Laminate Gluing Pressure

[Farrell]

"I'd be interested to hear about the techniques the manufacture used, and your reservations about the process."

As would I!

What I was specifically considering was whether I would get adequate clamping pressure if I put an 8-inch wide stack of 6  3mm-thick laminates on top of a male curved caul, apply Titebond to the spruce laminates, and put it all in a bag and applied the vacuum (I'm making an 8-inch wide laminated rib). I'm quite sure all would work, but whether the something-less-than 14.7 psi is going to be adequate clamping pressure on the stack of laminates. I fear not.

I understand how you are getting the increased pressure from less vacuum with your application Ron. Pretty slick.

Terry Farrell
  
----- Original Message ----- 
From: "Overs Pianos" <sec@overspianos.com.au>


> >----- Original Message -----
> >From: "Farrell" <mfarrel2@tampabay.rr.com>
> >Subject: Laminate Gluing Pressure
> >
> >. . . I am toying with the idea of laminating spruce ribs with Titebond and
> >providing clamping pressure with the vacuum bagging technique.
> >
> >
> >At 9:12 AM -0700 26/8/03, Delwin D Fandrich wrote:
> >. . . I would not trust the clamping pressures generated by vacuum-bagging
> >to adequately form any structural joint having a relatively small contact
> >area.
> 
> I could understand your doubts if one were to try it with the panel 
> on the vacuum table with the ribs being pulled down onto the panel 
> with the vacuum bag, but in our case the ribs are fixed to the gluing 
> table and the panel is pulled down onto the ribs. This multiplies the 
> gluing pressure between the ribs and panel to around six times the 
> applied vacuum, depending on the spacing between the ribs.
> 
> 
> >I know of at least one piano maker who tried
> >vacuum bagging ribs (against my advice) and gave it up after the associated
> >problems became overwhelming (which were consistent with my advice).
> 
> I'd be interested to hear about the techniques the manufacture used, 
> and your reservations about the process.
>