First 2" Canister "Style" Shell

[Bobosan]

....I don't like HDPE mortars with stapled in end plugs. I make sure the ones I buy are screwed or bolted in. I've seen too many HDPE guns lose a plug due to staples bending or coming out of the plug. If I'm going to blow a plug out, I want to know it's because I exceeded the limits of the gun, not due to cheap materials. With screws or bolts, the plug literally rips itself out of the gun, leaving streaks where the bolts of screws tore down the wall.

 

From what I've seen of the construction quality, I agree with the concerns on stapled plugs. Staples not fully seated and no evidence of an adhesive.

I'll be adding screws to the commercial HDPE's.

[eb11]

for my 136 gram 2 inch canister shells i use 5 grams of bp for lift

[nater]

... no evidence of an adhesive...

 

Adhesives don't really stick to HDPE.

[Bobosan]

Adhesives don't really stick to HDPE.

 

I figured that likely the reason.

[mikeee]

There are only several ways to join hdpe materials.

Ultrasonic welding

Friction welding

Hot Air welding

Thermal molding

Mechanical attachment

 

Good luck on trying to get any type of adhesive, glue or epoxy to stick to hdpe, it will not.

[Mumbles]

I get all my HDPE mortars from club shoots or these people: http://www.kastnerhd..._list.html The Kastners have always been extremely nice, and their products are very good. The fact that they're not too far from where I lived saved on the shipping and was nice in that regard too.

 

It doesn't necessarily take a big shell to wreck an HDPE mortar. About 6lbs is my limit for HDPE, and 10lbs for fiberglass. Fiberglass is generally better in terms of strength, weight, and price. HDPE really only has the edge on longevity, and maybe being American made if that's important to you. I really think they'll be phased out in the long run.

 

BlastFromthePast, I just wrote out a long message to eb11 about how I make my shells of this size. If you'd like a copy of it, let me know. It might help to have another persons method to see if you're overlooking something. You made it sound like you don't have the Fulcanelli articles handy to reference.

[BlastFromThePast]

 

BlastFromthePast, I just wrote out a long message to eb11 about how I make my shells of this size. If you'd like a copy of it, let me know. It might help to have another persons method to see if you're overlooking something. You made it sound like you don't have the Fulcanelli articles handy to reference.

 

That would be awesome if you would do that. Thanks

[eb11]

blast it helped alot take the info and run its amazing the help these guys give us
that is a picture of my last shell after spiking still did not blow like i wanted but mumbles is helping should get it soon Edited April 27, 2013 by eb11

[Mumbles]

This is a slightly edited version of what I sent Blastfromthepast. This is mostly traditional building. You will notice a huge lack of glue, hot glue, and tape compared to what you may see on youtube. I assure you that it works just fine without all that stuff. I tend to use 2 turns of 70lb for my casing and 2 turns of 30lb for pasting. It's also very common to use 3 of each instead. I don't mess with what works for me though. Feel free to use what you're comfortable with.

 

This is for building shells in the "normal" direction, which is bottom up. The time fuse end is the top and is inserted after the shell is filled. If you'd prefer to hear how I build them "upside down", with the time fuse end inserted first let me know and I can tell you about that. I generally build them all upside down now, but it does require a shell former with a hole, which you may or may not have.

 

Materials needed:

2" x 11.75" manilla folder

3.5" x 12" 70lb kraft

5" x 12" 30lb kraft for time fuse

5.5" x 12" 30lb kraft for spolettes

Timefuse or spolette timed to about 2 seconds

spiking twine - I like the 20lb or 1mm hemp jewelry twine that you can get from walmart

1/4" cut stars

4FA black powder

2x 1.75" solid end disks

2x 1.75" end disks with hole to accommodate timefuse/spolette

A stick or mallet - Anything really works here. I used a piece of 1" dowel than I nicknamed Mr. Tappy.

