I don't recall offhand whether there are any non-isocyanate curatives
for HTPB but even if there are, availability to amateurs is likely to be
low or nonexistent.
Chris Short carries something called ACME curative -- I've never used it
and don't know squat about it -- and PAPI 94; I have used the latter
with good results.
RCS sells E744; it's quite inexpensive, good pot life, and cures in a
couple of days at room temperature. For an overnight cure it can be
allowed to gel at room temp, then warmed in a heated curing container at
about 100-110F. NOT indoors!
https://www.rocketmotorparts.com/Modified_MDI_Isocyanate_Curative/p1577809_7835874.aspx
Regardless of what you buy, don't get more curative than you can use
within a few months, as isocyanates don't age well.
Side note: the cost of AP has skyrocketed; RCS is selling barrel
quantities for $20/lb or a 20 lb container for about $500. "Sugar"
propellants are beginning to look rather attractive...
Best -- Terry
On 1/30/2020 9:42 PM, Wyatt Harris wrote:
Appreciate all the replies! One follow-up question for now: I can't see what csrocketry has to offer for curatives since I'm not TRA level 2, but if IPDI isn't the best curative for HTPB, any advice on good non-isocyanate alternatives? I don't have the book with me, but I seem to remember ECP just mentioning various isocyanates as curatives for HTPB? Suppose I'll give the IPDI I have a try for now.--
I'd love to go to that APCP course, and maybe I will one day, but don't have the time now unfortunately.
Thanks,
Wyatt #2
