Chemicals that clump

[Excal]

Ok, I did a bunch of searches for any thread like this or to answer this question, and I found none.

 

What relatively dry pyro chemicals need anti-cake?, As in, they will clump without it.

 

I already found 1 which is KCIO4. I see it advertised as available with or without., but I don't see alot of the others listed as such.

 

I would assume that it depends a lot on where you live and the relative humidity, But assuming can get a person in trouble also.

[Algenco]

none, push clumped chems through a 40 mesh screen berfore using it isn't a big problem

[AirCowPeacock]

That breaks the clumps down to -40 mesh. Its nice to able to grab your bag of KClO4 and have no prep. I try to avoid clumping with a monthly dessication with CaCl2, and a good air seal, but durring the summer--its not good enough.

[Excal]

I would like to be able to grab it and go to work also without prep work. It seems that there is no really easy way around it, but it would be nice.

 

How about vacuum packing, with one of the reusable vacuum containers?

 

 

Or would that be a waste of time?

Edited November 10, 2012 by Excal

[pyroshell]

I have never vacuum sealed any hygroscopic powders, but what I can tell you is make sure they are confined in a container that will prevent and powder spilling. If you do not it will suck up your powder not giving you a good seal, wasting powder and if it is an oxidizer possibly a fire or an explosion. what I do with my hygroscopic powders is just seal them up in a gallon sized Ziploc bag with few desiccants that do not react with the hygroscopic powder. Also there are a Mother Fu**ing s**t load of chems that are hygroscopic enough to clump like kno3 or AN to name just two.

[Excal]

There is another question. What is a good desiccant bag to use?. I seen some clay type bags at Office Depot.

[Seymour]

No chemicals need anticake. It's only a matter of personal preference.

 

Barium nitrate and Potassium chlorate are two of the worst offenders when it comes to clumping in storage. In storage they seem to fuze in to a rock after a few months. I'm sure keeping them dry will help somewhat, but I have never seen anticake used with them and assume it does not help much.

 

For the chemicals that clump rather badly, you just need to screen or mill them soon before you use them so you have fresh powder.

 

As Algenco said, with KClO4 it's really no problem, any clumps in that stuff don't tend to be much of a difficulty at all.

 

When I use desiccant, I like to make an envelope, sealed around the edges with tape, filled with anhydrous MgSO4. I figure the paper will be largely powder tight, while being very permeable to moisture.

 

After a while, the MgSO4 needs to be baked dry in the oven again.

[taiwanluthiers]

Why not use cobalt chloride or copper sulfate? They change color when they go from anhydrous to hydrous so you can visually tell when its time to bake them.

[Algenco]

That breaks the clumps down to -40 mesh. Its nice to able to grab your bag of KClO4 and have no prep. I try to avoid clumping with a monthly dessication with CaCl2, and a good air seal, but durring the summer--its not good enough.

 

Ok, use a 100 mesh, when chems clump they don't grow into larger crystals, it's the same mesh it was before it clumped, they're just stuck together,some perfectly dry chems will still clump over time.

Mumble can explain the physics of the process better than I

 

Use of Anti cake is a personal preference, I choose not to use it

[Mumbles]

Cobalt chloride and calcium sulfate are weak desiccants and wouldn't really be particularly useful. They do sell real desiccants with these things mixed in though to do what you describe.

 

Chemicals will clump whether or not they are in a desiccated environment. Clumping occurs when the crystals of product settle together and interlock. Humidity does make this worse, but I really don't know exactly why. I've always kind of thought the moisture from the air dissolves the very surface of the particle and can lightly glue neighboring pieces together.

 

I'm with Algenco on this. Anti-cakes are a personal preference that I prefer not to use. I'd prefer to be 100% confident of the purity of my chemicals. There were some claims a few years ago that some of perchlorate coming into the US had anti-cake levels in excess of 30%. That is not a typo. If it's true, I'd be surprised if it ever burned. All compositions need to be screened anyway, so it's not a big deal to me.

[AirCowPeacock]

Its definently optional. I just see it as a convenience with little to no set back. When I screen my chemicals that clump through a 40 mesh sceen I get most of it down to the original fine powder, and some 40 mesh clumps, I end up grinding it a little to get the rest of the clumps out. Its especially convieniant for me when making flash powder. I make what I need for every project, to keep quantities down. So having to screen 5 grams of KClO4 every time I need flash is anoying. Its also harder to get the right amount clumps, I have to put clumps back and take out ones of a different size until I get the right clumps. However for making batch stars or black powder ect. screening is no annoyance, I do that less frequently and screen the composition anyways--thats not to say it wouldnt be nice to live in a world where chemicals dont clump.

[AirCowPeacock]

I've never had a problem with orange tendencies in my stars with anticake or without.

[Algenco]

Fumed silica reacts with charcoal to produce ammonia

for salutes I use Cinese perc w/anticake, eveything else gets high quality perc w/o anticake

 

chlorates I screen or blade mill

Edited November 12, 2012 by Algenco

[Excal]

Is the Chinese Perc with anti cake more static sensitive than the high quality without?,,as far as a safety standpoint?.

 

Does Anti cake make Perc or any static sensitive chemicals more safe?.

Edited November 12, 2012 by Excal

[Algenco]

Is the Chinese Perc with anti cake more static sensitive than the high quality without?,,as far as a safety standpoint?.

 

Does Anti cake make Perc or any static sensitive chemicals more safe?.

 

I don't know, same safety precautions taken regardless.

In my opinion once you start relaxing around certain comps/chems you'll get bit in the long run

The only reason I use Chi perc with anticake is price/availability, it's half the cost of domestic

[Potassiumchlorate]

What does Chinese potassium perchlorate cost in the US? In Europe the cheapest you can get without having a VAT number is about $10/kilo.

[Algenco]

drum quantity $5 kilo

[ExplosiveCoek]

That's not true KClO3

[WonderBoy]

Yeah, for a drum (50 kg) I pay about $4.50/kg, but in smaller quantities I'd pay about $9/kg.

 

A member of my club recently got a shipment of anticake free chinese perc. It was similarly priced and received rave reviews from other club members, but as far as I know they haven't done any testing beyond making stars and rockets with it. It is sounding like a decent alternative to expensive domestic perc. I too generally prefer chemicals without anti-cake.

 

 

WB

[Potassiumchlorate]

That's not true KClO3

 

To my knowledge you can't get it cheaper. If you have a VAT nr it's another thing

[dagabu]

That's not true KClO3

 

Yup, it really is real...

 

-dag