spollette dimensions

[MadMat]

I recently looked at a chart on skylighters website that listed dimensions for spollettes. According to this chart a spollette for a 3" shell should have an I.D. of 5/16" and an O.D. of .55". That sounded kind of large for me. My thinking on the matter is that a 5/16 hole would defeat the containment for the burst charge. For the 3" shells I have made so far, the I.D. of my spollettes was 3/16". I did this simply because I had the tooling on hand to make the tube and ram the powder for that particular size. I haven't had any problems with this size, so far, but haven't made that many shells as of yet. Is there a particular reason for making the I.D. of a spollette that large that I am just not seeing?

Edited June 3, 2016 by MadMat

[lloyd]

What Harry quoted is about right, Mad.

Lloyd

Edited June 3, 2016 by lloyd

[memo]

i have been using 3/8 id 1/2 od hand rolled 70 lb kraft , works well for me

 

memo

[Mike]

I always used 6mm i.d. 10 mm od on that size w/o problems.

[Carbon796]

There will not be any containment issues with a 5/16" ID spolette. That size is traditionally used all the way down to 1-3/4" inserts. A 5/16" x 1/2" spolette will probably have an edge in reliability. It will also deliver a larger burst of fire to the shell.

[Wiley]

I hand-roll 1/4" ID X 3/8" OD tubes from ~70# contractor's paper and watered-down Elmer's. They work great, and all my shells are 1.75" nominal. They've been in everything from single breaks up to 6 break-and-reports like these.

 

[Zumber]

OMG..!!

[Mixer]

3/16"ID here too. I`ve been using these for well over 40 years with no problems.

Edited June 5, 2016 by Mixer

[OldMarine]

I lucked up and acquired a case of 3" wide register receipt paper and have settled on rolling this 1/4"x3/8" tubes for use as passfires and spollettes. I may need to roll larger passfire tubes later as I move to cylinders larger than 3" but these should suffice for now.