Wheat paste

 

 

Roll the manilla folder paper over a 1.75" OD former. I personally have used a 4oz contact solution bottle filled with sand, but use whatever you have handy. There is enough file folder paper for 2 turns, plus a little overlap. After you're rolling it up, stop when there is about an inch remaining on the table. Insert the 70lb paper on top of the remaining file folder paper. Center the paper as best as you can. With the paper now interweaved, roll up the kraft paper. I like doing this as it seems to hold everything together better as I'm rolling. After it's all rolled up and you're satisfied that everything is tight and lined up I either tape or use a small dab of glue to hold the casing together on the outside leaf of the kraft, but leave it on the former for now.

 

I'm right handed. I roll the casing away from me, and orient it such that the end I intend to close off first is on my left. If you're left handed or find this method awkward, try switching so that end you intend to close first is on your right.

 

Depending on how you lined everything up initially, slide the casing down the former so that the kraft paper is overhanging but the manilla folder paper is pretty much flush with the end of the former you're using. Drop one of the solid disks in, and fold over the kraft paper. I take the inside turn of paper, grab the corner where it started and fold it down, and push my left index finger down on it. I take my right hand and run my index finger up along the paper until you get to the curve where it's already folded down. Pinch the paper there and fold down that flap. Replace the finger holding down the first flap to hold down the second flap. Repeat this until you've gone around the shell folding down the entire outer casing into little flaps. Take your mallet or wooden dowel and hit or smash the tabs down. This may seem odd but it's called setting the folds and really helps actually. It makes the shell end very flat and solid.

 

Slide the casing off the former. If everything is tight and well fitting you might even feel a slight vacuum formed if you have a solid former. Fill the casing about 3/4 way with stars. For bigger shell I do this part in layers, but for 2" shells I just do one addition. Give the shell body a little squeeze, just for comparison later. Add in 4FA and tap the shell. I use my tapping stick for this too. I tap the sides of the casing lightly to settle all the BP down into all the spaces. Keep adding BP until all the spaces are full and you can see BP all the way up to the top of the shell. If you squeeze the shell now, it should be very solid and probably not move much if at all. If your shell is not full up to the top of the liner add a few more stars and BP, or remove some if necessary, and complete to get everything solid and roughly to the top of the file folder liner. I tend to err on the side of more BP, as it makes the next part MUCH easier.

 

Now we need to close up the shell. Take your disk with the hole in it, and insert your fuse or spolette though. You don't actually need to glue it in at this point, but I like to. I use hot glue personally. I put glue on both the inside and outside and slide the fuse in and out a little bit to get it well sealed. I usually leave about 1/2" of fuse or 3/4" of spolette on the side intended to go inside the shell. Drop this disk into the shell. You'll probably have to squeeze the shell around the top a little bit to break up that good job of packing all the stars in we just did. I typically push down on the disk while I alternate squeezing the top to break things up and tapping the sides to solidify everything again. The idea is to make the stars and BP as densely packed as possible, but now we need to let it accept the space occupied by the fuse. You should be able to feel when it's all totally settled and the end disk is flush against the components. You may have to take the disk out and add a little more BP or stars, or remove a bit. I sometimes take a smaller dowel and tap down on the disk just to make sure everything is well seated.

 

Once the disk is totally seated, we need to fold the paper over just like before. The paper may or may not touch the fuse/spolette. It isn't a big deal either way. Again, take your mallet or dowel and set all the folds. Take your second disk with a hole in it and place it over the fuse and over the folds. I will regularly set the folds again on top of this second disk to make sure it's all the way down.

