Greg, I pretty much agree with what David has said, and I also use a setup very similar to his for clamping ribs to a panel. But I do like to hear about what other techniques others are using, and I'd enjoy hearing more details about how you do yours. Like David, I have a hard time imagining that vacuum bagging would be easier for a one-off soundboard ribbing. David's last sentence (quite sure I have this correct David....) is that by clamping the rib to the panel in a caul of the same radius of the rib, you are actually making the rib an additional 8 mm taller (if your panel is 8 mm). Now of course that is not entirely true because the grain angle of the panel is not nearly parallel to the rib - so the panel does not have the same resistance to compression forces that the zone of the rib closest to the panel has - but never-the-less, it does add to the rib - and you are adding no additional weight - so it's a stiffness freebie. If you are not pressing your ribs/panel in a radiused caul, you loose that potential benefit. How much is that benefit? I don't know - I presume it is fairly small, but real. Do you glue all your ribs on at once? How do you handle squeeze-out cleanup? What kind of glue are you using. Do you make a rib- positioning template for each soundboard design? Are you using radiused, laminated (or cut) ribs? Are you using original rib arrays? Original rib scales? I presume by a cut rib you mean a solid rib with a radius cut into it and a built-up rib is a rib laminated to a target radius? I've done quite a bit of vacuum bagging - pinblocks, laminated rib slabs, even an entire 3-ply laminated panel for a 7'+ Bluthner - but it seems to me better and easier to glue on the ribs one at a time in a radiused caul. Please share whatever you are willing to about your process. Thanks! Terry Farrell Farrell Piano, Inc. On Jun 13, 2010, at 11:54 PM, Greg Newell wrote: > David, > Not sure what you mean by the last sentence. If you've made the ribs > radiused in a caul what further need do you have for a caul? At that > point > your just attaching ribs to the board and with the melamine cut in a > negative rib pattern trying to prevent them from sliding around > while the > bag draws down the vacuum. The ribs already have the radius needed > and the > board will conform to them. I'm assuming built up ribs not cut ribs. > > Greg Newell > Greg's Piano Forté > www.gregspianoforte.com > 216-226-3791 (office) > 216-470-8634 (mobile) > > -----Original Message----- > From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] > On Behalf > Of David Love > Sent: Sunday, June 13, 2010 1:39 AM > To: pianotech at ptg.org > Subject: Re: [pianotech] Fire hose failure! > > I suppose if you were making the same board over and over again but > since > I'm not it's a lot of additional work. Also, one thing that happens > is that > the ribs are pressed down onto the panel and into a caul matching > the radius > of the ribs (even though the ribs are crowned) which is harder to > manage > with a vacuum press. > > David Love > www.davidlovepianos.com > > > -----Original Message----- > From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] > On Behalf > Of Greg Newell > Sent: Saturday, June 12, 2010 9:46 PM > To: pianotech at ptg.org > Subject: Re: [pianotech] Fire hose failure! > > You sure about that? If you use a template made of that melamine > stuff to > locate the ribs and tape the board to the melamine it works quite > well. Cut > slots into the melamine and the ribs sit in the cut slots and are then > sandwiched to the soundboard locating them well and preventing their > movement while the bag vacuum clamps it all together. I'm assuming > ribs that > aren't flat. Works quite well actually. > > Greg Newell > Greg's Piano Forté > www.gregspianoforte.com > 216-226-3791 (office) > 216-470-8634 (mobile) > > -----Original Message----- > From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] > On Behalf > Of David Love > Sent: Saturday, June 12, 2010 9:30 PM > To: pianotech at ptg.org > Subject: Re: [pianotech] Fire hose failure! > > Doesn't work for ribbing. > > David Love > www.davidlovepianos.com > > > -----Original Message----- > From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] > On Behalf > Of Greg Newell > Sent: Saturday, June 12, 2010 2:58 PM > To: pianotech at ptg.org > Subject: Re: [pianotech] Fire hose failure! > > A large vacuum bag. > > Greg Newell > Greg's Piano Forté > www.gregspianoforte.com > 216-226-3791 (office) > 216-470-8634 (mobile) > > -----Original Message----- > From: pianotech-bounces at ptg.org [mailto:pianotech-bounces at ptg.org] > On Behalf > Of David Love > Sent: Friday, June 11, 2010 11:15 PM > To: pianotech at ptg.org > Subject: [pianotech] Fire hose failure! > > Ribbing a board today I discovered that my pneumatic clamps > (firehoses) had > all sprung leaks to the extent that my compressor wouldn't keep > quite enough > air pressure (argh). So, while I did fashion a remedy for the short > term > I'm shopping to replace the fire hose material with something a bit > more > air-o-dynamic. Any suggestions? > > David Love > www.davidlovepianos.com > > >
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