Violin Forum/Message Board Forum Index Violin Forum/Message Board
Provided by Violin Vision
 
 FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   RegisterRegister 
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 

Invisible seams?

 
Post new topic   Reply to topic    Violin Forum/Message Board Forum Index -> Violin Making and Restoration Forum
View previous topic :: View next topic  
Author Message
Mat Roop
Senior Member


Joined: 24 Mar 2007
Posts: 911
Location: Wyoming Ontario

PostPosted: Wed Apr 11, 2007 9:22 pm    Post subject: Invisible seams? Reply with quote

After gluing a split as in the top, no matter how good the alignment and how tight it has pulled back together after regluing, there will always be a slight crack in the varnish that shows especially when looking at it with light reflecting off it. I have been able to fill this type of crack to a perfectly flush condition (by french polishing) so that the finish is totally flush and the crack is not visible except perhaps very slight coloration.
The problem is that this is an incredibly slow and tedious process... is there a better way to fill any slight cracks so that the surface is smooth and unbroken???
here is an example of such a crack. the alignment of the plate at the crack is dead on...and at the right side you can see that the crack is almost invisible where the shellac has completely filled the void.... but then my arm got tired!



Thanks for your advice!
Mat
Back to top
View user's profile Send private message Send e-mail Visit poster's website
Jeffrey Holmes
Member


Joined: 03 Apr 2007
Posts: 90
Location: Ann Arbor

PostPosted: Thu Apr 12, 2007 9:20 am    Post subject: Reply with quote

Hi Mat;

French polishing really isn't the way to go... The addition of shellac to the area around the repair will "kill" all varnish texture... and is considered invasive (an especially poor practice when working on older instruments). Also, polishing tends to discolor the crack (low area) as it works small bits of dirt that your cloth picks up and the oil used to lubricate the polish into the void.

Unfortunately, touching in cracks without affecting the surounding area is no less tedious... but the results are much better and more in keeping with conservative methods... and the crack, if the job is done correctly, can "go away".

The idea is to fill the void in the finish with a clear varnish. Some use their touchup varnish. I use a copal/sandarac/light shellac blend as it's easier for me to run a "bead" with, dries relatively quickly, and is very clear.

Once the fill is dry (a few/several days) it can be leveled using a very sharp scraper... then the area directly over the crack can be touched in. Touchup is accomplished by alternating color coats with clear or tinted sealing coats... all very thin and laid on carefully with a small brush. The surrounding varnish should be left alone.

As follows is a post I placed on another board about a year ago. It deals with a back crack and the procedure I used for the repair and should illustrate what I'm talking about and a bit more (but it will save me the time of composing a new post). Back cracks, in my opinion, are harder to touch in than top cracks (as the grain is less prominent). Lots of photos... sorry if it takes a while to load.

--------------------------------------------------------------------

Sorry about the color variance in the photos, they were shot under different lighting conditions at different times of day.

I hope you all understand if I don't mention the maker or owner of the instrument.

The violin was presented in this condition:



As sometimes happens when a break like this occurs, the arching on portion of the back that separated "relaxed" slightly. This essentially made the piece slightly longer, so aligning the lengths was required. To do this, I removed the back and spot glued it to a platform. The blue tape is holding down a piece of wax paper to keep the "free" part from sticking to the platform:



Then I installed brass posts and fashioned some pads and wedges to hold the ends of the pieces in alignment.



The center portion of the crack varied from square to bias through the plate and I felt it required some manipulation to ensure that the arch aligned correctly, so only the ends (from the edge into the purfling channel) were glued in the jig.



After removing the back from the jig, I used pillars, clamps and wedges to align the arch in three partial gluings, cleating the finished areas behind the work to ensure these portions would stay closed as I manipulated the plate when gluing the next section.



After the area was thoroughly dry, I shaped the cleats and moved onto the finish. They may be overkill, but when this amount of manipulation is required, I feel better with cleats... These are willow, and on the thin side.



