braddsn Posted January 19, 2015 Share Posted January 19, 2015 Pasting my very first 3" shells tonight. I have pasted many 4" shells, and a few 6". Seems like after 5 or 6 layers on a 4", there is not much clearance left between the shell and the mortar. However, I just pasted 8 layers on a 3 inch shell, and there is still probably 1/4" clearance on one side when shell is pressed against opposite side.. (1/8" clearance all the way around). I saw a post from a while ago where Mumbles mentioned that he seemed to get hemis that were too small when building 3" shells. What kind of clearance are you guys getting after 8 layers on a 3? Thanks! Link to comment Share on other sites More sharing options...
Xtreme Pyro Posted January 19, 2015 Share Posted January 19, 2015 After 8 layers on a three I get very little clearance for the leader it seems.. 6-7 is about right. The diameter of your hemis will vary depending on the brand. My lidu hemis measure at about 3.6" O.D. for a 4" and 2.6" O.D. for a 3". Link to comment Share on other sites More sharing options...
braddsn Posted January 19, 2015 Author Share Posted January 19, 2015 Thanks XP.. I just measured and I am also getting 2.6" OD for my 3" hemi's. I also just measured clearance. When I push pasted shell against one side of mortar, there is 1/4" clearance on other side. This seem acceptable? I guess I am just checking because I have never made 3's before! Link to comment Share on other sites More sharing options...
fish7days Posted January 19, 2015 Share Posted January 19, 2015 Check Ned Gorski's build video on 3" on Skylighter. Granted, he uses plastic hemis but he does say that the final product is smaller than the mortar and to use 1oz commercial BP. I think he also has a hybrid 3" build but I don't recall if he said anything about clearance in that vid. Link to comment Share on other sites More sharing options...
enanthate Posted January 19, 2015 Share Posted January 19, 2015 My friend, my shells are fired with a larger gap than that. Dont worry, you'll see Add an extra % lift if youre skeptic. Link to comment Share on other sites More sharing options...
FlaMtnBkr Posted January 20, 2015 Share Posted January 20, 2015 You can also make a dummy shell. Fill a shell with dog food, cat litter, etc that weighs the same as the contents of your other shells and tape up like your life shells. Go to a safe place (with no cars close by!) and fire to see if you get a good height. If not, add more BP and fire again. It can help to paint the dummy shell a bright color to make seeing and finding it easier. Â On big, heavy shells it might be worth putting a flash bag in the center to break it apart, reduce fallout, and to check timing. A big one will probably break apart when it lands anyway. Can be cheap insurance if you are unsure of your BP or how much to use or if you want to dial in timing to break near apogee. Or if you want it to break at some other time. Â Shoot during the day so you can see it and to give you something pyro related to do during the afternoon. Link to comment Share on other sites More sharing options...
Sparx88 Posted January 20, 2015 Share Posted January 20, 2015 I have about the same clearance on the 3's as you do braddsn. 1/4" or 1/8" all around. That works perfectly imho. I use 60 lb virgin kraft and paste 4 layers. 1 Link to comment Share on other sites More sharing options...
braddsn Posted January 21, 2015 Author Share Posted January 21, 2015 In my case, the clearance turned out not to be an issue. I used a flat 30g of lift for all of them that I shot, and they reached altitude nicely! I pasted 8 layers on them. The 3's pack quite a punch!! WOW! I have only built 4's and 6's up until now.. I was surprised how the 3's performed. Link to comment Share on other sites More sharing options...
enanthate Posted January 21, 2015 Share Posted January 21, 2015 If you check my latest video in Roger's topic (if you havent already seen it), the TT and dragon eggs. Its a 4" with a 2,5" attachment, and the difference was surprisingly small! Because of this, im back to making 3" only except for NYE etc. It seemed to me that the gap makes a bit of an extra Boom when lifting, compared to my earlier mortars which were a tight fit. This is only compared from memory tho, and might absolutely be wrong. I just remember how surprised I was with my first "gap"-mortar, it really was and still is extremely loud. The break itself does not compare to the lift. Any thoughts bradds? Link to comment Share on other sites More sharing options...
pyrojig Posted January 22, 2015 Share Posted January 22, 2015 I have found that even with a loose fit shells seem to fire to height quite well. I actually used to make my shells too tight, and after a flowerpot and other issues loading I reduced the pasting a bit. It seem s that 3" shells are quite forgiving IMO for gap in the mortar. I prefer to get my shells to have about 1/4" gap to one side Once you get over 3/8+gap your lift requirements will increase dramatically .!! . Usually the golden rule it to make sure it can smoothly fit in the mortar with the Q-match having enough clearance to not impede the shells loading . Link to comment Share on other sites More sharing options...
Sparx88 Posted January 22, 2015 Share Posted January 22, 2015 (edited) In my case, the clearance turned out not to be an issue. I used a flat 30g of lift for all of them that I shot, and they reached altitude nicely! I pasted 8 layers on them. The 3's pack quite a punch!! WOW! I have only built 4's and 6's up until now.. I was surprised how the 3's performed. Â Are you saying you use 30grams of lift for a 3"? I use 11 grams for a 130 gram shell for 300 ft. But I also use 24" guns so that helps. Enanthate Using shorter guns will require more lift and will be louder in my experience. Couple that with a loose fit and you have well, you know now Edited January 22, 2015 by Sparx88 Link to comment Share on other sites More sharing options...
enanthate Posted January 22, 2015 Share Posted January 22, 2015 That i didnt know Sparx!My 4" is 20" long, inc plug. ~30g lift.3" is around 16-17" long, ~20g lift. Link to comment Share on other sites More sharing options...
LikeRise Posted January 25, 2015 Share Posted January 25, 2015 I did 5 layers and well broke off! Link to comment Share on other sites More sharing options...
enanthate Posted January 25, 2015 Share Posted January 25, 2015 I did 5 layers and well broke off!Try at least 10!Im using 10-16 on 3", depending on the stars and break that I want. Link to comment Share on other sites More sharing options...
braddsn Posted January 26, 2015 Author Share Posted January 26, 2015 Now that I have shot a few, for me 30g of lift works perfectly. Actually, it's probably a little hot.. but I like the thump and they go to the moon. Actually about 350 ft.. but still. I am sure I could dial it back to 15g lift and they would perform fine. But the lift is just as cool as the break.. in my opinion. The clearance does not seem to be an issue. I found that 8-10 layers is great for the 3's, and there is still quite a bit of clearance. I also gotta say.... so far I have shot many 4" shells, a few 6" shells, and now some 3's.. and the 3's are no doubt the best bang for the buck. They cost almost nothing to make, and they are not too far behind the 4's in performance! Lovin' em! Link to comment Share on other sites More sharing options...
Vengeance Posted January 26, 2015 Share Posted January 26, 2015 I covered with 12 layers, scattering was smart Link to comment Share on other sites More sharing options...
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