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heada

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Ejection charge gases are acidic I believe. Not sure how it'd react with a basic powder. Should give off CO2 gas but might want to test it.
 

gldknght

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Black powder contains two sources of ACIDS. When sulfur burns, it forms sulfur oxides. When potassium nitrate burns, it forms various oxides of nitrogen. Both of these classes of compounds like to react with water and when they do, they form primarily sulfuric acid and nitric acid.

The CO2 should not be much of a problem, since would mostly be outside the rocket if there was any reaction at all. It sounds like the only time acids are produced is when there is water present. Generally, I don't fly my rockets with water in them.
 

John Kemker

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And, what would be wrong with neutralizing those acids with the baking soda? Drawbacks?
 

Donnager

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Not yet, but it's a thought!

Can anybody think of any reason to NOT try baking soda?
I'd expect the very high moisture released by the ejection charges might make the baking soda sticky, or clump. It may just be a cleanup issue, if it doesn't get wet and stick things together. It's slightly hygroscopic, so it may get a little sticky just being outside in the humidity.

In a cardboard rocket, after flight, you can tell the model has changed dimensions (couplers tight, motors stick), due to heating and moisture in the ejection charge. I'd probably not add something that was water absorbing/soluble to this.

I don't think you will cause major heartache, but I don't think baking soda will stay free flowing when outside in the humidity for a while.
 

rklapp

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Forgive me if someone answered my previous question, but I assume that cornstarch is bad because it's combustible. Crème brûlée in your BT is not ideal.
 

rharshberger

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I'd expect the very high moisture released by the ejection charges might make the baking soda sticky, or clump. It may just be a cleanup issue, if it doesn't get wet and stick things together. It's slightly hygroscopic, so it may get a little sticky just being outside in the humidity.

In a cardboard rocket, after flight, you can tell the model has changed dimensions (couplers tight, motors stick), due to heating and moisture in the ejection charge. I'd probably not add something that was water absorbing/soluble to this.

I don't think you will cause major heartache, but I don't think baking soda will stay free flowing when outside in the humidity for a while.
I dont believe the combustion of the BP releases moisture, the combustion byproducts though are highly hygroscopic so they absorb moisture from the air that creates the issue, and BP combustion also leaves a fair amount of soot to "gum" up sliding fits over time.
 

Donnager

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I dont believe the combustion of the BP releases moisture, the combustion byproducts though are highly hygroscopic so they absorb moisture from the air that creates the issue, and BP combustion also leaves a fair amount of soot to "gum" up sliding fits over time.
I agree with you, good point. Hydrocarbon combustion will result in the release of water, and this isn't a hydrocarbon, just my combustion background intruding. You are also correct, the combustion products ARE hygroscopic, as is NaHCO3. My assumption is water is in most everything at some level, and heating one location where it is, will normally drive it to a location where it is happier (hygroscopic media comes to mind). This is, in my mind a small issue.

I am more concerned about persons thinking NaHCO3 will be free flowing after being dumped into a rocket. I am in Florida, so humidity here may be a much larger issue for clumping than elsewhere.

If you want to put baking soda in your rocket to neutralize carbonates and sulfates, more power to you. He was asking for a reason not to. I had 2. 1) Combustion products may cause clumping. 2) Humidity may do the same.

Since clumping is the opposite of what you want to do with talc, I'd suggest looking at something else. My personal opinion, is it probably won't matter much and we are hair splitting. Just answering "Why not?"
 

prfesser

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A number of ceramic suppliers carry talc, about a buck a pound. I don't know the mesh size, you'd probably want to find that out before ordering.
 

rharshberger

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Mushtang

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I've heard of people filling the parachute with a LOT of powder and rolling it up in there, so that when the parachute ejects and unrolls there's a pleasant looking cloud that grows larger to quickly identify where the really high rockets are.

Does this really work and look good?
 

sjh1

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Unless they have changed the formula in the last 6 months, WalMarts Equate brand is talc, iirc the ingredient list was talc and fragrance. Look at the ingredient list many are corn starch which gets sticky when damp.
And it burns
 

sjh1

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An alternative is carpenter's chalk which is cheap $1.79 at home depot and comes in various colors.
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