 

Now we need to spike the shell. Place the second solid end disk and place it over the bottom of the shell. If you're worried about flower pots, take some masking tape and wrap two turns around the top and bottom of the shell, folding it over to seal the two disks down to the shell. This is generally very unnecessary, but I do it with bigger shells sometimes. For me, compression is key for good spiking. I use 8 vertical spikings, and however many horizontals look right, probably 6 on average. I take the string I'm going to use to and quickly wrap it around the shell vertically about 10 times, and then horizontally probably 10-15 more times. It's better to have too much than too little. Cut the string at this point, and unwrap the twine and tie it off to something solid like a tree, trailer hitch, post, etc. Tie the other end of the twine to your fuse with a clove hitch and walk back until the string is taut. Using moderate tension from leaning back wrap the twine vertically around your shell coming back up 180 degrees from where you started. Use your body weight to make the string bite into the end disks a little. When you pass the time fuse, use it as a lever and turn your shell 90 degrees. Repeat, so you should now have roughly a "+" on the top and bottom of your shell. Next turn the shell 45 degrees and repeat this operation until you have 8 equally spaced vertical spikings.

 

Once this is done we need to start the horizontal spiking. Run the twine to the left of one of your vertical strands. Bite it into the shell casing/disk and begin to run the twine down the side of the shell, turning it such that you rotate the shell horizontally and turning it so that the top and bottom of the shell are facing sideways. You should have sort of a swoop pattern. Run the twine along the bottom of the shell until you have 1 full turn totally at the bottom of the shell and start to move up slowly. The standard method is to make squares with the horizontal spiking and vertical spiking. I like to have a little tighter horizontal strands than this, so most of mine come out as rectangles that are wider than they are all tall. It's all personal preference. Spike up until you get to the fused end of the shell, and give it maybe 2 or 3 turns all around the top of the shell. We need to tie off the string somehow. To do this put your thumb over over the twine and take a step forward so the string goes limp. You want to make a loop. With your thumb on the string make a loop facing toward the top of the shell. Fold this loop over the shell and pull it tight. The string will be held down now. I typically do two of these loops just to be safe. If I'm not going to spike them right away, I put a smear of glue over these loops.

 

The shell is pretty much complete by now. Take the 30lb kraft and smear wheat paste over it, both sides. Fold the paper, crumble it, whatever. It will get darker over the course of probably 5-10 minutes. Wait until it's uniformly dark. You may need to add more wheat paste before you roll the shell up in this paper. There should be enough overhang on the paper to overlap the entire bottom of the shell for the full diameter, and onto the time fuse to seal it in as well. Before I start I usually place wood or elmers glue all around the spiking and around the fuse to seal it in. Start rolling the shell up in the pasted paper. I fold the paper over the bottom of the shell as I go, but leave the top as it is. I generally take some paste on my hands and rub it down the sides of the shell and all over the bottom. This smooths everything out and gets rid of air pockets and gaps. When I'm done with the bottom I set it down, sitting up. I put some more wheat paste on my hands. I bunch up the paper around the fuse, and put my hand on top of the shell with the fuse between two of my fingers. From there I press down and twist it around the fuse. This will lay all the paper down flat, and form a good seal around the fuse. I generally give everything a final rub down before setting it aside to dry.

 

Once dry, prime your fuse and finish however you want. The spiking should be very visible once dry. You can see what mine look like when they're finished here: http://www.amateurpy...435-insertsjpg/

 

I normally make them as inserts, so I don't generally finish them up with lift and leaders. If you need any help with that, I can certainly assist.

 

This turned out WAAAAAY longer than I expected. It might seem like it takes forever, but it really doesn't. If you're building a few at a time it actually goes pretty quick. Once you're set up to do one, it doesn't take much longer to build several more. Doing a few at once can help to practice and reinforce techniques. I bet I only put 15-20 minutes or so on average into each shell of this type when building a bunch at once.

 

I hope this helped and made sense. I'd be happy to help with anything you're having trouble with.

[BlastFromThePast]

Thank you so much for this. One question about the former that you mentioned needing a hole for the spolette...I need to reference 50AE's video as this is the only time I've seen something like this. I'm assuming that what he uses in that video is what you are describing above. ?

