Pyro Tools

[tentacles]

Bashed out a quick comet pump for Bonny today, and then decided that aluminum tubing I have is exactly the same size. Comet pumps ensued...

 

The big ones make 1.36" comets and the smaller ones make .875". The orange UHMW looks like crap because it's reprocessed stuff and machines like crap.

 

http://www.apcforum.net/files/DCP_2536.JPG

 

Bonny: Yes, that other small one is yours.

 

Frank: I can make you one of the big ones if you're interested. I have more tubing and UHMW.

[Bonny]

Modified my ball mill yesterday and it will now turn a tire to use for rolling stars. It looks pretty ghetto, but as long as works, who cares! Hopefully I'll find some time soon to start rolling.

[tentacles]

If you want, I could come over and try to show you how it's done I'm no expert, but I have the benefit of having rolled stars before. I have a small bag of lead shot too, it's the easiest core to start with.

[Bonny]

If you want, I could come over and try to show you how it's done I'm no expert, but I have the benefit of having rolled stars before. I have a small bag of lead shot too, it's the easiest core to start with.

Sounds like a plan, plus I'm eagerly awaiting those comet pumps. I'll send you a message as I have another lathe job for ya.

[pyromaster7500]

im selling one of these from walter pyro:

 

 

1 lb BP Rocket Kit ¾" ID 7½" long $101.0

 

ill accept any reasonable offers if anyone wants to buy it just send me an email on pyromaster@hotmail.co.uk

 

im in kent, UK

[marks265]

One thing that I don't hear much of is dust control. I am sure that a lot of us work in less than desirable conditions including myself. I was going to convert an old furnace blower into a homemade dust collector. Then I got lazy and bought a room size air purifier and use it as a table top dust collector. It has a hepa filter and filters down to .3 micron. I put it to the test and screened 1KG of BP fresh from a my mill and ran some lump charcoal through a blender and poured it into a container. I then checked the filters and was pretty surprised. The first stage is a charcoal type filter that caught most of it. Then the final HEPA filter was clean on the back side of it and the fan assembly did not seem to get any of the dust so far. I bought this new for about $130 but considering many aspects I thought it was well worth it.

 

http://www.hunterfan.com/pages/product_det...24&pageID=4

 

It even has a ionizer which I left off. I didn't not know how well the unit would react to the dust.

[Brakkie]

I hope this is the right topic for this. I couldn't find a general ball mill topic so I guess I'm in the right place.

 

I'm having a few problems with my ball mill and right now I got a major issue. My belts (elastics) would rip after about 1 or 1,5 hour and after milling for some time it starts to get annoying to keep replacing the belts. My poully (what the belt goes around) was rubbing too hard on the elastic which made it look molten after rupture. My dad said he could fix this problem for me and him being somewhat of a handyman I trusted him and let him take care of the job. I told him to use the specific measurements that were on the mill as it was because otherwise it would change the speed of milling.

 

You guessed it, he did it wrong and now my ballmill is running at about 300 to 350 rpm... I don't know how he fucked it up this bad but the fact is he did... And ofcourse, my dad stupidly didn't save the old poully and I don't remember the measurements anymore...

 

The measurements of everything is:

Axle = 8mm

small poully = 17mm

big poully = 50mm

Jar radius = 50mm

 

speed of the motor is unknown. It's Miech's old ball mill so I don't know exactly what the speed of the engine is. I do know that right now it runs at around 300 to 350 rpm. It's running so fast that the media is being slung to the walls of my jar and you don't even hear the milling anymore.

 

Anyone got an advice on what would be smartest to do? My dad stupidly didn't save the old poully and I don't remember the measurements anymore.

[Richtee]

Anyone got an advice on what would be smartest to do? My dad stupidly didn't save the old poully and I don't remember the measurements anymore.

Well..you either need a bigger small <motor> pully, or a smaller big pully <jar drive>. Try a few mm change.

[mike_au]

The measurements of everything is:

Axle = 8mm

small poully = 17mm

big poully = 50mm

Jar radius = 50mm

 

speed of the motor is unknown.I do know that right now it runs at around 300 to 350 rpm. It's running so fast that the media is being slung to the walls of my jar and you don't even hear the milling anymore.

 

By axle, do you mean the roller that the jar sits on? Are the measurements (other than the jar) diameters?

If the answer to those two questions is yes, that puts your motor at between 11029 and 12867 RPM. I think some of your numbers might be a little bit out.

 

Assuming ~1/2" media, the critical speed (where the media starts sticking to the walls) of your mill will be around 140. How are you measuring the RPM of your jar?

