Page 2 of 2 FirstFirst 12
Results 26 to 42 of 42

Thread: Repair of chip in sunburst

  1. #26
    Certified! Bernie Daniel's Avatar
    Join Date
    Oct 2006
    Location
    Cincinnati, Ohio, USA
    Posts
    7,712
    Blog Entries
    4

    Default Re: Repair of chip in sunburst

    Quote Originally Posted by HoGo View Post
    I would suggest using clear nitro for base and tinted shellac for color. Viloin restorers use shellac (or spirit varnish) as it is very easy to remove if one goes too far with quick wipe of q-tip and alcohol without disturbing the lacquer underneath. You should test that as well on your samples just in case... One never nows how these jobs will go.
    Thanks! I like that suggestion!

    When faced with this kind of situation the prospect (or even the possibility) of reversibility is borderline precious. Likewise I can stain shellac as easily as nitro lacquer with the TransTints. By next Tuesday I should have TransTint stains in two shades of amber, couple shades of light brown and orange.

    My shellac is a fairly new can of Zinsser "Bulls eye" clear. It is named "clear" but the actual product is a milky color -- maybe I should also consider buying flakes and mixing my own clear shellac?

    Another thought is I might add a couple of layers of base clear nitro just to provide extra protection from any pigments leaking into the wood?

    So , after reading your post I now have a plan.

    I sanded down a small (0.5 in X 6 in X 10 in) panel of Sitka that was left from a mandolin project and I will finish it like I think Gibson might have done my Sam Bush -- i.e. a thin coat of clear shellac, then the color (dye), then multiple coats of clear nitro lacquer.

    This should provide a simple mono color simulation of my top board. When this is cured up I can "damage" it with a dings like my mandolin.

    Then I can see how well I can handle an "easy" drop fill -- using the plan you supplied, (lacquer, stained shellac and lacquer) where the color of that I am trying to match is "known".

    If I can't fix that simple case then I know I can't fix the mandolin ding. If I can fix it we'll see about the next step.

    For sure I am going to learn something here! LOL
    Bernie
    ____
    Due to current budgetary restrictions the light at the end of the tunnel has been turned off -- sorry about the inconvenience.

  2. #27
    Adrian Minarovic
    Join Date
    Oct 2003
    Location
    Banska Bystrica, Slovakia, Europe
    Posts
    1,857

    Default Re: Repair of chip in sunburst

    Quote Originally Posted by Bernie Daniel View Post
    For sure I am going to learn something here! LOL
    Sure you are! And if you post your experience we can learn a bit as well.
    I typically refuse to do work on damaged tinted finshes or at least I do just basic repair with least possible finish damage and don't try to touch up finish, just seal it so someone more competent can do it later.

    Milky shellac is no good... perhaps water condensation got into it... I mix my own and it is always crystal clear (amber colored). I prefer using high percentage (99%+) alcohol sold for stackless fireplaces as eco-fuel (that's why it's very cheap) for shellac. Few layers of clear nitro underneath is good idea, but not filling the whole chip before you apply color. Sometimes applying clear shellac between the colored coats can help prevent smearing previous layers. Use tiny pointy brush rather than drop fill as the colored layers will rise at the edges and create dark outline of the chip.

    Have you tried just cleaning the damage with distilled water how it look when wet and if the fibers get back in place? Are there any loose lifted fibers?
    When I stripped F-9 it looked that there was kind of amber colored vinyl sealer righ over bare wood and brown nitro on top, the combination looks rather muddy so perhaps hey use more sophisticated way for higher models but I doubt straight dye over sealer. Thin nitro with color added is more likely.
    Adrian

  3. #28
    Registered User Ivan Kelsall's Avatar
    Join Date
    Mar 2006
    Location
    Manchester - Lancashire - NW England
    Posts
    12,997

    Default Re: Repair of chip in sunburst

    From Bernie - " For sure I am going to learn something here! LOL " Mostly about keeping your instruments in their cases - unless you're playing them !!.

    A tough lesson learned Bernie - i've been there !!,
    Ivan
    Weber F-5 'Fern'.
    Lebeda F-5 "Special".
    Stelling Bellflower BANJO
    Tokai - 'Tele-alike'.
    Ellis DeLuxe "A" style.

