pyrochris732 Posted April 23, 2010 Posted April 23, 2010 Hi guys, I ordered a 3/8 inch star pump from pyrodirect that came today. I would like to use this to pump some simple comps like TT and D1 or willow diadem stars. Is this sufficient for very small cylinder shells around 2 inches? Also, does rubbing alcohol help the TT comp integrate into itself better? or dry faster? My stars take forever to dry but I think they are too big. Also would like to say that the site looks great, really glad i found it and look forward to talking to you. Im a newbie so if i ask any stupid questions, just be patient with me, lol. Chris
mike_au Posted April 23, 2010 Posted April 23, 2010 TT and I think D1 as well use dextrin as a binder, which means you need water, you can't use straight alcohol. You can add a bit of isopropyl alcohol or denatured spirits (which is generally cheaper) to reduce surface tension (making mixing a little bit easier) and decrease drying time. I use about 15% denatured alcohol, 85% water v/v. Drying slowly is better than drying too fast. 3/8" sounds like a reasonable size for a 2" shell (I haven't made one that small myself, but it sounds OK). Welcome to the board and the hobby
FREAKYDUTCHMEN Posted April 23, 2010 Posted April 23, 2010 Hi Chris, you'll only need about 6 to 20% moisture to pump your stars. Depends on the type of star you're making. More charcoal means more solvent. You can up your alcohol to about 50%, but with such a little pump it doesn't really matter. Just pump some and you'll see.
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