Violin Forum/Message Board

actonern · Super Member Joined: 15 Aug 2007 Posts: 444

look carefully at the photos...

Chet Bishop · Posted: Sat May 25, 2013 9:17 pm Post subject:

The point being that in that particular sequence one can see that both sets of linings were in place before the mold was removed.

I have done them this way, but am not very good at it...so I use a two part mold. I have broken blocks and/or ribs trying to do exactly what Michael is doing in the photo-essay.

Henry Strobel teaches it that way, too. I just have never mastered that trick.
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dan bombliss · Junior Member Joined: 21 May 2013 Posts: 12

I'm not sure if we are talking about the same thing or not. I was just saying with a one piece mold (out of a solid, single piece of plywood or such) Can't come out after you put linings in both sides, as the mold has to slide through the ribs.

I'm building my cello with a breakaway mold, which comes apart inside of the ribs, so that even with linings on both sides, it will "collapse" if you will, and slip through.

I suppose this has tracked a bit off, which I'm sorry for, I had just meant to raise a brief awareness, but maybe I had iterated it poorly.

-Dan

Chet Bishop · Posted: Sun May 26, 2013 1:49 am Post subject:

Naw, you said it just fine-- yer just mistaken, that's all! Smile

(Which is fine. I've been wrongly adamant about things before and was able to learn from someone who could show me different.)

But as far as removing a one-piece, solid mold after both the front and back linings are in place, YES! I have done it; Michael Darnton shows a series of photographs of himself doing it, and Henry Strobel advocates doing it that way. It definitely works. (It does require a fairly thin mold.)

How it works is that you:
1. Pop loose all the blocks from the mold, and trim them as much as is practical, before attempting to remove the mold. Then,
2. Gain some slack by flexing the center bouts outward a little. There is quite a bit of slack to be had in doing so.
3. Slip the upper bout off the mold, using the slack gained at the C-bouts, then
4. Work the slack down around the rib garland to complete the removal of the mold.

It isn't easy, but it does work. I just chose to do as you did and make collapsible molds. Lazy, I guess. Smile

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dan bombliss · Junior Member Joined: 21 May 2013 Posts: 12

Whelp,

I sure do appreciate being corrected. Now I don't have to make a breakable mold for my violins (If I build anymore) Granted, I don't know if mine is too thick.

Thanks!

Chet Bishop · Posted: Sun May 26, 2013 1:57 am Post subject:

Well, Dan,

Frankly, I do not advocate doing it that way, because it really is easier your way.

There is such a thing as a "French" mold, however, which is thicker, and is used flush with the front of the ribs.

The back linings are installed and trimmed, the back plate installed, and then the mold is slipped out pretty easily, but the structure is already quite rigid, and it is easy to install the front linings, trim them, shape the blocks, clean up the inside, etc-- and then install the front plate.

I have done it that way, too, and it is a pretty fast way to work, but I guess I like the Italian style molds better.

Chet
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ctviolin · Posted: Sun May 26, 2013 2:31 am Post subject:

dan bombliss · Junior Member Joined: 21 May 2013 Posts: 12

Sorry guys, I hadn't seen the link of the mold until now. Those photo's make sense, that is a much thinner mold than mine, which is why it had never seemed to be plausible.

Thanks for the info.

kjb · Super Member Joined: 06 Feb 2013 Posts: 385

does anyone use outside moulds regularly?

actonern · Super Member Joined: 15 Aug 2007 Posts: 444

Roger Hargrave, in one of his many on line articles about the Cremonese working methods suggests that the reason the centre bout linings are mortised into the corner blocks is to help deal with the stress to the ribcage of removing it from these types of molds.

Interesting idea.

E

ctviolin · Posted: Sun May 26, 2013 8:13 am Post subject:

actonern · Super Member Joined: 15 Aug 2007 Posts: 444

Me too... I always imagined it would be more difficult to get corner tips to turn out well...

mikemolnar · Member Joined: 30 Mar 2007 Posts: 57

For removing the garland from the form, I use Darnton's technique and the procedure outlined by Bishop.

If you still have doubts whether their method will work for you, try this: Put in all the linings for the bottom side. For the top side put in the c-bout linings only. The remaining linings can be added after removal from the form.

Does anyone else have a comment about my original question regarding the issue of lining coverage of the ribs? I agree with Reedy, but wonder about acoustical effects. I suspect they are minimal.

Mike

mikemolnar · Member Joined: 30 Mar 2007 Posts: 57

I made an external form years ago, nicknamed the Iron Maiden. (grins) However, it is unnecessary and cumbersome. As I said above, I use the standard internal form method.

One bit of advice is to make sure that your ribs are bent straight and not lop-sided. Lots of us think we do that, but a quick check with a square on a surface plate will tell the truth.

Mike

Chet Bishop · Posted: Sun May 26, 2013 11:29 am Post subject:

Yep, and it Realllly makes a difference when you try to close the corpus, if the ribs are all twisted. The first side goes on easily-- the second is impossible to line up correctly, as the ribs are now rigid--and crooked.
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