I was reading an article by Michael Dresdner about hide glue this morning. He talks about how good it is for end grain and miter joints, and states “…you can make a strong “rubbed” joint without clamping.”
What, exactly, is a “rubbed joint”?
forestgirl — you can take the girl out of the forest, but you can’t take the forest out of the girl 😉
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Hey FG-
I've seen rubbed joints mainly in non-structural applications. Specifically, on drawer bottoms, where the builder would glue a small piece of wood to the underside of a plywood bottom and the surrounding drawer sides.
This joint is simple, just take a piece of wood, apply glue, and "rub" it into the area where you'd want to reinforce something, and hold it a few seconds. I think hot hide glue is the glue you'd use for this joint, as it has a very short open time and therefore, requires no clamping.
I think it is a good glue for miter joints for the same reason, just apply and hold the miters in place for a few seconds....
I wouldn't use the bottled "cold" hide glue for this type of work, you'd need to clamp then...
I have done it many times and it's very easy to do. I found out how from Tage Frid's book on joinery, (the 3 book set is the best buy in woodworking books-EVER-). You have to have real hide glue, (I bought it in pearl form from Woodcraft), and it is hot, but the stuff works great. I did 25 mitered frames in half a day, no clamps.
Basically, you just coat the ends to be joined with hot hide glue, and quickly "rub" them together until they stick, (about 5 seconds), them let them sit for a while. That's it. The glue is very forgiving, you can paint a coat on the ends, let it dry then add more and put them together, if needed, you can steam a joint apart, (hence, its use in violins for ease of repair).
I never bought a glue pot, just made a double boiler from some tin cans on the wood stove. Mixing and heating the glue is easy also, just remember to mix, heat, then cool, then reheat and it is good to go. You can add water and reheat as often as needed.
Enjoy, it's fun.
> ....I never bought a glue pot, just made a double boiler from some
> ... tin cans on the wood stove.
Brings to mind one of the historic events of Seattle: The great Seattle fire! (grin) Started by a glue pot tipping over on a wood stove.
...........
Dennis in Bellevue WA
[email protected]
That thought was always in mind! We did survive with less than standard equipment back then. I still use real hide glue quite often though, it is great for "clampless" joints.
Ahhhhh, someone I can ask for details from. As BG said in another thread, "I have an issues with glue-up." I would love to have an efficient way of glueing up what amounts to a mitered face frame, which then serves as trim on a shadow-box style jersey display case. The glue-ups are taking too much time and are easy to mess up. That part has to be exactly right, since it spans 32" x 24" and any deviation from 90* throws it way, way off.
So...when gluing up this mitered frame using hot hide glue, what technique would you use to ensure each miter is exactly at 90* before the glue goes from the liquid to the gel stage?
Another couple of questions: I use a drawer-lock bit for the main part of the case. Seems like hot hide glue might be an option for that also? If I were to try it and it didn't seem satisfactory, would I be able to remove it using hot water and re-glue using a different glue?
You mention in preparation that you heat, let cool and then re-heat. What is the purpose of the cooling step?
Thanks!forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)
I use a high quality PVA for all my stuff. ( would like to use hide glue but where to find it.......? )
Anyway, I rub all the long joints regardless. It gives a good even coverage of glue, pushes out any air bubbles and it will suddenly "grab". I then put the clamps on with meduim pressure so as not to force too much out and weaken the joint.
As for squaring something like a picture frame. Last one I did was quite chunky as per the customers request. I just glued and clamped and it self squared using the mitres as a guide. A quick check with a square before I left it showed it was fine.
Wood Hoon
Hi, WH. Lots of places to order hide glue flakes. You can get the liquid hide glue at most of the hardware stores now, I think, but it doesn't work for these joints -- takes too long to set.
I've got a pretty good system for doing this job with PVA and clamps, but the possibility of glueing up without them, and quickly, is very appealing.forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)
You don't need hot hide glue to do a rubbed joint. Simply use PVA. I do it with titebond all the time. If you doubt the strength, simply take a couple pieces of small scrap, apply some glue, rub together with moderate pressure and let it cure. Then try to break the joint.
This method does not replace well constructed and glued joinery. However, it allows the easy installation of reinforcement blocks and your picture frame miters will be a piece of cake. Yes, even on the partial end grain of miters. The glue will hold the joint long enough to cut spline joints or whatever. Again, try it and see if it works for you.
I cut all the frame parts with a miter saw that I took the time to tweak to a perfect 45*. Then glue up one corner so I had a bunch of half frames. Then the fun, gluing the halves, that's two joints at once, it took a bit of practice but after a couple it went just great. You are rubbing both miters at once. How well you cut your 45*'s is what determined the squareness of the frames. I did a bunch in red oak, (far from my favorite), and it went great.
You can steam the joint apart and I'm sure it would not effect the surface. Again, look at Tage Frid's book, that's where I learned it.
I'm proud to say that my 45*s are a true 45* (that took some time, LOL). I guess I'm just being paranoid, thinking about gluing up without clamps. Will make a little practice frame and give it a try!forestgirl -- you can take the girl out of the forest, but you can't take the forest out of the girl ;-)
My 45*'s never seem to stay that way........!
I think you will like hide glue, it does work very well, (look at all that great period stuff, it's all they had). As a side note, the stuff's edible, it is basically the same thing as gelatin.
Luthiers/Violin Makers often use a rubbed joint for the main, all important, joint between the two halves of the top and bottom plates of a bowed string instrument.
Altho some makers make one-piece tops and bottoms (plates) for violins, most makers make two-piece tops and bottoms.
In my opinion, the care given to the creation of a light tight joint prior to glue up is considerably greater than the attention we give to a joint when we're just gluing up case goods or hardwood furniture.
In the particular case of the violin maker, after making certain that the bottom surfaces of a the two pieces which will be glued together with a rubbed joint to form either a top or a bottom plate----are at right angles to the edge surfaces to be glued together, a jointer plane is clamped into an accessible vise on the bench.
The better the grade of the jointer plane, the easier it is to secure a good joint.
Considerable attention is paid to the sharpness and setting of the blade of the plane. The smallest possible setting of the blade above the sole of the plane is sought. The blade's edge must be in a plane which is parallel to that of the plane's sole.
The blade should readily shave hair.
Prior to starting the jointer phase of the planing the Maker has made the edge to be planed as nearly perpendicular to the bottom surface of the wooden plate as possible. The bottom surface must be flat.
The Maple or Spruce plate, depending upon whether it's a bottom plate or a top plate of the fiddle, is grasped with both hands, the edge to be planed is down, and that down edge is set upon the plane's sole, pressed down on the sole and pushed forward the full length of the piece of wood in one full-length continuous, unhesitating motion.
The shavings produced will form fairly tight curls.
The amount of force required to push the edge of the piece being passed over the blade is surprisingly great, even tho' the shaving curl produced is very thin. This is especially true with the Maple pieces.
As the jointer planing begins, there are often incomplete shaving curls produced initially. The shavings may be irregular in length, have holes in them, etc.
As the process is repeated, soon a complete shaving curl is produced which is intact from side to side and is full length of the piece being planed.
A certain amount of experience helps the Maker produce a true flat edge surface which will be light tight when placed against the other edge of the joint.
The Maker holds the two edges against each other and looks through the joint toward a window or toward a bright room light. The edges are slid back and forth against each other, and, rotated against each other, looking for possible flaws in the pefection of the joint. When satisfied with the physical characteristics of the two edges the Maker is ready to make the rubbed joint.
Fresh hot hide glue has been prepared. If one lets the wood set around for long prior to glue-up, changes in the perfection of the surfaces may occur and the joint won't be as good as if the joint is made soon after planing of the two pieces to be joined is completed. Further, the Maker avoids touching the prepared edge surfaces with his fingers or permitting them to touch any other objects.
One of the pieces is placed in a vise, edge-to-be-glued up. The edges of the two pieces are coated with hot hide glue with a glue brush. (I won't attempt to discuss the consistency of the glue which should be used.)
The second piece is held by the Maker. He presses it onto the piece in the vise.
He aligns the pieces so that their prepared long edges are flush with each other side to side and lengthwise. The Maker presses down very firmly, forcing much of the glue to the external surfaces of the joint. He pushes and pulls the piece in his hands forward and backward about an inch, that is, he "rubs" them together, until he feels the pieces "grab" each other. This usually happens in 5 seconds. The "grab" is powerful and one has little time to make sure of the alignment of the pieces when he first senses the "grab" occuring. Making sure that the pieces are well aligned, he may leave them in the vise, or remove the assembly and set the piece on the shop floor leaning against a wall.
When the joint is properly prepared, no clamp is necessary at all and the joint will have maximum strength and last for many, many years.
This is the meaning of a rubbed joint in the bowed string instrument making trade.
FWIW
William
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