14 replies to this topic

[mango]

I saw a grinder in a store today,made from steel,i bought it home,then used it grinder the BaNo3,30 seconds then it is fine powder.
Dont know if people here also need such a grinder also,want to get your opinion.Thanks!

[Bonny]

I saw a grinder in a store today,made from steel,i bought it home,then used it grinder the BaNo3,30 seconds then it is fine powder.
Dont know if people here also need such a grinder also,want to get your opinion.Thanks!

Not really sure what kind of grinder you are talking about...maybe some more info??

[wjames]

coffee grinder i presume ???

not angle grinder !!!!!

[Shake]

I have always had concerns with coffee grinders.
Before I had a ball mill I used 3 coffee grinders to mill powders. One was for oxidizers only and one for fuels only, the third for black powder.
My concern arose when I had to dismantle my BP only coffee grinder due to operational issues and, to my surprize, the motor and coil inside was coated with wonderfully fine BP; that immediately screamed.."Explosion Hazard!!!"
I quickly stopped using coffee grinders and made a ball mill.
I feel much safer!

[cooperman435]

YOU PUT MIXED BP IN A COFFEE GRINDER! and this didn't immediately scream EXPLOSION HAZARD to you!!!!!!!

Ill assume it wasn't a "don't ever do this" demo then.......

Edited by cooperman435, 28 August 2008 - 08:34 PM.

[Arthur Brown]

Ingredients are usually OK to coffee mill, products definitely NOT. Some products can be ball milled with careful choice of jar and media.

Flash components need to be milled finely, flash powder in NOT to be milled. ( diaper mix it on a sheet of paper or rubber)>

[mango]

It is like a blender but with streel jar and for grind harder materials like medicine ect.
I only use it to make ingredients to fine powder , works very good for that , i tried with KNO3 and BaNO3.

[wjames]

steel jar???? steel blade i presume ????

[mango]

ALso steel blade.I have a picture for it, but i can not find out how to attach a picture here .

[wjames]

well, i bought a delongi coffee grinder today. holds abour 100g of sugar ( just for testing)..granulated


30 seconds of grinding and its finer than commercial grade icing sugar....


seems easy !!!!

[Arthur Brown]

While the idea of a coffee grinder appeals, the idea of a random mix of fine powders leaking into the motor does NOT.

It would be really nice to have a grinder that had a seal between the motor and the mill chamber. Til then I have to say I prefer the idea of a hammer for pre-milling and a ball mill for fine work.

[wjames]

yeah, i see yor point.....

im my opinion, and its just that...so long you don't try grinding any sensitive chems...or any combination....then i think its all good......from what i understand, and i'll dismantle it to clarify.....the delongi version i got has a sealed motor...by that i mean the motor is housed in a plastic casing, and the shaft that connects the blade is sealed into the grinding chamber.......

there isn't all that much powder produced really....as long as you keep the level of powder well above the blade......the powder on the top stops the dust from becoming "air-born"

the only thing i would state, is, that there is a fair amount of heat generated....mainly through friction i presume.......the blade spins at at least 20,000rpm.....30 seconds produces a very fine powder, and it gets "luke" warm....

my only other concern, is the end-float between the blade and the base of the container...its about 2mm...if it had been 10 - i wouldnt worry.....but powder that gets trapped under there is subject to the most friction..

I'd say, and im open to advice from those with more experience/knowledge....that grinding up Kn03 on its own, in a grinder...is pretty safe...no more risky than grinding it in a M+P.....

[mike_au]

KNO3 is just an oxidizer, without a fuel it won't do a great deal no matter what you do to it. I guess under extreme conditions it might start to oxidize it's container, but I doubt a blender would do it. The biggest risk probably comes from using the same grinder for oxidizers and fuels, the simple solution to that is "don't".

(I'm probably being a little pedantic, but it is KNO₃. The "O" is a letter not a number and the N is capitalised. Most people don't bother with the subscript, but the capitalisation is necessary to understand what something is.)

[Arthur Brown]

The point is that if the mill retains some dust, especially in the motor area, then a sequence of powders going through means a mixture of powders retained. This could mean mixtures you wouldn't wish to make, add a spark from the motor and.....

I have a preference for the upright jug blender where you can remove the used jug and clean it thoroughly before reuse.

[wjames]

agreed