Carved vs. Pressed Archtops
thomas
difference between a carved top and a pressed top?
Chris Johnson
is a more 'polite' term) then it's pressed, no doubt about it.
For technical reasons, it's very difficult to press a solid top
so the general rule is that plywood is pressed, solid wood is
carved.
There may be exceptions to the last half of that rule but not
to the first half.
CJ
David Hajicek
You bring up a good point, however. If it were possible to press a solid
wood top without splitting (say pressure cook in ammonia first) -- It is
possible that this could be a decent top if thicknessed properly. It may
even be slightly superior in that the grain is running along the shape of
the top. I don't think this would be any easier to make (if done properly)
than a carved solid top, however.
Dave Hajicek
"Chris Johnson" <cmjo...@cfl.rr.com> wrote in message
news:3B16C0CA...@cfl.rr.com...
nick odell
wrote:
>thomas wrote:
>>
>> I'm lloking at some old budget archtops. How do you tell the
>> difference between a carved top and a pressed top?
>Look for plywood. If the top is laminated (plywood, but laminated
>is a more 'polite' term) then it's pressed, no doubt about it.
>
>For technical reasons, it's very difficult to press a solid top
>so the general rule is that plywood is pressed, solid wood is
>carved.
>
>There may be exceptions to the last half of that rule but not
>to the first half.
>
Spotting laminations can be tricky - especially if made up of sawn
rather than peeled veneers. If the wood is beech or birch or similar
and particularly if the grain appears in whorls rather than lines it
is almost certainly laminate.
Check the edges and the f-holes for horizontal lines and changes of
reflectability that hint at laminations. Bound f-holes suggest
laminate since makers of solid tops are usually proud to show this
off. Tortoiseshell-style binding usually has an almost-clear patch you
can peer through to check the wood.
A solid top guitar may not have a solid back so you can't rely on this
as a guide. But a solid back guitar almost certainly has a solid top.
On a laminated back/top the centre joint is a cosmetic feature and may
not be repeated inside. If there is a centre joint inside and
especially if it is reinforced with violin-type diamonds of wood
(ties) it is likely to be solid. A continuous centre strip of
"reinforcing" may be there just to hide the lack of a joint.
Finally, use a mirror to look at the grain on the inside. Find a
particularly recognisable patch of grain on the outside (three stripes
exactly the same width; a ripple; a change in colour; something) and
try to locate the same pattern in the same place inside.
hth
Nick
who, when a teenager, was sure he had bought a solid top guitar -
until he got it home :(
--
real e-mail is themusic dot workshop at ntlworld dot com
nick odell
odell) wrote:
<snip>
.... oh and if you can follow a grain line from the outside, down an
edge and inside, then it's pretty certain to be solid.
N
JimLowther
>You bring up a good point, however. If it were possible to press a solid
>wood top without splitting (say pressure cook in ammonia first) -- It is
>possible that this could be a decent top if thicknessed properly. It may
>even be slightly superior in that the grain is running along the shape of
>the top. I don't think this would be any easier to make (if done properly)
>than a carved solid top, however.
I think Kay, in addition to all the pressed laminate tops, made quite a number
of pressed solid top guitars in the 50s? Or maybe it was Harmony. To tell the
truth, it's hard sometimes to keep the individual old budget archtops straight
in my head. I remember encoutering one of these that was being sold as a
pressed solid top, which I doubted, but which both research and inspection
verified to be the case. But I just don't recall the details.
Best wishes
Jim Lowther
Hojo2x
Pressed solid tops are easily made in factory settings with the proper
machinery. It's an old technology - the Gibson-made budget Kalamazoos from the
late 30's were all pressed solid tops, as were many of the less expensive
Gibson archtop guitars and mandolins.
All you need is moisture, a mould and pressure (I think heat is involved in the
process, too.)
Right now, most of the Kentucky mandolins on the market are pressed solid tops,
rather than laminated or carved solid wood. The KM-250S has always been
pressed solid wood.
One way to tell if something is a pressed solid top rather than carved is to
check to see if there's any difference in thickness from one part of the top to
the next. Pressed solid tops will be all the same thickness, since flat plates
are much easier to press. Carved tops will be thicker in some spots than
others.
