guntoteninfadel Posted May 11, 2011 Posted May 11, 2011 H3 and KP? I tried searching but the search engine needs three letters to work. Remember reading somewhere that H3 I think is used for break charge, how does this compare with rice hulls and BP? Pros and cons? And what is KP used for? Thanks Gun
Peret Posted May 11, 2011 Posted May 11, 2011 (edited) H3 (77% potassium chlorate, 23% charcoal, +2 binder) is one of the burst compounds described in the Shimizu chapter of Lancaster's book "Fireworks Principles and Practice". The recommended binder is soluble glutinous rice starch (SGRS) but dextrin will do - you may need rather more than 2% dextrin. KP is often used just for potassium perchlorate but it's also used to refer to other burst compounds in the same chapter -Perc Burst 1Potassium Perchlorate 70Charcoal 18Sulfur 12SGRS +2Perc burst 2Pot Perc 70Charcoal 25Lamp Black 5Potassium Dichromate +5SGRS +2 You coat all of these on rice hulls just like BP. The H3 composition burns faster and hotter than the perchlorates or black powder and gives the hard break necessary for nice spherical bursts without any booster. The drawback is you cannot use it with any components containing sulfur, antimony sulfide or black powder, as the setback at launch may set it off, and be careful not to confuse H3 coated hulls with BP coated hulls because they look exactly the same. Edit: Also see Shimizu's book Fireworks: the Art Science and Techniques", section 15.1, where I notice he refers to the first perchlorate composition above as "KP" and he includes this table: Edited May 11, 2011 by Peret
Mumbles Posted May 11, 2011 Posted May 11, 2011 The KP as a single chemical vs. burst formula is why I typically call potassium perchlorate perc. In case you haven't figured it out yet, Madmandotcom has no idea what he's talking about for the most part. As Peret mentioned, these bursts came from Shimizu's work originally. H3 is good up to 6" to 8" shells with some dialing in. Some prefer to reserve it for the smaller shells, 4" or below. KP is a good burst, but has minimum size requirements as it has a sharp pressure dependent burn rate. If you try burning some in the open you'll be thoroughly unimpressed. In a shell however under pressure, it spikes rapidly and gives very nice breaks. This however also has the unavoidable consequence of getting too much confinement and giving essentially just salutes. In my experience, that is more easily said than done however. I don't often have a problem with over breaking. I typically don't use KP or the related mixes under 4" shells. One noteable exception is a gentleman on passfire using it in 2" plastic shells utilizing a whistle booster, which likely ramps the pressure up. Typically boosters with KP is a no-no and a good way to get to that salute stage I mentioned before. In case you're wondering the No. 5, 44, and 46 formulas referenced in the table Peret posted are related mixes to KP. No. 5 is all charcoal, no sulfur. 44 is the same as No. 5 with 5 parts potassium dichromate to speed it up, and 46 is the same as No. 44 but all lampblack instead. These compositions are really only recommended for bigger shells, 6"+ (I probably wouldn't go below 10" with No. 5). H3 is probably ok to use in smaller shells containing BP stars or prime, but it is an added risk some prefer not to take. Many people use a tissue paper barrier and say it should be alright. It is said that if a shell were to misfire and come back to the ground, it is pretty likely to go off on impact though.
killforfood Posted May 11, 2011 Posted May 11, 2011 H3 and KP? I tried searching but the search engine needs three letters to work. Remember reading somewhere that H3 I think is used for break charge, how does this compare with rice hulls and BP? Pros and cons? And what is KP used for? Thanks, Gun.Guntoteninfadel, Don't feel like you are alone on all of the abbreviations. I struggle with many of their meanings also. I usually try to avoid using them when I write because even the ones I do know may be confusing to others. Maybe someday the Newbie section will get an abbreviation sticky. Until then I read, read read.KFF
dagabu Posted May 11, 2011 Posted May 11, 2011 I too am confused by made up abbreviations, at least the chems names are online for me to look up. -dag
oldguy Posted May 11, 2011 Posted May 11, 2011 (edited) Don't use PP as an abbreviation for potassium perchlorate. The whole crew will point fingers & bust out laughing. I know……….. Edited May 11, 2011 by oldguy
dagabu Posted May 11, 2011 Posted May 11, 2011 (edited) :PP! He said PP! Edited May 11, 2011 by dagabu
killforfood Posted May 11, 2011 Posted May 11, 2011 (edited) Nitre beds require copious quantities of Pee Pee and Poo Poo so clearly PP is the correct abbreviation for Potassium Nitrate. MMDC should chime in any second now. Wait for it... Wait for it... Edited May 11, 2011 by killforfood
Pechovski Posted May 11, 2011 Posted May 11, 2011 So how normal is it for people to go over to a more powerful non boosted burst (KP) instead of BP + Whistle i.e? What is the benefits of doing this, or could i just go BP with boost all the way to 10". I also thought that BP was optimal for bigger shells.
dagabu Posted May 11, 2011 Posted May 11, 2011 So how normal is it for people to go over to a more powerful non boosted burst (KP) instead of BP + Whistle i.e? What is the benefits of doing this, or could i just go BP with boost all the way to 10". I also thought that BP was optimal for bigger shells. KP burst is really common in Chinese fireworks and is common in smaller shells for lift as well. I use whistle to boost my shells since I can tailor the boost for each shell independently without having to make another batch of anything. I will let the guys that make big shells comment of the burst but I chose confinement over booster with my 5" cylinders for a good break for all of the reasons that Mum cited earlier. -dag
Mumbles Posted May 11, 2011 Posted May 11, 2011 There is a trend that may not seem apparent if only looking at smaller shells. The larger the shell, the less burst:booster ratio you need due to an increase in confinement. It is for the same reasons as a more gentle burst is needed with larger shells. Without thinking about it, it may seem as if the larger the shell gets, the more booster you need. IE a 3" shell may use 3g of whistle, a 4" 5g, a 5" 9g etc, etc. What may not be directly obvious is that while the absolute quantity of booster is getting larger, the proportion to the burst is getting smaller. If you look at the total bursting charge it may go something like 10% whistle for a 3", 6% for a 4", 3% for a 5" etc. At some point that percentage will (or at least should) go to 0. It you kept using the same burst:booster ratio eventually it will start to over break. Some may like that look though. You certainly can use BP, with or without booster, essentially to an unlimited extent as a burst. I prefer perchlorate based bursts for a few reasons. Assuming everything comes from the same stock, it should be very similar batch to batch. There is no worrying about asymmetric distribution of loosely added booster, or variances in batch to batch of BP. An effect I never really noticed but was mentioned on passfire is that typically there are no burning burst embers upon opening of the shell. I don't know why, but they seem to give a more gentle push to the stars in my opinion as opposed to a boosted mix. The cost obviously is higher, but compared to the time I put into shells and cost of many stars I make, it's nothing. Also, I build more canisters than ball shells, so the added overall cost is pretty low.
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