braddsn Posted October 6, 2016 Posted October 6, 2016 I have made some more progress using phenolic resin and I wanted to share. I live in a humid area, and although I roll most of my stars, I do cut and pump some charcoal comps. When I cut 1/2 and 3/4 inch charcoal stars, it often takes 3 weeks for them to dry completely. Last night I cut some 3/4" charcoal stars, and instead of 5% dextrin I used 5% phenolic. I used isopropyl alcohol to wet the comp. This afternoon i checked the stars and they were rock hard, and 100% dry. This is a breakthrough for me, and will be using phenolic for binding cut stars from now on. I have not tried rolling with phenolic as the binder yet, I roll most of my stars and it is tempting. Im quickly falling in love with phenolic. Its some great stuff.
Merlin Posted October 6, 2016 Posted October 6, 2016 Thanks for sharing. I got some from ctpyro also and am about to cut some charcoal stars. Did you use 9:1 phenolic:hexamine or just straight phenolic?
DavidF Posted October 6, 2016 Posted October 6, 2016 Braddsn, you might want to reserve judgement until you fire those stars. Phenolic with colors is way different than phenolic with charcoals stars. I don't think you will like the charcoal stars.
braddsn Posted October 6, 2016 Author Posted October 6, 2016 David, good point. I have not tried the stars yet. I am testing them tomm night out of the star gun, I will report back as soon as I do. Fingers crossed!
OldMarine Posted October 6, 2016 Posted October 6, 2016 Dave, Jim Widman's Ti comet formula is basically a BP formula bound with phenolic/hexamine. Would there be a difference between pumped and cut stars?
DavidF Posted October 6, 2016 Posted October 6, 2016 I don't know about that OldMarine, but I think the phenolic will interfere with the way plain charcoal stars burn, making them not look as nice in the sky. It would be a shame to make a whole mess of them only to find that the display was unsatisfying. I'd like to be wrong though, I've got lots of phenolic
DavidF Posted October 6, 2016 Posted October 6, 2016 I got it from Jim. I know why you are asking. There was some phenolic sold that was different and didn't work in a few guys' formulas. I think that's why Grant ( Learner on FW) had such poor results. He used it for everything, and I think he had the 'less good' stuff
Maserface Posted October 6, 2016 Posted October 6, 2016 I couldnt remember if I sent you some or not, and I had the bad stuff.. Wanted to make sure you knew
braddsn Posted October 7, 2016 Author Posted October 7, 2016 Ok so I tested the stars last night, and they were PERFECT! This was a charcoal based comp with some aluminum in it. I am very impressed. I shot 4 into the sky with the star gun. From cut to completely dry in 10 hours is outstanding.. and I can bounce them off of my concrete floor and they don't break. These are 3/4" cut stars, I will use them mainly as rising tails for shells. I will get video of this comp and other charcoal comps that I plan to bind with phenolic resin. 1
DavidF Posted October 7, 2016 Posted October 7, 2016 (edited) Geez, I hate to be wrong- but I hate waiting 3 weeks too! I would like to try this. Can you share the formula then? Is the phenolic milled with the formula, powdered separately, or added as a 'liquor'? One of my pet peeves with charcoal stars is if they have crap raining down all over the place. These ones burn clean? I notice the title says 'More on Phenolic Resin and cut charcoal stars'. Was there a previous thread about this that I have missed? Can anybody direct me? Thanks! EDIT: nevermind, I took 30 seconds and found it. Edited October 7, 2016 by DavidF
OldMarine Posted October 7, 2016 Posted October 7, 2016 (edited) I just ordered me some Phenolic resin from Jim so I hope to join in the game soon. I'm wanting to try some 1-1/2" comets without having to wait until NYE to test them! Dave, I found the first edition of this thread here:http://www.amateurpyro.com/forums/topic/12037-phenolic-resin/?hl=%2Bphenolic+%2Bresin Edited October 7, 2016 by OldMarine
braddsn Posted October 9, 2016 Author Posted October 9, 2016 David, the formula I tested is simply TT + 5% Ti. The stars were perfect in the sky. I use Eastern Red Cedar for charcoal, fwiw. I will test more charcoal stars soon with phenolic and post results. All I did was simply replace the dextrin in the formula with phenolic, and instead of using water to wet, I used alcohol. Everything else was the same. And when I make charcoal stars, I always ball mill my charcoal, KNO3, dextrin (or in this case phenolic resin) for 30 mins. I do this because my charcoal is not airfloat, and my KNO3 is granular. Oldmarine, you won't regret ordering that phenolic. It is some fantastic stuff. The ONLY thing different I did notice with these charcoal stars is that the outer surface was smoother and harder than when bound with dextrin, thus..... I went ahead and primed them. Normally I don't prime my charcoal stars but felt like I needed to because of the super-smooth/hard surface that they had from the phenolic resin.
