5) Piegatura delle C

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  • Опубликовано: 31 окт 2024

Комментарии • 30

  • @bluehoo0
    @bluehoo0 3 года назад +3

    Those templates or moulds you used are an excellent idea for accurately bending the c bout ribs, I’ve just made some👍 thank you for the idea.

  • @tpistor
    @tpistor 2 года назад +2

    Is it better to soak the rib in water for a few minutes? Or is just wetting the surface sufficient? Is it bad to soak for a few minutes? (worried about breaking)

    • @DavideSora
      @DavideSora  2 года назад +2

      I prefer to moisten them only just before bending them, so that the steam forms in contact with the hot iron and penetrates more effectively into the wood. However, even if it may seem counterintuitive, water has not a great penetrating power like that of steam, and therefore soaking the ribs for a few minutes does have not a great harmful effect. However, I do not recommend soaking the ribs for a long time so that they completely absorb the water: this would probably not cause problems with regard to the possibility of causing breakages but would cause deformations especially in the transverse direction (waviness with the grain) that if you use little water or even dry, does not happen. This would be particularly a problem with cellos, where due to the great height of the ribs these ripples often occur, which would be avoided with the moderate use of a little water just to produce the steam. The cause of the breakage is almost always caused by an imperfect contact between the rib and the iron, or to an application of force not on the exact point of contact or in a non-progressive way, or an insufficient heating time of the wood (bending too much fast or too low iron temperature).

  • @tpistor
    @tpistor 2 года назад +1

    You take extra care to form the C-ribs into the exact shape of the form minimizing "excessive strains". Probably you could have gotten the C-ribs in position with just a little clamping pressure. Is the idea to minimize the strain? Is the theory that the un-strained c-rib will transmit sound better? Or is it a structural thing? I know everything move you make is for a reason - just wondering. Thanks for the video.

    • @DavideSora
      @DavideSora  2 года назад +1

      Bending the Cs accurately serves mainly to prevent the ribs from deforming once the form is removed. If not, the Cs would tend to open once the form was removed and the outline, especially the corner blocks, would no longer correspond to the outline traced on the plates. This would force you to push the ribs into place to respect the outline on the plates, which is not good and rather difficult to do. I suspect this forcing could also have negative acoustic effects, but it's hard to say for sure, also because with sufficient time (several years) the wood will tend to adapt to the shape in which it is forced, so this possible harmful acoustic effect would probably tend to disappear sooner or later anyway.

    • @tpistor
      @tpistor 2 года назад +1

      @@DavideSora Great point about the Cs opening up once form is removed. Thanks for the detailed answers.

  • @bluehoo0
    @bluehoo0 3 года назад +1

    Thank you for demonstrating this, are you using a piece of leather on the outside of the copper strap?

    • @DavideSora
      @DavideSora  3 года назад

      Yes, I use a leather strip which is useful to distribute the pressure more evenly and avoid burning your fingers. I say this in the captions, you can find the English translation of each caption in the description below the video.

    • @bluehoo0
      @bluehoo0 3 года назад

      @@DavideSora I did not realise you had the English translations below thank you again. I used to pause the videos and try to work out what was written. I’m an amateur maker and being able to view your working methods is very educational. I have spent my working life making furniture so I have the hand skills, and now in retirement am putting them to a different purpose which I find fascinating. It’s magical listening to a new instrument strung up for the first time, and hopping it sounds like I’d hopped it would. Take care👍

    • @DavideSora
      @DavideSora  3 года назад +1

      @@bluehoo0 I'm glad you are discovering violin making, having already a developed manual skill is a nice help, especially with the handling and sharpening of tools. I'm pleased to be of some help. All my videos have the translations in the description, if you click on the minutes at the beginning of each caption it takes you directly to the exact point of the video to which the translation refers. Anyway, trying to understand Italian is also very fascinating, it is the language of old violin makers, and my English is not so good.😊

  • @gmargiacchi
    @gmargiacchi 5 лет назад

    Ciao Davide
    Volevo sapere se dopo la piegatura incolli subito o fai passare un giorno per far assestare le fasce e ritoccarle senecessario...?
    Come sempre grazie infinite per la tua disponibilità

    • @DavideSora
      @DavideSora  5 лет назад +1

      E' meglio aspettare fino al giorno dopo lasciando le fasce in posizione sulla forma con i morsetti in modo da far assestare le fibre del legno, per evitare il più possibile un eventuale ritorno elastico.

  • @Irene_Iniesta
    @Irene_Iniesta 5 лет назад

    Hola Davide.
    Le estoy haciendo un cello a mi hija y no sé si el espesor de las "fasce" del cello es el mismo de 1,1/1,2 mm que en el violín. Muchas gracias por todo.

    • @DavideSora
      @DavideSora  5 лет назад

      Le fasce da cello io le faccio 1,5/1,6 mm, alcuni liutai le fanno anche 1,8 mm

    • @Irene_Iniesta
      @Irene_Iniesta 5 лет назад +1

      @@DavideSora Grazie mille maestro. Mia figlia è migliorata tanto come cellista e gliene serve uno fatto a mano. Grazie di aver condiviso la Sua conoscenza da liutaio

  • @Irene_Iniesta
    @Irene_Iniesta 5 лет назад

    Disculpe maestro que le pregunte otra duda. ¿Cual será entonces el espesor de la "controfasce" de un cello?

    • @DavideSora
      @DavideSora  5 лет назад

      Io faccio 2,2 mm, si può fare fino a 2,5 mm con legni molto teneri.

