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Shell construction question


cogbarry

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Hi gang,

Just wondering what most of you use for a method of sealing around the time fuse or whatever the penetrations in your shells. For the most part I have simply used hot glue but I don't know how reliable this is and I've noticed that hot glue (especially at the hotter setting) tends to form bubbles. I'd like to find an optimal way of ensuring protection from lift gasses. I've read or seen other methods such as using string dipped in paste.

Thanks in advance for any info, links, etc.

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hot glue and thin cotton twine wrapped around the TF while the glue is still hot.

Thie string/glue will compress under pressure

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It depends on the shell type and size. For small cylinders, I use a double disk where the first disk is hot glued in with the time fuse and the second is added while the hot glue is still hot and more hot glue is added above the second disk. It ends up being similar to Killerinc's method.

 

For spolettes and larger cylinders using time fuse, I use the pastewrap and make a cone around the passfire sealing it against fire the traditional way.

 

For ball shells, i take a page from the Chinese and use white glue and cotton string and make a cone around the time fuse(s) that is as wide at the base as the time fuse is tall. This method seems to work well for paper hemis of all sizes. With plastic, i use hot glue and cotton string like Algenco does.

 

-dag

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Hi gang,

Just wondering what most of you use for a method of sealing around the time fuse or whatever the penetrations in your shells.

 

I use high quality hotglue on both sides ( both outside and inside with hotglue around timefuse). I also take care to paste a bit overlapping over the slight hotglue blob on the outside. With ballshells effective sealing of the timefuse is an essential step to prevent problems such as flowerpotting and so forth.

 

Also, I use a slightly smaller fuse hole for my timefuse. It should be a tight fit, and not be able to move when placed. I use a 5 mm puncher for 5.5/6 mm timefuse.

Edited by fredhappy
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I use high quality hotglue on both sides ( both outside and inside with hotglue around timefuse). I also take care to paste a bit overlapping over the slight hotglue blob on the outside. With ballshells effective sealing of the timefuse is an essential step to prevent problems such as flowerpotting and so forth.

 

Also, I use a slightly smaller fuse hole for my timefuse. It should be a tight fit, and not be able to move when placed. I use a 5 mm puncher for 5.5/6 mm timefuse.

 

Hot glue, no matter what the quality, will crack when cold or is impacted. Hide glue and most white glue remains somewhat flexible while in cold weather and when impacted. The string helps in any case.

 

-dag

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String and paste, or string and PVA.

 

When I'm feeling the ghetto vibes, I will admit that on the odd occasion hot glue is used.

 

It's good seeing such consistency in methods.

Edited by Seymour
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Hot glue, no matter what the quality, will crack when cold or is impacted. Hide glue and most white glue remains somewhat flexible while in cold weather and when impacted. The string helps in any case.

 

-dag

 

I see your point dagabu. I do take care that the timefuse is a really tight fit in the hemi . For 6 mm timefuse I use a 5 mm puncher for the hemi, so I have to really push the timefuse in. I do however sometimes observe this bubbling of the hotglue as your guys mention.

 

When I glue the timefuse in the hemi, I go around the timefuse with the hot nozzle of my glue gun, smoothing out the glue blob. I do this both the inside and outside. Furthermore I always check with a light and magnifier how well everything is sealed . I am always very attentive during this step. I must say that this is a very good question being brought up , since it concerns such an important step when building ballshells.

 

I will give the string idea a try though, I've seen it used , and it seems like a good thing to add.

 

best

 

fred

Edited by fredhappy
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I've made quite a few 2" and 3" standard strawboard ball shells, and haven't had a single flowerpot with a homemade one yet. On the other hand the 3rd festive ball I shot recently flowerpotted! Thats scary stuff when its unexpected!

 

This is my method for strawboard 2" ball shells, using no hot glue

 

Anyway I am stuck with only good visco fuse, so what I do is drill a small hole in the hemi, (can't remember the size - around 1/8 or less), Then get my piece of visco, after I have cut it to length and straightened it, then wrap it really tightly with gummed tape (no water though). 1" wide tape gives me a good 3 sec delay, as with this method delay is timed by the width of the paper. I find rolling the tape initially on a thin nail helps it form to the fuse better. It must be tight any gas leak will cause a flowerpot, but be careful not to damage the fuse

 

Wrap the visco tightly until when inserted into the hole in the hemi it is a fairly firm fit, it should easily hold it self in. Usually I go over size and rip little bits of tape off till it just barely fits, then apply a little bit of damp to the end of the tape and seal it (so it doesn't unturn) (avoid getting the tape wet). Insert the fuse into the shell.

 

On 2" shells about 3/8" of tape remains outside the shell and this is used to glue the fuse to the shell. So I like to apply a few short pieces of gummed tape around the tape on the fuse to the shell, sorry I don't have any photos.

Using the 3 strip pasting method, I attach the first strip of every 3 so it is just on the fuse tape. When I have finished taping I usually like to add a few more little pieces of tape on the fuse tape to the shell to hold everything down. I have noticed that while pasting, the dampness of the tape is enough to completely seal the fuse tape onto the shell. You'll also notice doing it this way builds up the characteristic reinforcing ridge.

 

I have sort of devised this method myself, as hot glue on a 2" shell takes up too much room inside the shell, and mess's with symetric breaks.

It does take a little extra effort but this method has never failed for me!

Edited by Falcon2
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push it nearly all the way in glue the inside with glue of your choice, twist and pull the fuse out to where it needs to be and glue the inside again, glue the outside, paste over well and glue again when the final touches go on, cross match, leader etc.

never fails me.

 

dan.

 

 

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