Hide glue dillution.


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Sup.

 

Just bought some hide glue from Lee Valley. It says that the bloom strength is 260. How would I dillute this to get 140? I don't know how to approach the probably rudamentary math required to figure this out. I'm sure that the curve is not linear. When I follow the instructions it ends up like pure molasses.

 

Or, should I approach this from a much simpler angle, and dillute untill I get that perfect glue line drizzle from the brush?

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Sup.

Just bought some hide glue from Lee Valley. It says that the bloom strength is 260. How would I dillute this to get 140? I don't know how to approach the probably rudamentary math required to figure this out. I'm sure that the curve is not linear. When I follow the instructions it ends up like pure molasses.

Or, should I approach this from a much simpler angle, and dillute untill I get that perfect glue line drizzle from the brush?

Bloom strength tests the hide glue in a gelatinous state, seeing what force is required to push in the glue before puncturing the form. The manufacturer determines this. I always purchase different bloom strengths as they are readily available and prepare the glues to a consistent viscosity and use accordingly for each required task. Lee Valley for instance also sells a 150 bloom strength hide glue. This is simply how I was taught to use the materials and I don't believe overly thinning out glue actually changes the bloom strength.

DGSR☺

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Unfortunately, most tests like this require some empirical testing.

Here is one example of how dilution affects hide glue strength.

http://fixitwithshading.com/2015/08/02/the-ultimate-glue-test/

I don't believe any way one considers it, you are changing the "bloom strength" of the glue by over thinning it. With this logic, is one to believe as well that by using say, a 140 bloom strength in an extremely thick state they are then increasing it's bloom strength? I'm quite certain the answer is no.

Also, "bloom strength" (which is what the OP inquired about) is a specific test of the glue in a gelatinous state as I mentioned before. It's not tested by continually thinning out glue, clamping up wood and checking to see how much force is required to break the bond.

DGSR☺

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Sup.

 

Just bought some hide glue from Lee Valley. It says that the bloom strength is 260. How would I dillute this to get 140? I don't know how to approach the probably rudamentary math required to figure this out. I'm sure that the curve is not linear. When I follow the instructions it ends up like pure molasses.

 

Or, should I approach this from a much simpler angle, and dillute untill I get that perfect glue line drizzle from the brush?

Yo SUP!

Good information in Kevin's link

I was initially taught to use hide glue by looks. Add water to dry glue 2/1more or less, let sit till you have jello, 15-20 min. then heat. Then thin the resulting mixture till you have the desired consistency, or don't if it looks good. If you are anxious about it, put a drop on something and let it dry and watch how it progresses. Not very scientific, but it has worked for me for years.

I've recently started measuring the ratios just for fun using the recommended ratios from various glue suppliers/ info sheets, and let me tell you, THAT is some kind of fun. But I've found that I still mess around with the consistency after heating in most cases. I know what I want my glue to look like for the various applications, and just mix it till it looks like that. 

So yeah, do the last thing that you mentioned.

Excelsior!!!

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I don't believe any way one considers it, you are changing the "bloom strength" of the glue by over thinning it. With this logic, is one to believe as well that by using say, a 140 bloom strength in an extremely thick state they are then increasing it's bloom strength? I'm quite certain the answer is no.

Also, "bloom strength" (which is what the OP inquired about) is a specific test of the glue in a gelatinous state as I mentioned before. It's not tested by continually thinning out glue, clamping up wood and checking to see how much force is required to break the bond.

DGSR☺

 

You can't change the bloom strength, it is what it is. Of course you can make up a more dilute solution of the glue, which does seem to give a weaker bond. You can also heat it to a higher temperature and/or for a longer period. Both have effects on the glues strength.

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In a nutshell, if you want the strongest joint, you will use the strongest glue concentration which allows glue application, assembly of the joint, and clamping before the glue gels. This involves doing a dry run (which one should be doing anyway to make sure everything is in order) and timing it. Then you take your glue, and keep diluting it until a drop on a surface like aluminum foil takes about the same amount of time to just begin to gel (or a little longer to give you some wiggle room).

 

If you want weaker joints, you dilute more, and you'll learn from experience how much to dilute for the strength you want. For example, when attaching tops, I use a glue diluted to the point where it takes 3 minutes to start gelling on a piece of aluminum foil. This method is much more accurate and repeatable than things like rubbing between your thumb and fingers, or watching the shape of drops dripping off the glue brush.

 

A higher gram strength glue will gel sooner at the same glue/water ratio, so you will need to dilute it more to get the same working time. So while a higher gram strength glue is stronger in theory, in practice, it's kind of a wash.

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You can't change the bloom strength, it is what it is.

Exactly. And yes, as the link from Renée gave example to and common sense would dictate, one can thin out hide and the bond strength will weaken. And sure, it can be over heated to mess with the bond strength as well. I for one however wouldn't thin out something the nature of 250 bloom to a watery consistency to try and attempt an equal bond of 140 bloom. Feel free if that's what you'd do. To each their own. As I noted earlier, different bloom strengths are readily available, even from the same supplier the OP acquired his from. Right tool for the right job sort of thing, is my way of thinking...but to each their own.

DGSR☺

*edit* I feel I should elaborate here as my experience is what I was taught when cutting my teeth and it's the method I've used since. I would never suggest someone like David does something wrong as he is quite known as a very accomplished luthier and he's described a method that he uses with success. Clearly it's a good method used by an expert.

In the shop I started green at, 4 different grades of hide were used. I was shown how to mix these glues, all to a similar viscosity, and for which application they were used. If I used a certain glue for a "wrong" application, I was in hot water, so to speak. I still get the same 4 glues from the same supplier and use them for the different tasks they were suggested to me.

