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I'm with Clay on this....Glue too thin

Hey Brad. Forgive me please I only read your original post not having any time here with the rush of Christmas new instruments coming in for tune-ups.....

The notion of using HHG everywhere when building a guitar was once what they did because...... HHG is all they had...... For crying out loud as well you will find some purists here who attempt to compensate for poor endowment(s) by sticking out their chests and proclaiming that they do every joint with HHG.

What the hell good is this if you can't pull it off and issues and failures result????

Me, I'm not opinionated.....

My take on things since we have modern glues available to us is this. I used HHG for all braces, bridge plates, bridges, etc. I see no value in using it for linings, blocks, fret boards, head plates, nuts, frets, etc.

What's more important Brad is a guitar that can provide 100 years of trouble free service with perhaps a neck reset or two in there or the license to proclaim HHG purity.... with an audience of people, Luthiers who ultimately are not who you want to be pleasing?

So.... with all of this "spewed..." use HHG where it makes sense. Follow the guidelines for it's use and watch open times. I see far more benefit in seeing each guitar as something with a defined beginning, a defined ending and then of course..... next over getting all strung out over something that really has NO measurable benefit, HHG on every joint.

Now I am sure there will be those who don't agree with me and there will be some pretty notable Luthiers who don't use a drop of HHG anywhere too favoring good ole Titebond original. Who cares.... use it where it makes sense to YOU!

As for me I don't give a rat's arse what others think of me I'm too busy making money as a Luthier......... By the way that's not something that we hear very often either.....

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That's pretty much exactly what I was going to say


No, as long as it's tight enough to counteract the sides cupping from moisture expansion, it should be good.

Water expansion can be a problem for bridge rub joints too. Flatsawn ebony is a lot more risky than quartersawn rosewood. I also had one fail due to wide and thin bridge wings curling up (well, technically it's not a complete failure yet since the rest of the joint is still intact now over a year later, but I still need to peel it off and redo it one of these days). For less curl-prone shapes, you can scrape the underside of the bridge slightly concave so it will expand to flat. Expansion of the soundboard could theoretically be a problem as well, though I haven't had any trouble with it.

Makes sense. I’ll experiment a bit with it and continue learning. As always, appreciate the feedback.

Hesh, I hear you for sure. I have a self imposed requirement to tame the HHG beast. Not to boast of an all HHG build, but just to make sure the skill is truly available to me. Hope you had a great holiday!!

Brad



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This is a good point. I have some cork. I’ll put it on with the 3m spray glue and we should be good to go.

Thanks for the hint!

Brad


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I just saw this, the replies were fast and furious and I missed it.

The joint was really good, it’s using the radius jig I just finished up. I can just lay the block in there and it looks good.

No contamination on the sides.

Thanks for your glue recipe. I will try that and compare it, consistency wise, to what I’ve been using.

Thinking back across the whole process, I think I had glue that was too thin and maybe also starved the joint. Maybe not from clamping pressure (jury is still out) but maybe just too much glue running off the block while get it set up? I’m super focused on time, sounds like too focused on time. I’ll test on some scraps and get a better feel for it. That way I’m more relaxed when I’m in the middle of it and there is a lot going on.



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Never had any problem with HHG on neck and tail blocks (or anywhere else for that matter). I don't weigh or measure, just mix till i get the consistency of pancake syrup.
I use a wooden handscrew clamp for the portion of the block thats in the mold (and its tight) and the Irwin clamps for the four corners above and below the mold. Pre heat, clamp, 2 hours later, ready to move on. I'd look at the glue and do away with the padding plenty of squeeze out is better than less.
Took a class up at Ann Arbor guitars, feller named Hesh hustled me into buying the L-OO mold in the pic, going to be a nicely figured Honduran Mahogany Red spruce L-OO probably go with a burst on this one

If you are ever worried about a joint using HHG, I recommend that you "size" the joint first. Brush on a thinned coat of glue to both surfaces and let dry. Then come back with your full strength mix. Then you are assured that the joint will have glue in it.

But honestly, I'm with Hesh here. I glue all braces, linings, soundboards / backs to rims, and bindings with HHG. But there is nothing to be gained by using HHG for every joint. Some just make far more sense to use PVA, CA or epoxy. In the case of neck and tail blocks I use a PVA. And I'm another Luthier that makes a living doing this full time.

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Allen R. McFarlen
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Thanks, Allen! This is a good tip, makes great sense, and I would have never thought to do it. I appreciate it!


