34 replies to this topic

[alany]

That comet composition is a silver glitter, the high sulfur content is a dead giveaway. The Antimony Trisulfide content is quite low however. I'd imagine the delay is quite short, perhaps making it perform more like a pearl or flitter comet, but I think there will be bright flashes rather than a transformation-like effect.

The use of Boric Acid with Magnalium glitters is controversial, many suggest it harms the effect or causes nasty reactions with the MgAl, a few others say it is absoutely required. Batch size is probably a big factor, as it is for Aluminium-only compositions.

The use of such a high percentage of Alcohol in the dampening solution may cause crumbling problems, 1/4 water is scaresly enough to get Dextrin working.

[italteen3]

That comet composition is a silver glitter, the high sulfur content is a dead giveaway. The Antimony Trisulfide content is quite low however. I'd imagine the delay is quite short, perhaps making it perform more like a pearl or flitter comet, but I think there will be bright flashes rather than a transformation-like effect.

The use of Boric Acid with Magnalium glitters is controversial, many suggest it harms the effect or causes nasty reactions with the MgAl, a few others say it is absoutely required. Batch size is probably a big factor, as it is for Aluminium-only compositions.

The use of such a high percentage of Alcohol in the dampening solution may cause crumbling problems, 1/4 water is scaresly enough to get Dextrin working.

I will do tests with smaller batches. I probably wont be working with more than 500 gram batches, after a few 50/100g batches. I will try to see what I can dig up on the Boric Acid/MgAl combo. If I could get away without using Boric Acid and be forced to work with smaller batches I dont mind as long as it is safe and there is no heating up. Otherwise if the comet/star is still a dense silver Im happy even if it does not glitter.

Yeah sorry about the mixup it should be 75% water/25% alcohol .

Karl that looks like it will perform nicely! I am looking forward to any video! I should have high quality video up of my first cake I posted within a few weeks once I get my editing program in.

[karlfoxman]

Well it worked, the video didnt pick it up very well. With the software i will combine all the frames and make an image. I will see what i can do guys. I will post the video and if you can see anything then cool, even better if you can bring out the stars with software then let me know. Thanks. Very impressive stars though!!! PLEASED!!!

Long exposure pic (such a shame some of the most beautiful stars cant be picked up!!!!!!!)

Edited by karlfoxman, 19 September 2005 - 09:55 PM.

[italteen3]

Ok just got my editing software in today and had to install it, learn the extreme basics, etc. in about 15 minutes. So forgive me if the file is large at 14Mb for a 13 second clip. I have no host at the moment so if someone would not mind hosting it for me I can email it to you and I would appreciate you hosting it for me so everyone else can see.

From the video you can see me at about 25-30 feet away from the cake when the first shot lifts to about 45-55 feet. At the time I thought the 8 inches of extra vis-quick would have let me get farther but I was wrong. My brother filmed and was 100+ feet away but sorry for his zoomed in shaky filming. Also there is a curse word my friend yells in so I apologize for that. Went without a hitch besides it going off 2 seconds early and the one dropped shell. All safety precautions were taken so no injury/damage occurred. Though next time regular visco will be used for the first shot of all my cakes, or a REALLY long piece of visquick.

Hope you like it!

[LadyKate]

I have no host at the moment so if someone would not mind hosting it for me I can email it to you and I would appreciate you hosting it for me so everyone else can see.

I sent you a PM with my email but it didn't show up in my folder - if you don't get it, let me know.

[italteen3]

Finally got my video hosted..... Had to create the site I just remembered I get for free from when I bought my Mac........
Click me

Edited by italteen3, 22 September 2005 - 07:51 PM.

[LadyKate]

Finally got my video hosted..... Had to create the site I just remembered I get for free from when I bought my Mac........
Click me

That was a good cake. Is this the cake that you started the thread with? If so (or if it is a new one), do you have an updated picture? The links in the first message are dead.

Edited by LadyKate, 23 September 2005 - 12:08 AM.

[italteen3]

That was a good cake. Is this the cake that you started the thread with? If so (or if it is a new one), do you have an updated picture? The links in the first message are dead.

Thankyou!

Yes that was the cake I started the thread with. My other host is down so the pics are on my comp right now. I tried emailing you the video but got an error saying the address you gave me didnt exist??? I will send pics of it if you want.

At the moment I have 16 1/2" stars drying. They are the comp I posted early in thread. I will give them a go either tomorrow night or sunday. If the stars are nice, and the right size and comp for the effect I want, and I get everything dialed in correctly I will be making a nice Z-fan with them, which I will film.

[Pretty green flames]

Finally got my video hosted..... Had to create the site I just remembered I get for free from when I bought my Mac........
Click me

Nice. Really loud.

[The_Djinn]

Nice.. but...

couple of areas for concern, who ever is lighting the fuse is still next to the cake when it starts firing.. more delay fuse may be a good idea. Other point is this is being set off at the side of a road on the edge of a public car park.. surely you can find a nice field or open space rather than an area like this.