dynomike1 Posted October 13, 2016 Posted October 13, 2016 I wonder how rolling these stars will work? I haven't tried to roll with alcohol yet.
braddsn Posted October 14, 2016 Author Posted October 14, 2016 I am wondering the same thing Mike. I asked Widmann about it, and he claims it can get messy and sticky. I think I am still gonna try it.
dynomike1 Posted October 14, 2016 Posted October 14, 2016 I don't have any so i will wait on the test before i get any.
NeighborJ Posted October 24, 2016 Posted October 24, 2016 I've been testing various charcoal stars with the use of Phenolic resin. I'm am pleasantly surprised with the ease of ignition and the vibrant burn but they seem to burn very fast, in fact I'd not consider making stars smaller than 1/2" and many need to be made in the 3/4"-1" range. This limits their use to 5"or6"+ shells. My most recent attempt was a glitter I found on Cregans database:50kno3, 20s, 6 bakingsoda, 4 phenolic(dex), 10 mgal, 10 ERC. It was loosely bound and seemed to burn the Phenolic as fuel before the charcoal which left a huge tail of charcoal embers raining down. My question is what is the best option to extend the burn time and improve the binding properties without sacrificing ease of ignition. I'd like to use them in smaller shells and make my larger shells fuller.
Mumbles Posted October 24, 2016 Posted October 24, 2016 I'd start by using commercial airfloat instead of ERC.
ExplosiveCoek Posted October 24, 2016 Posted October 24, 2016 Very interesting, Brad. Thanks for sharing! I am too in a humid environment and can only dry things with my drying chamber. So this would be really interesting for me too. I have rolled some red gum bound with alcohol buell red stars. It does tend to stick more to your drum and dry in, but probably if you want you can still remove it with alcohol in there. The drying time can catch up to you indeed with rolling, you need to work a bit faster and spray more than you'd normally do with water bound comps. I didn't notice any 'sticking' issues. It was quite hard to start up the cores though, my cores (blasting grit) wouldn't pick up the comp as easy as it would with regular water. NeigbourJ, was your charcoal really fine? This can also be an issue with fallout embers. It needs to be thoroughly milled/fine in my opinion.
NeighborJ Posted October 24, 2016 Posted October 24, 2016 Coek, yeah I knew better than to use the Blade milled ERC, I haven't had time to make oak charcoal. I don't think that is the only problem though, I tried the pyroscience blue in our database and it also burned violently fast, I used them as inner petals of large glitter shells. I'm considering adding the resin in addition to the original binders just to slow the burn speed. I have not been pleased with the hardness of the charcoal stars, they are hard and dry but I can break them apart when I mash them between my fingers. The other option I've considered is to double the amount of resin when replacing dex,or sgrs. Once they are hard enough I'll try rolling but they've all been cut or pumped so far.
dagabu Posted October 26, 2016 Posted October 26, 2016 Jim published a white paper on the phenolic resin and states that you need to reach 8% resin to make for hard stars and better yet, use hexamine and heat to create the cross linking co-polymer. This makes the stars VERY hard, even with soft charcoals.  pyrobin.com/files/Pheno-Hex%20Binding%20ISF%202015.docx I don't know if this is part of your plans but if it is, may I suggest using denatured alcohol and finely ground (blade grinder works OK) resin with the hex to make a liquid syrup and kneed that into your comp? 1
dynomike1 Posted October 29, 2016 Posted October 29, 2016 Ill say one thing that is the stickiest stuff that i have seen. I wished i hadn't put it in my mill to grind it up , now i have to figure out how to get it out.
OldMarine Posted October 29, 2016 Posted October 29, 2016 Try throwing ice in with the media and milling it. The ice will make the resin brittle so it will flake off the media and mill walls. Use enough ice so that as it melts there is enough water to hold the resin in suspension. I've been studying up on this on FW to find the best way to reduce it.I'm going to try bashing the larger chunks in a leather bag using a big hammer then dissolving some 50/50 by weight with denatured alcohol. Binder and solvent in a pre measured package.
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