Terry Farrell wrote: > Greg, > > Like David, I have a hard time imagining > that vacuum bagging would be easier for a one-off soundboard ribbing. Me too, among other things. >If you are not pressing your ribs/panel in a radiused > caul, you loose that potential benefit. I don't see how, unless you're pressing the assembly into a tighter radius caul than that cut into the rib, like the folks who are doing this and pretending they're not making a high panel compression assembly. Just a bag, no caul, will bend the panel to fit the rib just fine. The things that bother me about vacuum bagging are these. If you're not using a big radius rib, something has to hold the panel in close enough proximity to the rib radius to keep the ribs contained within whatever guide you build. An 90cm rib, for instance at 9M radius has a crown height of about 11.3mm. With the rib ends over 11mm above the board, and your clamping guides shorter than the 5mm or so rib end thickness, you're 6mm short of an index with the panel lying flat on the table. Propping up the edges of the panel would work, but if you have multiple rib radii, wouldn't things get a tad strange and cumbersome? Assuming you have everything propped up and ready to go. You then have to apply glue to anywhere from say, 9 to 22 ribs all at once, depending on what you're building, and position them before the glue skins over. So what kind of glue are you using? It's probably not water based, like Titebond or liquid hide, or is it? If so, how can you do this? Assuming everything else works out happily, your clamping pressure (unless you make a wide footprint caul for each rib) is limited to some fraction of atmospheric pressure. It looks like 12 PSI is about the best you'll do. Most everything but epoxy ought to reasonably have at least three or four times that. Some say a WHOLE LOT more than that. So what's the glue used that waits that long for setup, and doesn't need over 12 PSI clamp pressure? Sorry, I don't see a benefit to vacuum bagging. It looks more involved, time consuming, expensive, at least potentially messy and at worst disastrous than building individual clamps. 'Splain to me please, the real details. Ron N Also, note the absence of accumulated past posts, except where specific comments were addressed.
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