Following the great advice I got here, I set up my joiner (sorry about
calling it a jointer; yeh, I know the difference) and glued two pieces of
cherry together with a single biscuit.
Although it took some effort, I was able to break it apart; and was
surprised to find the biscuit hadn't swollen noticably.
I measured a new one at 0.150" (Lemello #10) and put it in a glass of water
for 20 minutes. It only swelled to 0.159", and the width and length didn't
change much at all. I was expecting it to swell considerably.
Am I expecting too much, or is it a defunct biscuit?
Biscuits are for alignment, you still need glue over the whole joint as well
as in the biscuit slot.
The biscuits should be a push fit in the slot.
"Toller" <[email protected]> wrote:
>
>
>> Was the glue old? Was it Yellow Glue?
>
>Brand new yellow glue.
>It wasn't a "bad" joint, if I had glued the faces it probably would have
>held up; it just wasn't all that I was expecting.
>
Was the glue old? Was it Yellow Glue? I did thought about throwing some
biscuits into glass of water to see how much it actually swollen. I will try
it for myself. Keep in mind that biscuits are mainly for alignment, not
strength.
I remember reading that someone from this NG that he get all the slots cut
and right away when he apply the glue, he puts his handful of biscuits under
running water, then inserts them. Looks like a good idea, although I never
tried it. Maybe I will give it a try, since he did not say "do not try this
at home." :) :)
What you did was a very good experiment for yourself to actual see what does
what.
Chuck
> Although it took some effort, I was able to break it apart; and was
> surprised to find the biscuit hadn't swollen noticably.
> I measured a new one at 0.150" (Lemello #10) and put it in a glass of
water
> for 20 minutes. It only swelled to 0.159", and the width and length
didn't
> change much at all. I was expecting it to swell considerably.
On Mon, 15 Dec 2003 01:23:23 GMT, "Toller" <[email protected]> wrote:
>Although it took some effort, I was able to break it apart; and was
>surprised to find the biscuit hadn't swollen noticably.
They don't need to - slots should be accurate and a tiny expansion is
enough to hold it. Lamello biscuits _don't_ swell as much as the cheap
ones - neither do Tanselli (my usual brand). I assume that they're
optimising them for strength, not for foaming up to fill a badly cut
slot.
Here's an experiment. I did it last year, when faced with a whinging
hippy who didn't like using biscuits because they "weren't strong
enough". Take a couple of 2x4 chunks of a strong hardwood (I used
oak) and cut a couple of #20 biscuit slots in there. Attach one chunk
to the ceiling trusses and stick an eye bolt and a length of rope on
the other. Now take a pair of biscuits and assemble them wet with
_water_, no glue at all. Give it half an hour to swell, then dangle
yourself from the rope.
IMHE, most biscuit problems _in_assembly_ are caused by dud biscuits
(or operator error gluing the biscuit instead of the slot), and most
problems _in_failure_ are caused by dud slots.
--
What ? Me ? Evil Dictator of Iraq ?
Nah mate, I'm just a Hobbit, honest
I'm rather suprised that you could break the joint apart. A yellow glue
joint is supposed to be stronger than the surrounding wood. You may want to
look into your glueing technique.
The slot made by your joiner should be between 0.160 and 0.165 in thickness.
If the biscutt was swelling to 0.159 in the test, then that's about as tight
as you want to get without risking splitting the wood.
Make some test cuts and check your slot thickness. Your technique and the
joiners accuracy can definately have a negitive impact on the thickness.
The other post with the tip of wetting the biscuts first seems like a good
idea. I'll have to give that a try on some test joints.
Bernie
PC557 Faq www.huntfamily.com/pc557.cfm , but not yet updated to include Type
IIIs
"Toller" <[email protected]> wrote in message
news:[email protected]...
> Following the great advice I got here, I set up my joiner (sorry about
> calling it a jointer; yeh, I know the difference) and glued two pieces of
> cherry together with a single biscuit.
>
> Although it took some effort, I was able to break it apart; and was
> surprised to find the biscuit hadn't swollen noticably.
> I measured a new one at 0.150" (Lemello #10) and put it in a glass of
water
> for 20 minutes. It only swelled to 0.159", and the width and length
didn't
> change much at all. I was expecting it to swell considerably.
>
> Am I expecting too much, or is it a defunct biscuit?
>
>
In my shop we go through over 10K biscuits a year, Lamello brand and they
work just fine. If you aren't happy with your joint, perhaps you let the
joiner move during the cut and cut the slots too wide.
--
Rumpty
Radial Arm Saw Forum: http://forums.delphiforums.com/woodbutcher/start
- - - - - - - - - - - - - - - - - - - - -
"Toller" <[email protected]> wrote in message
news:[email protected]...
> Following the great advice I got here, I set up my joiner (sorry about
> calling it a jointer; yeh, I know the difference) and glued two pieces of
> cherry together with a single biscuit.
>
> Although it took some effort, I was able to break it apart; and was
> surprised to find the biscuit hadn't swollen noticably.
> I measured a new one at 0.150" (Lemello #10) and put it in a glass of
water
> for 20 minutes. It only swelled to 0.159", and the width and length
didn't
> change much at all. I was expecting it to swell considerably.