A small amount of missing wood was addressed, fill varnish was applied and allowed to dry, the filler was leveled, then a good number of color coats followed/alternated with sealing coats was applied. This photo shows the upper portion of the crack after 10 or 12 coats (I think. I never really count)... it's just at the point the damage is starting to fade away.



Pretty much finished... the final coat or two will be applied after the back is re-attached.


_________________
Jeffrey

http://holmesviolins.com
Back to top
View user's profile Send private message Visit poster's website
Chet Bishop
Super Member


Joined: 23 Mar 2007
Posts: 678
Location: Forest Grove, Oregon

PostPosted: Thu Apr 12, 2007 1:40 pm    Post subject: Reply with quote

Well, Jeffrey,

I never get tired of looking at that particular series of photos...and wishing I could learn similar skill.

Do you mind elaborating on "how" you addressed the missing wood? not putty, I assume-- did you find similar wood, and glue it in place, or what? From what I can see, the missing wood was basically a small splinter, no?

Seriously, I'd be thrilled if my repairs looked half that good.

Chet
Back to top
View user's profile Send private message Visit poster's website
Jeffrey Holmes
Member


Joined: 03 Apr 2007
Posts: 90
Location: Ann Arbor

PostPosted: Thu Apr 12, 2007 2:06 pm    Post subject: Reply with quote

Hi Chet.

Thanks for the compliment. Restorations are enjoyable for me... each one presents it's own challenge. Smile

Yes, the missing wood was a small splinter, irregularly shaped, in about the center of the break. It seemed to have been caused by a secondary impact of a metal portion of a shoulder rest when the fiddle hit the studio floor (I recommended that the player switch brands... I don't like exposed metal in that area).

I used lycopodium powder mixed with hide glue for the fill, in this case. After sealing it, I painted in a little "speckling" and adjusted the color very slightly so it would match the surrounding wood... then just touched it in along with the rest of the crack. Since the speckling was painted in at the base level, it reflects in a very similar way to the wood around it.
_________________
Jeffrey

http://holmesviolins.com
Back to top
View user's profile Send private message Visit poster's website
Andres Sender
Super Member


Joined: 23 Mar 2007
Posts: 275
Location: N. CA

PostPosted: Thu Apr 12, 2007 2:54 pm    Post subject: Reply with quote

Thanks for the breath of fresh air Jeffrey, we are very lucky that you are willing to share your knowledge in this way. Smile
Back to top
View user's profile Send private message
Jack H.
Super Member


Joined: 24 Mar 2007
Posts: 346
Location: Israel

PostPosted: Thu Apr 12, 2007 3:07 pm    Post subject: Reply with quote

Deft.
All the pros have been using it for a while!
Apply with narrow brush (disposable...)
Allow to dry.
Scrape down.
re-apply as necessary.
Color match and varnish over to finish.
Back to top
View user's profile Send private message Send e-mail
Jeffrey Holmes
Member


Joined: 03 Apr 2007
Posts: 90
Location: Ann Arbor

PostPosted: Thu Apr 12, 2007 3:19 pm    Post subject: Reply with quote

Jack H. wrote:
Deft.
All the pros have been using it for a while!


Well, maybe not "all" the pros, Jack. Smile

I do know some very fine restorers who do use Deft. They seem to get along with it... I also know a number of restorers who don't use it. I've used (tried) it on a few occasions in the past. Does work as a filler... easy to handle... surely easier than making your own (just open a can!)... but in the end there were some qualities I didn't like about it (at least in the way I wanted it to work; it's continued shrinkage... a little "soft", etc.).

Of course, what I make and use may not work as well for another restorer (especially if the touchup varnish they use is of a different texture) as it does for me.

