doncaparker wrote:
Impossible is a pretty strong word. Watch videos that show how quickly the factory workers move when working with their vacuum systems and Titebond. If you get it ironed out, with placement templates and the like, you can move that fast, too. Plus, a little (not a lot; a little) urea in your glue to extend the working time is not a bad thing. The glue still is plenty strong.
I don’t use vacuum clamping, just because I am doing OK with regular clamps, etc., and I don’t need to build that type of time saver (explanation below). But I think hide glue’s working time is an issue that can be managed, and need not be the thing that stops you from using it to glue braces in a vacuum system.
Having said all that: Just speaking for myself, I would only move to vacuum clamping if I thought it could give me a significantly better glue joint than regular clamps can. Why? Because it is the type of tool for guitar building that seems to exist in order to allow me to grind through a large number of identical clamping jobs in the same work session. In other words, large volume factory efficiency. But I am never going to need to grind out 100 brace gluing operations in a single day. I only need to do 1-3 at the most.
No offense intended to those who like building such tools, but I think we small time builders can fall into the trap of thinking we need that type of efficiency, the type that allows you to only spend 5 seconds on a task. But if the setup time, and setup cost, for that operation is significant, and if you are not doing it 100 times in a work session, but only 1-3 times, that level of efficiency might actually be very inefficient, and costly. If it also serves the purpose of increasing accuracy or some other measure of quality, then I am all for it. But if speed/efficiency is the only goal, I think overall speed/efficiency for a small volume builder might be better accomplished through lower tech means.
Just speaking for myself. YMMV, obviously.
Don, good points. While efficiency definitely is a benefit with vacuum pressing, for me, its a "fun" thing that I like, with great results. May as well enjoy building, right? Resulting benefit - no go bars, which take up a lot of space. Setup time for the vacuum? Plug in an air hose and electrical plug, takes less than a minute to charge up. The HHG takes more time to heat up than setup. Cost was usually prohibitive for vacuum pressing, for me, but once I dropped the $$$, I like it. Its not for everyone, and if I only used it for bridges, which I do, it was a good, useful, project.
Brad, yes, I glue braces with the vacuum. Its a two step process for tops as I glue in my braces square, and shape after gluing (my current process). I'll glue cross bracing and bridge patch, carve an hour later, glue in fan braces, and work on something else. Backs are two step as well. But, its still a two step process for me with Titebond and clamps, so I don't lose anything.