I recently had an 11x14 mirror with a 2.5" wide pine frame that got
damaged while on display in a store. They had it hanging on a door
and it got knocked off, I'm guessing about a 4 foot drop. The weird
thing is the glass didn't break, except a small chip in one corner.
All 4 joints on the frame came apart though, which is sort of the
opposite of what I would have expected. They were splined miters with
the spline about 1 inch deep at the joint. It appears the splines
were either slightly too thin or I didn't use enough glue, as the
splines came loose with no damage at all to the frame or splines. I
test fitted one and it seemed like a proper fit to me. I'm a little
confused.
So here are my questions,
With the proper joinery should a frame survive a fall like this or
should it be expected to fail?
Should I be making the spline deeper or adding a key for additional
strength?
-Leuf
Leuf wrote:
> I recently had an 11x14 mirror with a 2.5" wide pine frame that got
> damaged while on display in a store. They had it hanging on a door
> and it got knocked off, I'm guessing about a 4 foot drop. The weird
> thing is the glass didn't break, except a small chip in one corner.
> All 4 joints on the frame came apart though, which is sort of the
> opposite of what I would have expected. They were splined miters with
> the spline about 1 inch deep at the joint. It appears the splines
> were either slightly too thin or I didn't use enough glue, as the
> splines came loose with no damage at all to the frame or splines. I
> test fitted one and it seemed like a proper fit to me. I'm a little
> confused.
>
> So here are my questions,
>
> With the proper joinery should a frame survive a fall like this or
> should it be expected to fail?
>
> Should I be making the spline deeper or adding a key for additional
> strength?
>
>
> -Leuf
I'd keep making frames exactly like the one you built - apparently it
dispersed just enough energy, at an acceptable rate through its
destruction to save the mirror :-)
"Scorp" wrote in message
> 1" is pretty deep for such a small frame.
My experience is just the opposite ... with frame sides 2.5" wide, it is
hardly worth using "miter with spline" frame joinery with just a 1" spline.
At that width, the mitered surfaces being joined are over 3.5" long.
So, and just an off-the-cuff rough estimate, a triangular shaped spline with
2" height would offer over 4 times more glue area to reinforce the mitered
frame joint, more glue area being the whole point of this joinery method.
I would probably use a spline height of 2.5", which is about right, IME, for
frame joinery with sides of this width ... and it's easy to cut the spline
slot in the frame corners to this depth on the table saw.
--
www.e-woodshop.net
Last update: 12/13/05
On Sun, 1 Jan 2006 14:35:09 -0600, "Swingman" <[email protected]> wrote:
>"Scorp" wrote in message
>> 1" is pretty deep for such a small frame.
>My experience is just the opposite ... with frame sides 2.5" wide, it is
>hardly worth using "miter with spline" frame joinery with just a 1" spline.
Now wouldn't a 1" spline be 1/2" deep?
From the OP:
>They were splined miters with
>the spline about 1 inch deep at the joint.
I assumed the splines WERE 2" wide to achieve this. Other
translations may vary :)
--------------------
Steve Jensen
Abbotsford B.C.
[email protected] chopping out the mortise.
BBS'ing since 1982 at 300 bps.
Surfing along at 19200 bps since 95.
WW'ing since 1985
LV Cust #4114
Nothing catchy to say, well maybe.....
WAKE UP - There are no GODs you fools!
"Leuf" <[email protected]> wrote in message
news:[email protected]...
> So here are my questions,
>
> With the proper joinery should a frame survive a fall like this or
> should it be expected to fail?
>
> Should I be making the spline deeper or adding a key for additional
> strength?
The frame was made to hold something, not to protect it from a fall.
Especially when what's in it is very heavy. If you want protection in a
fall, you'll want something besides miters, keyed, splined or otherwise. A
sharp blow is going to break small glue surfaces apart.
On Fri, 30 Dec 2005 12:03:40 -0800, Scorp <[email protected]> wrote:
>On Fri, 30 Dec 2005 01:25:14 -0500, Leuf <[email protected]>
>wrote:
>
>>I recently had an 11x14 mirror with a 2.5" wide pine frame that got
>>damaged while on display in a store.
>>They were splined miters with
>>the spline about 1 inch deep at the joint. It appears the splines
>>were either slightly too thin or I didn't use enough glue, as the
>>splines came loose with no damage at all to the frame or splines.
>>With the proper joinery should a frame survive a fall like this or
>>should it be expected to fail?
>
>Maybe no joint would have held, how your joint failed however is a
>problem and I would think should have been much stronger, 1" is pretty
>deep for such a small frame.
>
>Was the spline also pine? Maybe a burnished or contaminated surface?
Thanks for all the responses..
The splines were pine. Closer inspection shows some of the splines
were slightly thinner than the one I tested, and that one barely has
any glue on it. Not sure how that happened.
I used elmer's yellow glue. The bottle doesn't list a minimum
temperature, the shop has been between 50-55 F which I know is
borderline for a lot glues. However there were also applied intarsia
pieces on the frame that spanned two of the miters and those both
stayed attached to the frame and stayed together, breaking in the
wood. Those were glued under the same conditions.
