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"Invisible" Bow Head Repair

 
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Nipi2
Junior Member


Joined: 19 Jan 2015
Posts: 14
Location: Greece

PostPosted: Sun May 06, 2018 5:18 am    Post subject: "Invisible" Bow Head Repair Reply with quote

Hello everybody again.

After my obligatory army service (a destructive period for any “creative” human being) I continue restoring and making some bows. So, I am trying something like the “invisible” bow crack repair (the first image is an example of this crack). For example – how can someone restore a “classic” bow crack on the top, without leaving a black “hair width” line? I tried to paint it with aniline dyes but in such case there is no transparency. My father who was a classical guitar maker and luthier, I remember that when he was repairing guitar top’s cracks, he was using layers of colors, with basic layer the gold dust (I know it sounds weird but gold dust as under layer was adding transparency). Also by small point brush strokes the result is better that straight strokes.

Which is the ideal glue? (Titebond, hide glue, cyanoacrylate etc.) Most of that glues have color and leave black line.

Of course we want an invisible repair so we cannot leave external signs like “biscuit” repair, pins etc. What can we do to reinforce the restored part? (Or can we say that Titebond and other glues are making stronger connection than wood itself?)

A patent I used lately was this one at the image. I used a micro drill (0,3mm if I well remember) from the back part of the bow head. After the insertion, I cut what left with a simple cutter, and I pushed it to go bit further. Then I closed the open hole with wood-glue dust and the result was great. When I varnished it, with bit colored varnished, I couldn’t see it.


I would be happy to hear your opinions. Thank you all and wish you a good time (and sorry for my English).



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whatwasithinking
Member


Joined: 26 Jan 2013
Posts: 230
Location: Washington State

PostPosted: Mon May 07, 2018 10:36 am    Post subject: Reply with quote

Welcome back to civilization!

Isn't your goal to have a robust repair? This bow has been severely compromised, and there is no merit in obscuring that fact. I believe nearly all professionals would use a spline for this kind of repair. Some even use ebony as the spline material just so there is no doubt about the head having been repaired. I've heard of the kind of repair you described, but always with disparaging remarks. It is not nearly as strong as a spline.

Here is an excellent procedure.

Some like CA glue, and some like epoxy. CA repairs are reversible, while epoxy is difficult to completely remove, but may be stronger.

Good luck!
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Nipi2
Junior Member


Joined: 19 Jan 2015
Posts: 14
Location: Greece

PostPosted: Tue May 08, 2018 8:08 am    Post subject: Reply with quote

whatwasithinking wrote:
Welcome back to civilization!

Isn't your goal to have a robust repair? This bow has been severely compromised, and there is no merit in obscuring that fact. I believe nearly all professionals would use a spline for this kind of repair. Some even use ebony as the spline material just so there is no doubt about the head having been repaired. I've heard of the kind of repair you described, but always with disparaging remarks. It is not nearly as strong as a spline.

Here is an excellent procedure.

Some like CA glue, and some like epoxy. CA repairs are reversible, while epoxy is difficult to completely remove, but may be stronger.

Good luck!



Thank you for welcome and answer.
Very nice the article. I know for the spline or "biscuit" repair. My point is that I don't want to leave any (if possible) repair traces. The repair at the article is the most common used and for sure is strong.

I would like to know also, beside potassium permanganate, what other colors she use for hiding the repair? Analyne dyes? Acrylics?

thank you again
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whatwasithinking
Member


Joined: 26 Jan 2013
Posts: 230
Location: Washington State

PostPosted: Tue May 08, 2018 9:31 am    Post subject: Reply with quote

May I refer you to this discussion? I hold Josh Henry and Jerry Pasewicz in the highest regard, and would carefully consider their recommendations. They identify the drawbacks in alternative repair methods,
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Nick Walker
Member


Joined: 17 Sep 2014
Posts: 48

PostPosted: Sat May 12, 2018 11:22 pm    Post subject: Reply with quote

The spline repair definitely is one of the most respected and it is a fairly easy repair of you have a lathe and cutoff saw. I've done it with a fine kerf backsaw as well.

I believe most reputable bow restorers prefer to not hide the repair. Otherwise, future dealers may attempt to sell a damaged bow for the price of one that is uncompromised. It's a practice based on ethics.
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