[Miech]

This is the mill we're talking about:

 

It used to run at 90~100 rpm depending on load, I've been counting for a full minute to find that out.

The 'axle' is the driving shaft of the motor, seen the size of it. It transfered its energy to a 45 mm pulley, so that gives a 8:45 ratio. The 45 mm pully was driving a roller, which I forgot the size of, but it seems it was 17 mm. The barrels are 105 mm, so that gives a 17:105 ratio. Assuming the barrel made 100 revolutions per minute that would mean the motor run at 3000 rpm. Thats close to what I remembered it to be and what's likely for a 12 VDC motor.

 

Seen the fact it runs about 3 times faster than it did, either the driving shaft or the roller has become 3 times bigger. As I think it is unlikely the roller has became larger, I think there is a pulley attached to the driving shaft now. Removing it or decreasing its diameter would probably solve the problem.

[Brakkie]

Ok well I decreased the size of the small pully and it was running at 110 - 120 rpm, measured by making a 30 second video and counting frame by frame how many revolutions it would make. There's a small sticker on there to see on the video and it was running perfect.

 

It has been running for about 2 hours now and now it just decided to quit all together... It doesn't run... Nothing is jammed, no cables were disconnected... I tried stripping the wires again but it didn't make a diffirence... Motor died?

 

I'll have a look at it with my dad tonight cause he's a lot better at electronics then I am.

 

*Prays that the ballmill can be fixed*

 

 

Edit: Probably just a blown fuse. Will get a new one tomorow and hope to get it fixed!

 

Edit2: Dad still had a few fuses laying around so it's fixed, Milling C as we speak! =D

 

Thanks everyone for your help!

Edited December 3, 2008 by Artistic

[FrankRizzo]

Be careful. A blown fuse indicates that the motor was overloaded. An overloaded wire can lead to sparks or excessive heat, which does not mix well with explosive comps. Edited December 5, 2008 by FrankRizzo

[Brakkie]

I know, the thing is my motor is quit small and the fuses are even smaller. I could look it up but the fuses aren't bigger than 1cm long, 2 or 3mm thick. The motor does get warm after a while but it's seperated by a sheet of MDF. My mill can't run more than 100 grams of comp and I'm right next to my mill when it's running because the belt tends to snap every now and then.

 

It's gonna be time soon to make a new one that will also function as a starroller.

[Bonny]

I know, the thing is my motor is quit small and the fuses are even smaller. I could look it up but the fuses aren't bigger than 1cm long, 2 or 3mm thick. The motor does get warm after a while but it's seperated by a sheet of MDF. My mill can't run more than 100 grams of comp and I'm right next to my mill when it's running because the belt tends to snap every now and then.

 

It's gonna be time soon to make a new one that will also function as a starroller.

 

It's not the size of the fuse that means anything but the rating of the fuse (amps). Changing the fuse to a larger capacity than the motor is designed for is a bad idea. The fuse is there to protect the motor from overloading and/or overheating.

 

Also if you have to be right next to your mill when it is running, FIX THE MILL OR MAKE A NEW ONE. That is foolish and VERY unsafe.

[Brakkie]

The fuse that I've put back in was exactly the right one. My dad bought a packet when he fixed my ballmill last time. I don't remember the exact number of amps but it's the right one.

 

It's only the first time this has ever happened. Is this reason enough to really give the mill a double/triple-check and fix it so it NEVER CAN happen again? I mean fuses here around the house blow "regularly"... Change them, put a new fuse in and it's fixed.... Or do I say something really stupid here?

Edited December 5, 2008 by Artistic

[Bonny]

The fuse that I've put back in was exactly the right one. My dad bought a packet when he fixed my ballmill last time. I don't remember the exact number of amps but it's the right one.

 

It's only the first time this has ever happened. Is this reason enough to really give the mill a double/triple-check and fix it so it NEVER CAN happen again? I mean fuses here around the house blow "regularly"... Change them, put a new fuse in and it's fixed.... Or do I say something really stupid here?

 

 

Usually if fuses are blowing "regularly" then you are using more power than you should be on the circuit.

 

What you said in the earlier post that was cause for concern was "I'm right next to my mill when it's running" is the concern. You should not be near the mill when it's running UNLESS you are only milling a single chem.

[Brakkie]

Well the problem is I don't have many other places to put the ballmill. I've tried putting the mill in the shed but it's so moist there that everything cakes up. What I usually do is mill my charcoal untill it's absolutely airfloat and then add the rest. But I hardly ever mill anything more than TT, mealpowder (to be made into pulverone) or some other charcoal type mixes. All the rest I don't mill at all because almost all my chems are airfloat to begin with.

