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Post by Deleted on Mar 16, 2013 8:14:36 GMT
For a minute, I wondered if this was a reference to my mispent youth . Anyway, whether its right or wrong, I believe a well known luthier puts a smeath of pritt to keep the biscuit / triplate bridge in contact with cones. I have done before following that, but not right now. Did it make a difference? It stopped the tricone buzz initially, but it came back. TT
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Post by oldnick on Mar 16, 2013 9:35:41 GMT
I agree with Andy, if the guitar is set up correctly string pressure is all that is required.
Nick
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Post by Michael Messer on Mar 16, 2013 11:28:53 GMT
There was a time when we were all quite naive about National guitars and all kinds of things were tried. The thin bead of Pritt Stick glue (paper glue) was one that I remember, but it very quickly got thrown out and discarded, along with all other forms of glue & gaskets that were tried.
Something that has to be understood, is that to get where we all are today with so much knowledge and understanding of National & Dobro guitars, is that through those years and decades a few of us around the world were buying instruments and learning about this stuff, and we tried everything and every combination of everything!
Shine On Michael
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Post by Stevie on Mar 16, 2013 11:58:27 GMT
Looking at it, a string cannot vibrate (of itself) as it approaches its anchor point, but the vibrations of the string must be transmitted across the static point to the rest of the instrument? No one in their right minds would glue a string down to the saddle to prevent it from falling off when under no tension would they? Why then would anyone glue a cone in? Of course, it would hold it in without string tension as has already been intimated. However, this analogy is a poor one because the string is under tension, but the cone is under compression. The cone has a static deflection when the strings are up to pitch. This is demonstrable because the action lowers as you tune up. Well, it does on my MM blues anyway. (This is a good enough reason for having a removable hand rest alone in my book) Here's where the similarity with a loudspeaker cone disappears. The cone on a loudspeaker has a flexible mounting and is not under any static deflection. As that string tension force acts down upon the cone, with no lateral restriction, the cone material is going to stretch and make the diameter imperceptably greater. This is not permanent, it's elastic deformation. If you bond the cone rim down with adhesive (or perish the thought, fasteners), it cannot stretch in the way I have described in sympathy with the string vibrations. and this must choke the cone vibration to some degree ? Now, as usual, I don't research Google before posting because I think that makes for a dull forum or interchange of ideas, and I am not a metalurgist. I do like to think these things through and use common sense and I try to think laterally. I write this as a caveat against receiving too much of a roasting from forum members better qualified in this arena than myself!
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Post by Keith Ambridge on Mar 16, 2013 13:05:52 GMT
Looking at it, a string cannot vibrate (of itself) as it approaches its anchor point, but the vibrations of the string must be transmitted across the static point to the rest of the instrument? No one in their right minds would glue a string down to the saddle to prevent it from falling off when under no tension would they? Why then would anyone glue a cone in? Of course, it would hold it in without string tension as has already been intimated. However, this analogy is a poor one because the string is under tension, but the cone is under compression. The cone has a static deflection when the strings are up to pitch. This is demonstrable because the action lowers as you tune up. Well, it does on my MM blues anyway. (This is a good enough reason for having a removable hand rest alone in my book) Here's where the similarity with a loudspeaker cone disappears. The cone on a loudspeaker has a flexible mounting and is not under any static deflection. As that string tension force acts down upon the cone, with no lateral restriction, the cone material is going to stretch and make the diameter imperceptably greater. This is not permanent, it's elastic deformation. If you bond the cone rim down with adhesive (or perish the thought, fasteners), it cannot stretch in the way I have described in sympathy with the string vibrations. and this must choke the cone vibration to some degree ? Now, as usual, I don't research Google before posting because I think that makes for a dull forum or interchange of ideas, and I am not a metalurgist. I do like to think these things through and use common sense and I try to think laterally. I write this as a caveat against receiving too much of a roasting from forum members better qualified in this arena than myself! Well put Sir!
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Post by Deleted on Mar 16, 2013 14:11:35 GMT
Im not disputing anyones years of experience, but... at the point where the string meets the saddle (in theory), the string is not moving at all, except for the movement of the saddle / bridge. If the string was 'glued' at that point (in theory), it shouldn't make any difference. I have less of an opinion with the cone, but I'll guess that at the point where it meets the well, it is also not moving, except for any movements of the well. To prevent it moving by glueing it (or screwing it) to the well should also make no difference (in theory). The issue then must be the effect the layer of glue has between the cone and well. Does it dampen it somehow? Of course, if its all set up right, the glue thing is irrelevant. TT
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Post by Stevie on Mar 16, 2013 15:06:15 GMT
Well, if you look at the rolled over shape at the circumference of a Continental cone, it does rather resemble the rubber mounting on a loudspeaker. When the cone deflects under vibration or string tension, the material has to go somewhere? The rolled over edge must absorb that temporary deformation like a spring? That means the periphery of the cone must move, if only in a see-saw fashion. If you bond it down, you must be resisting the cones desire to soak up its own movement at its rim? The swages in the cone make the structure itself quite stiff, that doesn't mean it doesn't vibrate- otherwise bells would not ring, but it must help transfer the energy to a point from which it can vibrate. I've become wrapped up in threads like this one before, and it is obvious to most casual readers that I have rather too much "theory" gleaned from personal observation, but I do think that we can move on our understanding of things in general and resos in particular from threads such as these. I'm ready to be persuaded by someone of gaps in my logic. As evidence of this, I started off following this thread with the conviction that it shouldn't matter because the cone is stationary at its mount point in the cone well. Now I'm not so sure that it is. I base this turn around of my opinion (and that's all it is at the end of the day) upon MM's experience and my questioning why he should think thus. You can't ignore all those years of experience, so there must be something else going on under the hood.
