Official Luthiers Forum!

Hi!

I'm watching John Mayes DVD and saw that he uses pipe clamp on his jig to put pressure when joining top and back.

I'm curious to how popular and how many of you use this method to join?
If you don't use this method, what method do you use?

Thanks, David

I use stretched masking tape to hold everything together while the glue dries. Works great! Though you do have to watch when you're taking it off that you don't pull the grain on top woods like Spruce or Cedar.

I currently use my go-bar deck and go-bars to attach my tops and backs. I have in the past use spool clamps but they take a while to get tightened down and it takes a lot of them. Any method that provides about 8lbs of clamping pressure distributed evenly across the the rim/linings that is easy for you to work with is fine. Keys to keep in mind are you want the entire top in contact and under equal clamping pressure everywhere and dependent on your glue of choice you need to be able to set this joint in a short time frame on center and on proper end indexing.

I will be using about 40 cam clamps , Ken hodges posted a pic of the procedure in the " questions about making cam clamps" thread also active on this site now. I am sure there are many ways to do it , this is how I was shown by a master builder. Jody

Oh I may have read this wrong, I was talking about the centre joint of the tops or backs!

Go bar deck for tops/back to rims here too

I'm talking about center joint. Not joing top to rim or back.

whats a centre?

Anyway I do it the way John does. I use three pipe clamps and four 2x4s to keep everything flat. I think he uses 2 and 3 respectivly. Works great.

I use two, straight, 2 inch wide boards, clamped parallel to each other and set apart approx. .100 or so narrower than my top. I put a piece of wax paper underneath to prevent gluing my top to the workbench. Apply glue to both edges to be joined and set them between the parallel boards, align the edges and press them to the work surface. Clean up the squeeze out before adding some weight on top of the glue line. The weight prevents it from popping up and keeps it flat. Works great.

Mark L.

Ahaaaa sorry about that.

I use 3 bar clamps, 2 pieces of 3/16 aluminum U channel, a 14" x 24 sheet of UHMF, 2" x 24" x 1/4" strip of UHMF and my go-bar deck.

The U Chanel goes on the outer edge of the plates as a place to the bar clamps to push against. I lay the 2 plates with the U channel against each other on a UHMW plate just narrower the the two plates combined, add my glue to the edges, rub the joint in add a 2" wide x 22" UHMW plate on top of the joint and use 6 go-bars barley clamped down the add the 3 bar clams across the plate assembly clamping against the aluminum U channel and tighten just enough to create some force on the joint but not enough to bow the plates more than 1/32-1/16. I then the increase the loading on the go-bars that are holding the 2" wide strip of UHMW dow ontop of the joint. This keep the plate joint level and the pressure from the bar clamps keeps it pulled in flush. You don need much force at all on the two plates. You just need to keep the joint flush and the plates level.

24"x24" ply with a 3/4" tall straight edge on one side that is perm.  I have other side with slots that some blocks can slide in.  I put work pieces in (wax paper under glue area) Use another piece of wood that blocks slide up to and that butts against work piece.  Get proper pressure on the join and tighten blocks, clean squeeze out. Put a metal bar on the join area and wights to hold the join down. Wait an hour and clean. You don't have to go to making slots, blocks and levers etc like I use.  Just get good straight edge to butt work to and other pieces of wood and shims on other edge to get tight join and then clamps to hold in place. I just wanted a dedicated rig I can quickly get to, setup and use.  For disclosure, what I use is not my design or idea but that of former boss.

I use the tape method and it works great - no jigs or stinkin clamps required.....

Since I wrote this toot http://luthiersforum.3element.com/forum/forum_posts.asp?TID=11048&KW=tops#forumTop I prefer to use HHG. HHG will actually draw the plates toward each other as the moisture evaporates. Of course you still have to have a gapless joint as well.

Here are some pics of the basic idea - joint, tape together with one plate angled, tent, glue, press in place, weight, wait.... - and Bob's your uncle.....

I use wedges to apply pressure and weights to hold it down to the joining board.

Hesh's method works great for me.

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Build log

I wish my camera was up and running. I would take pics of my wedge set. If you look up the C Fox field trip on frets.com, I'm almost positive that that's where I got the idea seven or eight years ago. I've been joining backs and tops with the setup since.

Two weeks ago, though, I joined a redwood top using the tape method I learned in the tutorial Hesh prepared and linked to above. Hide glue is a must, because like Hesh said, it will draw the two sides into each other. It worked well and took the same amount of time.

However, even though it took the same amount of time overall, the way you use your time is totally different. I couldn't use hide glue with the wedge setup because it took too long to tie the ropes and push in the wedges. Hide glue has a very short (about 30 seconds) open time. Most of your time with the tape method is in prepping the pieces with tape. Once you run your beads of glue, push the pieces into position and you're done . . . giving youenough time to use hide glue.

You guys got me to thinking and I remembered that I made a jig, this is called a Spanish Tourniquet, several years ago for joining plates. Right after I made this someone posted info on the tape method on the OLF and I tried that. So this jig was never used not even once and I just found it buried in a closet...........

This is what is often referred to as the wedge method. I think that LMI also sells these pre-built and has pictures of them in use in their catalog.

James my friend very good point on how HHG can be used with the tape method too.

Can you use the tape method if you are using LMI White or titebond?

Thx!

Glenn

Glenn buddy - absolutely!

Great!! I am planing down a "practice" top. I will try the tape method. I have another practice top, I will try the "wedge" method - see which one I like best. Although, you can't beat the simplicity of the tape method.

Thx Hesh!

Glenn

My favorite, so far. The thickness gauge isn't used here, it's just hanging out.

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now known around here as Pat Foster
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http://www.patfosterguitars.com

Being able to use hide glue is exactly why I like the tape method now. I'm really thankful that you did the pictorial on it, Hesh.

I tape one side to my car's rear bumper and the other to my truck, which has a big oak bumper on the front, then nudge the truck right up to the car - no gaps anywhere!

...or I do it like John does when my wife has the truck...

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Mitch

I start with the tape method, then wax paper over the seam and clamp a wood scab on top, clamp the ends, put some weights on it with wedges on the sides to push the seam closed and then put the whole thing into my vacuum press.
Oh I forgot the ropes…and the go bar deck to hold my vacuum press closed so it doesn’t leak so badly. If the go bar deck is being used I’ll park my truck on it. Most of the time I just get lazy and stop after the tape method.

Sorry I just couldn’t resist and man that wine with dinner was good.
Let me know if I am forgetting something.

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Rich S

"The inconvenience of poor quality will linger long after the thrill of a bargain has been forgotten"

I do it like Burbank, or the rope, wedge and batten method if the plates shapes are irregular, or so thin that aligning the plates perfectly is critical, or they are the lest bit cupped or twisted (but we never build with wood like that, right...?) Got to try the tape thing, I guess.

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Rian Gitar og Mandolin

Another vote for little wedges

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Jim Kirby
kirby@udel.edu

I made myself a jig for that purpose. Nothing new conceptually, but it has the advantage of being 'storable', meaning I can store in on a shelf while the glue dries, allowing my to work on something else during that time.

Pretty usefull for a small shop such as mind.

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Alain Moisan
Former full time builder of Acoustics, Classicals and Flamencos.
(Now building just for fun!)