Step 3Filling with stars/burst and closing
Arrange the stars around the wall of the hemispheres to the rim. The stars should be sticking a bit over the rim. If the shell is underfilled it will result in a visible area of no stars when the shell is launched.
Next cut two pieces of tissue paper, one of them with a hole to go over the time fuse or spolette. Put the pieces in each hemispheres against the stars and fill tighly with burst charge to the rim. A bit of "booster", such as whistle mix or flash powder is added in the center of each hemisphere and spread loosely in the burst charge with fingers. Not much should be used, maximum 1g.
Quickly snap the two shell hemispheres together. This is not as hard as it sounds like, but if done too slowly, the stars or burst charge might rearrange or fall out, and the previous steps will need to be repeated. If the rim each paper hemisphere touch eachother at this point, the shell is underfilled. However if done correctly there should be a small gap of around 1 cm at equator. Place the shell on the stand time fuse-side down, and use a wooden dowel to gently hit the upper hemisphere on different places. The stars will then arrange inside the shell and hopefully the two hemispheres will reach eachother. Seal up around the equator with masking tape to close the shell temporarily. Also put a piece of masking tape around the end of the time fuse or spolette to protect it from being damaged during the next steps.
Next cut two pieces of tissue paper, one of them with a hole to go over the time fuse or spolette. Put the pieces in each hemispheres against the stars and fill tighly with burst charge to the rim. A bit of "booster", such as whistle mix or flash powder is added in the center of each hemisphere and spread loosely in the burst charge with fingers. Not much should be used, maximum 1g.
Quickly snap the two shell hemispheres together. This is not as hard as it sounds like, but if done too slowly, the stars or burst charge might rearrange or fall out, and the previous steps will need to be repeated. If the rim each paper hemisphere touch eachother at this point, the shell is underfilled. However if done correctly there should be a small gap of around 1 cm at equator. Place the shell on the stand time fuse-side down, and use a wooden dowel to gently hit the upper hemisphere on different places. The stars will then arrange inside the shell and hopefully the two hemispheres will reach eachother. Seal up around the equator with masking tape to close the shell temporarily. Also put a piece of masking tape around the end of the time fuse or spolette to protect it from being damaged during the next steps.
Step 4Pasting the shell
The next step is pasting the shell, which is the hardest and most time-consuming part of round shells. The pasting method descriped here is the socalled 3-strip pasting method. Unlike the "normal" pasting method (pasting strips with a length of half the equator around the shell) the 3-strip pasting method does not "build up" near poles.
To make your pasting strips sticky before you paste you will need to add a glue to each 70x15 mm kraft paper strip on one side. This can be done quickly by arranging some strips on a wide wooden board. Next apply a thin, even layer of wheat paste with a brush. These strips are now ready for pasting, but you will need to repeat this step many times, since you will need a lot of strips to complete your shell.
The shell is pasted as showed on the picture. A strip is pasted from the "northpole" pointing towards the "southpole". Then a strip beside is pasted from the "southpole" pointing towards the "northpole". A strip is then pasted between these two strip. This pattern is continuously pasted around the shell. Press out the airbubbles under the strips, this will result in a nice-looking shell. Everytime you finish a way around the shell (layer) make sure to write on the shell how many layers you have pasted so far, you might forget it. When finished pasting the shell, multiply the layer-number by two, since each layer with this pasting method counts for two actual layers.
While pasting the shell, cut a ~8 cm piece of cotton twine and make a loop on it. Hot glue it to the top of the shell (the opposite hemispheres of the one with the time fuse in it) and paste like before, just making the strip covering the twine. This shell needed 10 layers of pasting (=20 layers) to complete. The ideal is to make the shell ~5 mm smaller than the mortar tube, in this case the OD of the shell should be ~7 cm. Making it this diameter might take hours for beginners to complete. After the layers of pasting, let the shell dry completely.
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: Ayoo sharingg.. :D