30 replies to this topic

[Creepin_pyro]

Hi Guys
Has anyone tried "THIS" and can we get the Visco fuse here in the U.K?

Thanks
Jim

You would be much better off trying dr thrust's suggestion or something similar. Even a modified blackpowder mix would give you more ability to tune the power than a visco rocket.

[Atom Fireworks]

this looks promising

A slow burning propellant. Great for sustainer engines.
Ammonium Nitrate 70%
Ammonium Perchlorate 10%
Polyester Resin 18%
Powdered Charcoal 2%
Not very powerful but useful. The charcoal helps keep the combustion steady.

As far as i am aware in the uk Ammonium Nitrate is hard to find due to its other uses so it may be difficult for him to obtain any.

[Dragonsinger]

Hi Guys
Dumper truck quoted Dr thrust

this looks promising
A slow burning propellant. Great for sustainer engines.
Ammonium Nitrate 70%
Ammonium Perchlorate 10%
Polyester Resin 18%
Powdered Charcoal 2%
Not very powerful but useful. The charcoal helps keep the combustion steady.

First up Thank you Dr Thrust for the formula

Second Dumper Truck said

As far as i am aware in the uk Ammonium Nitrate is hard to find due to its other uses so it may be difficult for him to obtain any.

I have about 2 kilos of the stuff at home right now. Fully legal and above board. You can get it over the counter at most chemists if you know the correct product
to ask for. No I can't tell you on an open forum since we are not the only ones who READ this board. But you can buy the stuff legitimately for other uses.
I am not worried about the danger since it requires shock detonation and I am reliably informed (I have never tried it) that it is hard to light. It is also as
hygroscopic as hull so it rapidly becomes a useless mass (the chemical reaction renders it inert) with even a whiff of water vapour.

As the motto of the Sirrius Cybernetics Corporation says:- "Share and Enjoy"

Thanks again for the tips

Regards

Jim

[Atom Fireworks]

Hi Guys
Dumper truck quoted Dr thrust



First up Thank you Dr Thrust for the formula

Second Dumper Truck said


I have about 2 kilos of the stuff at home right now. Fully legal and above board. You can get it over the counter at most chemists if you know the correct product
to ask for. No I can't tell you on an open forum since we are not the only ones who READ this board. But you can buy the stuff legitimately for other uses.
I am not worried about the danger since it requires shock detonation and I am reliably informed (I have never tried it) that it is hard to light. It is also as
hygroscopic as hull so it rapidly becomes a useless mass (the chemical reaction renders it inert) with even a whiff of water vapour.

As the motto of the Sirrius Cybernetics Corporation says:- "Share and Enjoy"

Thanks again for the tips

Regards

Jim

Ahh well there you go, ive not needed it yet however I suppose I assumed its availability would be restricted. These rockets you are trying to make are they the little reloadable ones with the screw on nozle? I think I have seen some small planes years ago

Jay

[Creepin_pyro]

No I can't tell you on an open forum since we are not the only ones who READ this board.

It's available from most chemical suppliers and all this is already covered in various threads on the board so I wouldn't worry about it. Attempting to purchase large amounts of AN will raise eyebrows if you don't have a legitimate use but it's perfectly easily available in small amounds.

Just looking at Dr thrust's formula again I'm not sure how well it would work on such a small scale, and with no core. I do think an AP formula could be made to work as a low-thrust motor as an end burner, just not sure where I'd start in terms of formula.

[Dragonsinger]

Thanks creepin_pyro.
I've broken out the AUTOCad and am currently drawing up plans for a motor with about a foot of 1 strand of Visco (a lump of broomhandle with a central hole and several fuse channels [holes] to let me wind enough Visco for a 20 second burn. Might try a spiral channel as well.
I want to try the visco rocket first. Could be fun.

Regards
Jim

[pyrotrev]

Interesting project Jim, I wish you luck. Dr Thrusts AN/AP/polyester composition may not be so hygroscopic that it's unusable, I was reading a rocketry tome a few weeks back and AN based propellants have been used commercially: you'd just need to make sure you have a waterproof tube (varnish) and cover the ignition end with a fairly waterproof igniter comp I guess: alternatively a short length of PIC with a dab of PU foam to seal might do the trick. Compositions with a lot of polyester tend to be very slow burning anyway, so an AP/polyester comp might be worth a try as well, and that won't have any hygroscopicity problems. One issue may be getting a lightweight tube that won't burn through (any slow burn motor will inevitably be an end burner I guess), you could try rolling some paper ones using silicate adhesive, or alternatively you might be lucky enough to find a phenolic/glass fibre one available off te shelf.