You can look at the wood grain, too - the grain in carved tops tends to look
like topographical maps, with a lot of curves and swirly lines like those that
symbolize hills and elevations, whereas pressed solid tops will have straight
grain lines like on a flat top guitar.
Hope this helps.
Wade Hampton Miller
Rogluthier
early '50s) were of plane sawn poplar which seems to lend itself to the task.
The heat and pressure seem to raise the grain and uglify spruce. You will also
notice the angle of the end grain seen in the f-hole area will follow the
curature of the arch. A carved piece has end grain which retains the
orientation before shaping.
Pressed wood has its own type of sound: a good attack but not much sustain.
(Would this qualify as "bark?") I bet the press job reduces the material's
springiness.
Roger Thurman
Thurman Guitar & Violin Repair, Inc.
900 Franklin Ave.
Kent, OH 44240
330-673-4054
http://members.aol.com/_ht_a/Rogluthier/
25 years in repair, making and sales.
Martin - Fender Warranty Repair
Visa/MC Shipment on approval
David Hajicek
Of course, wood type, bracing and thicknesses would have a lot to do with
that too. A molded top is probably a uniform thickness for production
reasons, which is not optimal. Poplar may be very lossy (too soft?).
Apples and oranges?
Ideally, molded tops should be actually stiffer, with less loss than the
carved tops (no cross-grain shear action in the wood). One would expect
that a carved top has a little more damping, which mellows out the response.
This sounds like a whole project in itself to figure out the best way to do
this. Much easier to just carve out the top. ;>)
Dave Hajicek
"Rogluthier" <roglu...@aol.comniljunk> wrote in message
news:20010601085217...@ng-ce1.aol.com...
Mike Dotson
them and scrapes the recurve just as a carved plate would get, and gets
excellnt results soundwise.
Stan Gosnell
<thdhbra...@corp.supernews.com>:
>Chris:
>
>You bring up a good point, however. If it were possible to press a
>solid wood top without splitting (say pressure cook in ammonia first) --
>It is possible that this could be a decent top if thicknessed properly.
>It may even be slightly superior in that the grain is running along the
>shape of the top. I don't think this would be any easier to make (if
>done properly) than a carved solid top, however.
>
>Dave Hajicek
>
>"Chris Johnson" <cmjo...@cfl.rr.com> wrote in message
>news:3B16C0CA...@cfl.rr.com...
>> Look for plywood. If the top is laminated (plywood, but laminated
>> is a more 'polite' term) then it's pressed, no doubt about it.
>>
>> For technical reasons, it's very difficult to press a solid top
>> so the general rule is that plywood is pressed, solid wood is
>> carved.
Stew-Mac sells solid pressed tops for a very reasonable price. It's not
that difficult. Pressed doesn't mean laminated, they are different terms.
Lots of budget archtops have been made with solid, pressed tops, & you
still see them.
There is a school of thought that says the pressed tops are actually as
good, if not better than, carved tops because the wood fibers are more
continuous, not cut by carving. With zero runout, the wood would be
completely continuous, not cut.
N.B., I said it is a school of thought, not that I subscribed to it. I
think it's too hard to generalize that much.
Rogluthier
>braces
>them and scrapes the recurve just as a carved plate would get, and gets
>excellnt results soundwise.
Isn't wood amazing? So many ways to use it. Such a useful, renewable resource
should be included and protected in every tree-bearing nation's constitution.
Grow trees in all backyards and vacant lots. Set aside a portion reserved for
deep forest in very county and township. Dream on, tree-huggers! `([:-(
Rogluthier
>this. Much easier to just carve out the top. ;>)
David:
Aren't there some older pressed top violins out there? I've heard of them but
can't recall--or didn't notice it at the time--seeing one.
I recall pressed top spruce guitars having very even grain lines which are
spaced a bit wider than expected in the solid carved top.
Sean Barry
: Aren't there some older pressed top violins out there? I've heard of them but
: can't recall--or didn't notice it at the time--seeing one.
