Piper fuselage adhesive

I doubt anyone still uses it. Cold bonding was found to entrap moisture.

Interestingly, that Aloha Airlines 737 was also manufactured in 1969.
 
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JAWS said:
Tom is correct. Beechcraft has stopped using scrim cloth as Hysol 9309.NA has micro balloons in it, which apparently serves the same function.
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Microballons are known as a thixotropic, they thicken the glues so it won't be running out of the joint. Microfibers will do the same thing but also make a stronger joint.
 
GlennAB1 said:
Never heard that term.
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Come out into the light, it's term used often in the fiber glass industry. talcum powder is also used as a thixotropic.
 
For idiots like me:

noun,
the property exhibited by certain gels of becoming liquid when stirred or shaken.

adjective,
(of fluids and gels) having a viscosity that decreases when a stress is applied, as when stirred: thixotropic paints or ketchup

Its derived from the Greek word, thixis the act of touching + -tropic

So there ya go folks - no charge as always ;)

ps - I added the ketchup thing
 
GlennAB1 said:
I don't believe microbaloons, alone, are thixotropic.
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I guess you are smarter than the marine tech instructors. that instruct in the local marine technical school.
 
Timbeck2 said:
noun,
the property exhibited by certain gels of becoming liquid when stirred or shaken.
adjective,
(of fluids and gels) having a viscosity that decreases when a stress is applied, as when stirred: thixotropic paints or ketchup
ps - I added the ketchup thing
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And I can walk down to our structures shop and get a bag of of microballoons and pour them out like sand or marbles.
 
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So does the bag come complete with an annoying micro dude that makes animals out of them for tips?
 
Guess who has a ATA degree in marine tech?
 
ay105324984a-yank-bunny-cal.jpg
 
GlennAB1 said:
Nothing you provided says microballoons are thixotropic, but it does say they reduce weight, which I said.
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Believe what ever you like, have you ever built boats? I have, plus two wooden aircraft. In the Fiberglass industry any thing that thickens the base resin is a thixotropic.
But you'er the expert.
BYE.
 
Run away, Tom.
Tom-D said:
plus here is a different agent /filler/ thixotropic / modifier
West 406 Colloidal Silica, a thickening additive used to control the viscosity of the epoxy and prevent runoff in vertical and overhead joints.

Talk about cherry picking, and that's not even microballoons.
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Tom-D said:
Believe what ever you like, have you ever built boats? I have, plus two wooden aircraft. In the Fiberglass industry any thing that thickens the base resin is a thixotropic.
But you'er the expert.
BYE.
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Boats... How about you show me something aviation related?

I did a search of 777,767,757,MD-10-10/30, MD-11,A300,A310 MMs and SRMs, which includes composites. No thixotropic.

I went through the Boeing Repair of Advanced Composite Structures training manual. No thixotropic.

I went through my ABARIS Training (worldwide leader in composites training that I've been to) Advanced Composite Structures Fabrication and Damage Repair. No thixotropic, except in the Glossary which basically repeats what Tim found but adds See ASTM D 907, which states: Thixotropy - the property of adhesives systems to thin upon isothermal agitation and to thicken upon subsequent rest. That aint microballoons.
The Glossary also differentiates between microballoons and microbeads. Microballoons are not uniform, used to reduce resin density. Microbeads are very close tolerance in diameter, used for bondline thickness control; much more expensive than microballoons.

Ever heard of syntactics?
 
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Well here I am again as a service to the English challenged:

syntactic. syn·tac·tic. adjective. Relating to the rules of language. An example of something syntactic is a sentence that uses the correct form of a verb; syntactic sentence.
 
Syntactics, or syntactic core materials are a composite material formed by mixing microspheres and other fillers with a thermosetting resin. It comes in cured and uncured form. Uncured, it can be formed into complex shapes (like modeling clay), and covered with composite face sheets. In the uncured state it might qualifiy as thixotropic.
 
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I'll ref this part for a minute, <----------- chemist with 15+ years formulating polymer/urethane systems, has 4 viscometers is lab down stairs.
For the most part microballoons, glass beads, calcium carbonate, talc, et al are not thixotropic. they do increase viscosity and can make newtowian liquids into very viscous newtonwian liquids and if you measured them across a large shear range, there would be a small amount of thixotropy. But they dont work nearly as well as fumed silica, clays and other specific additives.
When done right fumed silica or clay can produce something with 3,4,5 or 10x the viscosity from high shear rate to low shear rate. ie the viscosity measured at 60rpm is 1/5 or 1/10 the viscosity measured at 5rpm. A normal newtonian liquid is the same at any reasonable shear rate.

TL/DR - Micro balloons are not Thixotropic.
 
GlennAB1 said:
And I can walk down to our structures shop and get a bag of of microballoons and pour them out like sand or marbles.
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if you pour out micro balloons, it actually looks like smoke pouring out of a jar.
 
FWIW - Setting concrete, ketchup and mayonnaise are examples of substances that are thixotropic. Honey etc is not. Anything that could be added to epoxy to make it thixotropic would be very useful, but I can't imagine what it would be.
 
ChemGuy said:
I'll ref this part for a minute, <----------- chemist with 15+ years formulating polymer/urethane systems, has 4 viscometers is lab down stairs.
For the most part microballoons, glass beads, calcium carbonate, talc, et al are not thixotropic. they do increase viscosity and can make newtowian liquids into very viscous newtonwian liquids and if you measured them across a large shear range, there would be a small amount of thixotropy. But they dont work nearly as well as fumed silica, clays and other specific additives.
When done right fumed silica or clay can produce something with 3,4,5 or 10x the viscosity from high shear rate to low shear rate. ie the viscosity measured at 60rpm is 1/5 or 1/10 the viscosity measured at 5rpm. A normal newtonian liquid is the same at any reasonable shear rate.

TL/DR - Micro balloons are not Thixotropic.
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Had to look that up
https://en.wikipedia.org/wiki/Newtonian_fluid

Professor gobble gook, It the practical application any additive that will change the rate of flow of a liquid, either to slow it or increase the rate, is a thixotropy agent,
You add flour to your gravy you just changed the rate of flow, Got it too thick? add water .

Common sense, add it to your thinking, it may speed it up but it is not a thixotropic agent.
 
Don'tch just love it? Glen said he had never heard the term, prior to this thread, but now he's the expert.
 

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nrpetersen said:
FWIW - Setting concrete, ketchup and mayonnaise are examples of substances that are thixotropic. Honey etc is not. Anything that could be added to epoxy to make it thixotropic would be very useful, but I can't imagine what it would be.
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How about Part "B" that will sure enough change the flow rate.
 
Tom-D said:
It the practical application any additive that will change the rate of flow of a liquid, either to slow it or increase the rate, is a thixotropy agent,
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Still wrong. The additive itself could be thixotropic, or not. If it is not, it could be added to a liquid to make the mixture thixotropic. Microballoons are not thixotropic but added to epoxy resin they can make the mixture thixotropic.
 
See Folks.. What did tell ya.
 
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