high temp epoxy

[watermelonman]

Is either Rocketpoxy or 4500P up to the level of ES-whatever number, or whatever Cotronics product is popular for serious aero heating?

 

[dixontj93060]

It is likely that the Cotronics exceeds the unknown specs of 4500P. It is supposed that 4500P has better specs than JB Weld, but no one knows for sure. RocketPoxy publishes their specs and it is not high-temp.

From the Ether...

 

[watermelonman]

Awesome, thanks. I could still use more information but that is a heck of a lot more than the virtual nothing I had!

It looks like ES6209 was one of the product names I was looking for, and comes from Aeropoxy. What is the popular Cotronics product for this type of work? Their 4700 sounds a little intense for us, minimum 250 degree cure.

 

[woferry]

FYI in case you hadn't seen them, Wildman has some specs posted on his 4500P page (linked here). Not sure exactly how that 'post-cure' works, do you throw it in the oven immediately after using the epoxy and bake it for an hour, or do you let it cure for the normal 24 hours then bake it (the 'post' implies the latter to me, but somehow I think it's probably the former. I'm not looking for anything high-temp anyway so it's not a technique I'll be using).

 

[dixontj93060]

FYI in case you hadn't seen them, Wildman has some specs posted on his 4500P page (linked here). Not sure exactly how that 'post-cure' works, do you throw it in the oven immediately after using the epoxy and bake it for an hour, or do you let it cure for the normal 24 hours then bake it (the 'post' implies the latter to me, but somehow I think it's probably the former. I'm not looking for anything high-temp anyway so it's not a technique I'll be using).

Wow great!!!! Thanks for posting!!! New info I have never seen before.

From the Ether...

 

[Andrew_ASC]

I've used the 4700 before. You need a good respirator and a low budget house oven you don't mind trashing with aerospace grade toxins. Soviet spacecraft stink included. Open all Windows or gag a bunch. It survived a 168G acceleration with all those impact loads on a SEDS flight case bonded. We were M2+ application. Yes you can melt less materials during cure like shock cords if stupid. You have to preheat, stir, and mix then oven cure. Easier with spare friends with food laser. Mainly a giant pain in arse but the expense is worth it when you put lives on the line by a glue strength. Nothing else touches 600F and 11,100 psi. Placed third at SEDS... AeroEpoxy wouldn't even sell us an epoxy for that application by thermal loads. So if you need it then don't skimp.

 

[Andrew_ASC]

The oddest thing about Cotronics 4700 is it shrinks slightly when oven cured so you may need multiple coatings and cures.

 

[Andrew_ASC]

The other glue is Cotronics 4525 IP which is a real strong aircraft brake pad glue. The Cotronics 4700 is legit aerospace grade industrial epoxy. So if you melt Cotrobics products you have like a hypersonic scramjet and bigger issues...

 

[Andrew_ASC]

I've melted proline in an oven at 250F. You may want to test it yourself because it isn't what is advertised. If you call AeroPoxy a sales guy will give you all the TG temperature numbers of when the epoxy fails at and proline doesn't offer that information which is scary.

 

[Andrew_ASC]

Rocketpoxy G5000 beats most of the Aeropoxy aircraft epoxies thermally on TG for the money. The Cotronics 4525 IP is likely the strongest you'll get from a room temp cure. I wish we had some 4525 for the head ignition forward closures with live ignitors for the college competitions but we were stupid then.

 

[dixontj93060]

Rocketpoxy G5000 beats most of the Aeropoxy aircraft epoxies thermally on TG for the money. The Cotronics 4525 IP is likely the strongest you'll get from a room temp cure. I wish we had some 4525 for the head ignition forward closures with live ignitors for the college competitions but we were stupid then.

John Olevich, the developer of RocketPoxy, expressed caution in using it for high temp applications and alluded to a future product, RocketPoxy G6000HT, for extreme temp use. As far as I know, this follow-on product was never brought to market.

https://www.rocketryforum.com/showthread.php?55340-Rocket-Poxy-Review&p=614258#post614258

From the Ether...

 

[Andrew_ASC]

The best is Cotronics 4700 but that was too serious for you. Next time tell someone how hot you want something. The spec sheets are out there. You have to ask for certain spec sheets. The Rocketpoxy is a much higher TG than the Aeropoxy at 151F... I'm not talking room temp dude.

