Dextrin vs SGRS

[usapyro]

In my experience SGRS is a far superior binder to dextrin in binding BP. 2-3% SGRS makes for very hard granules once compacted and screened. It also seems to work better for stars too.

 

I have been reading around and it seems like others have had the same experiences. On average 2% SGRS is equivalent to around 3% dextrin in strength as a binder from what I have been reading on different guides and blogs.

 

So, this begs the question... Why are people using dextrin at all? I would assume screen granulated BP with a mere 2% SGRS produces just as strong granules and more power than 3% dextrin. Edit: Some state it's much much better... Quote from hobbychem: "You only need 2-3% added to formula for proper binding versus dextrin at about 5%. Shimizu states that SGRS is far superior to all other binders in the manufacture of round stars, and that stars bound with it dry harder and are more resistant to moisture penetration once dry."

 

 

I moved completely to SGRS a year ago because it was just easier to work with... Then I started to realize it was stronger and better!

Edited October 19, 2012 by usapyro

[marks265]

I use Dextrin because I'm cheap, I don't need stronger than what I use now, and dextrin is generally more readily available. As with any thing else you want to invest the least amount of money for a satisfactory product. I get that with dextrin. I use SGRS on some comps that require its use and never use SGRS with BP. You must not make a couple hundred pounds of BP a year. When it becomes a numbers game you may rethink it. Even with your ratio of using less I still spend less with Dextrin.

 

I'll reiterate a thought maybe in a different way than my usual. Making your own BP, if done in an acceptable manner, is easy to do as far as being more reactive to commercial powder. Commercial manufactures are very frugal when making their products and to date I have yet to here of SGRS being used. Also BP and round stars are two completely different animals. You may want to quote what Shimizu has to say about BP in reference to a binder.

 

The usual disclaimer is: Hey, if it works for you, go for it!

 

cheers

Mark

[Mortartube]

I use dextrin as it's cheap and easily made at home. It has never failed me when used in appropriate comps, so I see no need to change.

[pyrojig]

You are correct . SGRS is much stronger, and a better binder, but at what cost. I agree too< when making 100+ lbs of powder a year , it is not a cost effective approach . There is not enough gained to justify it in big production. I too use dextrin for the same reasons, and make quite a lot of bp every year as well. ( 50+ lb /year).

[usapyro]

How expensive can it be?!? Binder is total is only around 2-3% vs 4-5% for Dextrin on average. Then you have to consider that binder takes up very little of a composition. For 50lb's of black powder there is only 1lb of SGRS required.

 

Ok, so at APS.... Dextrin is $4/Lb, and SGRS is $12/Lb.

 

Lets say you use 2/5th's more Dextrin than SGRS in a comp for simplicity. That is a cost of $12 per 50Lb's BP for SGRS to a cost of $5.6 Dextrin.

 

So, it comes out to about $6.5 dollars more per 50Lb's BP you granulate. That isn't really much of a significant cost for hobbyists under 100lb's year of composition.

 

 

Personally... My BP cost is approx $2/Lb total with where I buy chems in bulk. $6.5 added in on top of $100... Meh, doesn't bother me!

Edited October 20, 2012 by usapyro

[Potassiumchlorate]

I use dextrin when rolling stars. SGRS takes considerably longer time to activate, so the composition won't stick to the stars when rolling slowly by hand. If I granulate BP or pump stars I use SGRS, though. The stars become really rock hard, and except for stars with high charcoal or aluminium content, you will never have to use more than 4% SGRS.

[pyrojig]

Well, I would agree it is not a large cost jump( for under 100#/yr), for the SGRS, but Potassiumchlorate made a good point. Dextrin is easier for star rolling. My costs for bp are so ridiculously low I'm almost ashamed to admit it. One trick to to buy bulk chems by the hundreds of lbs. There is where your savings are . Another thing is to make your own charcoals, and dextrin. This keeps the cost very low ( well under a $1/lb)for very hot bp. This however doesnt include the milling costs (electricity ) . I havent factored that in yet. .

[Potassiumchlorate]

I have made a batch of Lancaster silver with SGRS now. Still just mixed and wetted. It seems to need even more water for charcoal and aluminium stars.