On 1/16/18 8:31 AM, Leon wrote:
-MIKE- wrote:
All this talk of edge glue joints and glue starvation and clamping
pressure and blah, blah, blah.... SWMBO had a request so I needed
to do a quick panel glue-up. Just two 7" poplar boards edge joined
for some little side table thingie that wimenfolk like. I don't
know, I just make sawdust.

So anyway, I just wanted to put in the very minimum effort to show
how just a table saw can do what you need. Also, to show how
little glue is needed (I actually STILL used too much) and how
little clamping pressure and time are needed with modern PVA
glues.

The first 2 pictures shows *one* technique (I have several that use
the TS) for putting a straight edge on a rough-sawn board. Once
you have one straight edge-- flip and repeat and you have parallel
straight edges.

3rd pic shows a thin covering of glue on each edge. Again, I
still think I used to much as can be seen in the squeeze-out in the
following 2 pics.

The next 2 pics show how strong a glue joint is after only a
couple hours in the clamps. Spoiler alert! The wood breaks, not
the glue.

The last pic shows the stained panel and how tight and
imperceptible the joint is.

https://photos.app.goo.gl/pmyWHV7ANvFek7b62



You know, Jerry, the inventor of the Dubby sled uses masking tape to
clamp the sides of small boxes together while the glue dries. If
your Slye edges are true you do not need a lot of pressure.


It's all very interesting to me and always has been a topic that piques
my interest.
I still don't know if I've ever seen a scientific guide to clamping
pressure. You'd think it's been done and is out there, but I haven't
seen it.

The masking tape thing really has me curious. At some point, with
masking tape, you have enough PSI on a small enough section to be as
effective as a screw clamp.

I used masking tape to glue plyboo edging on this cabinet.
http://mikedrums.com/bamboo_veneer_clamp.jpg
Those "bandy clamps" from Rockler certainly provide enough pressure.

There comes a point with screw clamps where you have enough pressure for
a properly glued joint and anything more is just compressing the wood or
distorting it. I would argue that point is much sooner than most of us
would believe.

I think I may do a similar "experiment" with several glue-ups using the
same wood but with less and less glue and less and less clamping pressure.


--

-MIKE-

"Playing is not something I do at night, it's my function in life"
--Elvin Jones (1927-2004)
--
www.mikedrums.com