Corn Flour as a binder

[pornopete]

Ok Ive been doing some experiments on corn flour as a binder. First was a fuse test. i used 3grams of green mix bp and added about 1 gram corn flour with about 10ml of water i mixed this and soaked some 5mil thread in it, it took a while to dry about 1 hour and was slighty crumbly but the burn time was quite good. I am going to try this mix in some rockets.
Does anyone else have ideas on binders other than dextrin?

[arm]

Depends, there are quite a few, it just depends on what composition you are binding and why.

[Tuatara]

I've made fuse using cellulose wallpaper paste as a binder. Seemed to work well.

[pornopete]

I guess im just after a dextrin substitute.Yeah ive thought of using some sort of glue as a binder. I know flour and water makes a glue so i guess thats what im doing with the cornflour except it needs to dry harder.

[arm]

I tend to use Nitrocellulose (NC) laquer for some things. A less nitrated form of NC is available as ping pong balls. A good test to see if a ping pong ball is NC is to set it alight. If it burns well and smells of camphor then its NC. You can also get NC as single/double/triple based gun powders. A final source is NC laquer for use as a furniture laquer.

To make the stuff from Ping Pong balls or gunpowder simply dissolve in acetone until the needed consistency is achieved.

You can make great waterproof fuses with the stuff.

[pornopete]

Cheers for that. What ratio of bp would I use to the NC?

[arm]

Theres two ways of going about making NC fuse, I've done both but not in a very empirical way so I cant give you exact figues. I guess the concentrations of NC to acetone should be around 10-20%.

The method first is where you you take a fine string and dip it into the solution and then coat in powder. Repeating until you have a fuse 3mm or greater in diameter. The thread must be quite thin to result in a decent coat but not so thin that it doesnt pick up enough NC or just coils up. Coating is a bugger as well - im still working on a way to achieve an even coat each time without lumps or missed spots.

The second method is to make a slurry with the NC lacquer and BP. I dont like this way personally - its messy and the acetone evaporates quickly. To be able to use the fuse as quickmatch you also have to 'dust' the fuse with powder afterwards.

EDIT: Typo's Grrrr

[Bert]

Just add BP untill you get a good working consistency- No fixed ratio. I make mine thinner or thicker depending on the use I intend. If it's drying too fast, sustitute a portion of the acetone with amyl acetate, it will dry slower.

[scarletmanuka]

Shouldn't corn flour be the sme thing as corn starch, so maybe heating your corn flour in the oven at 250C for a while could give you dextrin? I tried corn flour as a binder once, but to get it to useful ratios as a binder, the resultant BP hardly ignited.

[Bert]

Corn flour (massa harina?) is not the same thing as corn starch. Home made dextrin will work, a long time ago I made my own by roasting food grade corn starch. Don't use your mom's cookie sheets...

I'm thinking pyrotechnic binders may be another subject worthy of it's own thread.

[arm]

I think there is a slight difference in US and rest-of-world culinary terminology here Bert. In the UK you wont find anything called 'Corn Starch' on the average supermarket shelf. We tend to call it Corn Flour (opposed to ordinary 'Plain Flour').

[nzrockets]

corn flour is corn starch and i have baked it at 250C till it all turned a light brown color, and it works great for stars and fuses

[Tuatara]

Bert, I think what you call 'corn flour' is the same as what we call 'corn meal'. Strangely enough sometimes the product called 'corn flour' around here is actually made from wheat starch!:confused:
So if you're gluten intolerant - check the label! FYI 'Fielder's Cornflour' really is made from corn (maize actually, but who cares)

[Mumble]

nzrockets: Your proceedure should yield dextrin. Perhaps there is just different naming in New Zealand.

I've never had much sucess with non-soluble binder personally. I have yet to get a good bonding. It is alright if making something like blackmatch, but generally not good for most things requiring binding. Perhaps a dissolved plastic would work suit your needs. A plastic grocery bag could be used I suppose. There are more pyrotechnic based plastics, such as Parlon or shellac(solid). Maybe picking up a little shellac from the hardware store and dilluting with acetone or something could be a viable option for you.

[pornopete]

OK so let me get this straight. In new zealand corn flour is corn starch and can be transformed to dextrin? I havent been able to find straight dextrin or corn starch as yet.

[static_firefly]

I had a hard time finding corn starch here (Australia) so i asked my sister who is a cheif. Apperently corn flour is corn starch, so i baked some "corn flour" until it was the colour of dextrin and it works great in stars and the like.

[Crazy Swede]

Mumble, your post doesn't make any sense! :mad:

What do you mean with " I've never had much sucess with non-soluble binder personally"? Of course a binder won't work if you don't dissolve it in a proper solvent!?

What do you mean with "A plastic grocery bag could be used I suppose"? Do you mean that polyethylene would be a good binder for black powder? It won't!

What do you mean with "There are more pyrotechnic based plastics, such as Parlon or shellac(solid)"? Parlon and shellac are NOT based on pyrotechnics! And, parlon is also solid! Has someone told you it was a liquid? Finally, shellac is not a plastic, it's a natural resin!


_______________
Edit: spelling + fixed my misunderstanding regarding comment on nzrockets last post.

[pornopete]

I cooked up some corn flour for about 30mins at 250c until it was a light brown colour. It seems to work quite well as a binder but my fuse is slow burning and extinguished as it went up the nozzle of a rocket. My black powder im using burns at a rate of about 1inch a second. I used about 20% dextrin with black powder and water. Is my black powder to slow or did i use to much dextrin??Also where can i buy commercial fuse from in New Zealand? Thanks

[Crazy Swede]

Pornopete, the amount of binder you tried is way too high! An effective amount for black match is usually between 2-6 percent by weight.

Try adding 5 percent dextrin to your black powder. Moisten it with water containing about 15 percent (by volume) alcohol until you get a smooth thick soup without any lumps. Don’t make it too thin! Work this into your cotton string so the mix really penetrates in between the fibres. Use gloves! Preferably, your cotton string should be slightly moist with the same alcohol solution in beforehand! Pull out the coated strings while letting them run through a suitable sized hole/restriction, for example created by your thumb and index finger, to get rid of excess black powder. Let the wet strings hang to dry with weights attached to make them straight. Or, wind it up on some kind of frame to dry.

Don't forget to protect the floor where you work to make cleaning up easier afterwards!

[nzrockets]

take a look at http://www.geocities.com/matt_fileserver/black_match.htm he uses "iron aid" spray starch as the " binder. and on this page http://geocities.com/mini_bielecki/how_to_make_pulverone.htm he uses spray starch for a binder in his stars

pete a simple search on google.co.nz for cannon fuse gives you two places to buy it from

matt

[pornopete]

Thanks Matt and CrazySwede your info has been helpfull:)

[metal dragon]

Icing sugar works wonders sometimes as binder on homemade black match. I usually dry mix my icing sugar with black powder then add a little NC liquor to make it moist then rub this mix in to Juita twine. It is reliable but the best thing about it is the sugar slows down burn rate a bit.

[T_Pyro]

Isn't icing sugar just plain well-ground sucrose powder? In that case, instead of using icing sugar, couldn't you just use normal well-ground sugar in your method?

[nzrockets]

Icing sugar also contains a small amount of starch

[Jsmooth744]

I know that corn starch heated in a oven can create dextrin which you can use in Black Match.

[roux]

if you plan on making your own black powder you could make what i like to call "white powder". all you do is grind up 3 parts potasium nitrate and 1 part glucose(by weight), add enough methanol to cover the powder, let the methanol evaporate, and gather the crystals. if you are using sodium nitrate, make the ratio 5 parts nitrate to 2 parts glucose.

[metal dragon]

Could you give us information on burn speed? If it is hydroscopic? Advantages? Disadvantages ?

[roux]

oops. its really 4 to 1 if you use sodium nitrate. and 5 to 1 if you use potasium nitrate. i dunno where i got the other numbers from. im not sure on what the burn speed is. it is hydroscopic, if you mean it disolves in water. an advantage is that it does not need sulfur, making it less corosive and smelly. i have no idea what any of the disadvantages are since i have not worked with it very much, nor in any large quanities.

[Nihilist_666]

roux: Hydroscopic means it readily takes in moisture from the air. Soluble is when it dissolves in water.

[kingspaz]

just like to point out starch turns to dextrin at 183*C (IIRC). best to turn the oven to 185*C lessening the need for checking and stopping the surface blackening which i've found to occur at higher temperatures.

[metal dragon]

Could you explain why there is a different ratio of KNO3 to glucose and NaNO3 to glucose?
They both contain the exact same Oxygen and nitrogen count but only differ in the metal at which they are ioncly bound, and both these metals have a one positive charge. In most equations they can be interchangeable. So why is this equation different?

[Tuatara]

Simple: molecular weight of NaNO3 is 85, MW of KNO3 is 101. So for equal mols of both the KNO3 weighs roughly 25% more.

You should know this :rolleyes:

[devilassassin]

Im pretty sure absorbing water from the atmosphere (although not to become a solution) is called hygroscopic. I'm not sure what hydroscopic means though, it could be a synonym(sp?). Substances which absorb enough water from the atmosphere to become solutions are known as deliquescent.(eg Copper Nitrate and Sodium Hydroxide).(This is in response to roux and Nihilist_66).

[metal dragon]

Tuatara, I have used KNO3 and NaNO3 interchangeably with no noticeably difference in performance. Should I re-write my calculations when using them in interchangeably? Because so far in all low order explosives it has made no difference to what I can see.

[roux]

the reason i didnt keep the nitrate portions the same is because if you were to switch the sodium to potasium nitrate you would end up with less of an oxidiser. and just the opposite the other way around. im just trying to be economical.