I remember that stuff, we stored in the freezer as a tan elastic uncured
rubber sheet with silica then lay it up at RT then pressure mold it and
cured at ~ 300-400F
where it turned dark brown almost black and extremely tough and extremely
stinky, I believe it had tellurium sulfide as the vulcanizing agent.
The stench would come out of my pores in the shower in the evening. Back in
the days when I was single. Glad those days are over. Used it in Titan
SRM,IUS,everything solid.
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On Wed, Apr 29, 2020 at 5:08 PM Anthony Cesaroni <anthony@xxxxxxxxxxx>
wrote:
Pro-Guard probably is and I worked on some custom formulations with the<https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail&utm_term=icon>
owner. There are some section cure limitations as the formula does not
contain anti-scorch compounds. Thickness cure limit is less than .125” for
most applications due to catalyst/peroxide levels employed. It needs air
for final cure. Cross-linking EPDM is a bit of a fine art. Pro-Guard does
not contain any aramids or rocket grade flame retardants. At most, you can
expect less than 50% of the performance of a calendared EPDM motor case
insulation product. That’s not the intended use of the product. It’s
intended as a roof coating, not a rocket insulator.
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 *Troy Prideaux
*Sent:* Wednesday, April 29, 2020 6:50 PM
*To:* arocket@xxxxxxxxxxxxx
*Subject:* [AR] Re: Phenolic liner repair
Pro-Guard still claims their product is the only true liquid EPDM, but I
think there are others around now since they labelled that claim.
I have a gal of the stuff they suggest for roof repair (still yet to be
opened). I didn’t realise it was sensitive to mixing ratios?
Not sure if they still supply the 100% EPDM product (F9921?) but I was
after some of that for another application.
JB Weld: just be mindful there are various flavours of JB Weld – you want
the high temp variety for this application
Other potential solutions:
Water Glass composite - I’ve made nozzles with that combination
Muffler putty based on Sodium Silicate (the stuff rated to 1000deg C)
Last Resort: Phenolic laminating resin (+composite) – Bill, contact me off
list if you need a small amount for this repair
Troy
*From:* arocket-bounce@xxxxxxxxxxxxx [mailto:arocket-bounce@xxxxxxxxxxxxx
<arocket-bounce@xxxxxxxxxxxxx>] *On Behalf Of *Anthony Cesaroni
*Sent:* Thursday, 30 April 2020 6:14 AM
*To:* arocket@xxxxxxxxxxxxx
*Subject:* [AR] Re: Phenolic liner repair
Pro-Guard Advanced Rubber Coatings?
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 *Edward Wranosky
*Sent:* Wednesday, April 29, 2020 3:38 PM
*To:* arocket@xxxxxxxxxxxxx
*Subject:* [AR] Re: Phenolic liner repair
I have never used JB-Weld, but I have used liquid EPDM. My biggest concern
with EPDM is getting the ratios correct to have a proper cure. I almost
always end up making a test batch, letting it cure, then making the same
batch size for actual use. Even with that there is an amount of finger
crossing that I do.
On Wed, Apr 29, 2020 at 12:16 PM Joe Bowen <joe.b.bowen@xxxxxxxxx> wrote:
Not sure if this is relevant to the discussion at this point but I
originally started using copper-RTV to seal that joint on my motor before
switching to jb-weld. But due to a combination of slop and the weak RTV
"glue joint", the post-combustion chamber was able to slide forward and
bypass the RTV. Also, the RTV itself (even though high temp) really didn't
hold up to temps inside the motor, which probably shouldn't have been a
huge surprise.
Joe
On Wed, Apr 29, 2020 at 10:56 AM Charlie Garcia <
dragonrider.hhcc@xxxxxxxxx> wrote:
Thanks for the tip Bill. That now makes me wonder how close to disaster
I've come in the past...
On Wed, Apr 29, 2020 at 10:46 AM William Claybaugh <wclaybaugh2@xxxxxxxxx>
wrote:
Joe:
Thanks, I’ll chew on this. Lot’s of folks seem to use JB Weld for bonding
rocket bits.
Bill
On Wed, Apr 29, 2020 at 10:05 AM Joe Bowen <joe.b.bowen@xxxxxxxxx> wrote:
I use JB-Weld to glue my phenolic post combustion chamber liner to the
plastic fuel grain for my hybrid motor and that seems to hold up pretty
well to the heat and minor forces. That may work here, although not sure.
Joe
On Wed, Apr 29, 2020 at 10:02 AM Charlie Garcia <
dragonrider.hhcc@xxxxxxxxx> wrote:
High temperature RTV has worked well for me in the past on smaller motors
and on other parts needing heat resilience.
On Wed, Apr 29, 2020 at 9:53 AM William Claybaugh <wclaybaugh2@xxxxxxxxx>
wrote:
In doing the final honing of the phenolic liner ID on my 9" motor I appear
to have chipped the edge of the lap joint between to the two pieces of
phenolic. I'm interested in ideas for how to repair that chip--or if
repair is needed.
Because it is at a lap joint, the chip only goes half way through the
liner; it is also in an area that will not see any heating until the last
hundred or so milliseconds of the burn.
If I chose to repair it what is a good solution? (I'm currently thinking
HTPB loaded with powdered phenolic from the honing operation.)
Bill
