Hello all,
I am making a simple set of shelves out of 3/4" plywood with the
shelves attached to the sides with biscuits. My question is: Do I
need to put glue on the ends of the shelves in addition to the
biscuits, or will just the glue in the slots work good enough?
Thanks in advance,
Ronnie Aldrich
B'ham, AL
I have made joints with glue only on the biscuits just for fun and they have
been plenty strong. (In fact I have used just water and they have been
pretty good.) Since you will have mainly shear stress, it ought to be fine
if you don't want to glue the ends for some reason; especially since end
grain gluing isn't worth much anyhow.
Is there a reason you don't want glue on the ends?
"toller" <[email protected]> wrote in message news:<[email protected]>...
> I have made joints with glue only on the biscuits just for fun and they have
> been plenty strong. (In fact I have used just water and they have been
> pretty good.) Since you will have mainly shear stress, it ought to be fine
> if you don't want to glue the ends for some reason; especially since end
> grain gluing isn't worth much anyhow.
>
> Is there a reason you don't want glue on the ends?
The only reason I have for not wanting to glue the ends is so I would
not have to deal with glue squeeze out.
Thanks for all you help.
Ronnie Aldrich asks:
>I am making a simple set of shelves out of 3/4" plywood with the
>shelves attached to the sides with biscuits. My question is: Do I
>need to put glue on the ends of the shelves in addition to the
>biscuits, or will just the glue in the slots work good enough?
>
Biscuits are primarily alignment devices, adding very little extra strength in
most cases. Add glue to the end of the wood, too, as well as to the slots and
the biscuits.
Charlie Self
"Half of the American people have never read a newspaper. Half never voted for
President. One hopes it is the same half." Gore Vidal
Greetings and Salutations....
On 26 Sep 2004 10:47:26 -0700, [email protected] (Ronnie
Aldrich) wrote:
>Hello all,
>
>I am making a simple set of shelves out of 3/4" plywood with the
>shelves attached to the sides with biscuits. My question is: Do I
>need to put glue on the ends of the shelves in addition to the
>biscuits, or will just the glue in the slots work good enough?
>
>Thanks in advance,
>
>Ronnie Aldrich
>B'ham, AL
Hum...I would use polyurethane glue (gorilla glue, etc),
and, would glue the end of the shelves as well as the biscuits.
However, since I am distrustful of shelves...I would
also put a slight dado (1/8" or 1/4") into the sides and inset
the shelves into them, and, skip the biscuits entirely.
If you put a back on the shelves, your plan will work
ok. However, if no back, then the shelves may rack a bit,
and break the shelf to side joints loose...dropping the shelves
out.
Actually, I also just think that butt joints like that
are kind of ugly, and I prefer the dado look...and it IS a lot
stronger and stiffer.
Regards
Dave Mundt
Mix of answers, what? The biscuits resist shear - the downward weight of
the books, in this case, very well. They don't do as well against racking -
the bump on the top corner or the attempt by someone to drag the case on one
end while partially unloaded. That is best served by a full back, fastened
to both sides and shelves.
The glue on the shelf ends would help a bit in keeping the joint butted
square and tight, aiding in both shear and rack. Probably won't be much,
but wouldn't hurt, certainly.
"Ronnie Aldrich" <[email protected]> wrote in message
news:[email protected]...
> Hello all,
>
> I am making a simple set of shelves out of 3/4" plywood with the
> shelves attached to the sides with biscuits. My question is: Do I
> need to put glue on the ends of the shelves in addition to the
> biscuits, or will just the glue in the slots work good enough?
>
> Thanks in advance,
>
> Ronnie Aldrich
> B'ham, AL
True, but the type of stress the joint must handle is still the starting
point. Then look at the biscuit (dowel, tenon, or whatever) and apply any
mechanical advantage, then finally the glue bond.
And an obvious mechanical advantage of biscuits is their swelling. Although
that decreases as they dry, the glue tends to prevent this. Further, even
without the glue, they will not return to their original thickness (try this
at home; it will vary with different makes of biscuits).
