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Binder Pre-Activation?


nwpyro

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I have been hearing about this new technique around the forum... Who thought this up? It definitely makes great sense for glitters... Mixing Dextrin or SGRS with hot water to fully activate it before mixing it into a comp.

 

If your pressing glitters and using low moisture (Around 4-8%) a lot of the binder probably isn't wetted enough to be activated!

 

So, for those who are doing this... What are your experiences? Does it work good with both dextrin and SGRS? Are there any issues with getting all of the binder evenly though the composition?

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Eugene Yurek touted the "dextrin liquor" a few years ago and Mike Swisher pointed out that it was an old technique. I do not have his photographic memory to recall his source, but it is probably in the Passfire archives if you are inclined to search for it.

 

He simply suggests making a 10% dextrin solution in warer and using this to granulate BP. I have always had to boil it to get all the dextrin to go in to solution. I also use a 20% solution to mix with flour when making paste for wet rolled rocket headers. (Kurt Medlin's tip) He claims and a few others verified that it makes the BP hotter. It is assumed this is because less dextrin gets into the BP and because the binder coats everything else and reduces the amount of KNO3 from recrystalizing. Others then started using the dextrin solution to stick prime onto dried stars and to dampen comp for cutting and pressing.

 

I cannot vouch for improvements in speed of BP, because I have not tested it. I have not had any problems getting the binder evenly through the composition. As I mentioned in another thread, I dampen the composition and run it through a screen a few times and let it rest to evenly distribute all of the moisture. The only glitter comp I have been using is D1 and this method works just fine. It has worked for me for the various charcoal streamers published by Shimizu. It has worked for me to prime stars bound by red gum or phenolic resin. I have not tried it with SGRS.

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4 to 8 % of water to activate the binders for pressing should be plenty, but it will vary some depending on the specific formula. Also how well/evenly your getting the water incorporated. And, weather your hand ramming or pressing, will also affect how the comp "feels" I've found, in general that with most of the glitters I've pressed. 7-8% would be to wet/sticky for my liking. I've never used the Dextrin Solution for wetting comps, but I do use it at 10% solution to prime stars with.
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