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Post by Stevie on Mar 16, 2013 15:13:17 GMT
Also, the analogy with the string brings to mind a similar thread regarding putting a magnetic pick (ie-not a piezo) right up next to the saddle(s), I reckoned that it should not work because there are no string vibrations right next to the saddle(s) to cut through the magnetic field and thus generate the alternating current. That contributor proved that in practice, whatever the theory, it did work....
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Post by Deleted on Mar 16, 2013 16:43:23 GMT
If the cones did move / stretch etc at the rim, would there be some sort of 'scraping' metal on metal, and the rim would start to show signs of wear? I'm guessing the rounded edges of the rim are far more rigid than the walls of the cone (think rounded f-holes), and it is only the walls of the cone that 'move'. I like a large debate on such issues, even if it transpires I'm talking rubbish. TT
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Post by Stevie on Mar 16, 2013 17:08:14 GMT
If it is that critical how the slots in a biscuit saddle are cut, that string choking can result, especially at the point where it has already been intimated "there is no vibration", then we must be considering very tiny vibrations indeed. I go along with the notion the the rim is stiff, but its design seems to allow the cone to vibrate in sympathy with the strings. I am still leaning on the side of believing that it is stabilising the cone at this point using adhesive (or whatever) that is responsible for the choking action. In the manner of the bridge pick up that I mentioned previously, why not record the instrument- just something easily repeatable, and then bond down the cone and record the result? I'm not going to do it to mine! I wonder how the use of felt or paper gaskets fit in with this discussion. MM has gone on record that these don't work either, yet I'm pretty sure that at least a few notable instruments have had gaskets, and I remember at least one having been documented as having had the gasket replaced to recover lost "tone" Clearly, there is something going on that, so far at least, we haven't managed to explain in a convincing manner. How's that for fence-sitting! (I used to be undecided, now I'm not so sure....)
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Post by slide496 on Mar 17, 2013 0:03:23 GMT
I wonder about two things with regard to contact with glue might be involved in degrading the tone. The sound has to then pass through that glue layer and how that would effect the tone? Also would the individual cone physically not be able to interface and settle in properly if it is fixed attached?
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Post by andys on Mar 18, 2013 10:32:26 GMT
Mind you I have repaired and re-coned guitars and found worse things than glue even.
Cones screwed down, with screws all around the rim.
Cones held in with bathroom sealer.
Bridges glued onto the top of the cone.
Hmmmmmm!!!
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Post by Deleted on Apr 2, 2013 20:04:32 GMT
How many times has a DIYer dry fitted a biscuit bridge only to find when tuning that the base of the bridge has caused flattening/crushing of the top of the cone in certain areas...I know its happened to me in the past as the base of the bridge had not been finished true...I have since that time used wood glue very sparingly applied around the edge and in a X across the base,once set this leaves a very fine film that provides good contact between base and cone with no noticeable effect on the sound produced to my ears or any one else's I believe.Wood glue dries harder than the wood itself...it must do it says it on the dispenser. While Im here anyone know a decent source of Dobby cones in the UK looking for a 10.5".... Cheers
T
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Post by pete1951 on Apr 4, 2013 12:38:21 GMT
If you have a very uneven surface glue could be used (I have never done this on a resonator but have on other instruments) 1) put a bead of epoxy on the area 2) cover with `cling-film` 3) put it together 4) when dry remove cling-film, You should now have a perfect fit , but the 2 bits will come apart Care should be taken not to use too much epoxy, you do not want it pushing up the film and `gripping ` the cone . There are better ways of getting a flat surface, but the tread does say `Cones and Glue` PT PS my National biscuit is nailed on! never been a problem.
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Post by bluesdude on Apr 5, 2013 23:50:38 GMT
back a few years on a trip to South Carolina I stumbled on a music store that was liquidating everything,after a couple of minutes looking around and trying a newish Dobro,the store owner informed me he had two National cones for sale, they were old National cones still in a box marked " National Stringed Instruments" new cones from the thirties that had never been used, I promptly bought them,and when I got home I noticed there were some felt rings the same size as the cone rest plat-form on my Duolian, I just threw them on my bench figuring I would never put something in between the cone and platform on my Nationals, a couple of years after,I tried installing them in a Duolian I had that had a strange overtone happening and the sound led me to the platform,it appeared flat enough but anyhow the sound after putting the felt in there was deadening lots of overtones lost,I left the guitar setup that way strung and hanging on the wall,with the intentions of removing it as soon as I came home again, by the time I tried it again was a couple of weeks and the cone had made a groove right through the felt ,not cut it but bottomed out ,the sound from this Duolian is in my opinion better than any other 14 fretter I've tried,all the reverb and overtones came back and the strange overtone/rattle was gone, I recently reset-the neck on this guitar and in took me quit a few tries to line up the cone rim to the indention on the felt lining, I was scared I would have to remove it! and maybe ten years ago I put the other felt and cone in NRP wood bodied Jazz-Blues and the way this guitar barks you would never think there is a felt lined platform in it,I'm not saying gluing cones would work the same and infact I believe gluing them in came from people seeing glue residue from felt lined platforms,mainly Tricones I have seen glue residue,
Kenny,
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