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Thread: French Polish Final Coats

  1. #1
    Registered Pontificator Roger Kunkel's Avatar
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    Default French Polish Final Coats

    I've been digesting a lot of FP threads, videos and tutorials, but it seems like there are many techniques and I'm a bit perplexed. I've built up some layers and I'm wanting to attain a pretty good gloss as a final result. I've heard that buffing to a gloss using a swirl remover is a common method, but I've also heard that just going thinner and thinner with your shellac mix is the best method for working up a gloss and that no buffing should be done. Also, do you wet sand after the last coat and before buffing or not?

    Thanks

  2. #2
    Mandolin & Mandola maker
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    Default Re: French Polish Final Coats

    Just add alcohol to the pad rather than a shellac mixture. It will then get thinner and thinner each time you add the alcohol. This is the best method IMHO and is the traditional way of doing it. You don't need to wet sand and you don't need to buff.
    Peter Coombe - mandolins, mandolas and guitars
    http://www.petercoombe.com

  3. #3

    Default Re: French Polish Final Coats

    I know you said you've digested a lot of tutorials on the subject. I found Orville and Bob Milburn's tutorial to be very good help on the few that I've done. If you haven't seen it, here's a link: https://www.guitarsint.com/article/I...ssical_Guitars
    Last edited by Mandolin Cafe; Oct-07-2021 at 11:16pm.

  4. #4

    Default Re: French Polish Final Coats

    Quote Originally Posted by peter.coombe View Post
    Just add alcohol to the pad rather than a shellac mixture. It will then get thinner and thinner each time you add the alcohol. This is the best method IMHO and is the traditional way of doing it. You don't need to wet sand and you don't need to buff.
    Thats the part I always find the hardest. Whenever I do that, I just seem to pick up shellac, or get lint stuck in the shellac, or both. At what point does it polish, rather than remove shellac!?

    I know I know, Micromesh is a cop out!

  5. #5

    Default Re: French Polish Final Coats

    If you use a pad ("muneca"/"rubber") that is brand new with nothing on it but alcohol, it will pick up the shellac. It needs to be as Mr. Coombe says, a pad you've been using to add shellac, which you then gradually lean out. The shellac on the pad is one of the keys, the other two keys are non-stop sweeping motion and the right amount of alcohol on the pad. I believe a bit of residual oil on the surface is important, too... spiriting off is partly about removing that oil.

  6. #6
    Registered Pontificator Roger Kunkel's Avatar
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    Default Re: French Polish Final Coats

    Quote Originally Posted by Tony Francis View Post
    Thats the part I always find the hardest. Whenever I do that, I just seem to pick up shellac, or get lint stuck in the shellac, or both. At what point does it polish, rather than remove shellac!?

    I know I know, Micromesh is a cop out!
    I find this hard too. Right now a have an area on my top where I effectively removed too much shellac by rubbing too much alcohol. Wondering if I can fix that by applying more shellac to the area hoping it will blend in with the surrounding area. Stressful.

  7. #7

    Default Re: French Polish Final Coats

    Quote Originally Posted by Roger Kunkel View Post
    Wondering if I can fix that by applying more shellac to the area hoping it will blend in with the surrounding area. Stressful.
    Well, if you don't have a sentimental reason for doing a traditional french polish, you could apply more shellac to that area with a spray gun (or brush... meh) and then sand it flush with the rest. If it's not dyed, then the shellac should have the same appearance as the rest of the top if it is the same thickness. Once you've got it back to a level build coat, you can play with French polishing it, spiriting out, whatever. While the method of application may have some tonal effects, 99% of what you get from a shellac finish is there regardless of how it's applied or polished.

  8. #8
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    Default Re: French Polish Final Coats

    Another suggestion from my experience in the printing industry.... You can buy lint-free cotton cloth rags in bulk from printing suppliers... However the very best rags for applying finish or rubbing finish are from 100% cotton underwear which has been washed about 400 times during its lifetime. In that number of washes virtually all the lint is gone and the rag is as close to lint free as possible. Any other material as rags will simply not work anywhere near as well, if at all..