 

[Andrew_ASC]

So how hot is your rocket going to get? You melt Nylon above 250F...

 

[Barkley]

I'm using PTM&W PT2846 for my latest build. Room temp initial cure, but a really complex post. But a great Tg when you're done.

Edit to add, a quick Google search gets you the spec sheet.

 

[dixontj93060]

The best is Cotronics 4700 but that was too serious for you. Next time tell someone how hot you want something. The spec sheets are out there. You have to ask for certain spec sheets. The Rocketpoxy is a much higher TG than the Aeropoxy at 151F... I'm not talking room temp dude.

Wow, your postings on this site are far, wide, and ignorant. CJ already called you out on it in another thread. Glad you bought your "big" 38mm Sandhawk, but do a couple decades of real high performance flying before you start blurting out expert opinions. Sure Tg isn't exactly the same as HDT, but in our applications with the aerodynamic forces involved, it might as well be. G5000 HDT is 150F: https://www.google.com/url?sa=t&sou...RCooQFggsMAE&usg=AOvVaw1UdKOFBq2_l2L_P2OkI4ZZ.

From the Ether...

 

[Andrew_ASC]

Yeah well I've actually used Cotronics 4700. I hate it when they want to argue about high temp and they haven't even specified how hot the rocket application gets. Hot is vague. Pick a number then match the epoxy to it.

 

[ksaves2]

For the neophyte be aware that the 4700 requires oven curing and 4525IP and it's predecessor 4525B were good for room temp cure and 500 degrees.
Actually 4525 makes half way decent fillets though it doesn't reflow as well with a heat gun. The heat simply cures it faster. I've got internal and external
fillets on a 4 inch Dominator 4 rocket that I believe will hold up decently.

Also, Cotronics mentions a shelf life of I believe 6 months? That said I used some year old stuff for mid power rockets and it has held up well. The curative
ends up darkening with age. Kurt

 

[markkoelsch]

Yeah well I've actually used Cotronics 4700. I hate it when they want to argue about high temp and they haven't even specified how hot the rocket application gets. Hot is vague. Pick a number then match the epoxy to it.

Andrew, you seem to be quite caustic towards others. You are not the first to do anything here I assure you. So, I suggest you consider your tone towards others when posting because you are rapidly developing a negative reputation amongst some seriously experienced folks.


Sent from my iPhone using Rocketry Forum

 

[ksaves2]

Sorry to diverge a bit but speaking of high temps............. I don't recall ever seeing a photo of a melted or deformed nosecone from aerodynamic heating.
Ostensibly that's the reason for the aluminum nosecone tips (aside from holding up better too)?

Does this mean that no one has sent a polypropylene NC to "melting" speed? That would be a sign of wicked intelligence not to do it I'd say.:wink:

Seriously, I've seen pics of scorched paint on NC's and delamination of fin leading edges but has anyone cooked an NC to failure by aerodynamic
heating alone. (Note well. I didn't say "heating" alone 'cause I'm sure a few of you would say you cooked an NC with a torch or barbecued one
after a launch!:tongue Kurt

 

[Andrew_ASC]

My experience with Cotronics4700 is the casings remain bonded to airframe tubing too hot to touch on MD applications permanently after tube walls have already failed elsewhere on the rocket. The BALLS flyers were recommending it. Other people have greater experience than I do. We didn't know the thermal loads on a casing with proprietary fuel blends so we went overkill on an epoxy. You can think of great epoxy as a good insurance policy when in doubt. The thermal loads were less by aero heating than the actual casing temperature for M2. You can call me ignorant. I am ignorant. It's hard to do a thermal analysis when you don't even have a heat flux to input into a CAD package. A lot of people would have used masking tape. We wanted to use a casing as an interstage coupler. First HPR trying 20k ft on an I staged. AeroFinSim also predicted a greater angle of attack before fin failure with increasing tensile strengths. The rocketpoxy inside the airframe away from the casing wasn't melted oddly.

 

[Andrew_ASC]

I've cracked Nylon nose at shoulder from thinness but the nose itself had no visible scorches from supersonic flight especially near tip. I'd guess the aluminum tips are good for M2.5-M3+ flights.