  4. #29
    Certified! Bernie Daniel's Avatar
    Join Date
    Oct 2006
    Location
    Cincinnati, Ohio, USA
    Posts
    7,712
    Blog Entries
    4

    Default Re: Repair of chip in sunburst

    Quote Originally Posted by Ivan Kelsall View Post
    From Bernie - " For sure I am going to learn something here! LOL " Mostly about keeping your instruments in their cases - unless you're playing them !!.

    A tough lesson learned Bernie - i've been there !!,
    Ivan
    I already learned that lesson -- again.

    But I keep my main instruments hanging on the wall of my office like any instrument stores do -- of course it should have been hanging there instead of resting in a "safe place" on my office work table.
    Bernie
    ____
    Due to current budgetary restrictions the light at the end of the tunnel has been turned off -- sorry about the inconvenience.

  5. #30
    Certified! Bernie Daniel's Avatar
    Join Date
    Oct 2006
    Location
    Cincinnati, Ohio, USA
    Posts
    7,712
    Blog Entries
    4

    Default Re: Repair of chip in sunburst

    Last night I sent an email to David Harvey to see if he will confirm exactly how the finishing was done on Gibson mandolins in 2001. Danny Roberts would also probably know too as he signed the mandolin. Given how thin the "color layer" is on the the Sam Bush-- i.e., there is clean wood less then a millimeter below the finish makes me kind ot think that Gibson did not use a wood stain (water or alcohol based) and then apply finish over top because that would have allowed the stain to penetrate to deeper depths? I'll comment back on his answer if he says it is something I can share. Or maybe he will comment on this string as I sent him a link to it.
    Bernie
    ____
    Due to current budgetary restrictions the light at the end of the tunnel has been turned off -- sorry about the inconvenience.

  6. #31
    Certified! Bernie Daniel's Avatar
    Join Date
    Oct 2006
    Location
    Cincinnati, Ohio, USA
    Posts
    7,712
    Blog Entries
    4

    Default Re: Repair of chip in sunburst

    Quote Originally Posted by HoGo View Post
    ....Have you tried just cleaning the damage with distilled water how it look when wet and if the fibers get back in place? Are there any loose lifted fibers?
    I have not yet tried that. How exactly would you suggest doing that? Use a soft camel hair artist's brush, wipe with a clean wet linen rag?

    Looking in a strong magnifying glass I THINK that I can see loose wood fibers -- for sure I think I see one corner that seems to have crumpled finish flakes -- looking like finish was pushed to the corner on the edge of the gouge of raw wood. If that make sense.

    Tried to show a better image of the chip. Ruler markings are mm.

    Adrian, is there a hint at the yellow coating you talked about on the F-9 there too?
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

Name:	chip mag311_2017.jpg 
Views:	36 
Size:	117.0 KB 
ID:	162527  
    Bernie
    ____
    Due to current budgetary restrictions the light at the end of the tunnel has been turned off -- sorry about the inconvenience.

  7. #32
    Certified! Bernie Daniel's Avatar
    Join Date
    Oct 2006
    Location
    Cincinnati, Ohio, USA
    Posts
    7,712
    Blog Entries
    4

    Default Re: Repair of chip in sunburst

    Anatomy of a finish chip.

    Trying to learn all I can before starting anything.

    I was able to look more closely at the chip in direct sunlight with a 4X mag and could see a lot of detail but I was unable to get a good photo -- the light/shadows/focus all combined to make a good shot impossible.

    But I now know there is no "bare" wood in the lesion. The bottom or "floor" of the chip is covered by a thin layer of pinkish gray film -- if I were to guess I'd say it is clear shellac. The upward pointing "V" is where the object hit and is the deepest impression -- estimated at 1 mm (0.040 in) deep --the lower part is "collateral damage" and is less then half as deep (estimated) and all of it is covered by the same film which I expect is the base sealant used at Gibson?
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

Name:	Chip Detail.jpg 
Views:	48 
Size:	77.7 KB 
ID:	162534  
    Bernie
    ____
    Due to current budgetary restrictions the light at the end of the tunnel has been turned off -- sorry about the inconvenience.

