engine burn temp

[bachsta]

how hot do E through H engines get when they burn (i have a glue that will hold until it reaches 600 degrees farenheit is that good enough?)

 

[BlueNinja]

wont matter as you are not holding your motor together.


even if it is directly touching the motor mount, it is a non-issue as the outside temp of motors only reaches 200 degrees or something, the outside temperature is regulated by some NFPA code i think.

 

[bachsta]

ok cool then my glue will work great. i just got an loc aura and i dont have any epoxy but ive got this stuff called JB weld and it has a max temp of 600 degrees farenheit so i was wondering if it would work

 

[BlueNinja]

JB weld's fine. heck, it is used on motor retainers where there is probably at least 500 degrees acting on the metal. I don't like it cause it's too thick and doesn't flow well for mixing in a graduated cup. If I were you and i was going to build more MPR rockets, I would contact www.uscomposites.com . They have some good, cheap epoxy. They also sell expanding foam for half the price as PML (almost)

 

[bachsta]

ill keep that in mind. but for right now all i have is jb weld so i guess ill use it cause i really wanna build my rocket. or should i wait and get some epoxy?

 

[BlueNinja]

JB weld might be a little heavier but otherwise i think your ok, i dont know its heavier but im just guessing.

 

[wwattles]

JB Weld will do fine, or you can get epoxy from Walmart, Home Depot, etc.

Temp-wise, the motors themselves only reach that temp for a short period, and as was mentioned already, the outer surface of the motor casing is a lot cooler than the burning APCP surface.

If your motor exhaust is recessed inside the fin can at all, you'll want to put some kind of protection around the inside of the outer tube to keep it from burning through. 2-ton (30 minute) epoxy works okay for that, but foil tape works better.

Were you able to get over to Fiesta Island for the launch this morning and talk to any of the folks out there?

WW

 

[bachsta]

i went but i got the kit this afternoon and wasnt able to get any advice from them. also i just realized that we had the jb weld and were out of epoxy. (got from andy this afternoon. got to help erect his huje vostok. didnt think to ask about glues to use. and the reason why i asked about if jb weld could resit the heat is because i didnt know how hot 600 farenheit was in the rocketry world, anyway i think it will work fin for at least the motor mount i might get epoxy for the fins though. it dries way faster)

 

[Justin Horne]

Personally I would NOT use the JB weld for that stuffs.. Would it work-absolutely. However, it's way too #$%#%# expensive to build with... Just go buy some 15 min epoxy and you'll be golden.. MUCH better value, and will work just dandy...
I use JB weld on the motor retainer, if I have one, and that's all.

 

[bachsta]

yah ok. its just ive got the jb weld stuff. had it for who knows how long. just opened it today cause i was outa epoxy so its not like im spending any extra money on the stuff so its all good.

 

[Justin Horne]

Well, Ok then. Good luck with the stuff.

 

[bachsta]

i take it jb is realy expensive (i wouldnt know) because its really strong, right?

 

[BlueNinja]

Yeah, it is more expensive than a comparable 2 part syringe of plain epoxy. I still say get something bulk, long as its not a 1:1 mix ratio, 1:1 isnt as strong cause it has fillers to make it a 1-1 mix.

 

[bachsta]

yah next rocket i build im gonna get some of the 2:1 epoxy from uscomposites.com

 

[Elapid]

Originally posted by Blue_Ninja_150
long as its not a 1:1 mix ratio, 1:1 isnt as strong cause it has fillers to make it a 1-1 mix.

is a little more complex than that.