 

[blackjack2564]

Ishkabibble ...pure & simple, BS!!!!

I'm not even going to waste my time with all the reasons. The Forum is full of answers.




Carbon plate fins glued on with Hysol will suffice for most of what we do. After M-3.5-4 use Al fins.

 

[AeroAggie]

Ishkabibble ...pure & simple, BS!!!!

The Forum is full of answers.


<snip>

Jim, can you link the thread where that picture is from? I'd like to read it.

 

[watermelonman]

Same. I know the information is out there, but it can be so difficult to find, and to know who to trust.

 

[blackjack2564]

I have been compiling many files for our Full Scale Sounding rocket...Sparrow-Arcus. https://www.rocketryforum.com/showthread.php?132380-Sparrow-HV-Arcus-P-N-project .I have over 200 PDf's monograms etc. just for this. 5yrs worth....LOL

I suggest anyone contemplating serious project do same. Every time I see REAL data about something, screen shot and put in file for future use. I just pulled it up from personal Krech file...lol.

Since I can search Forum post faster than most. I put Bob Kerch in search. Found his profile....latests post..worked my way back to the thread...Here ya go. Whole thing is packed full of knowledge.

Actual post go backward/forward to read all.

https://www.rocketryforum.com/showt...th-a-composite-airframe&p=1648761#post1648761

PS Edit: my thread above also holds the "magic" needed to make the Madcow Nike-apache 2 stage work. I built a 1/3 scale spin stabilized version ....3in 54 motor to 38mm airframe 29motor sound familiar...LOL

 

[AeroAggie]

Thanks for the links, Jim. Looking forward to reading your Sparrow-Arcus thread...that looks awesome.

I do the same thing. Twenty years of engineering have taught me that I don't have to know all the answers, just know where to find them. I've been compiling my own materials spreadsheets, parachute sizing, etc. so that when I need it I can just reference my compilation instead of spending time (re)searching.

 

[ksaves2]

I laugh very hysterically when I see someone dissing Bob's advice and hoping the "disser" doesn't get them or someone else killed. Especially if it involves a motor.

One thing about epoxy/glue I've learned is doesn't matter what the specs are, if the materials aren't up to par doesn't matter.
A long neck rocket I made with surface mount fins and a substantial fin fillet sheared a fin off after falling off a shelf. I lunged and
partially broke the fall. The fin and fillet tore right off the tube. That's the weak spot there. (ie. cardboard!):eyeroll:

Also had a 4" LOC tubed rocket that had a layer of "Quasi" glass (ie. ladies stocking with bar top coating) and since that was not substantial enough,
added one (or two wraps) of 6oz. cloth (I can't remember it was 10 years ago) with standard laminating epoxy. Had a basement flood last April and though the rocket was off the floor and unharmed,
when I stood the sustainer up against the wall, it slid over, hit the floor and the tube snapped in two several inches ahead of the forward centering ring! Granted, the thing is long and
heavy but I was surprised. Going to see if I can saw around the forward centering ring and slide in a fiberglass coupler for salvage.

Both the above were rockets completed 10 years ago and not flown "yet" when I was more stupid about things.

Robert DeHate had pictures of a project that was something like 20 seconds at > Mach 2 and the fin delamination of the leading edges were sobering.

Like Mr. Hendricksen suggests in #22 all that is needed are good materials and half way decent glue. If going really stupid fast for longer periods, it makes sense to "stick the pedal to the metal" to avoid a project being a "single use" one.

The techniques for dealing with preventing and abating fin flutter I think are much more relevant than "My glues better than your glue. My glues better than yours." Kurt :lol::bangpan:oint::tongue:

 

[blackjack2564]

"My glues better than your glue. My glues better than yours." Kurt :lol::bangpan:oint::tongue:

"NO it's not!!!!"..............cause mine tastes 'mo better.

 

[Andrew_ASC]

I laugh very hysterically when I see someone dissing Bob's advice and hoping the "disser" doesn't get them or someone else killed. Especially if it involves a motor.

LOL that first I1299N launch. We were humbled what that tiny can of WARP9 does to a MD!

 

[ksaves2]

"NO it's not!!!!"..............cause mine tastes 'mo better.

Ewwwww Kay!......... And it's way worse than Barium poisoning too I bet!!! Kurt:eyepop: