Why binder in bp?

[kingkama]

I newer added binder in my bp i tried dextrine but It slow bp a lot, so i use only water or acetone or alcool or a mix of them. Bp grain are hard and the performance endure in the time. So why add binder.

 

Recipes i use are:

 

75-15-10 Willow

74-14-12 "

72-20-09 wine

68-16-16 Willow

 

KNO3-charcoal-sulfur% kind of charcoal

 

First 3 four hour mill

Last One One hour mill

[Arthur]

Traditionally BP was made from wheel milled powder pressed into big cakes then broken (corned). This yielded a large variety of sizes of hard particles from blow away dust to 0FA. Amateurs don't usually have a press, so usually granulate the milled product, which produces a weaker grain structure. To increase the grain strength binder is added which usually hardens the grain but slows the burn. The granulating method usually determines the particle size distribution.

[Lozzard]

What percentage of dextrin were you using ?

 

[Lozzard]

i have never really noticed that dex reduces my burn rate ? I always granulate execept if im coating rice hulls i use meal but still add 3% dex.I have been using box elder for char on last few batches .

[MadMat]

I make my BP without binder, but as mentioned, I have a press. I dampen my mill dust with 80% water/20%alcohol and press into pucks. I then semi-dry these pucks and break them up and size the granules. I tried making a batch with dextrin (3%) and granulating. I then ran ran baseball tests to compare BP with and without dextrin binder. There was a very slight difference with the advantage going to my BP without dextrin. I have to stress that the difference was VERY slight.

[kingkama]

I used not much than the 3%, but I don't see the vantage of corning or binding bp(except if you want to use it in a gun) water make alone a good work (hard grain) , using acetone or alcohol you have a less denser BP but much faster,so I write this post to know other opinions. Edited October 11, 2018 by kingkama

[dagabu]

A few things to consider with your original question, why use a binder?

 

Hard grains are not achievable unless something is holding the chems together. Water allows the KNO3 to dissolve and as the crystals reform, they can help hold it together but they will crumble if pinched hard.

 

The binder has to physically bond the chems together to make hard grains, too little and the grains disintegrate and too much causes flame retardation and 'slower' powder. Most people find that their binder is sufficient with just 1.5-2% added while milling and 3-4% may be needed if added to the powder and screened in.

 

Most of the time, especially with smaller shells, the size of the grain is not as important as the weight of the charge when lifting or breaking the shell but if the surface of the powder is too great, the lift may cause a flowerpot or the break may cause the stars to fly blind.

 

If solid BP grains can be made consistently, sized by screens and used in a consistent way, your shells will lift and break more consistently as well.

 

Categorize your powders for the need, 2FA, 4FA, MealD and throw the rest back in to the next batch of BP.

[kingkama]

Usefull information dagabou,i forgot to follow the rule of the sorting and grain durability, hard grain are omogeneous and predictable, Dextrine or red gum made a big difference from water granulation.

Thank's for the insight.

[FrankRizzo]

+2% red gum dissolved in alcohol is my preference.

[dagabu]

BTW, my advice is NOT for pressed pucks, just ball and screening type BP.

[Boophoenix]

I newer added binder in my bp i tried dextrine but It slow bp a lot, so i use only water or acetone or alcool or a mix of them. Bp grain are hard and the performance endure in the time. So why add binder.

Recipes i use are:

75-15-10 Willow

74-14-12 "

72-20-09 wine

68-16-16 Willow

KNO3-charcoal-sulfur% kind of charcoal

First 3 four hour mill

Last One One hour mill

 

Quite the variation in ratios. You don’t See that often. I would be interested in hearing more about comparisons between performance. Most especially the willow as I assume it’s the same source material.It’s such a fascinating area that seems neglected these days.

[kingkama]

All four are very hot, the first three are for lift, the last for breaking, I sort that from all the reading I done. Pgi standard lift is the hotter lift but the wine one is cheaper and the performance are similar. The last one is a recipe used for mining applications in the oldies, a lot of gas at high temperature, fine for be used alone or with Spanish booster in shell breaking (it make break a bit louder). I newer used the last for lifting cause is not it's designed purpose. I tried adding dextrine (1.5 - 2 % in mill) and performance not suffered, predictably grain size helps consistency in lift and breaks.

[Boophoenix]

Thank ya, King.

[cevmarauder]

When you say "Wine", what do you mean? Grapevine?

I made BP using thick ivy vines (up to 2") since they have a solid core and easy to debark. It came out...okay...but I think my maple/ash/oak/elm mix was better.

...I really need to be more empirical with my charcoal making.

[kingkama]

Yes grape wine from a wine yard near my home. I use all the pruning that seasonally are made on grape wine, no debarking cause small branches are practically without bark and the proportion in mix are calculated to get rid of the higher ash content. I found wine charcoal easy to cook and very easy to pulverize cause it seems fragile than other (oak, pine, willow). The trick imo is to let outside, under the element, the wood to ripe (all wood quality), in a old book I found that the wood would be very good after two or three year of seasoning after the cut, rotten or partial spoiled woods give the better results, I personally observed termites eated willow yeald a f.... Hot charcoal were fresh cutted give a normal quality. Obviously after the seasoning time wood must be let to dry until a 10 - 15 moisture %. Edited November 11, 2018 by kingkama