First black powder batch

[ballmill]

I finally finished my ball mill and made my first batch of BP. Problem I'm having is that it's clumping up badly right near the opening of the mill jar. I'm using a 6" PVC jar with a reducer and rubber cap for the opening. It's clumping bad near the opening and I have to frequently go in and knock it down. I added 5% dextrin to this because I plan to use it for blackmatch and then meal prime for stars later. Could the dextrin be causing this excessive buildup? The KNO3, C, and S are all pretty dry to begin with so I don't think that's an issue. It was raining out today and about 50 degrees so I'd guess there is a fair amount of humidity in the air but I didn't expect such a huge clumping problem.

 

I milled for about 3 hours today and did a burn test. It seems to burn fairly slow but I am using hardwood airfloat and it's straight meal and not granulated.

 

Any tips, suggestions appreciated.

Edited March 6, 2011 by ballmill

[dagabu]

Yes, the BP will clump badly when wet. It only takes a few percentages for it to happen and is exacerbated by heat. I usually mill all my BP for the year in the winter and dry my KNO3 before using it in the ballmill.

[daron]

if ya put in airtight containers how long will milled bp last for

[dagabu]

if ya put in airtight containers how long will milled bp last for

 

Hundreds of years, really. On the discovery channel, they found a stash of BP hurried in a cave in northern Africa that had been used for a magazine in the 1500's. A sample was compared to modern commercial powder and was found to be very similar in performance and grain size. I will look for a link, it was on air maybe six years ago?

[ballmill]

That's real cool.. guess some things never change!

 

I'm gonna mill this BP again for a few more hours today. We got a bunch of snow and it's much colder so it should be a bit more dry than yesterday. I'll post a video of the burn test later.

Edited March 6, 2011 by ballmill

[Arthur]

Most hardwoods will make inferior powder, willow and maple produce good fast powder and (although it's technically a hardwood) balsa produces fine powder. However there is a whole thread on BP and the charcoals.

 

Clumping is always due to moisture. The only remedy is to seriously dry the mix and re-mill it.

 

Once you get the ingredients dry then set the mill rolling and remove a sample hourly, do a standard burn rate test on each sample and see what the effect of milling time is on the burn rate. When the next hour of milling achieves no increase in burn rate -that's your optimum mill time for your mill and media.

[SB15]

Milling with dextrin added definitely doesn't help the clumping issue. The presence of any moisture in the chemicals will turn it into a sticky glue and cause the material to clump. Dry your precursors and try milling without a binder.

[dagabu]

Hardwoods make inferior powder? You may be interested that Swiss and Goex use hardwood charcoals to make their BP. Also, as I stated, both heat and humidity will create clumping, one magnifies the other.

[Peret]

All angiosperm trees (broad leaf, flowering) are hardwoods. This includes willow, alder and balsa(!). Conifers are softwoods. The distinction is not whether the wood is hard or soft, but in the microscopic structure of the fibers. What wood makes a good black powder charcoal seems not to be very well understood but probably lies in a different difference in the fibers, since pine charcoal is well thought of. The denser hardwoods generally suck.

[dagabu]

In reply to "The denser hardwoods generally suck. " statement, it is just not true. Oak pretty much sucks as far as BP goes but even Iron wood burns at a rate of .43 seconds in Danny's test Vs. commercial 2Fg BP with a time of .51 seconds. Even Hickory has burn time very similar to commercial BP at .461 seconds.

 

 

Take a look here for more information. http://www.wichitabu...coal_tests.html

Edited March 7, 2011 by dagabu