7 replies to this topic

[RegimentalPyro]

Today I had a bash at making crossettes using my new pumps, meeting with limited success.

I mixed up a 100g batch of Chrysanthemum no.6 + 5%dextrin , but didn't mill it in any way, just screened the raw powders together.

I then tried making two different sizes of crossette. With both pumps I experienced the same problem. I could not get the damn crossette off the pump without breaking it! The problem always seemed to lie with the end with the star shaped hole in it. It *always* seemed to cling to the piston.

I tried increasing the amount of solvent, dipping the pump in water first, and wiping the pump with an oily cloth. Nothing seemed to do the trick.

Has anybody got any advice? I'm a bit stumped!

[Creepin_pyro]

I had the same problem with my first batch of 3/4" crossettes, and also tried wetting the pump with water which didn't work. I ended up genorously misting the cavity-forming section of pump with pure Isopropyl alcohol each time before pumping - seemed to do the trick. Not sure if this method should be any more effective than what you've already tried, but you might want to give it a go...

Good luck with those tricky little beggars : )

[Pretty green flames]

Regi, you could always try sprinkling some graphite on the piston, this should release the finished crossette
quite easily.

[Frozentech]

Today I had a bash at making crossettes using my new pumps, meeting with limited success.

I mixed up a 100g batch of Chrysanthemum no.6 + 5%dextrin , but didn't mill it in any way, just screened the raw powders together.

I then tried making two different sizes of crossette. With both pumps I experienced the same problem. I could not get the damn crossette off the pump without breaking it! The problem always seemed to lie with the end with the star shaped hole in it. It *always* seemed to cling to the piston.

I tried increasing the amount of solvent, dipping the pump in water first, and wiping the pump with an oily cloth. Nothing seemed to do the trick.

Has anybody got any advice? I'm a bit stumped!

Regi, two things I can think of are to wipe the piston with graphite and perhaps drop just a pinch into the cavity, or to try some PTFE 'dry lube' spray. Both of these methods have worked for me to ease removal of spindles while pressing rockets.

I recall some discussion of this several months ago on the rec.pyrotechnics newsgroup. I can't recall specifics of the solutions mentioned.

[GBthriller]

Today I had a bash at making crossettes using my new pumps, meeting with limited success.

I mixed up a 100g batch of Chrysanthemum no.6 + 5%dextrin , but didn't mill it in any way, just screened the raw powders together.

I then tried making two different sizes of crossette. With both pumps I experienced the same problem. I could not get the damn crossette off the pump without breaking it! The problem always seemed to lie with the end with the star shaped hole in it. It *always* seemed to cling to the piston.

I tried increasing the amount of solvent, dipping the pump in water first, and wiping the pump with an oily cloth. Nothing seemed to do the trick.

Has anybody got any advice? I'm a bit stumped!

Nothing to help you here, but I need to say thanks for the good info! I learn more from other pyro's complete descriptions of problems than I do from their "how to" tutorials.

Thanks!!

[Frozentech]

I did some more research about this Regi, as I just ordered a 3/4" wolter crossette pump myself. One thing I found mentioned several times was to have the comp *less* wetted, not more. I guess most comps do get 'stickier' as they get wetter. The other was the graphite advice. The newer Wolter tooling is coated with 'nituff' which evidently incorporates PTFE in the coating, but a light spray of PTFE drylube certainly could help.

[RegimentalPyro]

Thanks for the advice guys. I'm gonna go down the graphite route first. If that doesn't work I'll get some PTFE drylube.

Either way, I'll let you know how I get on.

[adamw]

Certainly the wetness of the comp will affect how easy it is to release from the cavity. Try tapping it off rather than trying to pull it off. Try dipping the cavity in IPA before making a crossette.