7 replies to this topic

[lord_dranack]

I have used these in various fireworks for some time, but never in devices that have been stored for any amount of time. I know that these will both corrode/rust when stored, and that there are ways of preventing this using linseed oil for the iron and potassium dichromate for the Mg. Will other (cheaper) oils work? Can Mg be used with a water soluble binder after it has been treated with potassium dichromate? What is the best method for treating them? (I did search but I couldn't find too much on this topic)
Thanks

[adamw]

You should be able to buy a 25ltr drum of boiled linseed oil for about ?20 from an agricultural merchant. It's used as a lubricant.

I should imagine most vegetable oils will work. Save it up after your fish and chips

[BigG]

I have used these in various fireworks for some time, but never in devices that have been stored for any amount of time. I know that these will both corrode/rust when stored, and that there are ways of preventing this using linseed oil for the iron and potassium dichromate for the Mg. Will other (cheaper) oils work? Can Mg be used with a water soluble binder after it has been treated with potassium dichromate? What is the best method for treating them? (I did search but I couldn't find too much on this topic)
Thanks

You can also buy linseed oil in B&Q or Homebase for a manageable price. Don't by in art stores. This linseed is cold pressed and extra pure and is very expensive.

You will need only 5% on linseed oil to coat iron/magnesium, so a kilo of powder will require only 50g linseed. Put the metal in a pan and heat on a hot plate. Mix in the oil and mix well until the metal is shiny and all is coated. Keep on heating to burn off the excess of oil and let cool.

I prefer to use more oil, and these make large clumps, which are not easy to handle, but the coated metal holds forever. When I need to use it, I heat in the over and shive through a non-sparking screen to get the size I want.

Note that you can also just mix cold. You can just shake in airtight bag and put into storage. The iron might hold this way for about a month, but will rust very quickly if mixed with water binder (in about a week or two).

Using potassium dichromate does not work for iron, but will for magnesium. Potassium dichromate is not a nice stuff, but quite easy to find. Read Lancaster for a good description on the coating of magnesium and magnelium.

[Phoenix]

5% parrafin candle wax can be used to coat Fe too. I've done this with no problems, but I've never stored stuff for long. Is Linseed oil superior for longer storage, or doesn't it make any difference?

[BigG]

Not really. I think paraffin wax is also used in the industry. I don't know is it affect performance in any way....

[Phoenix]

Good.

I have plenty of paraffin wax lying around, but no linseed oil, and I don't really want 25 litres, even if it is only ?20

[lord_dranack]

Do you dissolve the wax or melt it?

[Phoenix]

I melt it in, and boil off the excess (like with linseed oil). I think this is the normal procedure.