Minimizing Glue Cleanup When Gluing Plates

[Parker135]

I'm about to glue up a couple of top and back plates. I'm wavering between hot hide glue and Titebond, but the question is the same. Is there any way to minimize the effort required to clean up the glue squeezed out on the bottom side of the joint? In the past I've used the rope and wedge method which allows access to much of both surfaces. This time I'm trying an octave mandolin so I'm using my bench top with wedges along one edge to apply the clamping force. It's pretty simple to clean up what's on top, but the bottom is a different story where the plate rests on the bench, and I'm hoping there is a simple solution to this. What about a wide strip of masking tape on each side of the joint? Would the squeezed out glue penetrate the tape and make an even bigger problem? I could test this myself, but I'm hoping to be gluing tomorrow morning.

I guess it would be logical to glue with the top side up, so glue residue is on the inside surface. Maybe that's good enough.

[John Bertotti]

Elevate the two halves on a couple of boards so that the back seam is not up against anything and at the very least you just have clumps to clean or get creative and make something you could pull under to help clean it up.

[sunburst]

I usually glue center seams with the wood still over-thickness. Lay a piece or newsprint down and glue the plate on the paper. When cured, peel off the paper, give the glue/paper residue a quick scrape with a card scraper, then run it through the thickness sander to final thickness.
If I have to use wood that is already final thickness I do the same but scrape the joint more thoroughly so that all the glue is gone from the surface.

[Parker135]

My wood is close to final thickness as I don't have a large enough method of thicknessing. I like the newsprint idea. In this case I'm going to try elevating the pieces on some lath. I like the idea of excess glue having somewhere to go other than spreading out under the piece. Of course a little moderation in applying the glue will help.

Thank you both. This is such a great resource. Post question, go to bed, get up, make tea, read two very helpful replies.

[John Bertotti]

I don't know how helpful my reply will nbe. I also don't go straight to scrapping because I have clumps sometimes. I use a very very sharp knife/chisel/skew to cut the clumps off then scrape a bit. I need to try Sunburst's way it might be a lot easier. Sadly I have not added a thickness sander yet either.

[sunburst]

A sharp scraper with a large "hook", held at an angle to the direction of travel, and not much downward pressure to start, and those clumps can be safely scraped away. This is especially true if the wood is still over-thick because any small tears can then be sanded away.

[John Bertotti]

I was using knives like this when the pieces were level and pulled it along both edges of the seam, then scrapped. I tried a big scrapper once and had some tear out and my OCD kicked in. I bet I didn't have a good hook when I think abou tit now.

[sunburst]

You don't have to use a scraper from the get-go, it's just how I do it. Your way is probably better, just takes a little longer.

[Parker135]

I glued up four octave sized plates today with HHG using the lath to elevate the pieces. I'll get after it with my scraper tomorrow. I like that the glue didn't spread out on the underside. Success!

[John Bertotti]

Excellent!

[HoGo]

I do it like this...
https://youtu.be/0JwbcnWLG0Y

[John Bertotti]

Once I tried a rubbed joint on a 3/4” maple back but didn’t clamp it. I did use hot hide glue. I wonder how it will hold up over time.

[sunburst]

I've been using rubbed joints for mandolin tops and backs for years with no failures.

[John Bertotti]

Ooops! I’ll correct that is I can!

I didn’t clamp my joint just rubbed and pressed a bit to get the excess out. Do you clamp yours?

[sunburst]

I don't clamp rubbed joints. In the video I was surprised the first clamp didn't pop the joint open. That is the reason I started doing rubbed joints; the difficulty of clamping wedge-shaped pieces with even pressure.

He was using really thin glue, I use less water so a thicker glue.
For glued top/back wedges, I don't clean the glue squeeze out at all, just cut away the dried glue later.

[John Bertotti]

I noticed the consistency of that hide glue. Mine is also thicker kind of like a warmed maple syrup. At first I wondered what he was pouring. My very first hide glue joint was very visible and that was when I decided to rub more and apply more pressure when doing so. I didn’t like the darker glue line. It also made me wonder about its strength.

[HoGo]

I noticed the consistency of that hide glue. Mine is also thicker kind of like a warmed maple syrup. At first I wondered what he was pouring. My very first hide glue joint was very visible and that was when I decided to rub more and apply more pressure when doing so. I didn’t like the darker glue line. It also made me wonder about its strength.

Davide, like many other high end violin makers tend to stick to high bloom strength hide glue (450g) especially for centerjoints. This needs to be diluted with greater amount of water to work. Most mandolin makers I know uses lower grades like 192 suggested by Frank Ford.
His first clamp goes "over the arch" and bar touches the wood so it stops the tendency to open the joint. By the time he applies the clamp the glue alredy grabbed and holds the halves together.
BTW, from violin makers' history, the pure rubbed joint is not standard among best makers. The technique is said to come from the cheap German workers of late 18th to 19th century who were so poor they didn't have clamps and produced such quantities of cheap fiddles for export that they just couldn't afford to clamp it. Most modern makers rub and then clamp so the joint is held closed for security.
BTW2, Davide Sora's videos are considered some of the best instruction on top level violin making. Have a look at his gouge work around channeling....

[John Bertotti]

I really liked those little butterfly ended clamps. No idea where you get them, never seen them before, but they looked cool and easy to maneuver.

[Parker135]

I'm working on thin flattop pieces, so I didn't want to use just a rub joint, nor could I use the clamps as in HoGo's link.

Here's what I did, except I added pieces of lath beneath the pieces to give the squeeze-out somewhere to go as suggested by John Berttoti: https://www.youtube.com/watch?v=SUzGKl-1HY4

I radiused the wedges that go against the cleat so they could be more self-aligning.

[Tyko Runesson]

I also not really clean up my top and back joints. It is so easy to chisel away the hot hide glue afterwards so I just take away the easiest to reach with a wet cloth. If you want to clean it I really suggest you to stay away from paper in any form, use a normal moistured cloth (same type as you use in the kitchen f.e) instead. Much more sturdy and reliable in my opinion. And you can flush it out and use it again and again and again....