Troy:
I agree that hot gas is unlikely (1-2 out of five) but the consequence is
loss of a five figure asset (5 out of 5). This is a bit like the “too big
to fail” problem: if it was a hundred dollar motor I’d just test it and see
what happens; at $10,000 plus I’m given to making certain there is no gas
path.
Unfortunately, the liner tubes come in 36” lengths which means there is
insufficient leftover material to do as you suggest; in addition, having a
seam at the seal does leave a theoretical leak point. Again, the odds of
that being an issue seem very low...but the consequence of failure is very
high.
I—very briefly—considered ordering a phenolic tube to slip fit the joint
but the minimum order is near US$1,000 and provides enough material to just
make BATES grains...a solution to be sure but adding cost and reducing
performance (by 3% compared to a case bonded grain).
Bill
On Thu, Aug 23, 2018 at 9:32 PM Troy Prideaux <troy@xxxxxxxxxxxxxxxxxxxxx>
wrote:
Cut off a piece of liner tube, cut a wide enough slice out from the that
piece's perimeter so that you can fit the closed up piece snuggly inside
the
liner tubes and bond in place with plenty of HTPB/Tepanol/curative mix. You
can hopefully join the 2 liner pieces together piece by piece so there's no
stretching or reaching and keep in mind the chances of hot gas getting to
this point is quite remote, especially if there's minimal clearance between
the liner and casing ie. the casing wall will absorb lots of heat fast, the
flow will be extremely momentary and minimal and if both ends of the
liner-casing clearance were exposed, the middle section should stay quite
stagnant anyway.
Troy
-----Original Message-----just
From: arocket-bounce@xxxxxxxxxxxxx [mailto:arocket-bounce@xxxxxxxxxxxxx]
On Behalf Of John Stoffel
Sent: Friday, 24 August 2018 12:51 PM
To: arocket@xxxxxxxxxxxxx
Subject: [AR] Re: Sealing phenolic liner joints
For the bonding, you don't need to actually put the liners into the tube,
into a short enough length where you can get it more easily. If you cantake a
piece of pipe the same inside diameter, and cut it in half, then youcould
possibly use those halves a molds.try to
Crack it open, lay in the liner, but the joints with whatever (I'd maybe
scarf them and glue with epoxy) aand then put the other half on, clamp itshut
and put in the bladder in the inside to push out.Or if
The scarf could be 3/4" long, or possbily longer if you can make it work.
the liners are already in tube form, just a short section of the outsideneeds to
be supporting the joint when you butt them and glue them together.
John