[Mumbles]

This video I assume? http://www.youtube.com/watch?v=kduh-K5-pQw

 

At the beginning you can see that his former has a hole in it too. If you have a pipe the correct outside diameter, there really is no need to fill the end with plaster and drill a hole. The walls are enough to support the disk while you're building the casing or banging on it while setting the folds. I use HDPE mortars as the formers for most of my shells as it is, and there is a lot more open area on 5 and 6" shells.

 

You can also see the holes in some of the formers that bangkokpyro sells.

http://bangkokpyro.com/stock-sizes-for-sale.php

 

You can see that the holes in the formers that bangkok sells are much larger than 50AE's. 50AE's is meant to accept just a fuse. You can use a larger hole like in the formers above to accept a flashbag as well. 2" is probably too small to worry about that though.

[BlastFromThePast]

Okay and one other thing. When you talk about "setting the folds" unless I read it wrong, there's no mention of any glue being used, simply the force of the mallet is compacting everything. Wouldn't adding glue to the process make the shell less prone to flower pot or is the use of spiking in this method of construction generally enough to prevent that, thus eliminating the need for glue when setting the folds?

[Mumbles]

Except for maybe a little bit to hold the case together and around the fuse, I don't use any glue. As I said, those are the instructions for a mostly traditionally built shell. You can add some if you want, but it's not necessary. The pasting will seal everything up.

[BlastFromThePast]

Mumbles, I plan on using these as individual shells for now and am curious about how to incorporate a lift charge and leader fuse. I imagine this is still done after the spiking and final pasting is completed. Can you point me in the direction of how to go about doing this.

[nater]

The traditional way of attaching lift and leader is described in Pyrotechnica IX. After the spiking and paste wrap is dry, you secure the leader onto the spolette with a bucket and extend the leader to the bottom of the shell creating a bag. It is common to add another short length of black match to the piping of the leader where it is tied to the spolette. Another 2 turns of paper is rolled around the shell with a length hanging over the bottom. Some wrap this dry, others use paste only on the portion that will touch the shell. The reason for using paste is to help prevent burning fallout near the shooter and to create a nice and smooth looking shell. The lift is poured into the bag, the inner layer is folded shut over the lift and the outer layer can be cinched up and tied with twine.

 

Just note, that I usually put shells on rockets, so I might be overlooking a step.

[eb11]

hey blast here is the shell i just built and fired tonight with mumbles help

[BlastFromThePast]

eb, looking much better/farther than anything I've got. Is that the shell that you posted a pic of yesterday, with the spiking done? Edited April 29, 2013 by BlastFromThePast

[Mumbles]

Nater covered the gist of everything. There are three parts to finishing a shell so it can be fired. The lift, the leader, and the lift wrap. There are several ways to do each step, each with their own benefits and disadvantages.

 

Lift: This is pretty self explanatory. Use however much you want to get it to a safe height. The general rule of thumb is an ounce per pound up to 10lbs, and 1/2oz per pound for all poundage over 10. This works best for bigger or more elaborate shells. Fulcanelli has a table for smaller and simpler shells that has been reproduced around the internet. http://www.skylighte...les.asp#lift I prefer to use 4FA as lift for all shells smaller than 4". I also usually stick with the ounce per pound rule, rounding up to the next half pound or pound. I often see another rule of thumb of 10% of the shell weight being thrown around. I have never actually seen this recommended by anyone reputable, and seems to be proliferated amongst inexperienced builders. That's not to say that it's bad, but it's scope is limited to small shells.

 

Leader: The leader is typically 2 separate pieces is traditional shells. The leader is what you light, and runs only down to the fuse. There is also the passfire which accepts fire from the leader, and in turn lights the lift. The idea is that if the passfire lights, it can also be assumed that the spolette/fuse was also lit. Some people will just use a single piece of quickmatch. I did this for a long time actually, but it's actually a little easier to use the two piece method with spolettes. For a single piece I slit the match, and inserted the crossmatch from the timefuse or nosing from spolette. I also anchored it to the spolette or top of the fuse so I could lower it without worrying about damaging the fuse/quickmatch connection.