    • @Irene_Iniesta
      @Irene_Iniesta 5 лет назад +1

      @@DavideSora Muchisimas gracias Maestro. Espero que algún día nos enseñe cómo hace usted un cello.

  • @jung-hoonhan4927
    @jung-hoonhan4927 6 лет назад

    Hello Davide Sora. Thanks for your nice video. May I ask how thick is your bending strap? I am using spring steel bending strap but I wanna try something less spring. All the best!

  • @mrgolftennisviolin
    @mrgolftennisviolin 2 года назад

    A quick question about temperature if you don’t mind - have you ever found the need to turn the iron up hotter than temperature at which it passes the water drop test? I heard elsewhere that with the deepest flames, hotter is better, but on my first two attempts, I cracked one rib and scorched the next one pretty badly. I know experience is probably the best teacher in this case, but wondered if there is anything else I could try. (Pre steaming with a damp cloth between the iron and rib for example). Thanks for any advice!

    • @DavideSora
      @DavideSora  2 года назад +1

      The water drop test you see in the video indicates a temperature that is already quite high, I think about 170°, which is already at the limit to scorch the ribs if the contact time is too long. You could even increase up to 180°, but some burns become almost inevitable if you are not quick enough. The relationship between temperature and speed in bending is fundamental, everyone must find with experience what suits them best, and of course the one that suits the wood best. With heavily flamed wood the higher temperature might seem like a help, but the fact that it leads us to be faster in the bending could have the opposite effect, and cause us to break the ribs because we don't give the wood time to become plastic. Contrary to what one is led to think, the decisive factor for bending the ribs without breaking them (even the strongly flamed ones, and above all these) is to maintain perfect and very progressive contact with the bending iron, without allowing spaces without pressure on every single millimeter of the rib bending area. Technically, if the wood is brought uniformly to a temperature of 160 ° or even less, the pressure is applied uniformly (for example with a roller kept constantly pressed against the rib) and the rib is constrained at its ends to prevent it from stretching, it is practically impossible for it to break because the inside will go into compression and the outside will not stretch, physically preventing it from breaking. Trying to bend by hand with this principle in mind helped me a lot in learning how to bend without breaking.
      Then, to console you, sometimes it happens, some pieces are so difficult that they are destined to break, and you can't do anything about it. What the experience does is to develop the feeling that the wood begins to give symptoms of breaking but before it actually breaks, so as to be able to contain the failure to a simple surface flaking that can be solved by placing it strategically within the gluing surface with the block.

    • @mrgolftennisviolin
      @mrgolftennisviolin 2 года назад

      @@DavideSora this should help a lot!! Thanks so much, I’ll give it another go.

    • @mrgolftennisviolin
      @mrgolftennisviolin 2 года назад

      @@DavideSora first C bout bent successfully!! Like you said, there was one spot where the grain wanted to separate but it’s minor and well within the glue surface of the block so I should be ok! I’m really happy, and it’s all thanks to your advice. I wish I could repay the favor!

    • @DavideSora
      @DavideSora  2 года назад

      @@mrgolftennisviolin Well done!!😊

  • @jaminvincent5690
    @jaminvincent5690 3 года назад

    Ciao. Ho comprato un nuovo piegafasce con un sistema numerico per il discorso della temperatura. Purtroppo qualcosa non va. Continuo a rompere a repetizione le fasce nonostante la calma. Mi chiedo se non é dovuto alle imperfezioni della curva del ferro che ha infatti delle discontinuità(piccole ma ci sono). Può essere che la temperatura sale nonostante di come lo impostata. Mi chiedo se non devo rifare uno stage apposta per piegar le fasce 😂. Perché é assai frustante dopo aver spianato il legno con rigore.

    • @DavideSora
      @DavideSora  3 года назад

      Le discontinuità sarebbe meglio toglierle, ma se le fasce si rompono troppo facilmente potrebbe essere che la temperatura del ferro è troppo bassa. Hai provato a fare il test della goccia d'acqua? Puoi anche verificare l'attendibilità dei numeri del display misurando la temperatura del ferro con un termometro a raggi infrarossi, dovrebbe stare intorno ai 160/170°

    • @jaminvincent5690
      @jaminvincent5690 3 года назад

      @@DavideSora certo che la goccia saltava come nel tuo video a circa 165. Ho già rettificato le piccole imperfezioni del ferro. Facendo come da manuale la fascia si é rotta su tutte le marezzature con uno spessore di 1,1 per le CC. Non ti dico il nervoso che mi é venuto. Devo rifare tutto da capo visto che non mi é rimasto un listello in più. Non voglio mettere del legno scompagnato. Non riesco a capire se é il legno o io. L'unica cosa che mi sono accorto di questo piegafasce é che ia curva più ampia si trova a destra e mentre preferisco il contrario. Riprovero con degli scarti per capire meglio. Grazie.👍💯

    • @DavideSora
      @DavideSora  3 года назад +1

      @@jaminvincent5690 A volte può essere semplicemente il legno particolarmente problematico, specialmente se è molto stagionato e con marezzatura profonda, ogni tanto capita😕

    • @jaminvincent5690
      @jaminvincent5690 3 года назад +1

      @@DavideSora inizialmente il legno mi sembrava assai elastico. Comunque Amen. Le ditte che producono gli attrezzi devono essere un pò più certosine visto il prezzo che paghiamo. La stessa cosa avviene con pialle e piallete che ho dovuto sistematicamente modificare ( piani imperfetti, angolo di taglio). Non finisce mai 😂!!! Grazie mille 👍