[Dragonsinger]

Once more guys
Thanks for the encouragement.
I've had a bit of a sideways think about this and I reckon I MIGHT just get away with about a foot of Visco wound through a wood former [soak it in borax as a fireproofer] so that I get the 20 or so seconds burn time I need. It will need to be a serpentine wind to prevent multiple burn points but I hope that "THIS" will do the job. It may be a while before I can get to this, Christmas etc, but as soon as I pick up some visco I'll have a go.
If you want to know why it's called an Errol read "Guards Guards" by Terry Pratchett.

Thanks again
Jim

[whoof]

. I do think an AP formula could be made to work as a low-thrust motor as an end burner, just not sure where I'd start in terms of formula.

I know the formula (allegedly ) for the rapier reloads.

Unfortunatley one of the components is not available over here due to export restrictions.

[Creepin_pyro]

This one?

Ammonium Perchlorate 51%
Zinc powder 37%
Di Cyan Di Amide 6%
HTPB 6%
Di Iso Cyanate 0.6%

Looks interesting. Never seen Zinc and AP together. I wonder how these would perform as a pressed endburner without any of the other ingredients?

[Dragonsinger]

Creepin_pyro

Not surprised if it doesn't work. You have 106% there!

Ammonium Perchlorate 51%
Zinc powder 37%
Di Cyan Di Amide 6%
HTPB 6%
Di Iso Cyanate 0.6%

[Creepin_pyro]

I make it 100.6%

It's not uncommon for pyrotechnic formula to add up to slightly over 100%, although usually the main parts will add up to 100 then binders/optional ingredients added as a "+x%" at the end. I'm not familiar with the more exotic chemicals in this but it's possible the Di Iso Cyanate isn't essential. It could be balanced to remove the HTPB, I have no idea about Di Cyan Di Amide though. I'm sure one of the members more familiar with HPR propellants could advise.

[whoof]

Yep thts pretty much the recipie i have although a different placticiser
The isocyanate is essential as it is the catalyst for the httb, the other is i think a plastisizer to gice a softer binder.
The httb is the binder and is essential.
When using aluminium without it it would be a deathmix (flash type comp.)

Dont know about Zinc though.
Reason for the zinc is to reduce flame temp as during a 20 sec burn, the casings occasionaly burn through.



Dragonsinger
If you want genuine rapiers in the UK they can be had at various meets
drop me a PM for details.

[Creepin_pyro]

The httb is the binder and is essential.
When using aluminium without it it would be a deathmix (flash type comp.)

Thanks for the info. I've wondered this before - would it not be possible to remove the binders from a HPR propellant and treat it as a pressed endburner? Is the binder there to facilitate casting and making shaped grains, or does it also stop the mix from CATOing?

[whoof]

Thanks for the info. I've wondered this before - would it not be possible to remove the binders from a HPR propellant and treat it as a pressed endburner? Is the binder there to facilitate casting and making shaped grains, or does it also stop the mix from CATOing?

Well the binder is the fuel for a start, origionally ap And Polysulphone rubber was the origional Thiokol formulation.

Later it was discovered that the addition of aluminium improved the impulse.

With enough htpb it can be cast.

Now recently APCP was declassified as an explosive BUT ONLY for the grains made by Aerotech etc.
Some of the formulas out there with higher impulse, Space Shuttle, military etc are HE and will detonate.
Somewher on U tube is a video of a polaris launch booster being destroyed in the desert, Heck of a bang.

During mixing , agglomoration or clumping can cause localised deathmixes even in a non explosive recipe.
This has been suggested as a possible cause of the death of that american PHd Chemist.

Commercially i believe the binder and Aluminium are drum mixed for hours to ensure thorough coating befor the oxidiser is added.
Bit like linseed coating mag.

Not something to be tried at home IMO although i know some of our American friends do.

Edit


Mix without binder.

Edited by whoof, 10 December 2011 - 12:06 PM.