From that analysis, if we were to look instead at edge joining boards with
biscuits, it can be seen that the biscuits will aid in alignment, but add
little strength as compared to the long grain glue joint between the edges.
(Assuming, of course, that you haven't used umpteen biscuits.)
In other applications (such as the start of this thread), this can work out
quite differently.
GerryG
On Mon, 27 Sep 2004 15:07:34 GMT, "Leon" <[email protected]>
wrote:
>
>"jo4hn" <[email protected]> wrote in message
>news:[email protected]...
>>
>> It's actually more important that glue be spread across the mating
>> surfaces than in the slots. Biscuits will aid in alignment but add little
>> strength.
>> mahalo,
>> jo4hn
>
>Actually biscuits do add strength but not in all cases. If gluing long
>grain to long grain, they are better for alignment purposes. However as you
>start to introduce more end grain into the joint, 45's and butt joints, the
>biscuit adds significantly more to the joint in terms if strength. The
>biscuit adds the long grain to long grain glue surfaces within the biscuit
>slot to join to the long grain of the biscuit surface.
>
On Wed, 29 Sep 2004 11:46:30 -0400, "Rumpty" <[email protected]>
wrote:
>Mac I've been a commercial furniture builder for years, the biscuit is my
>method of construction. The only time I now use a mortise and tennon is when
>it's visible. Biscuits are available in several sizes including the S-6
>which measures 1 1/4" X 3 3/8", use a S-6 in a table leg apron joint and I
>defy you to make it fail in normal use. Double stack it and it's almost
>impossible to break the joint.
I think there is a use for what I consider "high end" joints like
dovetails and tenons, but mostly for looks or the woodworkers
pleasure/challange..
both methods are fine with me, I just don't have the skill level
involved for fancy, precision joints yet..
Mac
"Ronnie Aldrich" wrote in message
> The only reason I have for not wanting to glue the ends is so I would
> not have to deal with glue squeeze out.
Got a table saw and dado set, or a router with a guide? It's pretty hard to
beat a dado/groove for non-adjustable shelves in bookcases and cabinets.
("housed" joint, patriarch ;>) )
A simple blind dado/groove is hell-for-stout, will hide the joint, and it'll
last until your grandkid's grandkid's cows come home.
--
www.e-woodshop.net
Last update: 7/10/04
With most any joint of this type, glue on all mating surfaces is stronger
than not.
"Ronnie Aldrich" <[email protected]> wrote in message
news:[email protected]...
> Hello all,
>
> I am making a simple set of shelves out of 3/4" plywood with the
> shelves attached to the sides with biscuits. My question is: Do I
> need to put glue on the ends of the shelves in addition to the
> biscuits, or will just the glue in the slots work good enough?
>
> Thanks in advance,
>
> Ronnie Aldrich
> B'ham, AL
In article <[email protected]>,
[email protected] says...
> Hello all,
>
> I am making a simple set of shelves out of 3/4" plywood with the
> shelves attached to the sides with biscuits. My question is: Do I
> need to put glue on the ends of the shelves in addition to the
> biscuits, or will just the glue in the slots work good enough?
>
> Thanks in advance,
>
> Ronnie Aldrich
> B'ham, AL
>
Anything that increase glue area adds strength to a joint. So, no you
don't need too but the joint won't be as strong as it could be.
Is it good enough for your application. You got me, my crystal ball is
out for a tune up.
--
MikeG
Heirloom Woods
www.heirloom-woods.net
[email protected]
Mac I've been a commercial furniture builder for years, the biscuit is my
method of construction. The only time I now use a mortise and tennon is when
it's visible. Biscuits are available in several sizes including the S-6
which measures 1 1/4" X 3 3/8", use a S-6 in a table leg apron joint and I
defy you to make it fail in normal use. Double stack it and it's almost
impossible to break the joint.
--
Rumpty
Radial Arm Saw Forum: http://forums.delphiforums.com/woodbutcher/start
- - - - - - - - - - - - - - - - - - - - -
"mac davis" <[email protected]> wrote in message
news:[email protected]...