  8. #33
    Certified! Bernie Daniel's Avatar
    Join Date
    Oct 2006
    Location
    Cincinnati, Ohio, USA
    Posts
    7,712
    Blog Entries
    4

    Default Re: Repair of chip in sunburst

    Trial #1

    I decided to start simple so I prepared as small strip of Sitka spruce with amber finish in the manner I think my Gibson Sam Bush mandolin was finished: layer of clear shellac sealer, liquid stain, the five layers of clear nitro lacquer. (Pic#1)

    Then I prepare a selection of stained shellacs using TransTint dyes (amber, honey amber, antique maple, orange, and vintage brown) and procured some fine brushes that are suitable for oil media.(Pic #2)

    I had good deal of trouble making a suitable "ding" -- my first attempts were just "holes" not really "chips" -- I finally resorted to using a small wood gouge to make a chip that went down to the wood. (Pic #3)

    The you can see how the chip was filled in with two sealing coats of lacquer (Pics #4 & #5);

    Three coats of lightly colored shellac (Pics #6, #7, and #8);

    Finally a single drop fill of lacquer (Pic #9)

    I could go on with this, apply a second lacquer fill and then scrape the lacquer smooth and then rub it our with micro mesh but I think you can see in this simple test that it is possible to essentially make the chip disappear almost completely. There is a faint outline of the gouge in the last pic yet -- before leveling but this is not really visible to the naked eye looking at the piece.

    Next will follow a set of experiments using the same approach on a much more difficult media -- a spruce panel stained in a sunburst
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

Name:	Test Panel.jpg 
Views:	21 
Size:	31.3 KB 
ID:	162657   Click image for larger version. 

Name:	Dyes & brushes.jpg 
Views:	30 
Size:	120.3 KB 
ID:	162658   Click image for larger version. 

Name:	Gouge close.jpg 
Views:	29 
Size:	51.2 KB 
ID:	162659  

    Click image for larger version. 

Name:	Laquer1.jpg 
Views:	27 
Size:	54.1 KB 
ID:	162660   Click image for larger version. 

Name:	Laquer2.jpg 
Views:	31 
Size:	59.6 KB 
ID:	162661   Click image for larger version. 

Name:	Shellac 1.jpg 
Views:	30 
Size:	57.1 KB 
ID:	162662  

    Click image for larger version. 

Name:	Shellac 2.jpg 
Views:	29 
Size:	83.5 KB 
ID:	162663   Click image for larger version. 

Name:	Shellac 3.jpg 
Views:	32 
Size:	75.0 KB 
ID:	162664   Click image for larger version. 

Name:	Fill 1.jpg 
Views:	36 
Size:	59.6 KB 
ID:	162666  

    Last edited by Bernie Daniel; Nov-30-2017 at 4:06pm.
    Bernie
    ____
    Due to current budgetary restrictions the light at the end of the tunnel has been turned off -- sorry about the inconvenience.

  9. #34
    Adrian Minarovic
    Join Date
    Oct 2003
    Location
    Banska Bystrica, Slovakia, Europe
    Posts
    1,857

    Default Re: Repair of chip in sunburst

    That's magic!
    Stained sunburst ie easier to repair than colored lacquer, you just have to go slow and dry with the stains.
    When I repaired worn or damaged spots on stained SB mandolins I prepared Q-tips saturated with various colors of the SB and let tem dry completely. (I use alcohol dyes and don''t want them to touch the shellac/varnish as it would be difficult to remove any streak) I just slightly wet the Q-tip (I admit I often use my tongue even though wet sponge or paper towel would be preferred) and lightly rub it on the surface, let dry and follow with another application till the color matches. Sometimes I rub the amber base without drying to the bare spotand try to do as little overlap with finish edges as possible but any yellow on the shellac sealer become invisible after I aply new sealer over the retouch. I was able to retouch thumb sized worn spot on mando neck (at the transition from headstock) completely undetectale.
    Adrian

  10. The following members say thank you to HoGo for this post:


  11. #35
    Certified! Bernie Daniel's Avatar
    Join Date
    Oct 2006
    Location
    Cincinnati, Ohio, USA
    Posts
    7,712
    Blog Entries
    4

