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DonLeister
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Joined: 29 Mar 2007
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Location: Richmond, VA
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 Posted: Sun May 26, 2013 12:44 pm Post subject: |
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I have never heard that Michael. I aim for around 7-7.5, they might be less sometimes.
I probably pay more attention to trying to make the ribs be a little bit convex, just because that's what I hear the Cremonese did. I see it in some of the ct scans on the Strad posters. It's one of the things I try to remember to look for on the rare occasions that I get to look at an original closely. It's another one of those subtle things that adds a little life to the look of it.
Whether it makes a difference to the sound I can't say, not knowing.
Sorry to take the thread in another direction. |
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mikemolnar
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Joined: 30 Mar 2007
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| Posted: Sun May 26, 2013 1:20 pm Post subject: |
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| Isn't that the truth, Chet? As the twig is bent, .... |
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Cliff Green
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Joined: 01 Apr 2007
Posts: 111
Location: Amissville, Virginia
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| Posted: Sun May 26, 2013 3:36 pm Post subject: |
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MikeM
I've never heard of the 50% cover for linings either though 16mm does fit with MichealD's multiple of 32mm scheme. Makes you wonder. I start with 2X8mm lining stock and glue a little proud of the rib edge for final trimming so I end up with around 7.5mm.
For keeping the ribs square to the mould I've been temporarily(with3M adhesive) gluing 1mm or so stock to the bottom of the 6 blocks. When the ribs are glued I can easily observe that the ribs are square by comparing to a flat surface. The ribs are now evenly 1mm proud of the blocks for final trimming. I've used pennies and rib stock.
Cliff |
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ctviolin
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Joined: 07 May 2009
Posts: 961
Location: Roswell
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| Posted: Sun May 26, 2013 4:17 pm Post subject: |
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| mikemolnar wrote: |
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 |
Ok, I'll comment my feelings on this, or on these (exactly or carefully measured) type of things, generally.
If you are referring to the 50% remark earlier (where the linings will cover 50% of the rib's finished height - meaning the top & bottom linings heights, added together should equal about 50% of the full ribs height), then, yeah - it sounds about right. (as a rule of thumb - perhaps it's fine, ok?)
But, for one thing, often the exact rib height changes - depending on where you're measuring...
It could well be used as a *standard*, of sorts - but in my opinion, (for me at least), it is a bit arbitrary to have a "standard" in this type of area generally, to "go by" that's really or usually anything more than somebody else's opinion, or someone's observation. As "correct" as it may be. (like "use clothes pins as clamps" is a "correct" answer, but only part of the POSSIBLE correct answer, as we can look back and see)
So far, so good?
I very often (well, every time actually) when I make the linings for an individual violin, as I make the rib assembly - I will vary the height and width of the linings depending on things like, lining wood grain width, wood strength, bending qualities, & other individual wood characteristics of the lining material.
I make them exactly as wide and thick as I feel they should be.
The WIDTH OF THE RIB MATERIAL ITSELF, that's being used, (as another example) also makes my decision about the exact size and qualities of the lining wood (like - lining thickness) that's required, change - often radically.
It's more like a decision the maker goes thru, when considering the EXACT, INDIVIDUAL requirements of the instruments needs...
And, is "perfection" or philosophy a part of what's being discussed?, or is the (or a) general or particular method of construction only, being discussed?
Simple or complex, either way can be exactly what the poster needs or is looking for. Sometimes it is difficult to determine ahead of time - exactly what type of answer is being looked for.
Plus, when a simple answer is given - exact measurements or qualities are often added in (piece by piece or bit by bit) by other posters, as if they were accidentally left out...
Ahh, the internet. Honestly, I love posting on it, but it IS really interesting to see how things fall & how discussions have qualities that easily lead to squashed feelings or the like. One must simply recognise it for what it is and deal with it as it is part of the game and NEVER let it bother you to the point of reacting emotionally.
