24 replies to this topic

[ridley]

sssssssssssssssssss?

Edited by ridley, 14 February 2015 - 09:59 PM.

[cooperman435]

The pulverone is unlikely to have "gone off" but it could have gotten damp maybe?

If the shell goes down it will come out. A tight shell will actually result in a higher launch as the pressure build-up and speed of burn is increased.

If ya have a look at my old website there's a tutorial and info on ematches that many many people have sent me thanks for the reliable info and easy construction techniques.

[bigtonyicu]

Even if the pulverstone had goten damp that's a one tenth the height.

Sounds more to me like a fit thing, any chances these last shells were smaller?

Same mortars?

Edited by bigtonyicu, 20 August 2008 - 07:23 PM.

[Bonny]

Sounds like the pulverone is the problem IMO. Even a loose fitting shell should have gone much higher than 30 or 40ft, especially if you previously fired one 300ft with the same batch. My ball shells are usually quite loose in the mortar (1/8"+ all the way around) and they go up ~300ft with about 1/10 weight of pressed and granulated BP (-4+10mesh for the nice dull thump and easier on the shell).

For my homemade ematches I usually dip the nichrome wire and joints in NC first then allow to dry in order to protect the nichrome from corrosion..although I have skipped this step with fine results. I then dip into NC/BP slurry and voila!

[pyromaniac303]

Were you using dextrin to bind your pulverone? And if so how much, that could have caused a dampness problem.

On the subject of going off, I have left bp and other similar comps before and found a furry fungus-like deposit on them, although it doesnt seem to affect their performance. It only appears after they have been dampened and exposed to the air though.

[cooperman435]

The shells and tube were the same on the first launch as the second, as he got both of them from me.

Bigtonyicu? Are you suggesting that damp bp would still lift a shell to a decent height? From my experience any amount of moisture dramatically effects my own bp's ability to lift.

[karlfoxman]

How did you hold the Blackpowder inside the lifting cup? In a bag with the leader tied off? If it was loose inside the cup and your quickmatch leader isnt too thick, where the leader passes into the cup there is a gap. Lift can easily fall out the gaps dudring transport, all my lift charges are held inside plastic bags with the leader much like any decent quality commercial ball shell. This helps prevent damp and also keeps the grains from falling through unwanted gaps.

[bigtonyicu]

Bigtonyicu? Are you suggesting that damp bp would still lift a shell to a decent height? From my experience any amount of moisture dramatically effects my own bp's ability to lift.

I live in the Ottawa Valley in Canada were all are summers are at 100% humidex, I'm not saying that there's no difference from 0% humidity, but the generally the height difference on my shelf in no more then 20% (VERY MAX). The only way I could see humidity becoming a very big factor is if a large amount of dextrin is being used as binder (say +10%). My cups are nothing more then a small section of tube paste to the bottom of the shell, once dried, I fill them and tape over the bottom with aluminum tape, so nothing particularly air tight.

How did you hold the Blackpowder inside the lifting cup? In a bag with the leader tied off? If it was loose inside the cup and your quickmatch leader isnt too thick, where the leader passes into the cup there is a gap. Lift can easily fall out the gaps dudring transport, all my lift charges are held inside plastic bags with the leader much like any decent quality commercial ball shell. This helps prevent damp and also keeps the grains from falling through unwanted gaps.

That's more what I'm thinking might of happen.

Is you lift from the same batch? and if so how did you sort your grain size?

(If the grains are very big, you might not get the full power)

[ridley]

The pulverone is from the same batch and has been stored in a sealed food container.

Ridley

[ridley]

Oh and it was about 4% Dextrin.

[bigtonyicu]

The pulverone is from the same batch and has been stored in a sealed food container.

Ridley

not stored... sorted,

How did you seperate the grain size?

[karlfoxman]

Ridley:

How are the lift grains held on the bottom of the shell? Do you use the lift cup from Plasticos Gamon?

[ridley]

Yes they were in the plastico lift cup.

[karlfoxman]

Is there a gap where your match passes into the lift cup? I susspect that your lift has leaked from this gap if there was one and you have ended up with less lift.

[cooperman435]

He says he was using pulverone so theres no grains guys.

Bigtonyicu IM not trying to be funny (honestly) but I dont understand the last reply re Humidity? are you saying that when you have high humidity your shells show a 20% decrese in height? If so hight humidity is a long step from damp bp and a 20% decrese in performance surely shows that dampness effects the lifting performance dramatically?