[DrPyro]

If your mill jar is airtight/dustproof, which it should be, moist air when and where you mill should not affect anything.

-unless you load an unload the jar in a moist place

I have my mill outdoors and have milled in all kinds of weather, rain, snow, high temps and low temps, never had problem with caking.

[mike_au]

I got some 13mm brass angle the other day and cut it down to use as milling media.

 

After cutting it up, a lot of the pieces have sharp edges/burrs. What is the general consensus on using these as is?

 

I tried running the media through the mill for about 45 minutes and they scratched up the container quite a bit. Since I only intend to use the media + jar for oxidizers (just KNO3 for now, maybe KClO3 later) I don't think that should be too much of a problem, right?

 

If they do need to be cleaned up, does anyone have a suggestion on how to do it that doesn't involve "sit down with a file for about 5 hours"

[tentacles]

I'm not sure you want to use brass to mill KClO3, there could be an incompatibility there, corrosion related perhaps, and besides that it's sort of a waste of good brass media..

 

When I chopped up SS for media, I touched up the ends on my lathe as they came off the saw. I spent basically a whole day cutting media and deburring it. I actually put a small radius on the edges. A grinder would be your friend here, either a bench grinder or an angle grinder held in some kind of fixture (vise).

[Bonny]

I got some 13mm brass angle the other day and cut it down to use as milling media.

 

After cutting it up, a lot of the pieces have sharp edges/burrs. What is the general consensus on using these as is?

 

I tried running the media through the mill for about 45 minutes and they scratched up the container quite a bit. Since I only intend to use the media + jar for oxidizers (just KNO3 for now, maybe KClO3 later) I don't think that should be too much of a problem, right?

 

If they do need to be cleaned up, does anyone have a suggestion on how to do it that doesn't involve "sit down with a file for about 5 hours"

 

 

If your mill jar can stand the abuse, you can try just milling the media alone for (A LOT) longer than 45 minutes, maybe a few days. Adding some steel bearing balls would probably help too. Otherwise, as Tentacles suggested it's off to the grinder you go...

[Puriss]

I got some 13mm brass angle the other day and cut it down to use as milling media.

 

After cutting it up, a lot of the pieces have sharp edges/burrs. What is the general consensus on using these as is?

 

I tried running the media through the mill for about 45 minutes and they scratched up the container quite a bit. Since I only intend to use the media + jar for oxidizers (just KNO3 for now, maybe KClO3 later) I don't think that should be too much of a problem, right?

 

If they do need to be cleaned up, does anyone have a suggestion on how to do it that doesn't involve "sit down with a file for about 5 hours"

 

 

Had the same problem a year ago when I cut up alot of brass for my mills. I mounted a die grinder in the vise with the sandpaper upwards and started sand (using a fine sandpaper) the pellets. You only have to get rid of the most sharp edges, the pellets will be very smoth and nice when you have used the mill a couple of times.

[jacob]

I thought of using a bench grinder to debur some SS media but I'm worried that it'll overheat the edge and ruin the corrosion resistance, what do you guys think?

[Miech]

Stainless steel doesn't corrode, as it is completely made out of the same material. If you mean chrome coated steel balls however, sanding and grinding will remove the chrome outer layer, and it will start corroding. Overheating stainless steel does not cause a reduced corrosion resistance.

 

What I just thought of, maybe it is way easier to just put the freshly cut pieces of brass rod in a tumbler and add some aluminia or calcium carbide to it. The let it run for some time, and they should get polished and smooth I think.

[tentacles]

Actually, overheating stainless will affect it's corrosion resistance.. it's one of the bigger problems when welding stainless steel for foodservice applications. The heat affected zone (near the weld) will have a stronger tendency to rust than the weld itself, or the unaffected areas of metal. It has to do (typically) with excess carbon being absorbed from the atmosphere and any soot/oil that might be present. The carbon complexes with the chromium or something along those lines, inhibiting the corrosion resistance.

 

You're unlikely to overheat the SS just by touching it up on a grinder. Don't get it red hot or anything, but that would be somewhat difficult to do if you're just deburring it. Freshly exposed SS does not have the protective chrome oxide layer, however, you can restore this with a passivating bath of citric acid (or others) or just by leaving it out for a few days, exposed to air. I haven't had any problems with my media and I've even etched it in HCl twice now. Just let it passivate again and you'll be fine.