    Another suggestion for applying a finish is when wiping a finish on use lighter and lighter pressure and almost no pressure during the final wipes during each application... This is a matter of "feel" and is hard to explain but you will see and understand that some methods of wiping apply lint while a lighter touch, especially during the end wiping of an application (with a cotton rag) lifts the lint off the surface like magic.... As a teacher I would sometimes demonstrate this when teaching printing and my students were amazed that you could actually control lint through touch. In my years in the printing industry good cotton rags were like gold!!!
    Bart McNeil

  9. #9
    Mandolin & Mandola maker
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    Default Re: French Polish Final Coats

    French polish is all about practice, practice and more practice makes close to perfect. More perfect will take more practice, and perfect will take decades of practice. Don't expect to get it right the first time. The final coats are to get rid of the swirl marks and bring it up to a smooth gloss. As already mentioned, don't use a virgin pad. Use a pad that you have been using and it already has shellac in it. Add pure alcohol instead of shellac, but don't add too much alcohol. Keep the pad fairly dry, but not too dry (remember, practice will tell you how dry), and don't use too much oil. Use the bare minimum amount of oil, just enough to stop the pad from sticking. Keep adding small amounts of alcohol until you get the finish you want. The amount of pressure you need to use will come with practice.

    Rubbing out previous costs of shellac is a common problem. This can be caused by the pad being too wet or going over the same area too often, or not waiting long enough between sessions, or just not quite enough oil. It really depends on how bad the problem is, and what shellac you used, on how easy it is to fix. Darker shellac will be more difficult because you will need to match the colour of the patch with the surrounds. Often it is just a matter of lightly sanding with 1200 wet/dry and going over it with the pad a few times. You might need to repeat this a number of times before the patch disappears. Bad patches will require more aggressive sanding, and sometimes the only solution is to take most of the shellac off and start again. You usually only need to start again if you are using dark shellac and can't match the colours. Don't panic, it can be fixed fairly easily.
    Peter Coombe - mandolins, mandolas and guitars
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  10. #10
    Registered User Andy Morton's Avatar
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    Default Re: French Polish Final Coats

    You may want to check out this Youtube set of videos by "Steve," where he shares his FP technique...this helped me a lot.

    http://www.youtube.com/watch?v=a159B...feature=fvwrel

    Andy

  11. #11

    Default Re: French Polish Final Coats

    That link is spam.

    Here's a good one:
    [URL="https://www.guitarsint.com/article/Introduction_How_To_French_Polish_Classical_Guitar s"]

    https://www.guitarsint.com/article/I...ssical_Guitars

    Luthiers Merc Intl (LMII) is good as well

    https://www.lmii.com/blog/2017/10/07...polish-finish/

  12. #12
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    Default Re: French Polish Final Coats

    Quote Originally Posted by bmac View Post
    Another suggestion from my experience in the printing industry.... You can buy lint-free cotton cloth rags in bulk from printing suppliers... However the very best rags for applying finish or rubbing finish are from 100% cotton underwear which has been washed about 400 times during its lifetime. In that number of washes virtually all the lint is gone and the rag is as close to lint free as possible. Any other material as rags will simply not work anywhere near as well, if at all..

    Another suggestion for applying a finish is when wiping a finish on use lighter and lighter pressure and almost no pressure during the final wipes during each application... This is a matter of "feel" and is hard to explain but you will see and understand that some methods of wiping apply lint while a lighter touch, especially during the end wiping of an application (with a cotton rag) lifts the lint off the surface like magic.... As a teacher I would sometimes demonstrate this when teaching printing and my students were amazed that you could actually control lint through touch. In my years in the printing industry good cotton rags were like gold!!!

    "100% cotton underwear which has been washed about 400 times during its lifetime"

    Hah! Make me an offer!

  13. #13
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    Default Re: French Polish Final Coats

    I might sand once or twice during the building process. It wasn't necessary on the last project.

    Most problems I have had were due to trying to build too fast, not knowing when to stop for the day, or too damp a pad, especially when moving to the final alcohol steps.

    If the pad starts to stick, it's time to quit. If you see any cloudiness, wait a few minutes.
    If it goes away, you might be able to add just a little more. But if there is any doubt, wait.

    It took me a while to figure out the pace and timing. Once I started to get a hold on that, it started to become a very friendly way to apply finish. Time and patience are your best friends when French polishing.

    Use only pure grain alcohol. In the US, Everclear and Golden Grain are both suitable. Denatured alcohol can cause problems.

    Small areas are harder to do than large areas.

    I avoid using compounds. If I feel I need to increase the gloss or micro-smooth the surface during the building process, I use rottenstone and mineral oil, but only after several days drying time. If you use it after the final coat, wait at least 2 weeks, more if possible.
    Last edited by rcc56; Oct-07-2021 at 1:34pm.

  14. #14

    Default Re: French Polish Final Coats

    Since my last post in this thread nearly a decade ago, I have spent several hundred hours French polishing.

    My biggest mistakes in retrospect were:

    - Not preparing the wood well enough before varnishing. French polishing "reveals the natural beauty of the wood", sure. But it can reveal and amplify poor sanding preparation, miter joints, seams, etc. Whereas lacquer and other higher-build finishes give you a little grace in all those areas. I will say that using French Polish forced me to dial in all those aspects, which was a good learning experience (even though it was not fun at the time).

    - Not having a good enough oil varnish base built up before starting French polish. If the instrument doesn't look good when you start French polishing, it won't look good when you're done. It'll look the same, just shinier.
    Additionally, if you expect French polish to build significantly, be prepared to wait a long time before you can ship the instrument. I had several instruments that required extensive finish cleanup due to impressing case fuzzies all over. The instruments had cured for several weeks, but it wasn't enough. They really needed months. Fortunately the customers were willing to hang on to them and play them as-is for a bit while they hardened, then I was able to efficiently clean them up later. The one that came out the best was close to a year old when I cleaned it up.

    - Expecting the French polish to look like a buffed out lacquer finish. It won't. That's OK. Don't give yourself a permanent repetitive stress injury like I did by trying to get a French polish to match a factory-buffed look. That's not what it's for. Not saying it can't look good, but embrace the difference and save yourself some frustration.

  15. #15

    Default Re: French Polish Final Coats

    ^ I didn't realize that varnish had better "mistake covering" qualities than other finishes. I would appreciate links to articles discussing this feature of varnish.

    Thanks - Gary Davis

  16. #16

    Default Re: French Polish Final Coats

    Quote Originally Posted by GaryDavis View Post
    ^ I didn't realize that varnish had better "mistake covering" qualities than other finishes. I would appreciate links to articles discussing this feature of varnish.
    Maybe I don't understand your question. Any conversation involving "varnish" gets muddy quickly because lacquer is technically a "varnish", poly is a "varnish", etc. And that's before you get anywhere near the marketing around varnishes. I'll assume you mean the kind of varnish you pay extra for (oil varnish, alkyd resin varnish, etc).

    French polish doesn't really build like varnish does. It fills in and smooths the surface, but the surface should be pretty much glass smooth before starting.

    It's not about "mistake covering", it's about establishing an initial perfectly smooth and level surface before you start French polishing.
    Last edited by Marty Jacobson; Oct-09-2021 at 4:53pm.

  17. #17
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    Default Re: French Polish Final Coats

    As I'm learning FP, I've found that a 1lb cut is easier to smooth because it leaves less "ruts". Also mineral oil helps to prevent the pad from sticking.

  18. #18
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    Default Re: French Polish Final Coats

    In the kind of work that I do, which is usually smaller areas rather than a whole instrument, I also find 2 lb. cut to be too heavy, except perhaps for the first build coat.
    Yes, use mineral oil, but not too much, or the finish might not harden. A drop or two after you charge up the pad is usually sufficient.
    After the pad has been in use for a while and there is already oil on the finish, you may not need to add oil for a while.
    Look for the "vapor trail."

  19. #19
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    Default Re: French Polish Final Coats

    Quote Originally Posted by peter.coombe View Post
    Just add alcohol to the pad rather than a shellac mixture. It will then get thinner and thinner each time you add the alcohol. This is the best method IMHO and is the traditional way of doing it. You don't need to wet sand and you don't need to buff.
    Exactly. Alcohol polish. Very carefully. Practice on junk!!

    And I'm not looking for a gloss as much as a gleam!
    Stephen Perry
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