Breath..., breath..., breath..., in-out, in-out, in-out, there, doing ok?
Think so - don't think so?
comments please.
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Last edited by ctviolin on Mon May 27, 2013 5:46 am; edited 2 times in total |
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actonern
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Posts: 444
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| Posted: Sun May 26, 2013 6:57 pm Post subject: |
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Somebody mentioned the concavity of ribs found in golden period instruments...
I've observed that all ribsets lined on both sides on an inside mold (before being removed from the mold) exhibit this characteristic. What I don't understand is why that should be. If the ribs and linings are allowed to dry after being steam bent where does the tension come from that pulls everything inward? |
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DonLeister
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Location: Richmond, VA
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| Posted: Sun May 26, 2013 8:25 pm Post subject: |
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I believe it is convexity, where the ribs appear to have a slight bulge, veiwed from the outside. From my very limited observations it isn't an absolute, or not consistent all the way around.
To make that happen you can wet the ribs, compress the C's as you glue them in, compress the C bout linings when you glue them and also scrape the ribs down after they are on the mold.
If I had easy access to fresh (green) willow I would try gluing in fresh linings to see if they might shrink some and encourage it some. Crazy sounding I know but green willow bends like , well , steamed wood? There are precedents in joinery where green wood is advantageous, at least in the past, not so much a thing of today.
CTviolin, I agree with your comments regarding forum postings and not taking things too personally. I like how you have that awareness and encourage others in that regard. |
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kjb
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| Posted: Sun May 26, 2013 9:54 pm Post subject: |
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the first 8 or 9 I made were with outside moulds, so that is the way I learned, from that perspective I find the inside mould harder , but I am trying to learn it since everyone else seems to be doing it.
it has also be 20 years since I did the outside so my memory is not that accurate . that's why I was wondering if anyone is still using them, and what is the advantage or disadvantage |
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ctviolin
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Joined: 07 May 2009
Posts: 961
Location: Roswell
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| Posted: Sun May 26, 2013 10:50 pm Post subject: |
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.
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Last edited by ctviolin on Sun May 26, 2013 11:40 pm; edited 1 time in total |
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Chet Bishop
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Joined: 23 Mar 2007
Posts: 678
Location: Forest Grove, Oregon
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| Posted: Sun May 26, 2013 11:37 pm Post subject: |
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| actonern wrote: | Somebody mentioned the concavity of ribs found in golden period instruments...
I've observed that all ribsets lined on both sides on an inside mold (before being removed from the mold) exhibit this characteristic. What I don't understand is why that should be. If the ribs and linings are allowed to dry after being steam bent where does the tension come from that pulls everything inward? |
Ernie;
I kind of think it is the glue shrinking as it dries that causes this.
They sell Hide glue that is specifically made for flaking glass. They paint it onto heavy plate glass and then shove the plate into a heavy padded envelope and wait. as the glue dries, they hear "pinggg! pinnng!" as the shrinking glue literally pulls the surface off the plate glass, leaving a surface reminiscent of an obsidian arrowhead. Quite pretty, and fairly "obscure" glass.
So, if shrinking hide glue can cause that kind of change in glass, I imagine it could cause some changes in wood as well. I once painted thin hot hide glue on the inside of a spruce plate that I reckoned to be too thin, but did not clamp it flat. The plate curled up like a dry leaf. Fortunately I was able to wet it down with hot water, and clamp it flat before allowing it to dry again. It was very stiff after that. Pretty impressive.
Thus, as I said, my assumption is that the shrinking glue is what is curling the ribs
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ctviolin
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Joined: 07 May 2009
Posts: 961
Location: Roswell
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| Posted: Sun May 26, 2013 11:38 pm Post subject: |
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| DonLeister wrote: | | I believe it is convexity, where the ribs appear to have a slight bulge, veiwed from the outside. From my very limited observations it isn't an absolute, or not consistent all the way around. |
Yes, I believe you are correct about this, Don. I was going to mention something about this also - but I feel many of my posts are already much too critical about exactly what's being said in the post - so....
