chemtech89 Posted March 28, 2013 Share Posted March 28, 2013 (edited) I finally received my first crosette pump which I’ve been admiring for quite some time now. I tried pumping my first batch last night and I couldn’t get the crosette off the cross or spindle (unsure of the correct term, I would appreciate a correction). They crumbled one after another even after trying multiple methods of removal and pumping. I even want as far as unscrewing the cross from the rod and tried working it out of the crosette that way. Still didn’t work. The composition is a modified D1 so I used relatively little moister. I tried adding more and more moisture to the composition and I still had the same issue. I’ve read every crosette article/ post I can get my hands on and all that I've found is about assembling, not pumping. In addition, I've been using a hard plastic hammer to do the ramming along with everything else I pump. I’m leaning towards my issue being the lack of some kind of press. To me it seems I need to get more pressure on the composition so it has more strength when removing. Any suggestions or advice? Thanks guys Edited March 28, 2013 by chemtech89 Link to comment Share on other sites More sharing options...
Mia Posted March 28, 2013 Share Posted March 28, 2013 Dip the tip in graphite powder, you need to keep the moisture level low just enough to consolidate the mix it takes practise but you will get there. Link to comment Share on other sites More sharing options...
chemtech89 Posted March 29, 2013 Author Share Posted March 29, 2013 Yes now that I'm adding the word "graphite" into my searches I'm finally getting the information I've been looking for. Thanks for the help! Link to comment Share on other sites More sharing options...
Mumbles Posted March 29, 2013 Share Posted March 29, 2013 I've found lubrication to be the key. It's less of an issue for pumps with nituff, and slightly more of an issue with pumps without or with slightly rough finishes like those chinese brass ones. Graphite powder works. I've also had success with spray silicon, teflon, or graphite coatings. When I was first shown how to pump crossettes, we actually use cooking spray as a lubricant, and it worked pretty well actually. Cleaning off clinging bits of comp with an old tooth brush can also help prevent chipping and fragmenting. I've taken to using an arbor press personally. I find I can get more consistent results with it vs. hand ramming. The type of compression, and thus total compression in a way, will also play a role in how much water is required. Very hard pressing such as a hydraulic apparatus can get away with minimal water, around 1-4%. With a strong arbor press I only needed about 5-6%. With a weaker (1 ton) arbor press I typically needed 8-10%, maybe 12% on occasion. With hand ramming I typically needed maybe 10-14%. Link to comment Share on other sites More sharing options...
chemtech89 Posted March 29, 2013 Author Share Posted March 29, 2013 (edited) I probably would have gone with a pump using nituff if I had been able to find these discussions earlier. Ill try with the graphite and cooking spray at this point since they are easy to obtain. I’ve read you can get graphite powder at homedepot. Also, my moisture was at 10% which seems about right but ill try less next time since of course it easier to add then wait for evaporation. I have also read that in some comps 2% graphite is added to the mix to aid with release from the cross plunger and with the break... I can't wait to build and use a pneumatic press. Edited March 29, 2013 by chemtech89 Link to comment Share on other sites More sharing options...
dynomike1 Posted March 30, 2013 Share Posted March 30, 2013 I was having trouble with a star plate when i was beating on it, 1/2 my stares would break so i started using a vise. Fixed that problem.You used to could get an ignition spray that was to repel water on plug wires it was grafite based, that's what i use on my star plate. Link to comment Share on other sites More sharing options...
dagabu Posted April 9, 2013 Share Posted April 9, 2013 To expound on the methodology some, I like Mum use an arbor press but I also use an ejection tube to eject the cossettes from the pump and then simply pull the plunger back through the body, leaving the crossette in the tube. That said, even with graphite and my method of ejecting them, I still have issues with the cruciform holding comp and giving a clean separation. I personally found moisture and dwell time to be the most important to me and my son can make them all day long with perfect results each time. More magic than mechanical? Link to comment Share on other sites More sharing options...
PyroLoudness Posted April 9, 2013 Share Posted April 9, 2013 I tried to make my first crossettes but I had some cracks in the comets everytime. I guess the quality of the tool is also important. With my chinese brass pump, the surface of the cruciform part is not very smooth... so maybe a good tool would be a first step to success ?Good thread by the way, I'll try the ideas posted here Link to comment Share on other sites More sharing options...
azhomegrown Posted May 12, 2013 Share Posted May 12, 2013 IMO Moisture level is the first step in successfully pumping and removing a crossette from it's tooling, so I try to use the least amount I can get away with for a given composition. Next, some method of lubrication. Graphite seems to be the most commonly referred to lubricant to but I've had plenty of success simply using air float charcoal which is cheaper than buying graphite at the Depot and is generally more readily available to most pyros. I say this because it has worked for me and I have one of those quote, "cheap Chinese brass pumps." Also to note, I have found that for me prepping small batches has worked better. What I mean by this is that I only add water to small amounts of composition at a time. When I was doing this with larger batches I was having trouble with it drying and forming clumps and re-wetting was causing the composition to become kind of sticky thus preventing a proper release of the comet from the tooling. Link to comment Share on other sites More sharing options...
Recommended Posts