Violin Forum/Message Board

[jethro]

Been trying my new Lie-Nielson 14 inch low angle plane on a hard maple
back joint. Got some "spring" by skewing the plane about 15 degrees
and removing a tiny bit in the middle 80%. joined with hot glue. I let
joint set about 10 minuites while brushing more glue on sides of joint to
permote swelling in center. I wanted to know if the joint was solid
INSIDE where I can not see. I had a 150 watt spotlite. I turned out all the shop lites and put the joint in front of the bulb about 2 inches away,
kind of like an X-Ray. I started at top and slowly moved down. I could
see a very faint line of light. But down about half way I could see an
area about 1 inch long which was somewhat brighter. I took this to be a
zone where the wood didn't swell up enough to close the spring up all the way. I suspected the ammount of spring was a little heavy. The glue was
still soft so I just poped it appart. ( I just lost the previous plate because
there was a slight gap INSIDE the joint which couldn't be seen untill I had
carved the top surface.
Have any of you tried this method of wet joint inspection ??????????
If you have - I would thing you would see a LITTLE bright line because the
wet glue joint should transmit a little light through it's thickness.
I don't want to loose another plate because of a hidden flaw-----

Any feedback ??????

[violinarius]

Don't put water/glue on the joint after you have glued it.

This is a no-no.

You want perfect wood to wood contact for hide glue to work. This glue has no glue-line like other glues, and that makes it perfect for jointing plates.

The best thing to do is to glue the joint very soon after you have it planed, so that the surface does not get contaminated. Even oils from fingerprints can cause a joint to fail. Moisture changes in the air can cause the wood to change dimensions. The freshly exposed wood surface begins to oxidize immediately.

I do a combination of a rubbed, and then clamped glue joint that has never failed.

The benefit of a sprung joint is that the skill needed to obtain perfect wood to wood contact is not needed, and so beginners have more success with this type of joint, but the drawback to it is that it demands more finesse in the clamping stages.

This is where the combo rub/clamp joint helps.

Once you have your wood clamped and the glue has dried for a while, try removing, from a non critical place, with a gouge some chips that run across the joint. Bending them should produce a failure anywhere but the joint itself.

Practice on some non violin wood until you get it right.
Rome wasn't built in a day.

[Jack H.]

I suspect that the whole area that you saw light through is an area where there is no wood to wood contact and that is where problems would have occured.
I believe in getting the joint dead flat and then glue it with propper clamping pressure on top in th emiddle and the bottom.
You need a good straight edge and a great plane blade.

[jethro]

Jack: I can do good spruce joints without effort. I can get the maple
joints flat fairly quickly with my good plane. Getting the spring to be
a uniform taper end to end with no variation seems hard. I will try
cutting a set of scrap spruce to be flat and look at them through the same light and see how much I can see- maybe I can use that as a control.
I would expect SOME small ammount of light through if there is any glue
in the joint. Just not sure how much visualy speaking....
I tried the joints flat and watched as the center swelled and pushed the edged off (a lot too) so I will be sticking (no pun .... ) to the spring
method.
Does anyone have a reccomendation for where and what type of ruller
to use for this kind of work which may be depended on to be straight
and flat ? there are thick (3/16) hardened steel machinists rullers out
there from places like MSC that I think are surface ground on the edge.
but these might be overkill...... and they are expensive !

PS
I havn't had any "failures) of joints as in they break..... just failure
of the joint to be as cosmetic as I want. Sometimes I get a short
segment where I can see a hint of glue joint. It may not even go all
the way through to the back.... but it looks just as bad as if it did !
I too have launched PLENTY of expletives in the old either but sadly
that doesn't help me reverse it or do a better one ! I will try some more
untill I figure it out !

Thanks T.

[mapleleaf_gal]

[jethro]

I have heard of steaming out a small dent by dampening dent and ironing with hot iron to allow steam to Puff out the wood in the depressed area.
A little heat from an alcahol lamp spounds like an interesting idea. I have
a electric steam kettle with a stinger which pressureised steam shoots out
of. I use it for shooting a really localised steam jet into glue joints that I
am trying to loosen. Maybe safer than an open flame?????

I have been killing myself for the last week on this perfect vaccuum joint
thing. The 14 inch Lie-Nielsen sems to get the surface flat or very
slightly convex end to end (with maple plates back to back) I get it
flat first - OK. Then I tried angleing the plane about 15 degrees to get
a slightly deeper cut for the spring portion. After I do this--- I check
down both surfaces end to end with ruller - can get that OK. Touches
at ends but not in middle- little light pasing in center.
But then it gets strange!
I take the ruller and check at about 30 degrees to long ways and go doen the length and then check the other way down the length. This is a
shorter way of putting the ruller end to end on the diagonal. Most of the
time one direction all OK - but the other diagonal shows high in the
center at multiple spots. But at the same time straight end to end checks
OK. This must mean I have a saddle shape forming - probably due to
some asymmetrical cutting when I am angleing the plane . This seems to
be telling me I can't get away with angleing the plane to cut the spring.
I am thinking I need a slightly shorter plane which will tale a very small bite but that can be used exactly straight ahead - not skewed -

The new L-N is 14 inches long and I think the sole just bridges too much length to enable it to cut any spring. Would the L-N low angle block plane be too short ? Or do I want something about 9 inches ????????

Have you had the "saddle " shape bother you ????
And how long a sole do you think for the spring ?
I have tried my cheap stanley low angle block plane but it is WAY too
crude on the blade adjuster to easily get a small layer removed.
It's a piece of work !

Any thought ?????

Tim

[jethro]

I tried the water and alcahol lamp idea. I tested it on a couple of maple blocks which i purposefully cut a BiG spring into which I knew qould be
open. I glued the joint up - let dry about 3 hours. Big gap= maybe
5 -8 thousants or more in center. I wet a stripe on either side of the
crack - about 3/8 wide and let it soak in about 3 minuites. Re wetted again and then held it upside down over my head so I could look up and see the crack. Then I waved the alcahol lamp up and down the area
being carefull to stay in the clear area near the wick and to not stop moving. I did about 5 passes and rewet the area and repeated the
heat. I did this about 6 times and the big gap was about 90 % closed.
This gap was WAY biger than any gap that would ever happen on a plate joint. So I joined a plate last nite which had a little glue joint just barely
visible for the last 2 inches at the end on one side. The process fixed
it easily it appears. If it didn't I would just cut the joint and start over
again for the 5 or 6-th time ( AARRGGGGGHHHHHHH )

But It appars that you idea worked great ! The water in the wood and the coolness of the alcahol kept the wood from being any where near burning ! Plus water was being liberated from the burning alcahol, so I
bet that helps too !

Thanks a LOAD !!!!!!!!!!!!!!!!
Thats a great example of an awesome little trick that being formaly educated gives that self teaching never knows about !

Tim