The lowest strength is for seams. The next step up, suggested for a stronger bond for seams and joints like plates to blocks. The next two strengths are used for crack repair and joints where one really doesn't want separation such as plate centre seams and blocks to ribs. They are all mixed to a similar viscosity and as the strengths increase, the working time shortens.

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Usually in the 190 - 260 range. Above and the open time is shorter, below and many think it starts to get a little weak. Having said that I've made whole instruments (mainly guitars) with 140 pearl furniture glue and they have stood up to the string tension, especially the bridge which sees some 40 Kg of pull on it. These days I use the 260 high clarity hide, it's not as though it's any more expensive.

Yes, dilution does have an effect on the strength of the glue joint. See that test posted earlier.

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At one time I was told Milligan & Higgins were the only manufacturers of hide glue left in the US. I'm not sure if that was ever really fact, and if so, if it still remains true. I know the supplier I use was/is sourcing from them and I think the 4 bloom strength I use are 192, 222, 280 & 315. I don't know why but my supplier uses entirely different numbers for some reason that are not bloom strengths but I asked once and I'm pretty sure those are the numbers.

DGSR☺

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I prefer using common furniture grade glue with no problems at all. Most guitar and mandolin folks I know prefer the 192 gram glue as well. I suppose when you want similar working time using 315 like with 192 you need to dilute it more and thus create weaker glue then undiluted glue would form.

I wonder if anyone tested strength of joints made with the different grades of glue whether there is so much difference of strength to start with?

How much stronger is 315 than 192 in full strength application and whether it is still as strong as 192 when diluted to match the working time of 192 (a la Burgess aluminum foil gel test)....

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Naively, my mental picture of the different Bloom strengths corresponds to molecules of different length.  The long molecules in high Bloom glue curl up together easily and so need more water to disperse and 'loosen up'.  The lower Bloom strengths have shorter molecules and these find it more difficult to cozy up and tangle together, so less water brings them closer.

 

So with the model, dilute high Bloom glue is not the same as more concentrated lower Bloom strength glue, but they may function similarly.

 

Same thing happens when you monkey around with DNA.

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   Hello Nick

You cannot change the Bloom Strength by diluting the glue with water.

 

From Lee Valley site:

 

"Our granular hide glue is a very strong one (rated 260± Bloom strength) with a correspondingly short open time; it is good for uncomplicated assemblies where strength is of paramount importance.

 

Pearl hide glue, which also comes in dry form and is used the same way as granular, is not as strong (rated 150g Bloom strength) but takes longer to gel. With the longer working time, it is better for applications like veneering where you need time to fit, but where high strength is not required."

 

http://www.leevalley.com/US/html/56k5001ie.pdf

 

If you water down the glue too much, then the glue will run out of the joint and you will have a "starved joint" that will eventually fail.

Also thin glue can penetrate the wood too much (hungry wood is like a sponge) and you are left with a weaker joint.

 

Playing around by increasing the room and wood temperature will buy you some more time with any Bloom Strength Hide Glue.

 

I would advise that you try a thin penetrating sealing coat of hide glue first, then at least you will control the penetration aspect of a thin glue.

Do not over thin, and apply sparingly.

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Unfortunately, most tests like this require some empirical testing.

 

Here is one example of how dilution affects hide glue strength.

 

http://fixitwithshading.com/2015/08/02/the-ultimate-glue-test/

 

While this is an interesting test, it would be much more interesting testing the same on maple. It is difficult to glue a top and not having the glue joint stronger than wood, on maple it is the opposite.

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Much of my experience is with guitars but the 192 strength stuff mixed 2:1 holds steel string bridges effortlessly.

I can't imagine using it for seams un-thinned and counting on it's lower gram strength making it any easier to release. 

I like the idea of using lower gram strength glue for seams but I think it would have to be mutch lower than 190.

 

I raised a question on a thread about glue for fingerboards that still concerns/confuses me. If Diluting high gram strength glue, wouldn't any sizing or old dry glue remaining quickly bring the solids content back up to full strength?

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 I raised a question on a thread about glue for fingerboards that still concerns/confuses me. If Diluting high gram strength glue, wouldn't any sizing or old dry glue remaining quickly bring the solids content back up to full strength?

Yes, it can. Ideally,  you remove all the old glue with water before reattaching (if the fingerboard is all the way off).

The same thing can happen when re-gluing open seams.

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Thanks Mr. Burgess.

 

I realize experience and learning to work with tools and materials you have usually offer the biggest gains in skill.  Still, it seems possible DGSR's learned technique of different gram strengths at "normal" mix ratios might provide more control of bond strength. Assuming sufficiently low gram strengths are used.

 

Am I trying to solve a problem that does not exist for others? Any improvement in control over when glues hold or let go and how much damage results could save a lot of effort in repairs.

 

Perhaps lower gram strengths are not brittle enough for clean separation when dried?

Has anyone here experimented w/ very low gram strength hide glues?

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Does anyone have links to research, or tests along the lines MJ's dilution tests, showing that higher gram strength glues actually produce a stronger bond than weaker gram strength glues, once diluted to a point that they allow reasonable working time?  (There's not much we can do on a fiddle with glue that gels in ten seconds)

 

I realize that Bjorn says that the higher gram strengths have higher impact resistance, but I don't know if that's the characteristic we're most interested in with violin making or repairs, or know if higher impact resistance stays true once the higher gram strength glue is diluted to the viscosity at which we typically use it.

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I too have been wondering about that.  If you use glues that have the same working time, 192 glue will have less water in it than 315, and therefore the 192 will shrink less and end up with more solids in the joint.  I still haven't seen anything about the mechanical properties of the pure glue itself... tensile strength, impact resistance.  Is that published anywhere?

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