Edwin Posted March 9 Share Posted March 9 7 hours ago, Zumber said: For pillar ( pumped star/ comet) Changing relay is not necessary rather sequence of stars composition should be capable of igniting next layer of colour composition. In encyclopedic dictionary I have seen kraft paper tube is used where three or more colour composition of desired thickness is pressed and at the end prime layer is applied, this technique is useful in mines but for round stars changing relay is necessary. Isn't it because round color changing stars have a tendency to have the colors bleed into each other had there been no relay? Could it be that the kraft tube star burns only on one side of the cylinder and is therefore a bit easier to control the flame compared to the round star that burns radially? Link to comment Share on other sites More sharing options...
Zumber Posted March 9 Share Posted March 9 Dont you think step mixing of two colour star composition produce unwanted light and flame? Then how clear visible colour change is possible? Link to comment Share on other sites More sharing options...
Edwin Posted March 10 Share Posted March 10 I was just theorizing. Relating what I observe in practice with theory is what really stumps me. Link to comment Share on other sites More sharing options...
Mumbles Posted March 18 Share Posted March 18 Some color changing stars do in fact use a relay type composition. As you said, rolling one color comp directly onto another can cause the color to get kind of "muddy" for a bit. In the above blue to yellow example, the interface would probably look a bit greenish. Dark relays tend to make the transition look crisper in my opinion. They typically burn kind of a dull red when seen close up. In the sky it's generally imperceptible. Even if you can't detect it in the video, it doesn't mean it's not there. Ghost shells really aren't all that complicated in theory. It's the technique and putting it to practice that takes high levels of skill. Building a number at once can help just due to the economy of scale. It's easier to accurately roll a few thousand of the same star for one "segment" of the ghost shell, than it is to roll like 40 for a single shell. Link to comment Share on other sites More sharing options...
Zumber Posted March 19 Share Posted March 19 6 hours ago, Mumbles said: Some color changing stars do in fact use a relay type composition. As you said, rolling one color comp directly onto another can cause the color to get kind of "muddy" for a bit. In the above blue to yellow example, the interface would probably look a bit greenish. Dark relays tend to make the transition look crisper in my opinion. They typically burn kind of a dull red when seen close up. In the sky it's generally imperceptible. Even if you can't detect it in the video, it doesn't mean it's not there. Ghost shells really aren't all that complicated in theory. It's the technique and putting it to practice that takes high levels of skill. Building a number at once can help just due to the economy of scale. It's easier to accurately roll a few thousand of the same star for one "segment" of the ghost shell, than it is to roll like 40 for a single shell. Can you recommend good dark delay compsition please.? Link to comment Share on other sites More sharing options...
Sulphurstan Posted March 19 Share Posted March 19 16 hours ago, Zumber said: Can you recommend good dark delay compsition please.? @redbullzuiper has an excellent dark relay composition. He may disclose the recipe 🤔? Link to comment Share on other sites More sharing options...
Crazy Swede Posted March 19 Share Posted March 19 A very good dark relay composition can be made from potassium nitrate and Novolac (phenolic resin powder containing hexamine). Start with 90 % potassium nitrate and 10 % Novolac. To this you add binder (dextrine or rice starch) to desired binding strength for your star rolling application. About 4-5 additional percent is often enough. If the composition has troubles igniting next layer, you can try replacing up to half of the amount of potassium nitrate with potassium perchlorate to increase the temperature. Link to comment Share on other sites More sharing options...
Zumber Posted March 20 Share Posted March 20 7 hours ago, Sulphurstan said: @redbullzuiper has an excellent dark relay composition. He may disclose the recipe 🤔? Can you post if you have? Link to comment Share on other sites More sharing options...
Zumber Posted March 20 Share Posted March 20 7 hours ago, Crazy Swede said: A very good dark relay composition can be made from potassium nitrate and Novolac (phenolic resin powder containing hexamine). Start with 90 % potassium nitrate and 10 % Novolac. To this you add binder (dextrine or rice starch) to desired binding strength for your star rolling application. About 4-5 additional percent is often enough. If the composition has troubles igniting next layer, you can try replacing up to half of the amount of potassium nitrate with potassium perchlorate to increase the temperature. I dont have novolac but I do have phenlolic resin and hexamine seperately. Link to comment Share on other sites More sharing options...
ThunderEx Posted March 20 Share Posted March 20 Isn't Novolac just phenolic resin? Tried to find out more...old posts seems to treat them both as the same. Maybe there was some confusion in the beginning when phenolic came about. To my understanding Hexamine will act as a cross-linking agent and make the phenolic resin "cure" very hard, but does it also provide other properties in this application? Link to comment Share on other sites More sharing options...
Zumber Posted March 20 Share Posted March 20 (edited) Yes ....Here in our reagion two varieties are available one is white form and other is yellowish white or light brown. Yellowish phenolic have smell. Edited March 20 by Zumber Link to comment Share on other sites More sharing options...
Crazy Swede Posted March 20 Share Posted March 20 In this application, I would guess the added hexamine contributes to lower flame temperature and therefore less luminous flame. Phenolic resin powder of this type, it usually has a light yellow colour, contains about 10 % hexamine for cross-linking and has a bunch of industrial applications outside the world of pyrotechnics and is therefore rather cheap. It does not cake to the same extent as freshly milled phenolic resin of other types usually do so it is very popular as a reactive organic fuel in pyrotechnics and works well as a red gum replacement. 1 Link to comment Share on other sites More sharing options...
ThunderEx Posted March 20 Share Posted March 20 Cool! Tack! I have only seen the yellow type, and that probably explains why they are mixed up/used as the same then. Link to comment Share on other sites More sharing options...
Zumber Posted March 20 Share Posted March 20 3 hours ago, Crazy Swede said: In this application, I would guess the added hexamine contributes to lower flame temperature and therefore less luminous flame. Phenolic resin powder of this type, it usually has a light yellow colour, contains about 10 % hexamine for cross-linking and has a bunch of industrial applications outside the world of pyrotechnics and is therefore rather cheap. It does not cake to the same extent as freshly milled phenolic resin of other types usually do so it is very popular as a reactive organic fuel in pyrotechnics and works well as a red gum replacement. The phenolic yellowish version I have has a strong smell like you are breathing in paint shop. And it cakes rock hard...before use I use hammer to crack it into pieces then I grind. This version improves colour star deepness to great amount than white phenolic resin which is also available here. The white version is odourless. I am not sure yellowish version contains hexamine or not. -Zumber 1 Link to comment Share on other sites More sharing options...
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