Remember people, no matter where in the world you are from, keep it safe.

Mark

Edited by The_Djinn, 25 September 2005 - 11:36 AM.

[italteen3]

Nice.. but...

couple of areas for concern, who ever is lighting the fuse is still next to the cake when it starts firing.. more delay fuse may be a good idea. Other point is this is being set off at the side of a road on the edge of a public car park.. surely you can find a nice field or open space rather than an area like this.

Remember people, no matter where in the world you are from, keep it safe.

Mark

From an earlier post

""Fired it last night. Location was an abandoned parking lot surrounded by a field and woods. Nice hard pavement for stability so I decided against a back yard or a grass field as it was to close to houses. 10 small,2g, titanium salutes were used, double fused with 3/32" American visco cut at sharp angles for a greater chance of ignition.""

Djinn I understand your concern but the lot was not used for years no one really goes there but teens to drink in the woods and party. I opted for the lot because it provided more stability and less chance of tipping then the adjacent field As for the delay fuse, that was me who lit that. I was farther then it looks but still should have put more fuse like you said.

As for my fan cake I will be making one or two "fans" with the stars that just finished drying. Amidst my excitement in trying out the new formula I forgot to buy some tubes..... Luckily I put 10g of comp from the 100g comp aside just incase I overwet and used that to make a handful of cut stars. They dried and I tried them in a mine. It is a very nice comp and the magnalium gives it a nice little sizzling noise on the way up. Im hoping the 1/2" size will be enough for my desired effect or an upscaling will be needed. More vids to come soon. Dont worry ample delay fusing will be made.

I uploaded the pics of the cake to here also Pics

Edited by italteen3, 25 September 2005 - 09:55 PM.

[paul]

One quick qestions to the more experienced cake/comet builders:

For new years eve I?d like to press two or three 2" tigertail comets. How much water do you recommend to use?! The press is a 5t press.

I ask because I doubt they would get fully dry in a few weeks or so.


Thanks in advance,

paul

[Phoenix]

I probably don't fall into the category you specified, but I have made a few 1-1/2" tigertail-like comets (I say tigertail-like as I usually now up the potassium nitrate to about 50% and use only 3% dextrin). I couldn't say exactly how much water to use - I dampen it with 10% alcohol in water until it's just beginning to hold together when squeezed - somewhere around 15% w/w. However, this varies with the density of the charcoal used, and to be honest I haven't made enough comets of this size to establish a hard and fast rule as to how much solvent to use.

I then press them as I would BP. I have made comets with composition (unintentionally) dampened enough for water to run out of the pump when it was pressed (this doesn't actually feel very wet before it is pressed). This doesn't seem to be recommended, as the comets take longer to dry. However, comets I have made in the past were like this and worked, but only after long drying. My most recent batch of comets (intended to be used in my birthday display) was made with a much drier mixture - as I say, just holding together when squeezed. When I pressed these (also with a 5 tonne press) they showed no sign of "juicing," but came out nice and hard. They are now dry (less than a week in the drying cupboard) and will survive being dropped onto a concrete floor. However, I never fired them at my birthday display, since I didn't have time to fit them with lift charges or leaders (pity, but I was really having to work my socks off to get everything else finished in time), so I can’t yet confirm whether they'll survive being lifted. My guess is that they will, though.

Two final points, to avoid the comets becoming driven in:

Firstly, I would not recommend using more than 3 or 4% dextrin for tigertail, or a similar composition. My experience has been that charcoal streamers made with more dextrin than this are prone to becoming driven in, and 3% is all that is necessary to produce a sufficiently hard star/comet.

Secondly, do not dry them too fast at first, and not in the sun. This is widely reported to cause them to become driven in. I've recently taken to drying charcoal stars and comets under my ramming bench, where it is cool (and where, as an added bonus, a batch of stars could probably burn out without doing any harm - not that charcoal comets would be likely to self-ignite anyway), for 24 hours prior to normal drying. This does seem to have reduced the incidence of driven stars. Of course with "friskier" compositions, like aluminium/nitrate mixes, it's probably best to dry them as quickly as possible (again, not in the sun - a drying cupboard is handy here).

They shouldn't take too long to dry if they don't get driven in, but having now prepared a moderate sized display to a deadline, I'd say that if it'll keep, get it done good and early. Tigertail comp is very stable stuff, so there's probably no harm in getting them made and dry well in advance and then keeping them in a plastic bag or box until you need them. That way if they do get driven in, you should be able to get them dry (or crush and re-press) them in time.

Edited by Phoenix, 28 September 2005 - 10:20 PM.

[paul]

Many thanks to you, Phoenix!.

I knew that this question is a bit off-topic, but I did not want to start a new thread although I could not find a answer to this certain question with the search function here.

But I?ll try it, thanks for your tips!


with best regards,

paul

[Phoenix]

No problem at all

As I said - I've only made a few (9 or 10) comets this size, so I'm not especially experienced, and if anyone wants to contradict me or add anything go ahead!

Best of luck!