1. The IPDI poses about the same hazard as most isocyanate epoxy curatives.
So... don't drink it, and avoid getting it on your skin, as they tend to be
sensitizing agents for allergies. So if you are continually sloppy in your
handling eventually you will start getting an allergic reaction to it.
Using a standard organic vapor respirator isn't a bad idea, especially if
you are in a closed room. If you are getting worried about SDSs read the
SDS for gasoline to help ground yourself with something you are familiar
with. Gasoline is a pretty horrible substance in the scheme of things.
Main thing with APCP is do not mix your oxidizer and your metal powders
dry. You should have your metal powders fully wetted into the R45 (HTPB)
before any oxidizer gets mixed in.
2. The commonly available tepanol from firefox is already ancient. So it is
all the consistency of near frozen honey. It takes a while for it to go
into solution in the R45 but it does eventually. You should be getting an
ammonia smell if it is still active after mixing it with the AP. It has
probably lost some of it's efficacy at this point, but it still may do
things. There is at least some sort of chemical reaction going on. Honestly
for small motors it is not really required. All it does is increase the
adhesion of the AP particles to the R45. If you are doing small motors,
especially if you are not using large AP sizes like 400 micron, there is
not much need for it. As you are unlikely to get much AP pulling out of the
grain matrix as it burns; with small motors/small particle sizes and do
much to increase your burn rate.
- Apparently the other Wyatt
On Thu, Jan 30, 2020 at 11:25 AM Anthony Cesaroni <anthony@xxxxxxxxxxx>
wrote:
Toss the tepanol. Are you looking for a job?
Anthony J. Cesaroni
President/CEO
Cesaroni Technology/Cesaroni Aerospace
http://www.cesaronitech.com/
(941) 360-3100 x101 Sarasota
(905) 887-2370 x222 Toronto
*From:* arocket-bounce@xxxxxxxxxxxxx <arocket-bounce@xxxxxxxxxxxxx> *On
Behalf Of *Wyatt Harris
*Sent:* Thursday, January 30, 2020 3:10 PM
*To:* arocket@xxxxxxxxxxxxx
*Subject:* [AR] Introduction / getting started with APCP
Hi everyone,
I've been subscribed to AROCKET off an on for the last ~20 years, and I
believe this is my first post (I may have sent one when I followed this
forum back in high school, but I can't remember).
To provide a bit of an intro about myself, for those that care, or at
least to show that I'm not coming at this totally out of the blue:
I started building rocket motors in middle school and continued into high
school (early 2000's). They were almost all KNSB motors (thank you for your
website Richard Nakka!), with the exception of a large LOX/hybrid that I
built with a propulsion engineer from Raytheon, and launched at BALLS 2004.
I went on to get a BS in Astronautical Engineering, where as a senior I
was chief engineer for a boosted dart rocket project that was launched at
WSMR in 2009. Following college I got a MS in Mechanical Engineering, did
some other stuff for a few years, and am presently 1.5 years into a 3 year
PhD program in Astronautical Engineering (not researching anything
propulsion related however; I'm actually examining a GNC topic for
spacecraft RPO).
To the subject of this email: I recently got back into building small
rocket motors as a hobby. I've made a few small KNSB motors, though I'm
more interested now in moving on to APCP. I have the APCP/HTPB kit from
Firefox. For the time being, I intend to build and test motors with <50g of
propellant.
I'm reaching out to the forum with the hope that this might be a good
place to get some advice on working with APCP (especially regarding safety,
common pitfalls and best practices). I've got and have read through
*Experimental
Composite Propellant*, *Plastic Resin Bonded Fuel Systems *(Firefox
book), the CP technologies book (doesn't seem very helpful for APCP
though), and I also have Burnsim. I intend to proceed following the
procedures outlined in the first two books as closely as possible.
If this is the right place to ask, I suspect I'll have plenty of questions
moving forward, but to pose a couple to start:
(1) My main concern right now is proceeding safely, so any practical
advice out there regarding safe production of small APCP (<300g) batches?
My initial plan is to use an open garage with PPE including nitrile gloves,
goggles and VOC respirator. I've taken a look at the SDS's for the
chemicals involved, it seems that IPDI is is the nastiest component? The
SDS for this makes it sound very toxic.. how concerned should I be about
this for the small batches I'm making? Any concerns/things I should know
about other chemicals such as AP/HTPB/EHA/tepanol? I'm not planning to do
any crazy propellant formulations (exotic oxidizers/metals) at this point.
(2) I opened up the teponal (HX-878) from the kit and noted that it is
*extremely* viscous (challenging to remove any with a tongue depressor).
Since it's been a while since I bought the Firefox kit, wondering if this
is normal, or has it gone bad?
Thanks for reading the long email. Thank you in advance for any advice!
-Wyatt
