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Posted

I would be cautious about running a fan over your stars, fan motors have been known to short and spark- Please be careful.

 

As for overwetting, it happens- next time put the whole bowl onto the scale, and keep close track of the amount you add. You also seem to be working in extremely small batches, that makes it easier to goof on the moisture. You could also keep a portion of dry comp aside, that way you have at least one do-over if you get things too wet (it happens)

 

Good luck

Posted (edited)

I would be cautious about running a fan over your stars, fan motors have been known to short and spark- Please be careful.

 

As for overwetting, it happens- next time put the whole bowl onto the scale, and keep close track of the amount you add. You also seem to be working in extremely small batches, that makes it easier to goof on the moisture. You could also keep a portion of dry comp aside, that way you have at least one do-over if you get things too wet (it happens)

 

Good luck

 

It's ok, I'm not THAT dumb :whistle: it's a pedistal fan about 1 meter or so away blowing air from the side, not above.

Don't get me wrong - I'm happy for anyone to always point out potential hazzards.

 

Yeah, small batches does make it difficult when wetting - I was very suprised how quickly it turned.

It's all part of the learning process.

 

Thanks guys,

Cheers.

Edited by stix
Posted

Thought I should report back with my intermediate results.

 

It's all looking very promising. After about 4 days drying (1/4 inch stars) I've done a few tests and big golden crackling spritzels :D

 

However, I do have some concerns.

 

After a couple of days the stars were still easy to break but worked. After a day more they became much harder to break, now after another day they have become soft again :angry: wtf? - I somehow imagined they would just keep getting dryer and harder?

 

I wasn't aware of any hygroscopic issues, but it seems to be the case?. Should I now dry them with heat and/or store them in a container with desiccant?

 

btw. They still work well, but I'd prefer them not be crumbly or degrade in performance.

 

Cheers.

Posted (edited)

stix, potassium nitrate and charcoal based stars may take at least 1 week to fully dry if they are sitting out in the open, perhaps up to 2 depending on the humidity levels. I would suggest letting them sit for 3 more days. I usually let my stars sit in a dry place on an elevated screen away from direct sun for 2 weeks. After the 2 weeks I place them in an airtight container with desiccant.

 

If the stars are not hard after a week perhaps they didn't get thoroughly mixed before wetting. Thorough mixing (sifting) helps ensure the dextrin (along with the rest of the ingredients) gets spread out. Don't get discouraged, you will do fine. :)

Edited by Eric70
Posted

You could also make stars when the conditions are usually right... like spring and summer. making stars in fall or winter when everything is wet and cold... not very handy. I must agree, storing them in a container with desicant is a good one. For storage. Then again, i understand ''when you're in to it'' you want to make some...

Posted (edited)

stix, potassium nitrate and charcoal based stars may take at least 1 week to fully dry if they are sitting out in the open, perhaps up to 2 depending on the humidity levels. I would suggest letting them sit for 3 more days. I usually let my stars sit in a dry place on an elevated screen away from direct sun for 2 weeks. After the 2 weeks I place them in an airtight container with desiccant.

 

If the stars are not hard after a week perhaps they didn't get thoroughly mixed before wetting. Thorough mixing (sifting) helps ensure the dextrin (along with the rest of the ingredients) gets spread out. Don't get discouraged, you will do fine. :)

 

Thanks Eric70. I believe it was mixed well. If anything I thought I over-wetted the comp. I let it sit for around 1hr for the dextrin to activate properly, screened it quite a few times and mixed it by hand.

 

I think I now know why I had the drying issue - This past week has been very hot/cold humid where I live, and to make things worse I had them on a screen about 6 inches off the floor!! probably the worst spot for drying :wacko: I should have known better. I've since elevated them and now they seem a lot harder and when broken in half, have a nice snap.

 

I'll leave them for a few more days then store them in an airtight container with desiccant.

 

You could also make stars when the conditions are usually right... like spring and summer. making stars in fall or winter when everything is wet and cold... not very handy. I must agree, storing them in a container with desicant is a good one. For storage. Then again, i understand ''when you're in to it'' you want to make some...

 

Yeah Spitfire, I have to admit that perhaps I did jump into this prematurely. Although I was careful regarding the safety aspects, I didn't really give much thought to drying them - got a bit too excited :D.

 

Anyway, all looks good now. At some point I'll post a thread regarding using them for a 3/4 inch star mine.

 

Cheers.

Edited by stix
  • 2 weeks later...
Posted

Did some star mine tests:

http://www.amateurpyro.com/forums/topic/10445-attempting-my-first-star-mine-questions/page-2?do=findComment&comment=139408

 

I preferred test 2, and I reckon they could burn longer by adding more NaHCO3 - also fiddling with different charcoals will also be interesting. Next time I will take more care to "cut" them better, but overall I'm pretty pleased with the result.

 

Thanks to spitfire for the original post, and I'm pretty much hooked on glitters. I'll enjoy refining this, and then perhaps try it in a 2 1/2" inch shell :)

 

Cheers.

  • 10 months later...
Posted

Can you replace dextrin with red gum, and get rid of the water?

Posted

You can try. Glitters involve some relatively complex chemistry, and tend to be more sensitive to changes. If you want to go non-aqueous I've heard that PVB or phenolic can be made to work. I would expect at least some change in effect however.

  • Like 1
Posted

Doesn't the kno3 need to be dissolved for these to work? I've made them with varying percentages of water with alcohol and found that plain water produced the best most dense glitter flashes. Winokur 19 and 23 anyway.

If using red gum can you use dilute alcohol like 10% alcohol to water and have the red gum activate if let sit for awile in covered container?

  • 1 month later...
Posted

Doesn't the kno3 need to be dissolved for these to work? I've made them with varying percentages of water with alcohol and found that plain water produced the best most dense glitter flashes. Winokur 19 and 23 anyway.

If using red gum can you use dilute alcohol like 10% alcohol to water and have the red gum activate if let sit for awile in covered container?

That might be worth a try!

Posted (edited)

I'd encourage you to try my "Buttered Popcorn" glitter, also. It's different.

 

It was inspired by the Winokur formula, but re-formulated for big, very gold spritzels.

 

(The formula is 'around'; no need to re-post here.)

 

LLoyd

Edited by lloyd
  • Like 2
Posted

Buttered popcorn even has it's own dedicated thread. http://www.amateurpyro.com/forums/topic/7018-buttered-popcorn-glitter/

 

You need a fairly high alcohol content to activate red gum. 10% is certainly too low. I suspect you'll need to be north of 50% to get much of an effect. I believe 70% isopropanol can work, though I prefer the 91% stuff. You can probably get an idea for yourself by mixing in a scoop of red gum into various alcohol solutions. Red gum is....well reddish. The color of the solution can be used as a crude proxy for how much it's activating. Not all red gum is created equally, so you may still notice some insoluble sand, dirt, etc. even if using straight alcohol.

 

I firmly believe the nitrate dissolving is primarily responsible for the different appearances of pumped, rolled, and cut glitter stars even when made from the same formula. There are a lot of factors at play between density, particle sizes, and potential chemical reactions.

  • 4 months later...
Posted

you are using magnalium 200 mesh?? can you also roll these stars??

Posted

You can roll almost all glitters, at least I haven't had any problems with them. The crucial thing with glitters is how fast they are dried. One day in the shade and then to the sun or drying chamber.

Posted

If you are rolling glitter I would recommend a non-water based binder. Phenolic works well.

Posted

do you just prime with bp?

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