> On Mon, 27 Sep 2004 15:07:34 GMT, "Leon"
> <[email protected]> wrote:
>
> >
> >"jo4hn" <[email protected]> wrote in message
> >news:[email protected]...
> >>
> >> It's actually more important that glue be spread across the mating
> >> surfaces than in the slots. Biscuits will aid in alignment but add
little
> >> strength.
> >> mahalo,
> >> jo4hn
> >
> >Actually biscuits do add strength but not in all cases. If gluing long
> >grain to long grain, they are better for alignment purposes. However as
you
> >start to introduce more end grain into the joint, 45's and butt joints,
the
> >biscuit adds significantly more to the joint in terms if strength. The
> >biscuit adds the long grain to long grain glue surfaces within the
biscuit
> >slot to join to the long grain of the biscuit surface.
> >
> no kidding!!
> after reading this thread yesterday, I went into the scrap bin last
> night and played with a 18 x 8" frame that i'd made for practice...
> Made of 1 x 3" pine and butt jointed, 1 biscuit per joint... glued in
> slots and face/grain of joint..
>
> I locked it in the bench vice and started a sideways rocking, like the
> folks in the thread described as what would most weaken a box during
> use...
>
> After 4 or 5 minutes, I got one end (2 joints) to break loose... one
> joint had slivers of biscuit and pine on both sides, the other joint
> had an almost perfectly 1/2 biscuit shaped piece of pine attached to
> the biscuit of the other part of the joint..
>
> I don't know if I described that right, but there is a 1/2 oval of
> pine, from the side of the biscuit to the face of the board, and the
> other half of the joint has a matching 1/2 oval missing from the end
> grain...
>
> After breaking up several glue joints and some glue and dowel joints,
> I'm impressed with the biscuits!
>
>
> Mac
"Mike Marlow" <[email protected]> wrote in message
>
> it's good to see
> some real documented results.
> --
What? And screw up a good argument with FACTS?
"jo4hn" <[email protected]> wrote in message
news:[email protected]...
>
> It's actually more important that glue be spread across the mating
> surfaces than in the slots. Biscuits will aid in alignment but add little
> strength.
> mahalo,
> jo4hn
Actually biscuits do add strength but not in all cases. If gluing long
grain to long grain, they are better for alignment purposes. However as you
start to introduce more end grain into the joint, 45's and butt joints, the
biscuit adds significantly more to the joint in terms if strength. The
biscuit adds the long grain to long grain glue surfaces within the biscuit
slot to join to the long grain of the biscuit surface.
"mac davis" <[email protected]> wrote in message
news:[email protected]...
> no kidding!!
> after reading this thread yesterday, I went into the scrap bin last
> night and played with a 18 x 8" frame that i'd made for practice...
> Made of 1 x 3" pine and butt jointed, 1 biscuit per joint... glued in
> slots and face/grain of joint..
>
> I locked it in the bench vice and started a sideways rocking, like the
> folks in the thread described as what would most weaken a box during
> use...
>
> After 4 or 5 minutes, I got one end (2 joints) to break loose... one
> joint had slivers of biscuit and pine on both sides, the other joint
> had an almost perfectly 1/2 biscuit shaped piece of pine attached to
> the biscuit of the other part of the joint..
>
> I don't know if I described that right, but there is a 1/2 oval of
> pine, from the side of the biscuit to the face of the board, and the
> other half of the joint has a matching 1/2 oval missing from the end
> grain...
>
> After breaking up several glue joints and some glue and dowel joints,
> I'm impressed with the biscuits!
>
>
> Mac
Hey Mac - thanks for posting this. There's a lot of speculation that takes
place surrounding a lot of questions that pop up here and it's good to see
some real documented results.
--
-Mike-
[email protected]
[email protected] (Charlie Self) wrote in
news:[email protected]:
> Ronnie Aldrich asks:
>
>>I am making a simple set of shelves out of 3/4" plywood with the
>>shelves attached to the sides with biscuits. My question is: Do I
>>need to put glue on the ends of the shelves in addition to the
>>biscuits, or will just the glue in the slots work good enough?
