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I am a fourth grader doing a Science Fair project on testing what wood glue is strongest out of Elmer’s glue, Gorilla glue, and Titebond 2. I was wondering what glue you use and why? What glue do you think is strongest?

The way I plan on testing it is by gluing the end of one 8 inch board to the side of another board to make a 90 degree angle. Then hang a 5 gallon bucket 7 inches out then started filling the bucket with water and weigh it. I will post my results.
 

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These are the kind of experiments that get guys and gals of all ages excited because it's first hand knowledge tried and true!
Look forward to hearing about your results.
 

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Yes me too. I usually use elmers. Gorilla is crap as far as I'm concerned. Titebond gives me trouble sometimes, it does not seem to dry as fast as elmers.
 

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hold on there

The way you have your boards, one end butted to the other's face is the weakest possible way to join those boards and your test may be thrown off because glue does not work well in end grain.

A better test, in my opinion, would be to orient the boards so they are face to face, or face to an edge. There have been other glue strength tests so you might look at those to see how they did it.
You can do it the way you have them oriented, but they will probably fail prematurely. It's up to you .... as long as the same procedure is followed each time.



 

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We have an introduction section where you can say a few words about yourself. If you fill out your profile in your "User Control Panel", you can list any hobbies, experience or other facts. You can also list your general geographical location which would be a help in answering some questions. In doing that your location will show under your username when you post.

The way you have oriented the boards...end grain to face grain (long grain) will be the weakest of joinery, as the end grain would be the weak mate. You may already know this and is why you set up the pieces the way you did. So, it's not the orientation of the wood that is being tested, but the glue used. Have fun doing your set ups and recording the results. Take some pictures and post them if you can.









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cabinetman said:
We have an introduction section where you can say a few words about yourself. If you fill out your profile in your "User Control Panel", you can list any hobbies, experience or other facts. You can also list your general geographical location which would be a help in answering some questions. In doing that your location will show under your username when you post. The way you have oriented the boards...end grain to face grain (long grain) will be the weakest of joinery, as the end grain would be the weak mate. You may already know this and is why you set up the pieces the way you did. So, it's not the orientation of the wood that is being tested, but the glue used. Have fun doing your set ups and recording the results. Take some pictures and post them if you can. .
It's a 10 year old!
Tom
 

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"Premature failure" when compared with what? For index and test purposes, not an impossible joint to break at some weight with a bucket of water.

I'll bet that he left his 20,000lb shearing press at school.

Tom, when you make the glue joint,
1. Make certain that the surfaces are all covered = no air spaces inside that are surrounded by glue.
2. When you clamp(?) them together, that has to be the same each time.
3. The thickness of the glue layer between the two boards needs to be the same each time.
 

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The way I see it, the test will show which glue bonds the best to the end grain of the particular species of wood he uses and not the glue strength.
 

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to be more "scientific'....

The way I see it, the test will show which glue bonds the best to the end grain of the particular species of wood he uses and not the glue strength.
Agreed.

To use the Scientific Method, a good procedure for a Science class project, one would test multiple samples with each glue to take the average of the load necessary to break the bond. Testing multiple identical samples will eliminate any variation the the glue thickness, end grain structure, face grain differences, load application etc.

Then each different glue will have an "average" breaking point which can be compared. To test only one sample will not give a reliable or consistent result, only the result for that combination of variables ....JMO.

Typically gluing end grain offers the least effective bond which is why I said "prematurely" meaning sooner than expected based on other observations or methods...... :yes:
 

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glues work in a complex manner, but ....

http://newwoodworker.com/useglue.html
This article describes it in simple terms ...long grain to long grain is stronger than end grain to end grain because the glue wraps around and is absorbed by the fibers rather than just wicking up the ends of the pores ...etc. The glue become part of the molecular structure forming a bond stronger or as strong as the wood itself.

Quoting the article:
"Long grain to long grain produces the strongest joint because the glue can "grip" the fibers along their length. Conversely, when one or more short grain sections are involved, the joint will be substantially weaker because the glue has only the ends of the grain to grip."

For the highest strength glue....
http://www.garrettwade.com/special-202gf-high-strength-glue/p/62J01.01/
 

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Discussion Starter #16
Thanks for the responses so far.

I chose end grain to long grain because it is a common joint in cabinets. My research about people doing long grain to long grain the board failed before the bond.
 

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OK. and yes, that's true

You want to test the glue bond, so you picked the weakest type of joint. Good thinking, other wise you will be just breaking wood, but not at the joints. Like I said earlier, proceed, but use many samples to get the average of each brand of glue. Waiting for your results! :yes:
 
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