    Default Re: Repair of chip in sunburst

    Quote Originally Posted by HoGo View Post
    That's magic!
    Stained sunburst ie easier to repair than colored lacquer, you just have to go slow and dry with the stains.
    When I repaired worn or damaged spots on stained SB mandolins I prepared Q-tips saturated with various colors of the SB and let tem dry completely. (I use alcohol dyes and don''t want them to touch the shellac/varnish as it would be difficult to remove any streak) I just slightly wet the Q-tip (I admit I often use my tongue even though wet sponge or paper towel would be preferred) and lightly rub it on the surface, let dry and follow with another application till the color matches. Sometimes I rub the amber base without drying to the bare spotand try to do as little overlap with finish edges as possible but any yellow on the shellac sealer become invisible after I aply new sealer over the retouch. I was able to retouch thumb sized worn spot on mando neck (at the transition from headstock) completely undetectale.
    Thanks!
    Your plan of a lacquer base, shellac color, and then lacquer drop fill worked perfectly!

    Here is the new test panel. It is finished with five layers of nitro lacquer -- next week I'll gouge it. It is hard to damage a surface just the way you want!
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

Name:	Burst01.jpg 
Views:	35 
Size:	111.6 KB 
ID:	162681  
    Bernie
    ____
    Due to current budgetary restrictions the light at the end of the tunnel has been turned off -- sorry about the inconvenience.

  12. #36
    Registered User
    Join Date
    Sep 2002
    Location
    DeKalb, IL
    Posts
    3,261

    Default Re: Repair of chip in sunburst

    That looks great! In my experiences with this type of stuff, I find it very important to frequently get up and walk away from it. I can get way too focused on that little spot and lose perspective of the surface as a whole- obsessing, if you will. And move the project around into different lighting conditions.

  13. #37
    Certified! Bernie Daniel's Avatar
    Join Date
    Oct 2006
    Location
    Cincinnati, Ohio, USA
    Posts
    7,712
    Blog Entries
    4

    Default Re: Repair of chip in sunburst

    Quote Originally Posted by Dale Ludewig View Post
    That looks great! In my experiences with this type of stuff, I find it very important to frequently get up and walk away from it. I can get way too focused on that little spot and lose perspective of the surface as a whole- obsessing, if you will. And move the project around into different lighting conditions.
    Thanks I think that is great advice!
    Bernie
    ____
    Due to current budgetary restrictions the light at the end of the tunnel has been turned off -- sorry about the inconvenience.

  14. #38
    Certified! Bernie Daniel's Avatar
    Join Date
    Oct 2006
    Location
    Cincinnati, Ohio, USA
    Posts
    7,712
    Blog Entries
    4

    Default Re: Repair of chip in sunburst

    Trial #2

    This time a similar repair on the edge of a sunburst. The small piece of Sitka was sealed with shellac, stained in a sunburst with yellow, red and dark brown and then finished with 5 layers of nitro lacquer. Once I got it looking nice I chipped it with a small gouge then proceed to repair it with: 1) lacquer seal, 2) color via shellac layers. 3) lacquer drop fill.

    Results: 1) the raw chip; 2 & 3 lacquer seals; 4 to 8 shellac color (the last two were with shellac slightly darkened with orange and golden brown (it is and art and it is guess work!!); finally 9 & 10 are lacquer drop fills.

    I would still have to level and polish of course but we know how to do that -- I think the point is made that this technique can work.

    My next test will be make a chip deeper into the transition between amber and brown.
    Proceeding very very slowly is the trick!

    Still not ready to try the chip on my Sam Bush yet.....
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

Name:	C2.jpg 
Views:	20 
Size:	165.6 KB 
ID:	162765   Click image for larger version. 

Name:	C2 L1.jpg 
Views:	18 
Size:	168.3 KB 
ID:	162766   Click image for larger version. 

Name:	C2 L2.jpg 
Views:	16 
Size:	84.3 KB 
ID:	162767  

    Click image for larger version. 

Name:	C2 S1.jpg 
Views:	16 
Size:	83.2 KB 
ID:	162768   Click image for larger version. 