>>
>
> Biscuits are primarily alignment devices, adding very little extra
> strength in most cases. Add glue to the end of the wood, too, as well
> as to the slots and the biscuits.
>
Can I disagree here, Charley, without starting a religious war?
In this case, I believe these are much more analogous to a floating tenon,
and that what is being made here is much closer to a housed joint. The
added shear strength is important.
If we were discussing edge gluing, we would agree.
Patriarch
patriarch responds:
>> Biscuits are primarily alignment devices, adding very little extra
>> strength in most cases. Add glue to the end of the wood, too, as well
>> as to the slots and the biscuits.
>>
>
>Can I disagree here, Charley, without starting a religious war?
>
>In this case, I believe these are much more analogous to a floating tenon,
>and that what is being made here is much closer to a housed joint. The
>added shear strength is important.
>
>If we were discussing edge gluing, we would agree.
I'd like to test that some day when I have time. Not this year. But three or so
biscuits in the end of a 12" wide shelf do not seem to me to add anything much
to overall strength, though they do add a little. That doesn't reduce the need
for glue on the end of the board where it meets the vertical side of the shelf
carcase.
Charlie Self
"Half of the American people have never read a newspaper. Half never voted for
President. One hopes it is the same half." Gore Vidal
[email protected] (Charlie Self) wrote in
news:[email protected]:
> That doesn't reduce the need for glue on the end of the board where it
> meets the vertical side of the shelf carcase.
>
That's true.
I'll admit also that my tendency is to find a means of hiding some of
McFeeley's best in there as well. Over-engineered, since these things tend
to get overloaded. And somewhat abused, when moved around, during the
course of life.
The last set has pocket screws, biscuits, glue, and "brads 'til the glue
dries." Won't likely end up in a museum. Might not even sell in a yard
sale. But it's holding up 6 cases of engineering texts right now in my
office, and is 'seismically stable'.;-) I needed it quick, since one of
the kids needed to move back home 'for a while'.
What's Brother Roy say? 'Twill do. 'Twill serve.
Patriarch
"Swingman" <[email protected]> wrote in
news:[email protected]:
> "patriarch wrote in message
>
>> and that what is being made here is much closer to a housed joint.
>
> Not without a dado/groove, eh? It appears he was talking butt joint to
> me.
>
What I was thinking was a constructed mortise and tenon. Perhaps I used
the wrong term. Wouldn't be the first time.
"Ronnie Aldrich" wrote in message
> Hello all,
>
> I am making a simple set of shelves out of 3/4" plywood with the
> shelves attached to the sides with biscuits. My question is: Do I
> need to put glue on the ends of the shelves in addition to the
> biscuits, or will just the glue in the slots work good enough?
With plywood, glue _both_ the edges, and the biscuits, before clamping.
--
www.e-woodshop.net
Last update: 7/10/04
>
> It's actually more important that glue be spread across the mating
> surfaces than in the slots. Biscuits will aid in alignment but add
> little strength.
> mahalo,
Dang, I better change professions.......all of my work is about to fall
apart...
--
Rumpty
Radial Arm Saw Forum: http://forums.delphiforums.com/woodbutcher/start
- - - - - - - - - - - - - - - - - - - - -
On Wed, 29 Sep 2004 01:53:56 GMT, "Edwin Pawlowski" <[email protected]>
wrote:
>
>"Mike Marlow" <[email protected]> wrote in message
>>
>> it's good to see
>> some real documented results.
>> --
>
>What? And screw up a good argument with FACTS?
>
no way!
there is no place for facts or logic in a good thread...
I love the one's that begin with someone asking "how do I find the
center of a circle" or something and end up being a debate on quantum
physics..
Mac
On Mon, 27 Sep 2004 15:07:34 GMT, "Leon"
<[email protected]> wrote:
>
>"jo4hn" <[email protected]> wrote in message
>news:[email protected]...
>>
>> It's actually more important that glue be spread across the mating
>> surfaces than in the slots. Biscuits will aid in alignment but add little
>> strength.
