I called them.

    Are you in CA by any chance?
    Last edited by Phil Thien; 03-30-2011 at 8:30 PM.

  6. #6
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    it says water based, so why the words modified oil?

    Miracle Whip? MW=MinWax, and MW=Miracle Whip. Can't ignore that, can you?
    LOL! funny..


    Oils are quite often added to waterborne materials to improve flow and adhesion and to maintain a longer wet edge.
    IIRC, there's a certain percentage level where they have to declare the material as being oil modified. - when the oil becomes part of the carrier and not part of the resin.
    i could be wrong there - about the reason - it's been over 30 years since I rubbed elbows with the chemists @ the plant and research lab.

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    Quote Originally Posted by Rich Engelhardt View Post
    LOL! funny..


    Oils are quite often added to waterborne materials to improve flow and adhesion and to maintain a longer wet edge.
    IIRC, there's a certain percentage level where they have to declare the material as being oil modified. - when the oil becomes part of the carrier and not part of the resin.
    i could be wrong there - about the reason - it's been over 30 years since I rubbed elbows with the chemists @ the plant and research lab.
    Rich

    I thought they just tint the poly to make it a warmer color?

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    John, it is not Polycrylic MM product, which is much inferior to this newer product.... its also about 2x the price, but well worth it...

    This was my first use of this product, its relatively new, maybe a year old rep said... After a day of application, I am quite impressed with it....

    Steve, you were right-on, 220 way to coarse between coats. 320 min. is about right, maybe 400... as the goal is only to scratch the surface so it can better adhere to itself.

    Howie, I did speak to technical support from MW, sometimes helpful, sometimes bad information... hence my questions, sorry if you found them offensive. This IMO is the value of forums, seeking advise from others who may have already experimented... for example, MM tech and MM docs say 600grit after final coat, NO WAY... 0000 steel wool was the proper abrasive, anything coarser removed too much finish, cloudy appearance, and created excess dust. 0000 = Superb glass smooth CLEAR finish.... very happy with outcome, which is rare for me and finishes :-) Hence why I was seeking advise.

    BTW, Lowes sells this by the gallon $46, very low price.

    Based on tech rep, this product is the best of water based (barely any yellowing over time) and the best of oil based (application, drying, etc). Dry time here in the SW was 30 minutes... (directions claim 2 hrs, but dry here, but only 70 deg F) the key was, lightly brushing the piece every few 5 minutes where any build up occurred....in which case, the entire process goes very fast, and you barely need any final sanding....

    MM makes the same product in a Wipe-On Poly... I tried that first, but rep advised me, it takes 3 coats of the Wipe-On, to equal one Coat of the Brush-on. I will save Wipe-on for intricate work or areas that will not get abuse, lesson learned :-)

    So the "water based, oil modified" is a marketing term, what else is new... as it turns out, this is quite common to have oil in the Water based products, interesting...

  9. #9
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    >>>> If the product you bought was Minwax Polycrylic

    No, the OP said he was referring to Minwax® Water Based Oil-Modified Polyurethane. http://www.minwax.com/wood-products/...yurethane.html
    Howie.........

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    >>>> sorry if you found them offensive.

    What did I write that makes you think I found your posting or comment offensive? I certainly didn't intend that.
    Howie.........

  11. #11
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    Prob. mis interpretation on my behalf....

    Before applying the poly, what is finest grit paper you should sand to?
    I remember Howard mentioning anything finer than 150 grit would make the finish harder to adhere too.... make sense... did I recall this accurately?

  12. #12
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    Quote Originally Posted by Will Blick View Post
    Prob. mis interpretation on my behalf....

    Before applying the poly, what is finest grit paper you should sand to?
    I remember Howard mentioning anything finer than 150 grit would make the finish harder to adhere too.... make sense... did I recall this accurately?
    150 grit is too coarse
    I think you meant 320 grit.

  13. #13
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    Before appling poly (varnish) meaning raw wood; I would say anything finer than 220 is wasting time and sandpaper. Between coats 220 or 320 is about right.

    Of course I don't use poly on anything but floors... so, I use 80 or 100 on raw wood and 120 between coats.
    Scott

    Finishing is an 'Art & a Science'. Actually, it is a process. You must understand the properties and tendencies of the finish you are using. You must know the proper steps and techniques, then you must execute them properly.

  14. #14
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    Here is some info about sanding grits and sanding of both the wood and intermediate finishing steps.

    Sanding wood--hard or soft--beyond 220 does little more than burnish the wood making staining difficult. This is particularly true if you are using a pigment stain which sits on the surface and relies on "nooks and crannies" to impart color. Softer more porous woods can be sanded to to 220 but harder less absorbent woods may stain best if only sanded to 150. The best compromise is to aim for 180 grit.

    A number of years ago a large cabinet/custom furniture shop I was involved with did series of adhesion tests with various finishes and sealers. As part of this test we explored adhesion based on sanding grit. We found about the same adhesion up to 180 - 220. Beyond 220 adhesion dropped off due to burnishing of the underlying wood particularly when non-linear machine sanders were used. This was tested on birch panels. We also found that the resulting smoothness of the first coat of finish was not materially affected by the smoothnes of the underlying wood for sandpaper grits between 150 - 220.. The smoothest surface substrate for final finishes was obtained by sanding lightly after the first coat of finish was applied and dry. Which makes the case for a thinned first coat of finish.

    So our conclusion was that sanding beyond 180-220 was not necessary and could be actually detrimental.

    But, most important was that there was a big appearance affect if the surface was not HAND sanded in the direction of the grain using the highest grit used on the sanding machine. A flat pad sander produced a much flatter surface than a ROS. However, both required final hand sanding with the grain for optimum appearence. If not hand sanded, swirl scratches could show. Final hand sanding using a sanding pad in the direction of the grain is a must.

    To carry it one step further, sanding at 320-400 grit after the first coat and subsequent coats was the optimum. No improved appearence was noticed by between coat sanding beyond 400 for varnish. 400 was the sweet spot for thinner finishes. Between coat sanding was always done by hand whether for flattening or for adhesion.

    I think you will find similar thoughts in the popular finishing books but YMMV.

    Finally, the first coat of ANY finish will soak little shards of wood and cause them to raise whether the surface was sanded, planed or scraped. When the first coat of finish dries these hardened shards are what causes the surface to feel rough. Sanding with 320 paper will remove these hardened shards and subsequent coats will go on smoother. So, smoothness counts after the first coat of finish, but not much before that.

    The machine finish determines the starting grit. Jointers, planers, belt sanders etc, should leave a finish that allows starting with 100 grit. From there, go to 120 grit and sand until the marks from the prior grit are gone, then move to 150 and finish at 180 grit.

    Plywood is factory sanded to 180 grit. Therefore, it's best to not sand plywood except with 180 grit and sand by hand. Get the first coat of finish on and then sand with 320. That way you are sanding the finish, not the wood. This avoids sanding through today's very thin surface veneer.
    Howie.........

  15. #15
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    Scott

    On floors.

    Do you use 120 grit sanding screens and hand sand?
    Last edited by Steven Hsieh; 04-01-2011 at 11:27 AM.

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