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That's especially useful for endgrain joints. Most glues will be starved due to the pores sucking up glue after you get it clamped. But since hide glue sticks to itself, you can use it to seal the pores before doing the actual glue up. Not quite as strong as a side grain joint, but still can be a pain to get back apart if you ever need to.

I always size my headstock scarf joints, since they have some endgrain to them.

FWIW vlnmakers use a special bristle brush for gluing HHG check howard cores vlnmaking supplies website to get an idea. I use chinese bristle brushes (black) from e vil bay through china. Yes, I would not use quick grip clamps .You can purchase Small metal clamps from HF cheap vy handy. You might also make some test samples to see how long it takes for your HHG to set ! if your not doing it quickly enough consider a 1o per cent salt addition to depress the gell time , urea is used as well . Check around, there might be a few more gel depresants that can slow down the gel time of HHG. ?? Oh yeah a cheap kitchen timer from the dollar store or a count dwn timer from amazon , radio shlock ebay etc can give you an idea of how long it takes to glue your block in place .Good luck and parctice on scrap first.!

Brad--

The replies came pretty fast, so I am probably not going to add much that is new, but I do have a few things to suggest.

First, don't feel pressure to be all that precise on the ratio of dry glue to water. Make the glue as thin or as thick as you need for the job. I see in your quick YouTube video that you have one of the neat brass glue pots from MusiCaravan. I love mine, because it fits into my work habit of making just a few ounces of fresh glue for every task. Do I need thick glue for this job? Then I make thick glue. Do I need thin glue? I make a little thin glue. Do I need it to stay liquid a long time? I make some, then add some urea. you get the picture. For this job, I think you feel your glue was too thin. So make it thicker, and work by feel instead of by measured parts. You can always thin it out if it feels too thick.

Second, use gravity to your advantage instead of letting it kick your arse. If your glue is running down the joint, and running out of the joint, then position the work so that the surface that has the glue on it is horizontal, with the glued surface facing up. You can thicken up the glue to solve this problem, but you can also just keep the glue in the right place longer by not fighting against gravity. This makes hide glue pretty different from working with aliphatic resin glues. Once spread, you can turn AR glue upside down, and it will stick to the workpiece. Hide glue has to be made really thick to accomplish that same stickiness. I vary the thickness, but I also try not to fight against gravity.

Third, this might be obvious, and I apologize if it is, but are you certain that the dry glue you are using is good quality glue, in good condition for general use? In other words, have you just tried doing a simple glue-up of two pieces of wood, using this glue, to test the glue itself? I would do that before messing with anything else.

Fourth, assuming the glue is good, don't throw out good processes while trying to solve problems. Heating the parts is good; clamping firmly is good; working with deliberate speed is good. Keep doing those things, but attack the specific problem at hand. You are probably winding up with a starved joint because all the glue winds up on your bench, the floor, or paper towels. So fix the problem of the glue not staying where it is useful, but keep doing all the other good stuff.

Fifth, no offense to Hesh, but if I were you, I would not let the answer to my problems be to abandon hide glue for this operation. There is something going on here, with this particular operation, that is vexing you, and you will get to the bottom of it if you keep trying. You probably won't feel right if you give up, so don't. Gluing blocks is actually not the hard part of how to use this glue, so you need to figure out this mystery, or it will be a bigger problem than you should have to deal with.

I am going with the clamps. The Irwin clamps in my experience are not that great either for getting good pressure or maintaining pressure.

Second, I agree with Hesh and others, end block joints are hard to get perfect as far as congruity. I see no advantage to hide there or for linings. I have always used LMI white when it was available and now Tightbond Extend.

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I wonder too about the cleanup process. Here is what I’ve been doing so far:

1) After glueup wait about 3-4 minutes and cut the worms free using a sharpened popsicle stick.

2) Wipe the sides and the edge of the block with a dampened strip of shop towel. I try t stay out of the very corner of the joint with the shop towel because of how much water is in it.

3) Use Q tips dipped in the glue pot to clean up in the very corner of the joint. Again, trying not to get any dripping water directly in the joint.

Should I be waiting for steps #2 and #3 until the joint is fully set up? Maybe waiting an hour or two?

Brad




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Nothing wrong with your cleanup process. However, rather than using a soaking Q-tip, I use a damp rag wrapped around a sharp stick to get the corners. This minimizes water getting into the joint which may be an issue in your setup.

