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Thread: FP blacktop finish

  1. #1
    Registered User Rob Grant's Avatar
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    Default FP blacktop finish

    Is it possible to get a decent blacktop finish using FP? Any suggestions appreciated. Most of the info I can find uses nitro as the clear final coat.
    Rob Grant
    FarOutNorthQueensland,Oz
    http://www.grantmandolins.com

  2. #2
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    Default Re: FP blacktop finish

    I don't think FP would give you a good clear black top. It would look a bit muddy or grayish more than real black. Even varnish would be a bit better but lacquer would give the best results in my opinion.
    Have a Great Day!
    Joe Vest

  3. #3
    Registered User barry k's Avatar
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    Default Re: FP blacktop finish

    Hello Rob, There will be 100 replys of how NOT to do it my way , but I will divulge anyway. Prep the wood as always for stain, or whatever final coats, then "I" use flat black Krylon (nitro lacquer) spray bomb several coats as required then 1-2 coats of clear nitro or sanding sealer. After a day or two start your FB...should shine up like a new dime. The same process can be done with spraying oil varnish as a final coat.

  4. #4
    Mandogenerator Mike Black's Avatar
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    Default Re: FP blacktop finish

    Here is the process I've tested on some scrape pieces and have had some good results. I too use the simi-gloss black spray paint then apply several coats of the KTM Spar Varnish, then FP the final coat. As I've said...I haven't done this on an instrument yet , but the scrape pieces look nice. I suggest that you too test whatever method you go with.

  5. #5
    Registered User amowry's Avatar
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    Default Re: FP blacktop finish

    It can definitely be done. This one is just French polish on top of a few coats of sprayed shellac, but I've also done it on oil varnish, and on KTM-SV, as Mike described. French-polishing a blacktop is more demanding than other colors because the black highights every irregularity, but other than that there's no difference. It ends up just as black as with any other finish. I usually level with 2000 wet or dry before my final FP sessions on a blacktop, to get it really smooth and level, and then use a very dry pad to bring it from there to the final sheen. That way you end up with minimal texture on the final surface. Like I said, it's demanding, but it can be done. The nice thing is that irregularities in the surface tend to diminish with time, as the finish shrinks and the texture of the grain lines become dominant. Of course once it gets in the customers' hands it will show every scratch and ding, but I try to make that clear to people before they order a black top. It's just the nature of the beast.








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  6. #6
    Registered User amowry's Avatar
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    Default Re: FP blacktop finish

    Here's another. I forgot to mention that I use the Krylon flat rattle cans: two coats on bare wood, then a shellac sealer coat before scraping the binding. If you let the Krylon sit too long on celluloid it will start to eat away at it, so I scrape within a few hours. Then I just spray a few coats of shellac and build with whatever base I'm using at the time, level sand to at least 1200, FP until I can level with 2000, then the final FP.
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    Registered User sunburst's Avatar
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    Default Re: FP blacktop finish

    Thanks, Andrew.
    I have a black top mandolin in the works and my test scraps will be sprayed with shellac and lamp black followed by spirit varnish. I'll try to remember to report on how it turns out.
    I wish I could find someone to teach me FP. I'm able to touch up shellac finishes with FP, but the idea of doing the whole instrument, from build coats to final surface is still beyond my grasp.

  8. #8
    Registered User Rob Grant's Avatar
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    Default Re: FP blacktop finish

    Thanks gang for the excellent responses. So it can be done with FP. I'll have to see if I can get black lacquer. Nitro based paints are a bit difficult to source locally. I do have a small tin of clear that I scored several weeks ago to repair a customer's mandolin. I may be able to add a black tint and apply it as a base colour coat. Apart from the recent repair, I have zero experience with nitro finishes.

    The blacktop idea came about after I decided that a spruce topped f5 I've almost completed has a few minor visual defects that bother me. Replacing the top with something more visually appealing is not an option, so I decided to have a go at a blacktop. The beautiful examples from Andrew's gallery are a real stimulus for me. Thanks for the advice Andrew. And, also, thanks again John, Mike, Joe and Barry.
    Rob Grant
    FarOutNorthQueensland,Oz
    http://www.grantmandolins.com

  9. #9
    Mandolin & Mandola maker
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    Default Re: FP blacktop finish

    If Gilchrist can do it with french polish, it can be done.

    Rob, if you want some Nitro, try Durobond Paints in Sydney (http://www.durobond.com.au Get the 851 Guitar lacquer. My guitar making colleagues have told me it is the best nitro lacquer available locally. They will do black for around $41 (plus postage) for 500ml.
    Peter Coombe - mandolins, mandolas and guitars
    http://www.petercoombe.com

  10. #10

    Default Re: FP blacktop finish

    Quote Originally Posted by sunburst View Post
    I wish I could find someone to teach me FP. I'm able to touch up shellac finishes with FP, but the idea of doing the whole instrument, from build coats to final surface is still beyond my grasp.
    John, you are such a gifted finisher I find that hard to believe. I am in the final stages of my first french polish on a new build and can honestly say its not something I would wish upon anyone! It really makes lacquer seem like a dream, although its easy to forget that has a steep learning curve at first, too.

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    Default Re: FP blacktop finish

    FWIW, I've found that going with flat black lacquer is best as the base coat.