Some modern violin makers believe that the classic Cremona makers
(Stradivari, Guarneri del Gesu, etc) in fact did not carve their plates
but bent them and then carved the channel and a few other details. Bill
Fulton of Idyllwild, California has been the strongest proponent of that
idea, and he builds beautiful violins by that method that are are very
well regarded. Problem is that without cutting a Strad top lengthwise and
examining the grain continuity, no one can prove whether the tops were
carved or bent--we only have their tools and limited construction records
to go by. No one seems willing to sacrifice a Strad to find out, either.
Intriguing though, and it would be foolish to dismiss Fulton's
ideas--they're as well reasoned and backed by the limited available
evidence as any other set of Cremona construction ideas.
Sean Barry
David Hajicek
I'm out of my element here. I know how to press wood, and I know what
happens when you form materials. But I don't have much knowledge of what
various instrument makers are using. It would make lots of sense to use
pressed wood on "student violins" and such, to get costs down.
The grain spacing would normally get wider in some places when you
"stretched" the wood in the form. It would take a more sophisticated
technique to minimize this. So I would expect the grain spacing to be wider
in the belly area and tighter around the rim. Possibly even a bend in the
grain at some point near the edge. This would probably not be noticeable on
a guitar since there isn't much "belly" involved and the curves are
relatively gentle. But I am just speculating.
Dave
"Rogluthier" <roglu...@aol.comniljunk> wrote in message
news:20010602000210...@ng-mp1.aol.com...
David Hajicek
You would think that the grain runout would be visible on a carved top.
Perhaps we are talking some of each? They would have to bend each half and
then fit it together (hide glue wouldn't hold during bending). Lots of ways
to skin that cat, I guess.
Dave Hajicek
"Sean Barry" <sjb...@runner.ucdavis.edu> wrote in message
news:9fa2fg$8pj$1...@woodrow.ucdavis.edu...
Sean Barry
: Sean:
: You would think that the grain runout would be visible on a carved top.
: Perhaps we are talking some of each? They would have to bend each half and
: then fit it together (hide glue wouldn't hold during bending). Lots of ways
: to skin that cat, I guess.
Part of the problem is that the well-varnished old instruments don't show
any end grain where you would expect to see it (just below the apex of the
arch under the fingerboard and tailpiece). Most modern makers believe
that's because the wood was so well sealed (sized) that grain
irregularities did not stain or varnish differently--Cremona sizing, or
ground, is the subject of a great deal of study and controversy. My
understanding is that Bill Fulton does indeed bend hide-glued bookmatched
tops. He just waits for the glue to cure completely--cured hide glue
joints can generally be heated and stressed with impunity (as long as
there's no appreciable humidity in or out of the joint). And again, he
still does quite a bit of carving on the bent top (particularly the
channel, and the flat on the bottom side). He maintains that a top with
continuous grain is inherently more stable and stands a better chance of
being tonally focussed than does a hollowed-out top, and there is no
escaping the logic of his assertions--we all know that bent wood held in
place until it cools is very strong and stable. Whether the logic
translates to reality is another thing, but again his instruments sound
great, and may even sound like Cremona instruments 300 years from now.
So might modern carved-top instruments though. The difficult part is
proving that's what the early makers did. Either way.
Sean Barry
David Hajicek
Great information. Thanks.
Dave
"Sean Barry" <sjb...@runner.ucdavis.edu> wrote in message
news:9ff39q$rjf$1...@woodrow.ucdavis.edu...
Mitch Dickson
you like to start with a 4X12 and saw out the sides :)His theory was that
pressed and bent wood kept the stress in and that would prevent full
vibration! By the way, that is still the reason fiddle tops (ok violin for
you purists) and backs are carved rather than pressed :)
CU Mitch
--
"I was born naked, wet and hungry......Then things got worse!"
mi...@volstate.net
"Stan Gosnell" <sgos...@bigfoot.com> wrote in message
news:90B3B961Fsgos...@204.52.135.10...
Chris Johnson
Mitch Dickson wrote:
>
> Gentlemen, don't forget that Mr. Gibson even carved the sides! How would
> you like to start with a 4X12 and saw out the sides :)His theory was that
> pressed and bent wood kept the stress in and that would prevent full
> vibration! By the way, that is still the reason fiddle tops (ok violin for
> you purists) and backs are carved rather than pressed :)
>
> CU Mitch
>
>
Actually, violin backs and tops are carved mostly because it takes only
simple, basic tools to carve them and a press is MUCH harder to come by.
