TruOil over French Polish/rubbed on shellac

Discussion in 'Finely Finished' started by PingGuo, Sep 1, 2018.

  1. PingGuo

    PingGuo Tele-Holic Silver Supporter

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    anyone doing this and oiling their cloth as is normal for French polish?

    Will adding olive oil or mineral oil to my French polish wad prevent the TruOil from bonding?

    So far the only thing I know is that I must use 100% dewaxed shellac.
     
  2. PingGuo

    PingGuo Tele-Holic Silver Supporter

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    Here’s where I’m at so far... but I’m getting to the point where the pad isn’t as smooth over the surface as I’d like.

    Mixol oxide white in the shellac... BC3DEDD2-2C07-41D3-9563-DB69C6031909.jpeg D7250B1A-9A1A-432B-B0F5-FB891175610F.jpeg
     
  3. RLee77

    RLee77 Friend of Leo's

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    I always thought one of the main advantages of truOil was the oil seeping into the grain and enhancing it... it seems to me that wouldn’t happen if you put it on top of shellac. But I have no experience with that so just guessing.

    I’d be inclined to reverse that and use truOil under shellac... but again, same disclaimer, my finishing experience is limited.
     
  4. Chunkocaster

    Chunkocaster Poster Extraordinaire

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    I only use tru oil by itself or with a tint. I don't see the point in mixing different finishes unless you are trying to refinish over something pre existing. If the existing finish is dry and stable it should be ok to go over with tru oil. I dyed a rosewood fingerboard with a ebony wood paint pen, let it dry a week and finished over that with tru oil to lock it in and it seems to be holding up. It drastically changes final dry time though.
    Using tru oil I just apply around 20 coats lightly level sanding after every 4, level sand the last coat with grades of micro mesh and if needed apply one or two more coats before polishing to a high gloss. I have seen people use olive oil but that was as a lubricant for wet sanding.
     
    Last edited: Sep 1, 2018
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  5. brucerbc

    brucerbc TDPRI Member

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    Tru-oil over shallac was a recommended finish by one of the luthiers who works on my gear. He suggested it when I said I was considering a DIY walnut finish like on the Elvis Costello Jazzmaster. He said get your colour right with dewaxed shellac / dye / alcohol French Polish, then rub on many thin coats of Tru-oil to protect it. I haven't tried it yet, but he's never steered me wrong before ....
     
  6. PingGuo

    PingGuo Tele-Holic Silver Supporter

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    Olive oil with the Tru Oil? That’s what I’m most curious about.

    As long as they’re compatible all is good.
     
  7. Chunkocaster

    Chunkocaster Poster Extraordinaire

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    Yes but that was wet sanding using olive oil. One of the tru oil videos on youtube has a guy using it to wet sand a cut trunk table top. The only thinning of tru oil I have seen was with a tiny amount of thinners on the final coat to help the gloss. I have not tried that myself. If you are on to tru oil coats I would just stick to the tru oil only process. If in doubt test it on scrap first.
     
    Last edited: Sep 2, 2018
  8. Silverface

    Silverface Poster Extraordinaire Ad Free Member

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    Test on something else first. That should be done any time you use something for the first time. It may or may not work depending on the results you want.

    As mentioned above Tru Oil is designed to soak into wood. It's closer to a Danish Oil than a varnish and provides very little film build. If you want tt to soak in and its resin system to harden the wood - don't seal.

    It's so thin I see no advantage to wet sanding between coats. It doesn't build enough film to need leveling between coats and has some re-wetting properties. 20 coats seems excessive to me as well - each coat will not build up like a traditional coating, and it tends to just be wiped around the surface. If a coatings system is really desired there are more appropriate products.
     
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  9. trapdoor2

    trapdoor2 Tele-Afflicted Gold Supporter

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    Olive Oil and mineral oil are not "catalyzing" oils. That is, they don't form a hard film. In the French polishing process, non-catalyzing oils are used to prevent the shellac pad from sticking to the previously laid shellac. The shellac does not mix with the oil and the oil remains on the surface. You have to remove it afterwards in a process called 'spiriting off' (which just means you use some sort of solvent and a rag to wipe the oil off the surface). You don't do that until your finished building your shellac layers...which can take days. Naptha works great when you need to get the oil off...doesn't touch the shellac.

    Tru Oil is a mix of linseed oil and "modified oil" in a Naptha and mineral spirit solvent. It is designed to penetrate the wood grain and then build layers quickly, eventually coming to a fine, hard finish. It is simply designed to go on easily and dry quickly. Probably the #1 gunstock finish.

    I don't see where Tru Oil would not work on top of shellac...but it seems backwards to me.

    I would seriously test any oil used with Tru Oil. Adding a non-catalyzing oil might interfere with the chemistry.
     
    Last edited: Sep 2, 2018
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  10. Chunkocaster

    Chunkocaster Poster Extraordinaire

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    If you want to achieve a level glass like finish you need a bunch of coats, if you don't scuff to level it out every four or five coats it gets wave like and you get trash in it. It also doesn't re wet or mix with the previous dried coat. It builds like separate sheets of glass which gives it it's excellent chatoyance. I apply very fine coats. Almost like rubbing oil on and off again in the final stages. I treat it much like auto clear coat on the final coats. If you do say only 10 coats thin like that you can still see wood pores etc. The final 4 or 5 coats I do just to cover tear through and build a high gloss before switching to buffing and polishing.
     
    Last edited: Sep 2, 2018
  11. PingGuo

    PingGuo Tele-Holic Silver Supporter

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    Thanks for this!

    The idea with the top coat of TruOil was to provide a little more hardness/alcohol resistance than the shellac provides.

    I started with the shellac because it's such an excellent sanding sealer, and it sticks to everything. I also used to to carry my color. Which I'm really pleased with so far.

