RE: Re: glue testing, how about Titebond?

From: hermann andresen <hermanna_at_hotmail.com>
Date: Mon, 25 Jun 2012 10:01:43 +0000

Back 50+ yr ago, Bob DeBatty converted to White Glue (like Elmer's) even for indoor.. Later there was Carpenters Glue. Titebond added II, water resistant which I used to repair a Redwood fence 10yr ago. Now there is also T III which is claimed to be waterproof.
Being water based they are much more user friendly both odor wise and removing from fingers. Also does not have the CN (Cyanide) component of instant glues.
They work great for end grain as glider dihedral joints and have little warping effect.
Weight on ribs is about equal to extending the rib about 1/8". This is easily determined by taking a stick, 1/2" to 1" long, mark the balance point, add glue to one end, then, after it dries, rebalance. The equivalent weight is twice as much as the balance point moved.
Like concrete, most glues lose strength with thinning, so I've always used it straight. Have not had any problem with rib/spar joints, but they could be strengthened with a thin film of glue top & bot.
A simple strength test would involve making T's out of 1/32 sq, 1" long then destroy by pushing the end of the "rib" on a block on a digital scale.That provides an almost pure bending load on the joint which should be very reproducible between samples.

At least if you get Titebond III and don't like it for models you can use it for household repairs or build a boat.
H

To: Indoor_Construction_at_yahoogroups.com
From: jannis1indoor_at_yahoo.com
Date: Mon, 25 Jun 2012 02:59:41 +0000
Subject: [Indoor_Construction] Re: glue testing
















 



  


    
      
      
      Neil,



A good reference is a paper written for the 1974 Sympo titled "An Experimental Evaluation of Some Popular Modeling Adhesives" by Thomas Ersted and Edmond Smith. They developed a method to gluing two pieces of balsa wood and then subjecting a bending load to the glued joint until failure. At that time ambroid tested out better than testors A and B. Jeff Annis



--- In Indoor_Construction_at_yahoogroups.com, Neil Dennis <wombatt_at_...> wrote:

>

> FWIW, in our "tech wars" stuff, the students build truss bridges to a

> set of size specs, then they are tested to destruction with the "added

> weight" load.

>

> IMHO, if you straight pull a butt joint that's tensile, a shear joint

> would be a pair of strips laid side to side , then pulled apart.

>

> wombat

>





    
     

    
    






                                                 
Received on Mon Jun 25 2012 - 03:01:45 CEST