41 replies to this topic

[Atom Fireworks]

Hi peeps, a question for all you shell builders out there.

I am having difficulty finding information about how to paste shells properly. I have been using the 3 strip method with success but you are not supposed to get build up at the poles and i am getting that so i presume i am doing some thing wrong. I place 1 strip top to bottom and one next to it over lapping at each pole and in the middle barely touching. i repeat this many times over to get my desired diametre.

Do you guys no of any better ways or even easier ways to do this, some diagrams or maybe point me in the directrion of some online info about it.

Many thaks to those who respond,
Dumper

[crystal palace fireworks]

Mighten it be an idea to hold the shell in `C` shape vice (a bit like a atlas globe) with ends that grip but turn freely, whereby you start the taping in the north pole by turning the shell to overlap the taping slightly down to the south pole so to speak, .....you can then do this again starting at the equator until the required thickness is achieved (that way there is no full overlaping of tape at the poles or equator).

[Pretty green flames]

Simple is always best. I use paper strip that go from pole to pole all around the fuse, from the fuse down to the south pole. I cut them only as long so they don't overlap at the bottom, eliminatig paper buildup. The last strip is pasted on the south pole to fireproof the small part that has been left unpasted (because the strips dont overlap on the bottom).

[Night Owl]

I cut my strips into a point at the top, just a point on one side not an arrow point this avoids the build up and its how the chinese do it:)

[Arthur Brown]

The three strip method requires that the strips be the same length as the diameter of the shell. This way a strip from a pole goes to the other tropic latitude, the second strip goes from the arctic circle to the antarctic circle the third strip goes from the south pole to the far tropic line.

Get a globe it really does make sense.

This means that you have three strips over the equator region and only one strip over the polar region.

[Atom Fireworks]

Cheers fellas, i like the idea of cuttin the ends of the strips down to a point sounds lodgical. Arthur i am sorry if i sound absolutly dumb but i still dont understand exactly what you mean in the 3 strip pastin method are you sayin the strip need to be layed from one pole to the other but it will only make it to the equator and then anoth from the other pole that just reaches the equator and then a strip centered over the equator?

Also if u just went at it with some long strips of gummed tape and made sure as you do it it stayed as spherical as possible would this method be acceptable or not?

Cheers guys much appreciated.
Dumper

[Arthur Brown]

Try the three strip method but use strips of paper as long as the diameter of the hemi.

http://www.pyroguide...3_strip_method)

Here are pictures

It's quite normal for commercial shells to be pasted, dried, then sanded smooth then given an almost decorative final coat of strips from shaped strips prior to having the lift cup and the label attached.

The WASP shell paster does take gummed paper strip in long rolls and make a ball without polar thickness problems by virtue of it's mechanism and programming. It also costs big money but will wrap a 12in shell in about 5 minutes!

[digger]

Yep them fancy dancy WASP's really take the labour out of shell pasting. However getting the programming right for the small 3" shells was a bit of a chore. The big un's are a doddle though.

[Night Owl]

Pasting machine, take a look

[Atom Fireworks]

Yea i have seen that pasting machine, i bet its expensive and as i only make maybe a shell a week or less wouldnt be cost effective. Also guys this is abit off topic but i have been using bp coated rice crispies as burst in 3 inch shells, they do burst but not like a big full spherical ball, i no pasting has a big influence on this but i believe its the burst in this case. do you guys use anything different to burst 3 inch and smaller, i am about to move on and make some 4 inch and test them and then when i get that right maybe a 5 see how the 4s pan out first.

Dumper

[digger]

I use KP on crispies in 4"ers and in 3"ers I use either H3 or KP depending on star composition. You could always just add 10g of a good quality catalysed whistle as this will give you a good break.

[Atom Fireworks]

I use KP on crispies in 4"ers and in 3"ers I use either H3 or KP depending on star composition. You could always just add 10g of a good quality catalysed whistle as this will give you a good break.

Hi digger, i have read somewhere about h3 and kp. Is this a sensative comp as apposed to normal bp. And also could you give me the ratios that work for u. Also i use all perchlorate stars so which one is best for burst?

Dumper

[digger]

H3 does have issues as it is chlorate based, so you can't use it where it will come into contact with a prime containing Sulphur. KP however is far more tolerant. I use between 4:1 and 6:1 of either of these to crispies. If you use KP in a 3"er you may still need to boost it with whistle or flash.

KP:
Potassium Perchlorate 70
Charcoal Airfloat 18
Sulfur 12
Dextrin 5

H3
Potassium Chlorate 75
Charcoal Airfloat 25
Dextrin 5

Ultimately the cheapest and easiest option is to use BP with a booster.

[Atom Fireworks]

H3 does have issues as it is chlorate based, so you can't use it where it will come into contact with a prime containing Sulphur. KP however is far more tolerant. I use between 4:1 and 6:1 of either of these to crispies. If you use KP in a 3"er you may still need to boost it with whistle or flash.

KP:
Potassium Perchlorate 70
Charcoal Airfloat 18
Sulfur 12
Dextrin 5

H3
Potassium Chlorate 75
Charcoal Airfloat 25
Dextrin 5

Ultimately the cheapest and easiest option is to use BP with a booster.

If i am gettin a burst (spread of stars) 35+ meters with just my milled bp on crispies is that good enough or should they be being thrown further in say a poeny shell, obviously willow shells are different animal and do not need to be burst and spread hard.

Cheers guys Dumper

[digger]

If i am gettin a burst (spread of stars) 35+ meters with just my milled bp on crispies is that good enough or should they be being thrown further in say a poeny shell, obviously willow shells are different animal and do not need to be burst and spread hard.

Cheers guys Dumper

Depends on the size of the shell I guess. 100ft+ sounds good for a 3" shell.