Newsgroups: rec.pyrotechnics
From: tip@mercury.aichem.arizona.edu (Tom Perigrin)
Subject: Re: Epsom Salts
Followup-To: rec.pyrotechnics
Date: Mon, 27 Nov 1995 17:11:19 GMT
Lines: 24

In article <491dd8$45q@ixnews5.ix.netcom.com>, silent1@ix.netcom.com (The
Silent Observer) wrote:

> I don't think that formula would work as a smoke bomb, though it might 
> be useful in very small doses as a laxative.  Sulfates, in general, are 
> not known as oxidizers, which would be the role you've cast your Epsom 
> salts in in this case.

It's true.  They aren't "known as oxidizers".  BUT that is actually a
commonly misunderstood point.  Sulfates can be oxidizers at high enough
temperatures and with very reactive fuels.   For example, there is a lot of
debate on the glitter reaction, but at least one theory states that K2SO4 +
Al -> Al2O3 + K2S (not balanced) is repsonsible for the flash.  Rutger Webb
sent me an article by Shimizu wherein he (S) found that some sulfates are
quite useful oxidizers for Mg and Al. 

However, Epsom salts are probably best used by pyros as a bath additive to
help sooth aching muscles after laying out and picking up a large show.


---

If I was smart, I'd have a clever .sig

Newsgroups: alt.engr.explosives
From: nelson@cs.rochester.edu (Randal Nelson)
Subject: Re: Al power & H2S04  powerfull, but what is it
Date: Tue, 19 Dec 1995 18:30:07 GMT

In article <4b4mp2$i2n@cville-srv.wam.umd.edu>,
Wayne Shanks  <Aleph@shanks.umd.edu> wrote:

>>>while experimenting one weekend, I discovered the 
>>>consentrated sulphuric acid and Al powder will react exothermically to 
>>>form a fluffy grey foam/powder.  This powder will then ingite, with no 
>>>added oxidized, like flask powder.  Raw Al powder will not do this.  What 
>>>is it.  Perhaps some form of ULTRA high surface area Al.  
>>
>>Sulfuric acid reacts with aluminum to form hydrogen gas, which is
>>flammable and explosive. The mixture is very hazardous because it 
>>can spatter the acid into eyes or on skin. It would be safer and
>>just about as exciting to sit around and watch old tin cans rust.
>>
>>Jerry (Ico)
>
>The production of H2 was why we tried the mixture, but I do not think 
>that H2 is the main product.  As I said, the reaction yealds a fluffy 
>grey powder.  Typically we would put a table spoon or two of Al powder in 
>a zip lock sandwich bag, then squirt in enough H2SO4 to just wet all the 
>Al.  We then squeese out all the air in the baggy and squish the mixture 
>around untill it is well mixed into an Al-acid mud.  If the air is 
>squezed out of the bag, the mixture will keep unreacted for many hours, 
>but it is NEVER stored mixed.  This precaution is just for handling safty 
>for the 15 os so seconds it takes to mix and handle.  After it is mixed 
>the baggy is riped open an thrown into a clay flower pot.  The mixture 
>will sit for five of ten minutes.  It seems that air is needed to 
>initiate the reaction.  After five to ten minutes the reaction will take 
>place.  The reaction is very quick and exothermic. Taking about one to 
>three seconds, the Al acid mud will expand to about ten times it's 
>origional volume, and boil off the remaining sulphuric acid.  There may 
>well be H2 produced, but it typically will not detonate.  You get a cloud 
>of sulphuric vapor, but it quickly dissapated (ALWAYS DONE OUTSIDE).  As 
>I have said you are left with this grey foam.  It crumbles when touched, 
>but you can still pick up chunks several inches across.  This stuff seems 
>to be stable.  It will not detonate with precussion, and does not seem to 
>degrade with time.  When ignited the, material in foam form, or 
>cruched/crumbled back into a powder form acts like flash powder.  A 
>brilliand white flash, maby several milliseconds long, with practically 
>no residue.  Neat stuff, but I never did figure out what it was.
>
>Any ideas?
>
>Wayne S


Sounds like you ended up with a mixture of aluminum sulfate and
aluminum. Aluminum will reduce sulfate quite energetically, and
there are some pyrotechnic and explosive formulas based on the
combination.
The delay in the initial reaction might be due to absorbing moisture
from the air, which accelerates the reaction between concentrated
H2SO4 and Al. Depends on how concentrated your acid was to begin with.

RN



-- 
  Randal Nelson			 716-275-8488	University of Rochester
		      nelson@cs.rochester.edu	Computer Science Department
..!{allegra,decvax,rutgers}!rochester!nelson	Rochester, New York,  14627

From: glhurst@onr.com (Gerald L. Hurst)
Newsgroups: rec.pyrotechnics
Subject: Re: This damn smoke bomb recipe wont work!
Date: 14 Aug 1996 04:48:34 GMT

In article <1996Aug13.175541.8853@cs.rochester.edu>,
nelson@cs.rochester.edu (Randal Nelson) says:

>In article <4up4l6$o5u@geraldo.cc.utexas.edu>,
>Gerald L. Hurst <glhurst@onr.com> wrote:
>
>>Bob, someone has steered you up the garden path.  Epsom salts makes
>>a moderately good fire extinguisher with its high proportion of water 
>>of hydration but it has no oxidizing properties whatsoever and thus
>>will not react with sugar.  Perhaps you are confusing epsom salts with
>>saltpeter.
>
>Actually, if you tried hard enough, you might be able to get epsom salts
>to oxidize aluminum, as there are pyrotechnic compositions using Al with
>a sulfate oxidizer (see a discussion here a few weeks back).
>But don't hold your breath.

Not likely. 

You can get a thermite class reaction from anhydrous magnesium 
sulfate but not from epsom salts per se -- too much water of
hydration.

YAWN. If you are really interested in reductio ad absurdum 
reasoning, choose an alkali metal as a reductant and then you
can legitimately say that epsom salts acts as an oxidizing agent.

Jerry (Ico)