Name:	C2 S2.jpg 
Views:	16 
Size:	124.1 KB 
ID:	162769   Click image for larger version. 

Name:	C2 S3.jpg 
Views:	16 
Size:	152.9 KB 
ID:	162770  

    Click image for larger version. 

Name:	C2 S4.jpg 
Views:	16 
Size:	93.8 KB 
ID:	162771   Click image for larger version. 

Name:	C2 S5.jpg 
Views:	20 
Size:	140.5 KB 
ID:	162772   Click image for larger version. 

Name:	C2 LF1.jpg 
Views:	22 
Size:	132.5 KB 
ID:	162773  

    Click image for larger version. 

Name:	C2 LF2.jpg 
Views:	30 
Size:	117.5 KB 
ID:	162774  
    Last edited by Bernie Daniel; Dec-02-2017 at 6:26pm.
    Bernie
    ____
    Due to current budgetary restrictions the light at the end of the tunnel has been turned off -- sorry about the inconvenience.

  15. The following members say thank you to Bernie Daniel for this post:


  16. #39
    Registered User sunburst's Avatar
    Join Date
    Nov 2003
    Location
    Kentucky
    Posts
    13,944

    Default Re: Repair of chip in sunburst

    I have your address, Bernie. Be prepared for all my finish repairs to show up at your door!

  17. #40
    Certified! Bernie Daniel's Avatar
    Join Date
    Oct 2006
    Location
    Cincinnati, Ohio, USA
    Posts
    7,712
    Blog Entries
    4

    Default Re: Repair of chip in sunburst

    That would be risky.

    But sealing the bottom (the wood) with clear lacquer then the adding color via shellac seems to be a stable and controllable approach. The fear that the repair might go too dark is greatly reduced. (I think).

    You can make small adjustments to the color of the shellac as you go. I'm getting a feel for that and I test a lot on spruce shavings made with a plane - that helps a lot.

    Another good thing is that adding the final lacquer drop fill also (so far) as not given me a surprise change in shade or intensity. That is also a good thing.

    At this point in time the element of luck might still be part of the reason things, are (or seem to be) working. So I'll be practicing for while yet until I know for sure I'm really in control.

    Working under a fishman's fly-tyer magnifier with an LED light you can direct is a big help too.
    Bernie
    ____
    Due to current budgetary restrictions the light at the end of the tunnel has been turned off -- sorry about the inconvenience.

  18. #41
    Certified! Bernie Daniel's Avatar
    Join Date
    Oct 2006
    Location
    Cincinnati, Ohio, USA
    Posts
    7,712
    Blog Entries
    4

    Default Re: Repair of chip in sunburst

    Summary of Trial #2

    Shows the initial gouge and then the final repair after fill and leveling. The color is a little different but it is hard to control that on the cell phone camera -- these images are magnified (i estimate) circa 2.5 to 3 X.

    It is obvious now, after the fill and leveling, that I probably should have used one more layer of shellac color or made my covering sample a little darker. This slight color difference was not obvious before the fill. It is a learning experience.

    If anyone has any other thoughts on how this process might be improved I would like to hear them.

    So it is possible to substantially eliminate a chip even near a sunburst area. Most likely anyone not knowing where the initial damage was would not be able to find it even on this small test panel. For sure it takes the eye away from the damaged area.

    However, a final confirmation of the utility of this approach will be made by making a chip deeper into the amber-tobacco interface.
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

Name:	C2 final compare.jpg 
Views:	35 
Size:	67.7 KB 
ID:	162795  
    Bernie
    ____
    Due to current budgetary restrictions the light at the end of the tunnel has been turned off -- sorry about the inconvenience.

  19. The following members say thank you to Bernie Daniel for this post:


  20. #42
    Bluegrass Mayhem marbelizer's Avatar
    Join Date
    Apr 2016
    Location
    Washington State
    Posts
    33
    Blog Entries
    1

    Default Re: Repair of chip in sunburst

    You're on to something here. Your tenacity is impressive.
    I'll be referring to this thread in the future.
    '95 Gibson F-5V
    '93 Donaldson F
    2015 Martin D-18

  21. The following members say thank you to marbelizer for this post:


Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •