Grog and Nozzels

[fred815]

Hey, After screening a Lb of commercial bought Grog (40Mesh) I end up with 4 oz's if I'm lucky??? Is this too fine for making a super strong nozzel as outlined on Skylighter's site.?? Or is this how it goes!!! Bite the big one or figure out a way of grinding the gravel left over??

[nater]

That would have to depend on the distribution of the particle size of the grog your purchased. I bought some from Axner and it was as fine as it was advertised to be. That said, I don't use it. I mixed up some nozzle mix and found the grog was tearing up my tooling. I've had good luck with waxed hawthorn bond clay. Edited April 7, 2012 by nater

[dagabu]

Apparently, they just used a larger mesh screen and allowed the stuff that stayed on top to pass for 40 mesh grog. Don't try to to grind it, you will just wear down your media. I pay $.42 a pound for grog locally so if I found that the grog was to coarse, I would just go and buy some finer mesh grog.

 

I only use grog for endburners since I can make another spindle in 10 minutes if I crap out the old one but like Nater, I no longer use grog on core burners due to the wear.

 

-dag

[fred815]

Hey thanks axner good site ! BUT As usual a simple question explodes into a complex topic. I really really appreciate all your experienced answers but another newbie is off on a new quest to find out what everybody is talking about. Kinda discourages new participants doesn't it?? SO here goes!!! Let's see can't use grog unless as fine as at least 40mesh. But wait a minute grog tears up spindles. Is that after one or a thousand uses?? Try hawthorne bond clay. Which one 40 50? Substitute or use only and forget the bentonite? What's the diff between Hawthorne and bentoniute? OOPS wait a minute There's this stuff called Mulcoa and it comes in 35 or 48 or what ever?? How about Molochite or silica Mayby Kyanite or the Kaiolins?? Are these stand alones or additions to bentonite?? Waste an hour or more at axner and I'm right where I started. I'm a newbie. I don't have my own fabrication tools. Spending $100 or more on ONE set of rocket tooling is enough. I just wanted a stronger nozzel not cato's. Please understand I'm NOT "P ed" off just discouraged like all the newbies I've talked too ?? Hell I don't even KNOW what to ask half the time!!! Hey Newbies UNITE :D :D

[nater]

Don't be discouraged, I'm a newbie myself. I noticed damage to my tooling using grog after 5 or 6 motors were rammed on it. I couldn't tell you the difference between bentonite and hawthorn bond clay. I just bought 5 lbs of fine hawthorn bond clay, it is what I have and it works. I also have a small amount of fine bentonite that was part of a skylighter kit and it also works.

 

There's also no best way to make a nozzle. I've used kitty litter, hawthorn bond clay, plain bentonite, and the nozzle mix from the skylighter link you posted. All have worked just fine. I think the hawthorn bond clay rams into a harder nozzle than bentonite, but I have no proof besides casual observation. I have only had one nozzle blow out, and it was a motor that had sat for several months and I used inferior tubes in a pinch.

 

So, just ask away if you're confused, someone will help. Just remember there are many different approaches people have, and they could all be right. I have 2 sets of core-burner tooling, and it has been an ongoing process getting rockets to fly good. I haven't even attempted heavier payloads yet.

 

edit:

 

I'll point you to an expert and his opinion on clay: http://www.wichitabuggywhip.com/fireworks/rockets/clay.html

Edited April 7, 2012 by nater

[fred815]

Thanks again.. I know it's trial and error. But it's strange that I've been reloading my shot gun and rifle ammo forever and there is NO margin for error. Precise or die. Will try that hawthorne clay seems cheaper and have heard of it quite a few times!!

[warthog]

Well, I don't think reloading is THAT bad, I have been reloading for a long time now (probably longer than you have been alive ) and I know you can fudge a bit here and there without killing anyone. Heck that is how I develop new loads!

 

I know nothing about rockets though bnut I can say that replacing a spindle is cheaper than buying a new set. All of my rocket tooling, all pristine and unused except the super bottle rocket, have removable spindles on them.

 

As a soil scientist, I can tell you the differences between the clays usually has a lot to do with how well it adheres to itself when rammed into a nozzle and this I would think may be relatable to its cation exchange number. I don't think this is a study that has been done yet though so maybe this is my big chance to make pyro history.. LOL

Edited April 9, 2012 by warthog

[dagabu]

Thanks again.. I know it's trial and error. But it's strange that I've been reloading my shot gun and rifle ammo forever and there is NO margin for error. Precise or die.

 

Interesting, I have a reloading manual from 1982 in which there is a 42 grain difference on the table for the same weight bullet depending on the velocity of the bullet that you want... Seems to be a huge variance depending on the wanted outcome. I think this is true of pyro as well.

 

-dag

[WSM]

I suppose enough grog down the hatch and the nozzle is irrelevant !

 

Seriously though, using a good fireclay with added wax and maybe some graphite added, too; aught to work without grog, if you ram it in the case tight enough.

 

My 2 cents...

 

WSM