  12. #12

    Default Re: FP blacktop finish

    Quote Originally Posted by Tony Francis View Post
    John, you are such a gifted finisher I find that hard to believe. I am in the final stages of my first french polish on a new build and can honestly say its not something I would wish upon anyone! It really makes lacquer seem like a dream, although its easy to forget that has a steep learning curve at first, too.
    I tried it once on my first and totally enjoyed the process and didn't think it was all that hard to master. My first time finish came out beautiful. I buffed it with the palm of my hand. If my case hadn't melted into it, probably caused by keeping it in my truck while I'm at work, I would be FPing all the time. I try not to leave it in the truck anymore. What else can you do at a festival though.
    Richard Hutchings

  13. #13
    Registered User Rob Grant's Avatar
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    Default Re: FP blacktop finish

    Dale,

    Just checking the web on "Japanning technique." Several Oz wood butchers use one of our locally available flat black "super etch" primers as the base coat. I just happen to have a pressure pack at hand. I'll lay some of the product down on a sample of spruce, rub it back and try a few runs of FP. Using a flat black as the base coat does make sense. Thanks for that.
    Rob Grant
    FarOutNorthQueensland,Oz
    http://www.grantmandolins.com

  14. #14

    Default Re: FP blacktop finish

    I have no experience with using it, but there is black shellac available. It's a machine made TN shellac flake thats black.

  15. #15
    Registered User bernabe's Avatar
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    Default Re: FP blacktop finish

    Quote Originally Posted by barry k View Post
    "I" use flat black Krylon (nitro lacquer) spray bomb several coats as required then 1-2 coats of clear nitro or sanding sealer. After a day or two start your FB...should shine up like a new dime. The same process can be done with spraying oil varnish as a final coat.
    Ive personally never tried it, but have heard conflicting info about FP over nitro [from reputable guitar makers]. Alot of folks say you can, alot say you can put nitro over shellac, but not the other way around. The claims are apparently based on the two materials' ability to maintain their bond due to the difference in how the two substances shrink over time. I guess if nitro underneath shrinks more or faster than the material over top, then it could start to peel a few years down the road. Why its worked for some people who have tried and not others may have to do with the amount of laquer underneath the FP and cure time of nitro before FP [degre of shrinkage after FP application]. This cant be determined on a scrap of wood unless you wait around a couple years. Anyone else have input?

  16. #16

    Default Re: FP blacktop finish

    I can't imagine a situation where you would want to FP over a built up lacquer finish but I don't think there's a problem with using lacquer as a sealer or color medium as long as it's scuff sanded. Shellac sticks to about anything.
    But don't quote me on that.

  17. #17
    Registered User sunburst's Avatar
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    Default Re: FP blacktop finish

    Quote Originally Posted by Jim Hilburn View Post
    I can't imagine a situation where you would want to FP over a built up lacquer finish...
    Sometimes in repair work.

  18. #18
    Registered User amowry's Avatar
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    Default Re: FP blacktop finish

    Hey John, if it makes you feel any better, I've French polished 70 instruments, and I pretty much feel like I'm starting from scratch every time. I think it may come easily to some people, but for me it's the single most challenging part of building. It think it's because unlike woodworking, it's not predictable, i.e. following the same steps doesn't always seem to produce the same outcome. I too wish I could find someone to teach me how to do it.

  19. #19
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    Default Re: FP blacktop finish

    Clarification: I'd never FP over lacquer. I put down the black lacquer base coat and then lacquer over it with clear coats. You can FP/shellac over varnish. That's commonly done. Build up finish with varnish and finish with shellac for the visual appeal. But shellac over lacquer? I'd be very skittish about the shrinkage issues, as mentioned. As well as solvent issues. It seems that anything will grip to shellac if you're spraying but I don't know about the other way around. (If John's done it, I'm sure it's OK).

  20. #20
    Registered User sunburst's Avatar
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    Default Re: FP blacktop finish

    The "conventional wisdom" is that shellac is fine under or over lacquer. I've only touched up small places on lacquered instruments with shellac to restore gloss and make things "hide" better, and I think of it as an escape from a rather involved lacquer repair, almost as a temporary solution to a problem that may or may not be fully repaired later. I've never tried to apply a full shellac finish over lacquer, so I can't say how well that would work.

  21. #21

    Default Re: FP blacktop finish

    If you do just that first couple of coats of lacquer with the color your not going to have enough build to worry about shrinkage.

  22. #22
    Registered User Polecat's Avatar
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    Default Re: FP blacktop finish

    Itīs a little O.T. but I hope no one will mind too much - can anyone suggest a way to treat a shellac finish to be less sensitive to water/moisture?

  23. #23
    Registered User Rob Grant's Avatar
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    Default Re: FP blacktop finish

    Andrew wrote:
    "Hey John, if it makes you feel any better, I've French polished 70 instruments, and I pretty much feel like I'm starting from scratch every time."

    A little "deja vu" here too!<g> I haven't done near as many instruments, but I experience the same thing everytime I lay down FP on another new mandolin.

    My skills with nitro are a bit limited, so I tend to touch up repair jobs with FP. It's weird, but I find some touch ups more successful then others. I ran into a recent repair that seemed to defy any attempts to lay down FP on nitro. After much mucking about, I bit the bullet and bought a 500ml tin of clear nitro.
    Rob Grant
    FarOutNorthQueensland,Oz
    http://www.grantmandolins.com

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