 

Two piece construction isn't all that hard. About an inch or two of match is bared from the passfire. The match can be tied over the spolette, but I tend to intermingle it with the match from the crossmatching/priming of the fuse/spolette. The other end of the passfire should be long enough to reach the center of the bottom of the shell. It also has an inch or two of exposed match on the end. The passfire is then tied to the spolette. Sometimes a little glue is used too. From there some glue is spread on the spolette and the bucket is tied over the top. If you're coordinated, you don't have to tie the passfire to the spolette first. A bucket is just 2 turns of kraft, about 3" long. Some people even use coil wrappers. Think of it like a fat quickmatch. It's supposed to contain the fire and spread it to everything around.

 

The leader is tied into the bucket. It should be long enough to stick out of the top of the mortar. I like to bare an inch or two of match before inserting it in. You can insert visco into the other end, or bare several inches of match to light the shell.

 

Lift wrap: This is about what it sounds like. It gives a way to contain the lift. It can be done either wet or dry. Dry is faster, but it leaves burning or smouldering fallout and debris. If this debris stays in the gun, it can build up and cause lift issues for other shells.

 

Dry wrap, as Nater said, is just 2-3 turns of 30lb paper wrapped around the entire shell after the leader has been installed. At the top of the shell the paper is bunched up and cinched down. This is then tied off near the top of the shell. Tie it again a few inches up. This tends to take some of the strain off the leader if you're lowering by it. Cut off any excess paper. I like to tie a loop of string around the bottom of the shell. This helps to prevent lift from migrating up the sides of the shell since the lift wrap isn't physically attached. In the bottom of the shell, fill in that area with lift. The paper is gathered into a bunch and tied off. I prefer to fold the first layer of paper over the lift itself, and then bunch up the second turn and just tie that off. It seems to contain the lift a little better.

 

The wet wrap makes the shell look nicer in my opinion. A piece of paper long enough to make two to three turns around the shell, and wide enough to cover the entire side plus the entire diameter of the shell is cut. The paper is pasted were it will overlap the sides of the shell. The shell is rolled up and allowed to dry. The bag formed at the end is then filled with lift. it is then closed the same way.

 

Alternatively, there is another way to finish the shell similar to the pasted wrap. It's mainly for aesthetic reasons, so it's usually reserved for special or particularly large shells where a great deal of time is already invested. The paper is folded down over the lift, and then covered with one or more pieces of pasted paper. This leaves a smooth lightly rounded end, and looks very nice, and tends to give a little more protection to the lift charge. Often the side of the shell is covered with decorative paper. You only need to use maybe 1.5 turns of paper to form the bag itself, and it really only needs to be pasted into the last inch or two if the shell to adhere it. The pasted on decorative paper protects the passfire that is otherwise covered with a full length lift wrap.

[eb11]

no this shell is the second 1 that i made while i was communicating with mumbles i change the burst from 4fg to 2fg and 3 grams of flash to help it out. the shell looked the same on the outside as the 1 i took a picture of

[BlastFromThePast]

Isn't that just awesome, I got everything put together and ready to spike and I pulled out the twine that I had swiped from my parents house and realized it's sisal twine...Not the easiest stuff to use to spike nor is anywhere near the right stuff to use. Going to have to put this shell on hold.

[pyrokid]

Walmart has 20# hemp jewelry twine available for around five dollars.

[eb11]

thats what i use works great just cant get to agressive when pulling on it to spike the shell

[BlastFromThePast]

That's what I'll be picking up then. Just out of curiosity, what kind of twine do serious shell makers use? As far as durability, strength, etc...

[dan999ification]

Cotton, jute or hemp, depending on region and preference.

 

Dan.

[eb11]

my latest 2 inch shell