    Personally, I love the way the rubbed on shellac feels. But all the guys on the forums make it sound like it's not protective enough for a guitar.
     
  12. PingGuo

    PingGuo Tele-Holic Silver Supporter

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    Also worth mentioning...

    The shellac goes on so much easier with the oil! If the TruOil doesn't stick, or does something weird... Then I just sand everything off and start over.
     
  13. Silverface

    Silverface Poster Extraordinaire Ad Free Member

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    Absolutely, and that's the way it's intended to be used. I've used plenty of it and caution against coats that are thick enough to need between-coat sanding. There's a danger of solvent entrapment, which can cause haze, microbubbles, and even blisters. It does have some re-wetting properties - that's the essence of its chemical adhesion. It's not self-dissolving as lacquer or shellac so it's often not noticed.

    I would never apply it to create a glossy finish like lacquer, polyurethane or varnish, though. It's wasted effort for the amount of surface protection provided because of its extremely low dry film thickness. If a glossy, varnish like finish is desired - which is precisely what you get - I'd simply apply sanding sealer and a couple coats of marine varnish. Virtually the same results with far less effort.

    The only differences with Tru Oil are its low solids/high VOC content (which is why it can't legally be purchased or used in some areas), which allow it to penetrate raw wood very well, and hardening resins that reinforce the grain. It is made for application to raw rifle stocks where its grain hardening and water-repellent qualities are desirable but a glossy finish is not.

    Over a sealed surface it provides neither and acts only as a very thin varnish.
     
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  14. jvin248

    jvin248 Poster Extraordinaire

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    If you want a real-world review of long term shellac performance ... log into your local craigslist and type in 'sewing machine table'. All the main brands of fold-up hide-away sewing tables from the 30s-50s were finished in shellac. People spent more time with the tables sitting closed than open, plants got put on them, or used for drink glasses, all kinds of water rings.

    The oils on the buffer pad are used to keep the pat from sticking while building layers of shellac. I experimented with French polishing and it comes out ok, surface finish repairs are easy unless the damage stained the wood below the shellac. I can see why it was used for a while as a decent working finish can be completed every twenty minutes or so and in a semi-production environment that is important. Today the factories spray on catalyzed paints that finish cure practically as fast as they can spray it.

    Truoil contains a lot of plain polyurethane and oils that evaporate. Wipe-on poly could do the top coat for you.

    I'm not sure either is a good choice on top of shellac. But, take a scrap board, repeat your shellac finish and then try different top coat materials and see what works the best.

    .
     
  15. Mat UK

    Mat UK Tele-Afflicted Silver Supporter

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    Shellac under truoil is compatible (in my experience)

    I had to use shellac first on a particularly oily piece of African Black Wood that wouldn’t take the TruOil - the shellac acted as a barrier meaning I could build up my truoil coats.
     
  16. RLee77

    RLee77 Friend of Leo's

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    What do you think about laying down a good TruOil finish first, to get the nice grain enhancement it provides, then finishing with shellac on top to seal it?

    I’m currently doing a test of several different finish types on a hard maple board, in preparation for finishing a flame maple neck, and I just added that method to one of the open panels on my test board. I’m really liking the excellent grain-enhancing properties of TruOil as it soaks into the wood, and I know I can get a great deep gloss from shellac, as I have some experience with that.
     
    Last edited: Sep 4, 2018
  17. PingGuo

    PingGuo Tele-Holic Silver Supporter

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    It’s an interesting thought. It seems easier to grain fill with shellac to me I guess.

    Tru Oil takes so many layers. But time will tell.

    Tonight I took a card scraper to my shellac. And it leveled it wonderfully. And got out some of my oopsies.
     
  18. Silverface

    Silverface Poster Extraordinaire Ad Free Member

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    I wouldn't do it under any circumstances. Shellac's adhesion to smooth surfaces is marginal, being mechanical-only (there's no chemical bond). Tru Oil provides an extremely thin film, being more of a penetrating stain/sealer than true finish coat, and it would have to be sanded to provide some "tooth" for the shellac to "grab" onto. There's not much of a film to sand because it doesn't build mil thickness like finishes do, so sand-throughs are possible.

    Shellac's abrasion resistance and solvent resistance are also very low, so it may be stained or scratched more easily than other systems.

    I use shellac as a sealer in specific situations, and only as a finish on historical instruments (like vintage Weissenborn and many related guitars) and violin family instruments originally coated with it. As a finish it has no advantages over alternative systems.
     
  19. Mr. Neutron

    Mr. Neutron Tele-Meister

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    I'm definitely no "Expert" at refinishing. I tend to be the type that learns from mistakes. I have "re-finished" my Warmoth hybrid body about 4 different times now. Always find something I don't like about how it turned out, not happy with the color, or my grain fill, or doing the wrong thing to fix whatever screw up I made. But I have to agree with Silverface's post #18 above here. I don't think shellac over Tru-Oil is a good way to go. Tru Oil will be a much better protective barrier than shellac would be, in my (limited) expperience. and even then, it's not "The Ultimate Finish", which is mythical........

    There's been a lot of advice here to use shellac before applying ANYTHING. For one reason or another, I haven't been too happy with my results using shellac at any point of a finish attempt. Either my brushing technique was bad, or the hot temps in my barn made it cure too fast, or it wouldn't harden when I thinned with Denatured Alcohol, or something I did was just wrong. And I want heavy emphasis on the "something I did was just wrong" part. It just seems for something so many say to use, and I've seen used in various videos, it hasn't been that friendly to me.....

    I'm not saying to not ever use it. I just think it may not be necessary at all sometimes, or there may be a better sealer-type of product, depending on what you're trying to achieve.
     
    Last edited: Sep 8, 2018
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