KonkreteRocketry
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hot glue sticks
can you possibly burn hot glue sticks ? is there any flexible rubber-plastic like material that can burn with relatively less residue ? thx for
answers.
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ScienceSquirrel
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Mood: Dogs are pets but cats are little furry humans with four feet and self determination! 
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Hot glue sticks are a polymer mixture, see here;
http://en.wikipedia.org/wiki/Hot-melt_adhesive#Materials_use...
The common EVA based ones are often used by fishermen for running repairs on tackle in the field where they are melted with a cigarette lighter or
miniature torch. They will catch fire and burn with a luminous flame and drip hot burning glue blobules if you let them.
They do not burn very well though and you can easily blow them out.
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franklyn
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Acrylic
www.youtube.com/watch?v=TLPWqCMb7DE
www.popsci.com/diy/article/2013-02/gray-matter-watch-hybrid-...
How to construct it
www.youtube.com/watch?v=p-iAyp88qb4&NR
http://blog.makezine.com/2012/10/11/homemade-hybrid-rocket-e...
http://hackaday.com/2012/09/26/hybrid-rocket-engine-uses-acr...
Polyethylene
www.youtube.com/watch?v=p-iAyp88qb4&NR
How to construct it
www.youtube.com/watch?v=RDkjsVUcxmw
_________________________________
This is cute. Uses N2O cylinders
www.aeroconsystems.com/motors/Screamer_folder/screamer.htm
www.ebay.com/itm/170898489729
www.ebay.com/itm/170648854658
www.ebay.com/itm/261090614290
Just because material is available in a convenient form does not
make it ideal rocket fuel. PVC has been applied but it makes HCl
fumes. I recommend melt cast asphalt as the grain to use with
oxygen.
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IrC
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Since you understand the chemistry behind them can you tell me why I cannot get the stuff to make an electret? I held it between plates in liquid
state for hours with 20 KV applied to the plates, and allowed to cool to room temp. Even then shorting the plates and storing for months, makes no
difference. I think a tenth of a volt is the most I see assuming it's not just stray fields messing with my meter. I have tried this a few dozen times
with many varying brands of glue sticks. Total failure every time. I have long thought it was due to a structure re-arrangement during cooling which
ignores the applied voltage (which I kept steady all the way down to room temp.).
"Science is the belief in the ignorance of the experts" Richard Feynman
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MikeSomething
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Just a guess, but I'd assume that any vinyl compound would be too electrically lossy. I know using a PVC form for a Tesla coil will drastically reduce
its efficiency due to the PVC absorbing too much of the charge. IIRC, the loss is actually due to PVC having a lower impedance as the frequency gets
higher.
Either way, PVC is not a good choice for high voltage insulation. Maybe the same is true for PVA?
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ElectroWin
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hot glue sticks do burn, often with lots of smoke; if you mix with an oxidizer in the molten state and cast that, it might work quite well as a solid
rocket fuel.
but be very careful! this stuff is sticky and can give you pretty bad burns
i have mixed hot glue with paraffin to make a safer casting material, but i have not tried mixing with oxidizer, myself. you'll need one that is
stable at hot-glue melt temperature
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IrC
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Quote: Originally posted by MikeSomething  | Just a guess, but I'd assume that any vinyl compound would be too electrically lossy. I know using a PVC form for a Tesla coil will drastically reduce
its efficiency due to the PVC absorbing too much of the charge. IIRC, the loss is actually due to PVC having a lower impedance as the frequency gets
higher.
Either way, PVC is not a good choice for high voltage insulation. Maybe the same is true for PVA? |
Not so sure the reason is dissipation. The 2 mv Tesla coil I built on 24" diameter PVC pipe has very low damping. I was thinking it may more related
to hydrogen bonding and crystal structure. Something I had not considered a few years ago when I was trying the material in electret building. From
the wiki page mentioned above:
"Hot glue sticks are usually based on one or more base material, with various additives. The composition is usually formulated to have glass
transition temperature (onset of brittleness) below the lowest service temperature and a suitably high melt temperature. The degree of crystallization
should be as high as possible but within limits of allowed shrinkage. The melt viscosity and the crystallization rate (and corresponding open time)
can be tailored for the application. Faster crystallization rate usually implies higher bond strength. To reach the properties of semicrystalline
polymers, amorphous polymers would require too high molecular weights and therefore unreasonably high melt viscosity; the use of amorphous polymers in
hot melt adhesives is therefore usually only as modifiers and additives. Some polymers can form hydrogen bonds between the chains, forming
pseudo-cross-links strengthening the polymer."
Electrets are made from an amorphous material and require the charge separation to be 'frozen' in place upon cooling. I am thinking even at 20 KV
applied on the outside, the force is low compared to neighboring molecules forming into a crystal structure. To me this sounds like the likely reason
for failure.
"Science is the belief in the ignorance of the experts" Richard Feynman
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Fantasma4500
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well when i use hot glue i just melt it with a lighter, if you keep it in the blue part of a normal lighter's flame then it will just melt and wont
become black.. wont be a problem if it would start to burn anyways..
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