I had been applying glue only on the inside of the spline and not to
the spline itself, when I put it on the spline it just gets scraped
off when inserted and the frame has a rough edge that I can't sand so
squeeze out is a problem.
I'm thinking making the spline a little deeper, applying glue lightly
on the spline itself in addition to in the joint, and putting a clamp
to make sure there's good contact should be enough. I don't think
I'll do a drop test on it though...
-Leuf
On Fri, 30 Dec 2005 01:25:14 -0500, Leuf <[email protected]>
wrote:
>I recently had an 11x14 mirror with a 2.5" wide pine frame that got
>damaged while on display in a store.
>They were splined miters with
>the spline about 1 inch deep at the joint. It appears the splines
>were either slightly too thin or I didn't use enough glue, as the
>splines came loose with no damage at all to the frame or splines.
>With the proper joinery should a frame survive a fall like this or
>should it be expected to fail?
Maybe no joint would have held, how your joint failed however is a
problem and I would think should have been much stronger, 1" is pretty
deep for such a small frame.
Was the spline also pine? Maybe a burnished or contaminated surface?
--------------------
Steve Jensen
Abbotsford B.C.
[email protected] chopping out the mortise.
BBS'ing since 1982 at 300 bps.
Surfing along at 19200 bps since 95.
WW'ing since 1985
LV Cust #4114
Nothing catchy to say, well maybe.....
WAKE UP - There are no GODs you fools!
"Leuf" <[email protected]> wrote in message
> The weird
> thing is the glass didn't break, except a small chip in one corner.
> All 4 joints on the frame came apart though, which is sort of the
> opposite of what I would have expected. They were splined miters with
> the spline about 1 inch deep at the joint. It appears the splines
> were either slightly too thin or I didn't use enough glue, as the
> splines came loose with no damage at all to the frame or splines. I
> test fitted one and it seemed like a proper fit to me. I'm a little
> confused.
>
> So here are my questions,
>
> With the proper joinery should a frame survive a fall like this or
> should it be expected to fail?
>
> Should I be making the spline deeper or adding a key for additional
> strength?
The frame protected the glass by absorbing the shock. Take a look at things
like the bumpers on your car, crumple zones, the foam packaging
appliances/electronics come in and what do they have in common? They all
absorb shock.
If you want the frame to absorb the shock of a 4' fall, it must be designed
into it. Strong materials do not always do the job as they transmit, not
absorb the energy. Frames, with purpose in mind, are made to look pretty,
hold pictures or mirrors, and provide support for hanging. Never has
falling come into the engineering.
"Leuf" wrote in message
> With the proper joinery should a frame survive a fall like this or
> should it be expected to fail?
>
> Should I be making the spline deeper or adding a key for additional
> strength?
Judging from your description I would say that there was most likely a
combination of factors that caused the behavior.
That said, good glue, properly applied in the right temperature range, would
not have normally allowed the parts, particularly the splines in a miter
joint, to come apart as cleanly as you describe.
In addition, 1" splines probably didn't give you enough extra glue surface
area in a miter joint joining sides of that size.
--
www.e-woodshop.net
Last update: 12/13/05
It is a little surprising, I agree. I guess the energy of the moving mirror
was absorbed by destruction of the wood structure thus protecting the glass!
Just out of curiosity, what kind of glue did you use? I think a deeper
spline would have better protected the frame from opening up with humidity
changes over the years.
Dave
Not enough glue.
"Leuf" <[email protected]> wrote in message
news:[email protected]...
> I recently had an 11x14 mirror with a 2.5" wide pine frame that got
> damaged while on display in a store. They had it hanging on a door
> and it got knocked off, I'm guessing about a 4 foot drop. The weird
> thing is the glass didn't break, except a small chip in one corner.
> All 4 joints on the frame came apart though, which is sort of the
> opposite of what I would have expected. They were splined miters with
> the spline about 1 inch deep at the joint. It appears the splines
> were either slightly too thin or I didn't use enough glue, as the
> splines came loose with no damage at all to the frame or splines. I
> test fitted one and it seemed like a proper fit to me. I'm a little
> confused.
>
> So here are my questions,
>
> With the proper joinery should a frame survive a fall like this or
> should it be expected to fail?
>
> Should I be making the spline deeper or adding a key for additional
> strength?
>
>
> -Leuf
"Leuf" <[email protected]> wrote in message
news:[email protected]...
>I recently had an 11x14 mirror with a 2.5" wide pine frame that got
> damaged while on display in a store. They had it hanging on a door
> and it got knocked off, I'm guessing about a 4 foot drop. The weird
> thing is the glass didn't break, except a small chip in one corner.
> All 4 joints on the frame came apart though, which is sort of the
> opposite of what I would have expected. They were splined miters with
> the spline about 1 inch deep at the joint. It appears the splines
> were either slightly too thin or I didn't use enough glue, as the
> splines came loose with no damage at all to the frame or splines. I
> test fitted one and it seemed like a proper fit to me. I'm a little
> confused.
>
> So here are my questions,
>
> With the proper joinery should a frame survive a fall like this or
> should it be expected to fail?
>
I am not surprised it broke; that is a lot of weight.
I am surprised the glue broke; when I have broken joints on purpose, it is
always the wood that fails. They must have used way too little glue like
you surmised. If you can reglue them properly you should be fine.