Whatever one chooses, it should be at least as hard as the upper layers of touchup varnish (softer won't work)... or just a little harder (which I think is better), release all it's solvent in the drying process (so it stops shrinking), and be compatible with what is used for touchup (so that the color and varnish stays where it's put, doesn't crinkle, and stays stable).
_________________
Jeffrey

http://holmesviolins.com
Back to top
View user's profile Send private message Visit poster's website
Mat Roop
Senior Member


Joined: 24 Mar 2007
Posts: 911
Location: Wyoming Ontario

PostPosted: Thu Apr 12, 2007 8:10 pm    Post subject: Reply with quote

Jeffrey, Thanks so much for a view of that super repair...sooo impressive!
When you run the bead of light shellac with copal/ Sandarac, how can you be sure it does not dissolve the existing neighboring varnish and create a ridge... or is the bead very thin and in multiple layers?... or does that work only on oil varnish finishes as opposed to spirit varnishes?
When you apply the touch up varnish after the fill, what technique do you use to blend the edges of the touch up so that an edge ridge of varnish thickness is not visible?
Thanks! Mat
Back to top
View user's profile Send private message Send e-mail Visit poster's website
Jeffrey Holmes
Member


Joined: 03 Apr 2007
Posts: 90
Location: Ann Arbor

PostPosted: Thu Apr 12, 2007 9:50 pm    Post subject: Reply with quote

Mat Roop wrote:

1) When you run the bead of light shellac with copal/ Sandarac, how can you be sure it does not dissolve the existing neighboring varnish and create a ridge... or is the bead very thin and in multiple layers?... or does that work only on oil varnish finishes as opposed to spirit varnishes?

2)When you apply the touch up varnish after the fill, what technique do you use to blend the edges of the touch up so that an edge ridge of varnish thickness is not visible?
Thanks! Mat

Thanks Mat.

Your questions:

1) In order to actually run a bead, the varnish must be on the thick side. Too thick, and it's uncontrollable (stringy; won't flow). Too thin and it will "pool" (flow to the edges; not form a bead). One runs as thin a bead as possible. The varnish does "bite" any existing varnish it touches enough to adhere, but not enough to really dissolve it. It is possible to "build up" a bead of sorts, using thinner varnish and many applications, but it's much harder to keep the application "tight" (just over the crack) that way and you have to wait for each coat to dry.

2) When the bead is leveled (with a very sharp scraper) you take it down to the point it's level with the surrounding varnish, then just a bit further... just over the crack itself. It doesn't take much. I use a curved scraper and magnification for this, as I want to touch the varnish surrounding the crack as little as possible... I can say "not at all", but in reality, if you actually level the fill just past the top of the existing varnish, you do barely touch the edge of what is/was there... but you shouldn't touch it enough to see that you have (if you get what I mean). In other words, try not to touch it at all (and you will anyway)... and make sure you stay above the wood itself... and don't make a racing stripe!

When touching in the area, start with small "dots" of color, working in the areas that may be a tad lighter first, then moving to the less light areas. I work with what some term as a "dry brush". Really, it would be more accurate to say that the brush is barely loaded. I test it on my thumbnail before applying the color to make sure only a spec at a time will be applied. If the varnish is intense in color, I seal with varnish that's slightly tinted. If the varnish is less intense, I'll seal with clear. Again, a very fine application. Check out the size of the brush I'm using. It's very small. Be patient, it takes many applications to get to the color you want and build up a significant film. Building up things slowly will also allow you to adjust the color as you build up the film (correct as you go).

I always strive to have the last coat leave the brush at the same level as the surrounding varnish, leaving the same texture and gloss (There are a number of ways to effect texture, gloss and flow out the film to reduce brush marks... I won't go into that or pigment/dyes now, as they are pretty big subjects... but I am in the middle of writing an article that will touch on that stuff). Again, my goal and reality rarely meet to my satisfaction, but I do get pretty close. If any treatment is required on the surface, it's usually accomplished with minor use of fine abrasives applied only where they are required (to the new varnish) and maybe a single pass of a "polish" cloth (again, to the new varnish).

Some hints:

David Burgess taught me this one when I worked with him. I use it every now and then when I feel the color will be tricky to duplicate: If you feel you need to experiment a little to find the color you'll need and the film thickness required, you can place a piece of saran wrap over the crack area and build up a film on it. Helps get things rather close. Once you're comfortable with the color and film thickness you're getting, remove the wrap and apply the same ideas to the job at hand.