If there is adequate glue on these pieces, there is no way there is glue starvation from clamp pressure with Irwin grip clamps. Impossible as those clamps are mediocre at best when it comes to clamp pressure. When applying any emulsion-based glue, I prefer to rub the parts together and ensure complete coverage. Maybe I'm assuming incorrectly that the OP has sufficient glue in the joint. From his posts, he seems pretty thorough - I suspect the issue is the Irwin clamps. I simply would not use them for most any guitar clamping task. The fact that they inherently loosen after applying pressure makes them a complete wildcard.

No offense intended on the clamp observations ... as I said, I use Irwin clamps for various tasks around the shop. But just to be thorough, let me respond specifically to the OP's 4 points:


No, this simply gives more open time on the glue. I warm my parts with either a hot plate or a hair dryer. Just provides a bit of open time insurance.

Unless you are superman, there is no way you didn't wait a few seconds from when you brushed the glue on one piece, then another piece, then set the brush down, then picked up the first clamp, clamped that, then the second clamp, et cetera ...

Not possible with those Irwin clamps, as previously mentioned.

You're mixture ratio is in good company. If it is good enough for Frank Ford and Milligan & Higgins, it's going to be fine for the rest of us.

I hope this is helpful to you. Good news is you are using hide glue. Wipe the wood clean with hot water on a damp cloth pad, so there is no glue ridges anywhere. Go through your process again, using screw clamps. I suspect your problem will be solved. Let us know ...

Just one other thought ... I'd make sure your glue is as hot as you think it is (around 140-150) ... just to be safe. You should be fine on the glue-up, but feel free to keep things warm with a hair dryer if you are concerned about the glue cooling off before you get full clamp pressure.

Andy

Brad.l I would sand or better yet scrape the block smooth. That helps
maximize glue area. I also would clamp your caul last.


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Thanks. A question - The way I have been clamping the rims into the mold is that the soundboard side is flush with the mold and the “guitar back” side is sticking up past the mold. The “guitar back” side is where the caul is used.

When installing the block with the mold soundboard side down on the bench it is very easy to then place the block so it is flat against the bench. Then you know for sure it is aligned with the rims and everything is flush on the soundboard side.

What would be the process to then clamp that side first? I would think it would be very easy to get the blocked skewed a bit if it wasn’t being “pushed” down to the bench.

Do you put the mold in the center of the rims so there is some protruding from both the soundboard side and the “guitar back” side? Or perhaps just line it up flush and with your center line by hand and clamp away?

Brad


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Andy, I’m going to try the Bessie clamps. I have a few already of the 12” with 3 1/2” jaws. They are heavy!

I keep a thermometer in the pot. I guess I could check the thermometer against a second one.




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The thin piece of clamped scrap holds the block on center. On top of the block is a go bar.
There is a block that screws across the mold joint to make it as tall as the block for gluing.

Nope. Sounds like your temperature is good. So long as you are clamping up before the glue sets, it is definitely the clamps in my book.

Andy

Thanks, Dave. The pics help a ton. In the first pic it looks like the clamp is more toward the middle of the block. So you’re thinking here is to put the first clamp more toward the middle and then flip the mold so that the clamps on the soundboard side are installed first and then the side with the caul, like RR suggests above?

The shim is a nice touch.

I have the LMI molds that are MDF and have the big hinge with the PVC stopper. I’ll have to think about how I could concoct a block / caul like you have here.

Appreciate it!!


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The pics are years old but you probably have it right.
Even more so with titebond, I have a habit of clamping lightly with the first clamp. If you let the pieces slowly displace the glue and come together, they tend to stay lined up until they grab. If you clamp hard on a thick glue line, you get a strong sideways skating force.

Here is a side by side comparison of glue that I used for the block in question and the patented br549 glue recipe that Mr Farmer shared. My glue mix (1.8 / 1) is on the right. Mr Farmers patented formula (45g / 25g) is on the left.

The volume was different between the containers so I tried to dip the sticks in the same amount so they picked up similar amounts of glue.

Edited: Mr Farmers mix is about the same as mine (math is hard).

So....

1) Is this a thick enough mix?
2) Does the flow rate look correct for these mix ratios or do I have a bad batch of glue (or a bad scale

http://youtu.be/K3aRAScluCQ

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Brad Buddy I can't tell much from the video but one of you guys are pregnant.....

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