Core burner or End burner?

[LambentPyro]

Copper, many copper alloys, and certain grades of stainless steel are all non-sparking or spark-resistant (which is the same thing). They produce cold sparks if any at all. The same can not necessarily be said of ceramics, which you seem to be fine with using.

 

Never said I'd use Ceramic, I said Alumina.

[Col]

alumina is a ceramic

[schroedinger]

Depends on what he meant.

 

The white Al2O3 stuff is a ceramic but alumina itself would be a metall

[Mumbles]

In english, the language in which I was writing, alumina is not a metal. I was mostly using ceramic as an all encompassing term for all types. Low alumina ceramics, which have the remainder largely made up of silicon dioxide I believe, has no use in anything remotely flammable or explosive. High alumina ceramics and zirconia ceramics in generally considered to be safe with combustible mixtures. That doesn't mean that they don't spark or have the potential to ignite materials, just that the frequency is low enough.

[MWJ]

As far as I thought, copper is non-sparking. I'll have to get some lead balls from Steve when I can. I do have my pine charcoal I made. How do I test it to see if its good enough for hot bp? For core burners anyway. I saw that Skylighter has hard wood charcoal and I read that soft wood charcoal is best for bp?

[Mumbles]

The only way to really test and see if a charcoal is hot enough for BP is to try it. As a general trend, the best charcoals seem to be lightweight, sometimes to a fault. Some of the very best can be so fluffy that they're hard to work with. Pines in general seem to be fairly good. Honestly, if you cook it yourself and choose relatively lightweight wood, you should be able to make decent BP.

 

For core burners you don't necessarily want the hottest black powder. Well, if you intend to use a clay nozzle you don't want the hottest black powder as they will explode. For nozzless, then you do want the hottest black powder you can muster.

 

Charcoal is a subject with a lot of confusing information and some debate. Hardwood charcoal is typically better than softwood charcoal. This classification is based on how the tree reproduces. The only difference is that hardwoods produce covered seeds, and softwoods produce bare seed, like pine cones.

 

Hard woods however are nearly always worse than soft woods. Note the space, as it makes all the difference. This is based on physical properties of the wood itself. So basically physically soft hardwood reproducing trees are the best. These include all the common "holy grail" type charcoals; willow, paulownia, plum, alder, maples, and even balsa. Several soft woods, like some of the less sappy pines and cedars are also very good.

 

The stuff that skylighter sell is a mixed hardwood blend. It's probably a mix of maple, oak, and other common consumer woods. It honestly is kind of medicre. It's wonderfully convenient for stars, but as far as rockets with good thrust or BP that burns quickly, you'll probably want to look elsewhere.

[MWJ]

I ball milled my BP and WOW! what a difference! It's a lot faster now. I'll post a video when I soon to show you all. I did talk to Steve about his balls and the price is very good. I'll get a few from him when I can. My .30 cal. bullets seem to work for now.

[ddewees]

I did talk to Steve about his balls and the price is very good.

[ianagos]

Man .30 cal bullets are expensive man go for the lead although I'm probably late here I just saw 2014. Anyways I'm in the same boat as you on the picking which type of rocket.

[Mumbles]

If you're going to go as small as .30 caliber, I'd suggest looking into 00 or 000 buckshot. Buckshot is hardened, and tends to be a cheaper than round ball bullets.