Wiley Posted March 5, 2014 Posted March 5, 2014 Since I don't currently have dextrin or any of the other "traditional" binders, I thought I'd try binding pulverone with NC laquer. +5% shotshell powder by weight dissolved in acetone made a very thick, crumbly dough and after pushing it through a 15 mesh screen, made very crumbly grains. I next tried +10% smokeless by weight (50g pulverone +5g smokeless dissolved in acetone). This made a much more workable dough ball, but after drying the resulting granules, I can still easily crush them between my fingers. The intent here is only to make a flammable filler for cylinder shells, but I think the grains need to be more durable than this. Any thoughts on why the NC is such a weak binder in this case? I'll have to get some real dextrin soon, along with some commercial airfloat. I had thought that one could easily make airfloat charcoal in a coffee mill, but it turns out that is not the case.
ddewees Posted March 5, 2014 Posted March 5, 2014 You can make your own dextrin by cooking corn starch in the oven. Do a search here to find the proper instructions... it's very easy to do, and works well enough.
Wiley Posted March 5, 2014 Author Posted March 5, 2014 ddewees, I've read Dan Creagan's instructions for that procedure. Thing is, quite a few people say it gives terrible results, and all say that it smells weird when your're cooking it. That last one alone would kill the deal right there: I'm not the only one in this house .
Niladmirari Posted March 5, 2014 Posted March 5, 2014 How about glue for wallpaper? http://en.wikipedia.org/wiki/Carboxymethyl_cellulose
ddewees Posted March 5, 2014 Posted March 5, 2014 It doesn't smell that bad... and it gives ok results.
nater Posted March 5, 2014 Posted March 5, 2014 The smell is subjective, it made my eyes burn, but my wife could not stand it and said no more of that. Dextrin is cheap enough to buy it and keep the peace.
ddewees Posted March 5, 2014 Posted March 5, 2014 Lol, I wonder if the corn starch makes a difference? I could barely smell it... of course, I made it while everyone was gone.
Wiley Posted March 5, 2014 Author Posted March 5, 2014 I may just do that . What about the charcoal though? Should I be able to get airfloat out of a coffee mill? As it is, I'm getting mostly fine powder, but a very noticeable amount of some far larger particles in there as well that won't pass through a 20ish mesh screen.
Wiley Posted March 5, 2014 Author Posted March 5, 2014 I'm only just covering the blade with some rather finely smashed charcoal. It's a lot less weight than with kno3, and my other grinder does a nice job of reducing that to powder.
ddewees Posted March 5, 2014 Posted March 5, 2014 Try adding something with it... such as kno3. Just be careful.
Wiley Posted March 6, 2014 Author Posted March 6, 2014 How about the ratio of charcoal and sulfur that you need for BP? That'd be 40% sulfur and 60% charcoal by weight. You could then screen together 75% KNO3 and 25% of this charcoal/sulfur mix to make greenmix.
Wiley Posted March 6, 2014 Author Posted March 6, 2014 (edited) Well, the grains may be crumbly, but the powder isn't too bad, power-wise. I made a 1" diameter by 1" long "shell" just as I would a star shell, but minus the stars (kraft casing, 1/16" end disks, two turns of posterboard in the casing). I packed the casing full and tight with my pulverone, just like I would with a real shell, and spiked it with doubled up 3# crochet thread. Once spiked, it was pretty firm. Could have been a bit tighter, but it was good enough for a test. No pasting. Went off with a surprisingly loud, echoing bang and big, bright splash of charcoal sparks at least 10 feet in diameter. The casing and its spiking was all turned into tiny shreds. Quite impressive, considering the coarse charcoal, screen processing, and crumbly grains. This pulverone is obviously a bit better than just filler, and seeing how that little test shell broke, I'll be making a real shell with it for burst+filler very soon. Edited March 6, 2014 by Wiley
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