>
> Am I expecting too much, or is it a defunct biscuit?
>
>
"Andy Dingley" <[email protected]> wrote in message
news:[email protected]...
> On Mon, 15 Dec 2003 01:23:23 GMT, "Toller" <[email protected]> wrote:
>
> >Although it took some effort, I was able to break it apart; and was
> >surprised to find the biscuit hadn't swollen noticably.
>
> They don't need to - slots should be accurate and a tiny expansion is
> enough to hold it. Lamello biscuits _don't_ swell as much as the cheap
> ones - neither do Tanselli (my usual brand). I assume that they're
> optimising them for strength, not for foaming up to fill a badly cut
> slot.
>
> Here's an experiment. I did it last year, when faced with a whinging
> hippy who didn't like using biscuits because they "weren't strong
> enough". Take a couple of 2x4 chunks of a strong hardwood (I used
> oak) and cut a couple of #20 biscuit slots in there. Attach one chunk
> to the ceiling trusses and stick an eye bolt and a length of rope on
> the other. Now take a pair of biscuits and assemble them wet with
> _water_, no glue at all. Give it half an hour to swell, then dangle
> yourself from the rope.
>
> IMHE, most biscuit problems _in_assembly_ are caused by dud biscuits
> (or operator error gluing the biscuit instead of the slot), and most
> problems _in_failure_ are caused by dud slots.
>
1) I have been putting glue on both biscuits and slots. Does also gluing
the biscuits hurt something?
2) You seem to be disagreeing with the people who say that the biscuits for
for alignment only.
On Mon, 15 Dec 2003 01:23:23 GMT, "Toller" <[email protected]> wrote:
>Following the great advice I got here, I set up my joiner (sorry about
>calling it a jointer; yeh, I know the difference) and glued two pieces of
>cherry together with a single biscuit.
>
>Although it took some effort, I was able to break it apart; and was
>surprised to find the biscuit hadn't swollen noticably.
>I measured a new one at 0.150" (Lemello #10) and put it in a glass of water
>for 20 minutes. It only swelled to 0.159", and the width and length didn't
>change much at all. I was expecting it to swell considerably.
>
>Am I expecting too much, or is it a defunct biscuit?
>
I know you're not supposed to do it, but I spread (a thin coat of)
glue all over the biscuit before using it. If your cherry board broke
along the glue line, something is not right!
Buttermilk works for me.... Oh...wait... um...nevermind.
"Rumpty" <[email protected]> wrote in message
news:[email protected]...
> >Having two bottles also allows you to keep two dilutions of glue (if
> you're using white PVA).
>
> I have found "Yellow" Elmers to be the best glue for biscuits. Not too
> runny.
>
> --
>
> Rumpty
>
> Radial Arm Saw Forum: http://forums.delphiforums.com/woodbutcher/start
>
> - - - - - - - - - - - - - - - - - - - - -
>
>
On Mon, 15 Dec 2003 15:08:00 GMT, "Toller" <[email protected]> wrote:
>1) I have been putting glue on both biscuits and slots. Does also gluing
>the biscuits hurt something?
Biscuits expand when you moisten them. If you pre-wet the biscuits,
you've a real problem getting them in the slots. Store them _dry_
(mine live in the house, not the workshop), keep them sealed up and
don't wet the biscuits themselves.
Almost as useful as a biscuit jointer is a glue bottle with a biscuit
shaped nozzle. Lamello's auto-dosing one is an insane price, but you
can also get cheap squeeze-bottle ones for just a few bucks.
Having two bottles also allows you to keep two dilutions of glue (if
you're using white PVA). My slot bottle is always runnier than the
roller bottle for doing the face.
>2) You seem to be disagreeing with the people who say that the biscuits for
>for alignment only.
Not really disagreeing.
Biscuits are strong enough to hold a joint together, and so is
face-gluing it (if it's long-grain to long-grain, or if you're Bay
Area Dave). Biscuits also aid alignment. You could make an adequate
joint in tension by just gluing either one of these items. As we
normally glue both, then the joint shoudl be over-strong. A
well-glued biscuit should be comfortably in excess of its tensile
strength - i.e. the biscuit will snap if you pull hard enough.
The strength of a good face-glued joint is another reason why you
don't need to use huge numbers of biscuits. People made this sort of
joint for a couple of centureis before biscuits, and used no
reinforcement at all.
There _are_ a couple of cases where it is useful to rely on the
biscuit's strength. Edge-glued MDF is often weak (for much the same
rasons as end grain) and so biscuiting in MDF needs to be based on the
strength of the biscuits alone. Similarly for framing work, where
there's an end-to-long grain joint. Less commonly, an edge jointed
tabletop can sometimes fail if the outboard board can be bent
downwards under load. Particularly in a less stiff timber, this allows
the stress to concentrate at the top edge of the glued joint, causing
it to break progressively downwards through the whole joint. A biscuit
can stop the flexing here that alllows the stress to concentrate in
one place.
--
What ? Me ? Evil Dictator of Iraq ?
Nah mate, I'm just a Hobbit, honest