My main reason for not wanting to go to dextrose is the viscosity. Sorbitol
is quite thin and thus I can load it up pretty high with KNO3, Mg, & other
things. My current formula for a fast propellant is only 30% sorbitol and
still can pour easily into my 29mm casting setup (with coring rod already
in place). Paraffin was a thought because it is even thinner when melted
and I was hoping it would allow me to go higher on the KNO3 percentage.
This is why I started up in the 80%s. Mainly I'm looking for things that
are different to do. Eventually I'll be able to do APCP and get all of the
performance I want, but for now it is fun to see how much I can get out of
cheaper ingredients.
Trevor
On Thu, Mar 28, 2024 at 11:07 PM Lincoln Ross <lr21643@xxxxxxxxx> wrote:
BTW, Trevor, if you're trying to save money, you might consider dextrose.
I think Baker's Authority has it at something like $79 for 50 lbs. As
usual, Richard Nakka has quite a bit of info about using it in fuel grains:
https://www.nakka-rocketry.net/dex.html Note that the hydrated form
melts at a low temperature and doesn't give up all that much specific
impulse.
On Thu, Mar 28, 2024 at 8:21 PM Lincoln Ross <lr21643@xxxxxxxxx> wrote:
There is also something called Gulfwax, commonly found at supermarkets. I
think mine might be from the previous millennium, though. Unless there was
some kind of aging over that time, I bet it is about the same stuff. In
bulk, of course, the stuff is cheaper.
On Thu, Mar 28, 2024 at 5:36 AM Tr Mu <tl01001101@xxxxxxxxx> wrote:
I just used some I found at Hobby Lobby. It was labeled as being pure
paraffin for candle making.
Trevor
On Thu, Mar 28, 2024, 12:56 AM Lincoln Ross <lr21643@xxxxxxxxx> wrote:
Any specifics or does the paraffin just end up covered with tiny bite
marks? ;-)
On Thu, Mar 28, 2024 at 12:53 AM Bruce Beck <bbeck7@xxxxxxxxx> wrote:
Nitrates are lousy oxidizers for paraffin.AP works well but chuffs at
low pressure.
On Wed, Mar 27, 2024 at 4:16 PM Tr Mu <tl01001101@xxxxxxxxx> wrote:
This past weekend I had the idea of trying a paraffin based
propellant. Has anyone tried this? It melts at a lower temp than sorbitol
and based on the prices I found, it would end up cheaper than my current
sorbitol motors.
I tried some small 10 gram batches of 80:20, 85:15, & 90:10
KNO3:paraffin. These were based around 85:15 being an "ideal" ratio as
per
ProPep3 None of them would sustain combustion. I want to try it again
this
weekend with finer ground KNO3, but I wanted to see if anyone else has
tried it.
Trevor
