Star rolling

[Sparx88]

Do you find that cut stars take realllly long to dry? 3/8" or less they dry rock hard, but when I get to the 1/2" sizes, they seem to form a skin and take up to 2 weeks for the middles to dry and they are softer. I do have a star roller that I made but have only rolled stars to about 3/8". Do rolled stars at 1/2" or better dry faster and harder? I'm making some inserts/comets using 1" od 13/16 id spiral tubes filled halfway with wetted comp and rammed. It's been almost a week and they feel like they are still soft in the middle. At that rate it's gonna take a couple weeks. Is that normal? I'm using 10% dextrin and 50/50 water alcohol. Some stars over a half inch had a hard shell but were soft still smelled of alcohol in the middle after 10 days.

[pyrokid]

Larger stars take longer to dry. You summed it up rather well when you described the skin that forms on larger stars.

 

I've cut some 1/2" or larger charcoal stars and those took quite a while to dry.

 

When large stars are rolled, they are rolled in stages, and allowed to dry in between rolling sessions. Rolling 3/4" stars in a single session is asking for trouble, for example.

 

Any reason for 10% dextrin? I've never used any more than the 5% commonly called for, and I've never had any issues.

 

I think you have to be very careful when adding wet comp to tubes. Obviously, the tube will impede drying and you'll have to wait significantly longer. When aerolites and such are made, they usually use wetted comp, but it's on the very dry side of wet, still crumbly, even dusty perhaps.

[Shizznt]

10% dextrin is way too much. 5% will do you just fine.

I have never made cut stars, but a 1/2" star pump will work. They dry pretty fast for me.

The biggest rolled stars I made were a bit bigger than 3/8" but smaller than 1/2" and they dried pretty fast as well.

I think that tube might slow down the dry time in the middle, but I have never made 1" comets before.

[TYRONEEZEKIEL]

The technique of star rolling generally won't allow more than 1/4-3/8" of comp per day. Otherwise your stars will have drying problems, (long dry times, cracking, driven in etc)

[Shadowcat1969]

Tyron is correct, at least in my experience, rolling should be limited to no more than about 3/8" a day. Preferably more like 1/4" and at least a day between for drying, depending on the environment where you live. Higher humidity is going to take longer to dry, of course. You are going to have the longer drying times no matter what process you use though, cut, pumped or rolled, especially with an aqueous binder. And wetted comp pressed or rammed into a tube is going to increase your drying time, probably substantially.

 

Patience is your friend.

 

Do lower your dextrin content, again depending on what composition you're using, you should be able to find a formula for what you're making, and I can't think of much with that high a dextrin content.

 

I'd also suggest moving your alcohol/water solution to more like 25% alcohol 75% water (this is what I use and it works well), or even a 20/80 mix, as with the higher alcohol content it may not activate your dextrin (or SGRS) as well.

[LambentPyro]

Never use that much Dextrin, you've caused the stars to be driven in. Also, get yourself a food dehydrator (enclosed heating element for obvious reasons) and after a day of air drying, throw them in there.

 

In Bleser's round stars and shells book, he desrcibes to stay under 7% Dextrin in comps. Also, "Stars containing red gum in percentages higher than 10% and bound with 95% alcohol will become driven in for the same reason" (Bleser). He also says to not dry a layer thicker than 1/4", but 3/8" layers should be fine.

 

Edit: I highly suggest you PURCHASE the book from PyroDirect for $20, I am having a great time reading it and have learned lots going through it.

 

Good luck.

Edited January 27, 2014 by LambentPyro

[Mumbles]

Bigger stars do take more time to dry. A few weeks of drying time is not unheard of for larger cut stars, especially compositions high in charcoal. Are you by any chance trying to force dry these stars? Getting impatient and trying to hurry up the drying process often makes it take longer. You can usually get away with sloppy shortcuts like that with smaller stars, but once you get too big you pay the price.

[Sparx88]

No not at first. I only put them in front of a fan after 2 days and left them checking in each day and was having real slow results. From what I have read here it does sound like I'm getting the comp too wet because when I go to knead the dough I can squeeze a small amount of moisture out between the glove fingers. And trying to make too big of star at one time as well. Put those 2 together and that seems like bad muggee. I was hoping it was something like those because those are easy to fix. And the too much dextrin problem stemmed from the thought that they needed more binder to "dry" faster.

 

Ok, so less dextrin 5%, less alcohol rich mixture 60/40, and no more than 1/4-3/8" per session. Ok, I did'nt know you can do a single batch of stars in more than one session unless they are to be multi colored etc. Thats good to know lol. I can't count the times I had this similar problem before finding this place, and just chocked it up to be par for the course. Well, progress is what keeps us in it and a little progress goes a long way. TY

[LambentPyro]

You don't want to waste too much KNO3!

[Sparx88]

You don't want to waste too much KNO3!

 

 

As soon as I can get it , I can breath easier and go hog wild!

[LambentPyro]

As soon as I can get it , I can breath easier and go hog wild!

Haha, enjoy my friend!