Soluble glutinous rice starch

From PyroGuide

Description: Soluble glutinous rice starch more commonly referred to as 'SGRS' is a binder used by the Japanese star makers. SGRS is used as a water-soluble binder in many of Takeo Shimizu's formulas. This is not just because SGRS is more easily obtained in Japan than cornstarch derivatives like dextrin. SGRS does indeed have superior binding characteristics than dextrin, and somewhat less of it can be used than dextrin in most formulas.

Hazards: Soluble glutinous rice starch is not particularly toxic or dangerous.

Sources: Soluble glutinous rice starch can be hard to come by, but can be made at home:

"Glutinous rice is polished and soaked in cold water for a week. This is then steamed in a steam basket and pounded into a cohesive mass. The mass is stretched into a thin plate like a squashed cake, which is parched at a suitable temperature. The parched cake is ground into a fine powder. The powder is somewhat brownish, but has a large cohesion power and is perfectly gelatinized in combination with water. This is the most useful binding agent for firework stars." - Shimizu

I have recently made some SRGS: soak rice in cold water for a week, steam for an hour, dry out in oven. Powder in coffee grinder. All worked fine but seemed a lot of effort and time consuming. Second attempt: put dry rice in coffee grinder mixed resulting flour with water, brought to boil and simmered for 15 minutes, stiring continously. Transfered resulting 'glue' to low oven to brown. Put dry mixture in coffee grinder to produce identical SRGS in just over two hours.

The warm mix of the rice flour reminded me of wallpaper paste. I have now made some stars with 'Polycel' powder and another lot with a propietry 'boiled flour' wallpaper paste. Using the quantities of these wallpaper pastes as given for SRGS I have got a series of identical stars. I will use Polycel in future as my binder as at £1.50 for 200g, it is cheaper and a lot less effort. A visit to this wallpaper site is most revealing: www.wallpaperinstaller.com/adhesives.html - JR