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Coating steel powder


crumbbum25

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I just received some very fine steel powder and have seen and heard about treating steel powder to with oil to prevent rust. What is that process and what oils are used?

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I'm curious on what answers you get, I have not tried it myself but often have steel turnings I wonder if I could keep and use in a fountain.  

From what I've read, Boiled Linseed Oil is used (which I guess for store bought, just means some form of drier is added to it.).

I've also read where people describe heating up some oil and dumping in metal to be coated.  Then the powder / metal is stirred to evenly coat it.  Once that's all done, it's apparently left out to dry for a couple weeks. If done correctly, metal should have a chemically altered surface that protects it from rust.

Again, this is what I've gathered from reading - but not actually doing.  So I'm curious if anyone knows how it's actually done!  

Edited by cmjlab
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I am not aware of coating steel powder but I have heard that magnesium is treated with linseed oil.

I dont know exact process but linseed oil takes too long time to dry out naturally thats the reason why coated mg with linseed oil is dried with special heating technique ( Still I dont know exact method).

What type of firework you are preparing with steel powder?

If it needs wetting use non aquous system.

For gerb or fountain I use cast iron.

As this fountain is fired within 24 hours there is no issue of corossion.

I store cast iron boring by follwing simple trick.

I usually take glass bottol with rubber lid Then I take two to three camphor tablet crush it to form powder and rub campor powder and cast iron boring together in cotton cloth.

Then I pour cast iron boring in glass bottol half amount and fill upper empty space with sulphur and press rubber lid.

Sulphur Is very stable it acts as a barrier between atmostsphere and cast iron boring.

When needed you use cast iron, simply screen sulphur away.

Thanks

Edited by Zumber
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Hm, I wrote a long comment to this but it is gone...

Anyway, steel or cast iron powder/shavings usually are coated with stearin or paraffin wax.

Just add 5 % stearin or wax by weight of the metal powder to be treated and heat until melting in a frying pan or similar. Stir until a homogenous mass and spread out in thin layers on paper to cool. Pass through sieve to break up lumps.

An interesting version of this is to also add a few percent of dark or bright aluminium dust to the mixture to also coat the iron with some aluminium. A famous Danish pyrotechnist invented this and claimed it to make his cast iron sparks to burn brighter!

Boiled linseed oil gives an even better protection. Use 4 % of the weight of the metal powder, stir well to distribute the oil evenly and let cure in very thin layers. Curing additives is usually not needed but it might take a week for the oil to oxidise/polymerise. Cuirng goes faster at elevated temperature but remember that organic materials like paper and cardboard can self ignite if soaked with linseed oil!

Iron can be treated with a chromate conversion coating just as magnesium but it is seldom needed in practice unless finished products are to be stored for a long time.

I personally know that fenol/formaldehyde resin of resole type has a very good corrosion inhibiting effect on iron but it is very messy to handle, can cause allergy or worse (never get it on your skin!) and easily creates agglomerates of the iron shavings.

Edited by Crazy Swede
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Swede - that is very helpful thank you.

I had never heard of most of that, only about the boiled Linseed Oil.  The reason I was curious is mainly from drill press turnings when taking on metal working projects (like making a steel plate riser table for my 3t Arbor Press), where I have a considerable amount of steel shavings that aren't coated with anything but cutting oil.  I sure hate throwing that stuff away, and Boiled Linseed Oil seemed like a good way to ensure long term protection.  

I did try coating some of the metal shavings in Boiled Linseed Oil, but when I heated up the coated shavings to help dry some of the excess oil off, it created a god-awful smoke that I don't ever want to smell again!  In hindsight, I used too hot of a temp, but still....

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Thanks guys. I was going to make some fountains/ gerbs and try my hand at sparklers. I asked because I've read that storing with nitrates causes it to rust quickly. I would have a hard time with the paraffin getting it back to a fine powder. I may try linseed oil.

I find it weird that many have stated the rust issue but really haven't described the process. Thanks for the info. I will attempt the linseed oil method in the summer when is hot. 

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2 hours ago, cmjlab said:

...I did try coating some of the metal shavings in Boiled Linseed Oil, but when I heated up the coated shavings to help dry some of the excess oil off, it created a god-awful smoke that I don't ever want to smell again!  In hindsight, I used too hot of a temp, but still....

Yeah, that is how it smells when it cooks off at somewhat to high a temperature, but it leaves a very good protective coating.

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1 hour ago, crumbbum25 said:

...I find it weird that many have stated the rust issue but really haven't described the process. Thanks for the info. I will attempt the linseed oil method in the summer when is hot. 

It might be because it is described in many of the basic pyro books that we, the more experienced, assume everyone has read.

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2 hours ago, crumbbum25 said:

Thanks guys. I was going to make some fountains/ gerbs and try my hand at sparklers. I asked because I've read that storing with nitrates causes it to rust quickly. I would have a hard time with the paraffin getting it back to a fine powder. I may try linseed oil.

I find it weird that many have stated the rust issue but really haven't described the process. Thanks for the info. I will attempt the linseed oil method in the summer when is hot. 

Metal when come in contact with oxygen forms metal oxide.

And source of oxygen is from surrounding or water or oxidizer present in composition.

Iron (Fe) corrodes and forms ferric oxide(rust).

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6 hours ago, Crazy Swede said:

It might be because it is described in many of the basic pyro books that we, the more experienced, assume everyone has read.

I recently actually asked about good books recently. I did principles and practice... lightly perused it, I'm sure I may have missed something but it does state treating under the iron description. I didn't see the actual process yet in there. Thanks for the help!

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Last time I checked, it was described by Shimizu. Might be so he is the only one providing more detail. 

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8 hours ago, crumbbum25 said:

I recently actually asked about good books recently. I did principles and practice... lightly perused it, I'm sure I may have missed something but it does state treating under the iron description. I didn't see the actual process yet in there. Thanks for the help!

If you wanna check actual process

Purchase steel wool (wires should be very fine) & hydrogen peroxide.

Place steel wool over glass plate and spray hydrogen peroxide over it all the way using atomizer spray. Repeate same process 5 times daily and within 4 to 5 days you will see steel wool corrodes and finally you will get ferric oxide powder (RED).

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