29 replies to this topic

[pyrotechnist]

Them Vibro mills seem ok but I prefere my set up which uses an enclosed milling jar and a cheaper machine lol. I may try a test batch of BP soon, if I don't come back online you know what has happened fingers crossed it works. I know it will, I am sure

[Arthur Brown]

Be safe! The benefit of tried and tested methods and machines is that someone else tried for the darwin award. This time it's you..... Distance is your friend consider doing the first 100 batches at 100m behind sandbags. Remember that your home insurance doesn't cover this hobby!

[pyrotechnist]

Will normal pens coins suffice still for this or should I use lead media? the first batch will be dampened and placed on a low setting, most likely 1 or 2, for 20 minutes fully secured and away from causing danger.

[wjames]

i agree with arthur....distance is your best mate....without doubt....I remember testing my first batch of flash, from a good 100M away !!!! it wasnt even that much...."better safe than sorry" was always my motto !!!!


Seriously though.....read up as much as you can prior to testing anything like this.........And even after that.....test small amounts to begin with.


I'd hate to hear of an accident arising from this !

[crystal palace fireworks]

Yeah, be very very careful Pyrotechnist,................as said by the others, at least do the following;- take the machine outside when the weathers good (there is no way your should attempt this inside your home), seperate yourself from the experiement by placing a few sandbags around the base of the machine/jar, and wear some PPE.

Weigh the contents of the powder, media, container, and note container size, tape up the lid of the jar as well (duct tape), also measure length of test, but don`t return to examin the jar until for 10 minutes or so after it stops vibrating.

Its a shame we do not have access to some professional lab equipment (I would like to see an infra red camera in action to detect any possible heat from the vibration).

good luck and be safe!

[pyrotechnist]

Thank you all I will be careful. I am going to do a few tests with just the media leaving it run for an hour to see how hot it gets or if any weird things start to happen and report back here. If all else fails I guess it gives individual chemicals fine enougth for a motor and pestle to handle and make into reasonable BP if wet. Its cool cause I have never handled chemicals so fine before you basically cannot feel them at all.

Before trying this I used to use a motor and pestle to make all my black powder spending at least 3 days on making it, 1 hour preparation with 1 and a half days of grinding and then corning. It is hard work but kinda makes me feel like I have added more time and effort in its making. But now this will make grinding individual chemicals so much easier and hopefully I will be able to make small batches of BP.

[Arthur Brown]

Ingredients may be OK but I still wouldn't try mixtures! EVERY mixture is impact sensitive and rolling milling seems better than impact milling.

Also consider getting an ASDA blender. Their "jug over motor" blender was less than £10 recently, The spinning blades reduce most things to dust, in fact to an interesting mixture of particle sizes. Sometimes airfloat isn't what you want.

[pyrotechnist]

Will try one of them when I next go to ASDA. If I do try a mixture it will be with all safety precautions and the mix will be dampened enougth to stop heat or sparks and the container will be fully earthed and secured in place with padding to stop shrapnel or side ways explosion. It is a good thing that this exercise machine has 16 speed variables and a timer to help out.

[Arthur Brown]

Just think that a 3in shell contains about 20g of burst and flings stars for about a 20metre burst diameter, so 20g of powder will fling those mill media if it sparks.

[Mortartube]

Well, this afternoon I have been experimenting with the inverted orbital sander idea to mill powders.

I fixed a 500g margarine tub on the vibrating plate with a strip of gaffa tape held in place by the clamps that would usually hold the sandpaper.

I put in some fairly coarse KNO3 powder and some ceramic baking beads used in cooking. (A bit bigger than a large pea). I put about 1/3 of media in the tub and KNO3 up to the level of the top of the media.

5 minutes produced a mixed grade powder where about half was fairly fine but not airfloat. I swapped the media for 20 x 2p pieces and another 5 mins reduced almost all of the powder to quite fine. Fine enough to pass a very fine tea strainer.

I think this method will produce a fairly high percentage of fine powder although more experimentation is needed. If you feel the powder, you can feel very small grains, so it is not as fine as talc but I think it will produce a higher percentage of fine powder per batch than a coffee grinder, but will take a bit longer than a coffee grinder.

It is not far from talc though so a very short time in a ball mill would complete the job I reckon.

More experiments required. If anyone wants a go be my guest. I held the sander and have that funny hand feeling, so some sort of clamping system is a must for prolonged use.

This was only an experiment and 2p pieces are steel so do NOT use them for actual chemicals you will use in a mix. This was to test the principle only.

Edited by Mortartube, 18 November 2008 - 04:10 PM.

[wjames]

One thing to note.....Surely, as you held the sander in your hand, then a fair amount of the vibrations would pass from the sander to your arm....All forces = and opposite and all that..........

I think your right as to the clamping thing.

[pyrotechnist]

It seems that the exercise machine I use produces more fine particles in a short period of time due to the very nature of its circular movement of the vibrations and sheer power. If I add large rock salt with mixed coins e.g. 1p's, 2p's, 20p's ,1 pound coins I get a lot of fine powder with coarse particles still contained but if ground for another 5 mins the powder is virtually as light as icing sugar.

I Find weighing the container down from the top helps as it makes the vibrations much more violent. Without extra added weight the vibrations are to weak taking longer to get a good even particle size. The rock salt method I listed above was done by securing the container to the vibration plate but when weighed I got a much finer powder within 5 minutes than what I did before hand. Coarse KNO3 is also ground to talk within 5 minutes with no feel of uneven particle sizes passing a fine tea strainer with ease.

My next tests will involve lead media being used with 5 g of dampened black powder on a speed setting of 1 for 15 minutes. The black powder will simply be misted with the amount of water normally used to produce pumped glitter stars.

P.S Mortartube try adding weight to your container and make sure your device is on a surface that wont soak up the vibrations removing it from your milling jar and contents.

Edited by pyrotechnist, 19 November 2008 - 12:25 AM.

[Mortartube]

Thanks Pyrotechnist. I will try weighing the container down. Yesterdays experiment was very much a case of "I've got a spare half hour or so, let's go and see if it might work". I will knock together a wooden stand soon and work on fixing the container on in a better fashion.

I think the vibrartory process has some merit and will be useful.

[pyrotrev]

Since the motion of these vibratory devices is all in one plane, using cylpeb shaped milling media ought to be more efficient maybe? When I worked in a lab we had such a device, the pot was filled with layers of 7 cylpebs with just enough space between to make sure they didn't get jumbled up as it were. It was very efficient at grinding up rock samples.

[Arthur Brown]

Have to say I like the idea. A vibro mill fed with compressed air from a fish tank pump and some rough bits of charcoal and an outlet carrying literally airfloat out to a settling jar. all in soft rubber pipes.