Watch the red. It's easily overdone... and what appears red or orange can often actually be several layers of yellow. Look at the worn areas of the instrument's finish for clues as to how the color was accomplished. Also, some don’t see red or green as well as others (color blindness). Make sure you are actually seeing what you’re applying.

Look at each coat of color application in different "light" (daylight, bulb light, etc.) and at different angles. If you build up the color too quickly, the touchup will appear opaque (dark) from one direction or another.

Hope that helps. Give it a try and good luck!
_________________
Jeffrey

http://holmesviolins.com


Last edited by Jeffrey Holmes on Fri Apr 13, 2007 4:22 pm; edited 1 time in total
Back to top
View user's profile Send private message Visit poster's website
Jack Rushing
Member


Joined: 23 Mar 2007
Posts: 170

PostPosted: Thu Apr 12, 2007 10:26 pm    Post subject: Invisible Seams? Reply with quote

Beautiful job Jeffrey.!!! How did you remove the back so clean?
I don't see any little chips or splinters anywhere.
Back to top
View user's profile Send private message Send e-mail
Jeffrey Holmes
Member


Joined: 03 Apr 2007
Posts: 90
Location: Ann Arbor

PostPosted: Fri Apr 13, 2007 8:18 am    Post subject: Re: Invisible Seams? Reply with quote

JacK Rushing wrote:
Beautiful job Jeffrey.!!! How did you remove the back so clean?
I don't see any little chips or splinters anywhere.


Thanks Jack;

I’ve had a lot of practice removing tops and backs. Smile That helps.

Although a back is generally attached with stronger glue, if you go about it’s removal slowly and carefully, it’s less likely to splinter than the top.

If the edges are healthy, I sometimes use a small shaped softwood block and a hammer with a sand-filled head to tap the underside of the bout edges lightly (those not attached to the blocks) first. This usually yields some small openings in which I can insert my opening knife. The goal here is to gain access to insert the knife at different locations so I can be sensitive to the grain (move the knife in a direction that won’t cause a lift). I then work around the plate, into the block areas very slowly. I use a syringe to run in small bits of alcohol along the blade in the tough spots (alcohol crystallizes the glue and allows a clean release as long as you allow it time to work).

The tricky area of the back is the button. This is a large glue surface and does not allow good access. Any stress applied in this area can cause a crack. I work slowly with a very thin opening knife from the sides and rear (over the top block), applying small amounts of alcohol and waiting, until the area releases.

I would warn against trying to remove the back an instrument owned by someone else the first time… Better to give it a try on something one owns themselves.

The same techniques can be used for removal of the top. I do usually get a few small splinters here, but not terribly many. Older instruments that have had their tops removed a number of times in the past will tend to leave behind some fill or old splinters that came off in the past. I glue the wood back into the edge and replace the fill (with wood) before reattaching the top.
_________________
Jeffrey

http://holmesviolins.com


Last edited by Jeffrey Holmes on Fri Apr 13, 2007 4:24 pm; edited 1 time in total
Back to top
View user's profile Send private message Visit poster's website
Jack H.
Super Member


Joined: 24 Mar 2007
Posts: 346
Location: Israel

PostPosted: Fri Apr 13, 2007 8:52 am    Post subject: Reply with quote

Nice repair Jeffery!
Back to top
View user's profile Send private message Send e-mail
Jeffrey Holmes
Member


Joined: 03 Apr 2007
Posts: 90
Location: Ann Arbor

PostPosted: Fri Apr 13, 2007 4:19 pm    Post subject: Reply with quote

Thanks Jack.
_________________
Jeffrey

http://holmesviolins.com
Back to top
View user's profile Send private message Visit poster's website
Display posts from previous:   
Post new topic   Reply to topic    Violin Forum/Message Board Forum Index -> Violin Making and Restoration Forum All times are GMT - 4 Hours
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum


Powered by phpBB © 2001, 2005 phpBB Group