Also, proper thickness graduation of violin plates is critical to
performance.
It's also a LOT of fun! Anyone who is interested in building a musical
instrument should definitely try to make at least ONE good violin.
It is to be recommended.
CJ
jimseprodi
principle of stretched top wood has been used on flattops as well, the
slight curve of bracing using the "go stick" method. according to the
fixture StewMac sold, it was a 20" radius. Benedetto makes the point
that bent wood is stronger than unbent wood, and violin braces were
given 'spring' for added responsiveness. Makes sense. He also warns
that braces such as these lose their tension and need replacing. (My
personal thought, wonder if a carbon graphite reinforced brace would
do the same? intriguing....) Anyway, back OT. It would seem to me that
the pressed solid top would be stronger, and more responsive, but
would need replacing. I played one of the old Gretschs and really
couldnt tell much of a difference between it and a Gibson L-50,
(except of course the Gibson neck was in a hell of a lot better shape)
I think I am going to try this out as it is not a bad idea, as my
other hobby is metalcasting, i think I might be able to make a good
enough die from aluminum. Find a method for heating it (refractory
concrete and nichrome wire element, i think) The bracing would need
experimentation. Any thoughts or if you want to tell me Im crazy, or
if you have already triedthis I would like to know
David Hajicek
It would be a major investment of time and money to make the cast mold, but
I'm sure you could do it.
For an experiment, I would be tempted to make something out of just
refractory cement (or even plaster) with imbedded heating wires. It might
be possible to get away with no heating element, just by heating the molds
ahead of time in an oven or with a propane torch. If you like the results,
then invest in a permanent mold (though machining plate might be easier).
Caution: don't torch or rapidly heat cement or plaster which still has
moisture in it - it could explode from steam pressure.
I would soak the wood for about an hour before hand, to make sure the wood
is wet all the way through. Hot water would be better. I'm not sure how
much curve you want, but if it is a lot, pour very hot (boiling) water over
the top prior to putting it in the mold. Let it dry in the mold.
Good luck, let me know how it goes.
Dave Hajicek
"jimseprodi" <jimse...@yahoo.com> wrote in message
news:57ccc225.01061...@posting.google.com...
jimseprodi
> Jim:
>
> It would be a major investment of time and money to make the cast mold, but
> I'm sure you could do it.
>
> For an experiment, I would be tempted to make something out of just
> refractory cement (or even plaster) with imbedded heating wires.
to insulate electrically the nichrome elements from the mold. I have
an electric melting furnace using scrapped dryer elements, castable
refractory, inside a small galvanized garbage can that works
WONDERFULLY for Al and pot metal (dont laugh, its great stuff,
stronger than iron when cast in thick sections. Gets its bad rep
through thin die cast stuff that provides me with scrap almost free
:-} ) You would be surprized how easy and fun metal casting is!! If
you are interested go to Lindsay Books and check out the books by
David Gingery. they are a revealation. Back OT.
It might
> be possible to get away with no heating element, just by heating the molds
> ahead of time in an oven or with a propane torch.
> moisture in it - it could explode from steam pressure.
got hit in the leg by shrapnel. Know what you mean, bro!!!!
> I would soak the wood for about an hour before hand, to make sure the wood
> is wet all the way through. Hot water would be better. I'm not sure how
> much curve you want, but if it is a lot, pour very hot (boiling) water over
> the top prior to putting it in the mold. Let it dry in the mold.
Read somewhere that 335s and the like were molded much like this
> Good luck, let me know how it goes.
Thanks man, I will. If you decide to check out the casting info (a
luthier can never have enough tools, especially cheap ones, if you
have any questions Ive done or am doing most of the projects. I can
tell you where some of the rattlesnakes are :-]
David Hajicek
I cast metal myself (or did until my son burned out my smelter), just not in
such large quantities (only a pound or two). You are talking about a pretty
large pour compared to what I'm used to. Thanks for the offer of help.
I don't know if you have an Axeman (surplus store) where you are, but I've
found nice heating elements there very cheaply. Then you can just drill a
hole and plug them in. Might be easier than using nichrome wire. But the
wire is certainly a cheap way to go.