Rib convexity - something that many makers elsewhere apparently strive FOR, since it can be found in various older instruments.
| DonLeister wrote: | | CTviolin, I agree with your comments regarding forum postings and not taking things too personally. I like how you have that awareness and encourage others in that regard. |
Thanks Don, I must say that;
- I very much enjoy posting here, and
- I very much appreciate that there ARE NO posters here, that loose it and become argumentitive or "bossy" over simply a difference in opinion.
- you guys even allow my BOCA EL MAGNIFICO DEL GRANDE here... hmmm, go figure that one out...
- yes, no other way to say it, the mgmt. here is about right for the mentality and activity of the posters - what a very cool thing, and somewhat a singular thing - I must say.
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Last edited by ctviolin on Sun May 26, 2013 11:46 pm; edited 2 times in total |
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ctviolin
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Location: Roswell
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| Posted: Sun May 26, 2013 11:40 pm Post subject: |
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And, oh, by the way, Don...
If it's ok, since I do have such an, mmm, massive grande boca - I was planning on posting everything in all caps, from now on, at 24 or 30 pt. type...
And perhaps in various glowing colors.
??
(ok, sorry, I'll stop now.)
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actonern
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| Posted: Mon May 27, 2013 7:29 am Post subject: |
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"...They sell Hide glue that is specifically made for flaking glass. They paint it onto heavy plate glass and then shove the plate into a heavy padded envelope and wait. as the glue dries, they hear "pinggg! pinnng!" as the shrinking glue literally pulls the surface off the plate glass, leaving a surface reminiscent of an obsidian arrowhead. Quite pretty, and fairly "obscure" glass. .."
That is just unbelievable! |
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DonLeister
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Joined: 29 Mar 2007
Posts: 383
Location: Richmond, VA
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| Posted: Mon May 27, 2013 8:30 am Post subject: |
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I should say that I have seen many of my ribs go wavy - both convex and concave. It takes some encouragement to get them favor convexity.
I - think- it is helping to only put glue on the linings and not the ribs when they go in.
Craig I love bad boy humor and being the father of a 10 yr old boy I really have to make an effort not to go there. But since you started it, can you make the words flash and moved across the page?  |
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ctviolin
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Joined: 07 May 2009
Posts: 961
Location: Roswell
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| Posted: Mon May 27, 2013 11:48 am Post subject: |
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| DonLeister wrote: |
But since you started it, can you make the words flash and moved across the page?
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I'm TRYING, and I've been TRYING for some years now..., ok?
(Mainly though, I've been trying to get my name to flash across the screen in giant gold and silver letters. - all this time, I've suspected that it was you Admin. guys that've been messing me up on this...)
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Chet Bishop
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Joined: 23 Mar 2007
Posts: 678
Location: Forest Grove, Oregon
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| Posted: Mon May 27, 2013 12:08 pm Post subject: |
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| actonern wrote: | "...They sell Hide glue that is specifically made for flaking glass. They paint it onto heavy plate glass and then shove the plate into a heavy padded envelope and wait. as the glue dries, they hear "pinggg! pinnng!" as the shrinking glue literally pulls the surface off the plate glass, leaving a surface reminiscent of an obsidian arrowhead. Quite pretty, and fairly "obscure" glass. .."
That is just unbelievable! |
I have a friend who made the obscure glass for his bathroom that way. It is very pretty, but not quite "obscure" enough for a bathroom, in my thinking.
Lets you know how strong hide glue really is, though.
Here's a link...looks like they sand the surface a little, first, to give it some tooth, but, still...
http://www.woodfinishsupply.com/GlassChipping1.html
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Last edited by Chet Bishop on Mon May 27, 2013 5:18 pm; edited 1 time in total |
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