>> mahalo,
>> jo4hn
>
>Actually biscuits do add strength but not in all cases. If gluing long
>grain to long grain, they are better for alignment purposes. However as you
>start to introduce more end grain into the joint, 45's and butt joints, the
>biscuit adds significantly more to the joint in terms if strength. The
>biscuit adds the long grain to long grain glue surfaces within the biscuit
>slot to join to the long grain of the biscuit surface.
>
no kidding!!
after reading this thread yesterday, I went into the scrap bin last
night and played with a 18 x 8" frame that i'd made for practice...
Made of 1 x 3" pine and butt jointed, 1 biscuit per joint... glued in
slots and face/grain of joint..
I locked it in the bench vice and started a sideways rocking, like the
folks in the thread described as what would most weaken a box during
use...
After 4 or 5 minutes, I got one end (2 joints) to break loose... one
joint had slivers of biscuit and pine on both sides, the other joint
had an almost perfectly 1/2 biscuit shaped piece of pine attached to
the biscuit of the other part of the joint..
I don't know if I described that right, but there is a 1/2 oval of
pine, from the side of the biscuit to the face of the board, and the
other half of the joint has a matching 1/2 oval missing from the end
grain...
After breaking up several glue joints and some glue and dowel joints,
I'm impressed with the biscuits!
Mac
Wow, did you get some replies that hit most of the possible range! Maybe we
can look into this a bit more. Now, gluing end grain to face will be a very
weak glue joint. And if the end grain is plywood, it'll tend to be even lower
density and even weaker (depending on the plywood being lumber core, hardwood
ply, or mdf core). Also, any even small racking in the frame will likely break
that glue joint.
While biscuits are primarily used for alignment when edge gluing, that's not
the only way they can be used. Adjustable shelves, for instance, can hold
quite a bit of weight with even a 1/4" dowel used in four holes at or below
the ends. That's because you're relying on the shear strength, which is pretty
high. If your shelves are fairly tight fitting, I would suspect a biscuit
would have about the same shear strength, and that the shelves would hold up
with nothing but dry biscuits in them (assuming the frame prevented racking).
Gluing the biscuits adds little to the shear strength, but holds the edge of
the shelf against the face of the side, helping to stabilize the frame against
racking. I suspect the strength of this joint is such that gluing the sides
won't help significantly. Of course, it really won't hurt, either.
For more information on this subject, try it at home. Prototype a shelf with
dry biscuits and load on alot of weight. If the shelf's a couple of feet long,
I'll bet it bends first. Then take two plywood scraps and glue one to a face
with biscuits, and the other just with glue on the edge. Let dry overnight,
then break each to see the difference, and conclude for yourself if it's worth
gluing the edge.
BTW, remember that you are free to use as many biscuits as will fit, and four
on an edge are much stronger than two, of course.
GerryG
On 26 Sep 2004 10:47:26 -0700, [email protected] (Ronnie Aldrich)
wrote:
>Hello all,
>
>I am making a simple set of shelves out of 3/4" plywood with the
>shelves attached to the sides with biscuits. My question is: Do I
>need to put glue on the ends of the shelves in addition to the
>biscuits, or will just the glue in the slots work good enough?
>
>Thanks in advance,
>
>Ronnie Aldrich
>B'ham, AL
Well, you surely won't be alone. All the people who've driven a nail or screw
into the edge of a shelf will be right behind you.
Actually, just happened to be reading Choosing the Strongest Joinery for Doors
by John Wagner, in FWW Practical Design Solutions & Strategies. A little
different as it's not shear resistance, but he compared bolts, T&G, dowels,
M&T and biscuits for failure in door joints. On pure strength, biscuits came
out on top.
GerryG
On Sun, 26 Sep 2004 21:26:36 -0400, "Rumpty" <[email protected]> wrote:
>>
>> It's actually more important that glue be spread across the mating
>> surfaces than in the slots. Biscuits will aid in alignment but add
>> little strength.
>> mahalo,
>
>
>Dang, I better change professions.......all of my work is about to fall
>apart...
