Storing r candy grains & completed motors

[Redrocketman]

With r candy being hygroscopic, what advice is there for the best way to store recrystallised motor grains & large ( 1.5 - 2kg ) nozzle-less core burners. Would be stored for no longer than 2 weeks, tho could be longer. I have been making my rockets on or before launch day as I didn't want deterioration. I have had some ignition issues, should I pack the end of the core with some BP before taping core??

[MadMat]

Would what your talking about fit into large zip-lock bags? That's what I have used for my rockets (a bit smaller though). It has worked well for me for the time period you speak of. It might not hurt to try doubling the bags for a larger surface area.

[Redrocketman]

I thought of that, I have been wrapping then in heaps of clear food wrap ( large motors ) then keeping the fridge, being that it's basically an air conditioner I thought this could help illimitate moisture, am I correct in this thinking? Small motors I zip lock, but had heard if making a diccasant ( not sure on spelling! ) container containing rock salt to draw atmospheric moisture? Ie an esky. Make sense??

[Aspirina]

I live near the beach, for this reason I can only allow to dry my stuff when it's sunny, Included candy grains. The rest of the time I keep everything in a big tupperware with silica gel. If I dont do this my stuff no dry especially the candy never dry.

 

You can find big tupperware like this:

http://stat.homeshop18.com/homeshop18/images/productImages/348/tupperware-super-storer-large-5-litre-medium_268ec1415708b3c077d8714f9de67da0.jpg

especially the candy

And silica gel its easy to find, try in ebay.

 

regards

[schroedinger]

What you need is a big container with a sealing lid (army water canister, of from the food store). Then you add dry silica gel (can be bought as kitty liter in big bags) to make the drying champer. Salt doesn't help you. You can also use drain cleaner if it is made from NaOh (white powder).

[dagabu]

I agree with schroedinger, the silica kitty liter and a gama-seal bucket may be your best bet for keeping those motors dry.

[Arthur]

Find yourself a reusable silica gel pack first. Don't just assume that kitty litter is silica gel -the other standard assumption is that kitty litter is bentonite -one of those must be WRONG! Read the information on the package.

 

Dry the silica gel as per the instructions then put the motor(s) in a large sealed bucket or bag til wanted. Maybe buying the silica gel is a good plan Typically silica gel is heated to say 150 - 200C for an hour in an oven to drive moisture out then used at room temperature for days to absorb moisture. Self indicating silica gel is available -it turns blue when wet -then you must dry it by heat.

[Redrocketman]

Thanks heaps, I'll check the kitty litter contents ( as I use bentonite clay litter for nozzles ) if at all suspect, will find silica gel packs.

[stix]

For short term storage you may want to consider Calcium Chloride (CaCl2) Crystals. It's very cheap. Being in Oz you can purchase it from your local hardware store in the laundry section - the brand I know is called DampRid.

 

It has great capacity to suck the moisture out of almost anything. Which is especially good for sticky r-candy motors - they will become bone dry after a few days. The negative is that because it absorbs moisture so well, long term use (ie. 6 months+) is not a good idea unless you check and replace. I found this out the hard way.

 

I had some r-candy test strands stored for around 1yr that I didn't check on. Some of them were ruined because the ziplock bag wasn't sealed properly or had a small hole and the crystals were saturated with water - which is what they will do given the opportunity.

 

I think it's very important NOT to seal the grain/motor until it's been dried.

 

My method for small motors: Using a square of standard paper towel, place 2 teaspoons of crystals near one end spreading to approx. one third wide. Roll it up like a cigarette to about halfway then fold the ends in and continue rolling. Secure it using an elastic band. Drop it into a ziplock bag along with your grain. You can excavate any remaining air using a straw - although I've often worried about that part - or just squeeze the remaining air out by rolling. Then bag it again.

 

For larger motors: use a plastic container with a good sealing lid. Use a hosiery stocking and fill with the crystals - approx, 200gms per 5ltr volume has worked well for me. Put in the newly made grain/motor and seal the lid. After a few days it will be bone dry. Only when it's dry, seal the grain with cling wrap or baggies and put it back into the container. Check periodically to ensure that the crystals have not become saturated. I've done this and after 2yrs+ the grains are still dry.

 

I've read that using calcium chloride crystals for drying out pyrotechnic compositions can be detrimental as it can dry out stars "too quick" and cause cracking. Fair enough, but in my experience this isn't the case for sticky r-candy motors, it's a benefit.