Number of layers when pasting

[ChloRure]

Well I need to do some 3 inchs and 4 inchs that I want to fire in about 1 month and it actually take so much time to paste them.

 

I read on forums that people use about 2 layers per shell inch size.... so 8 layers for 4 inchs ?

 

I am asking because my shell require a lot more I think... or I just paranoid and I can fire them with less layers that im used ?

 

Here is the gummed take I use... http://www.pyrodirect.com/ecom-catshow/kraft_tape.html

 

I use the 1/2 inch and 1 inch size, and for 3 inchs I do 12 layers so I get a gap of about 4-5mm before fuse. 12 layers is pretty long when you want to make a lot of shells...

 

Do you think I should use less ?

 

Thanks

[Mumbles]

This is unfortunately a question that does not have a definitive answer. It depends strongly on your burst, and on personal preferences. Weak bursts will require stronger confinement to get them to preform well. Overly strong bursts (heavy flash) will allow you to get away with much less at the cost of a few other things.

 

I personally use a KP type burst in 4" shells, and around 9 layers of 1" 35lb paper tape. I use 7 of 3/4" tape on 3" shells. Once you get into a rhythm, pasting doesn't take all that long once you're all set up. I paste shells of this caliber in one sitting. A 3" shell takes me less than 10 minutes, and a 4" shell takes me less than 15 or 20. Many others can go much faster, especially when a few jigs are made. I wet the tape in arm span increments by pulling it through a damp cloth. I actually use the same number of layers when bursting shells with BP on puffed rice. It will not give a big chinese style burst that some of fond of though.

[Potassiumchlorate]

I use 2" paper tape for 5" and 6" shells. I have been making shells since 2009, but sometimes the burst looks assymetric for no apparent reason. Could the tape be the cause?

[50AE]

Assymetry can be reason of various reasons:

 

-irregular pasting - do you switch poles when pasting?

-weak pasting - by paper tape, do you mean the soft one for painting jobs? If yes, this one sucks for the job - it's weak.

-break too soon or too late, shell not at the apogee. This one could be tricky and needs practice to perfectly achieve and is mainly dependent of the lift powder quality, shell to mortar size, mortar length, and lift to shell weight.

-shell hemispheres very hard, or burst too weak. The harder the shell wall, the more the equator gap will be significant. I have achieved excellent results with the soft vacuum formed hemis.

-stars shape - cut stars for example can results in a crappy break shape for a ball shell.

Edited April 22, 2012 by 50AE

[ChloRure]

Well, when doing 1.75" I dont use any booster at all, just Rice Hulls. The sound is not that loud but I almost get 0 blind stars. As for the only 3 inch I did previously, I used 12 layers and about 2g of Kclo4/al booster and break was too big. I guess I can try to paste a little less or juste use no booster in the 3 inchs. But if you use less layers, you probly need to add more lift.

[Potassiumchlorate]

The tape is strong. I think you are thinking of masking tape. It's not masking tape.

 

I don't always switch the poles. That might be the reason.

[Mumbles]

For small shells, the diameter gained from pasting is relatively small. For instance the 9 layers I add to a 4" shell adds only 1/16th of an inch to the total diameter. Adding or removing a few of those layers is not going to make any difference. Even if it did, so what? I don't see what your argument is with that. Are you saying that you'd rather over paste a shell to save on lift?

[ChloRure]

For small shells, the diameter gained from pasting is relatively small. For instance the 9 layers I add to a 4" shell adds only 1/16th of an inch to the total diameter. Adding or removing a few of those layers is not going to make any difference. Even if it did, so what? I don't see what your argument is with that. Are you saying that you'd rather over paste a shell to save on lift?

 

No no.. was just afraid to remove layers and have a too large gap and thyen a flower pot. I guess I will go with the trial/error way and see.

[Potassiumchlorate]

Does anyone have any opinions about my tape being 2"? I bought my first pasting tape together with other stuff from a guy who quit the hobby. He used it for 5" shells, and they looked great in performance.

[dagabu]

I split 2" rolls and use 1" tape for 4-6" shells, 1-1/4" for 8" and 1-1/2" for larger shells and use 1/2 to 3/4" tape for 3" and smaller. I use a copy of Kyle's tape dispenser for pasting shells.

 

http://passfir1.w07.winhost.com/portals/1/images/volume7_1/tape_shells_15.jpg

 

 

-dag

[Potassiumchlorate]

Hm, maybe I should split it, then. I have 1" and 30mm as well but usually use it for 2" and 3" shells.