Ronnie Aldrich wrote:
> Hello all,
>
> I am making a simple set of shelves out of 3/4" plywood with the
> shelves attached to the sides with biscuits. My question is: Do I
> need to put glue on the ends of the shelves in addition to the
> biscuits, or will just the glue in the slots work good enough?
>
> Thanks in advance,
>
> Ronnie Aldrich
> B'ham, AL
It's actually more important that glue be spread across the mating
surfaces than in the slots. Biscuits will aid in alignment but add
little strength.
mahalo,
jo4hn
[email protected] (Charlie Self) wrote in message news:<[email protected]>...
> Ronnie Aldrich asks:
>
> >I am making a simple set of shelves out of 3/4" plywood with the
> >shelves attached to the sides with biscuits. My question is: Do I
> >need to put glue on the ends of the shelves in addition to the
> >biscuits, or will just the glue in the slots work good enough?
> >
>
> Biscuits are primarily alignment devices, adding very little extra strength in
> most cases.
Charlie,
Somewhere I recall reading an article comparing the strengths of
various end-to-edge joinery techniques. Included were a plain butt
joint, dowels, M&T, two biscuits, three biscuits, and maybe others
(all were glued). I was surprised to read that the two and three
biscuits provided as much strength as the M&T (additional strength
from the third biscuit was insignificant). The article implied that,
properly used, biscuits add _a lot_ of strength. As a relative newbie
(have yet to use biscuits), I am left wondering what to believe.
Perhaps I'm misinterpreting your position. If so, I'd appreciate a
little light on the subject. TIA.
Cheers,
Mike
> Add glue to the end of the wood, too, as well as to the slots and
> the biscuits.
>
> Charlie Self
> "Half of the American people have never read a newspaper. Half never voted for
> President. One hopes it is the same half." Gore Vidal
On 26 Sep 2004 10:47:26 -0700, [email protected] (Ronnie
Aldrich) wrote:
>Hello all,
>
>I am making a simple set of shelves out of 3/4" plywood with the
>shelves attached to the sides with biscuits. My question is: Do I
>need to put glue on the ends of the shelves in addition to the
>biscuits, or will just the glue in the slots work good enough?
>
>Thanks in advance,
>
>Ronnie Aldrich
>B'ham, AL
Hello Ron,
Are the shelves for Video Casettes for your business or something
heavier? Providing additional glue to the edge and face of a 90'
plywood joint without a dado or T&G joint will fail over time. Using
Lamellos with glue may be sufficient ( and probably will be). Please
note...the potential of glue "squeeze-out" may compromise your
possible intentions of staining the shelving unit(s) Clean up that
excess glue.
BTW...Opps. I just read through my post prior to sending and saw that
I used the word Lamello. It's a brand name from the Swiss who
developed the first biscuit joiner machine I think. Most folks look
at me funny in the shop when I ask them to fetch the #20
Lamellos...LOL Good Luck Ron.
On Mon, 27 Sep 2004 05:18:03 GMT, GerryG <[email protected]> wrote:
>Well, you surely won't be alone. All the people who've driven a nail or screw
>into the edge of a shelf will be right behind you.
>
>Actually, just happened to be reading Choosing the Strongest Joinery for Doors
>by John Wagner, in FWW Practical Design Solutions & Strategies. A little
>different as it's not shear resistance, but he compared bolts, T&G, dowels,
>M&T and biscuits for failure in door joints. On pure strength, biscuits came
>out on top.
>
>GerryG
I can believe that!
I was looking at some of the practice joints in the scrap/firewood box
that I did while learning to use the biscuit jointer and they will NOT
break loose as my old "screw & glue" or "dowel & glue" joints do...
A problem with biscuit joints at my current skill level is that the
mistakes and rejects could out live me...
Mac
Edwin Pawlowski said:
>
>"Mike Marlow" <[email protected]> wrote in message
>>
>> it's good to see
>> some real documented results.
>> --
>
>What? And screw up a good argument with FACTS?
LMAO!
Greg G.