Polyester Resin Rocket Fuel

[Arkangel]

I was thinking about casting solid grains for rocket motors, and many of these, such as caramel candy, require heating of the fuel prior to casting. I've grown up around fibreglass, and I know that the polyester resin used, when burnt, is quite vigorous, and produces a ton of black smoke.

It occurred to me that if you were to mix some resin with it's catalyst, and then mix that all up with something like a chlorate, you'd have a solid material that was quite energetic, yet was easy to cast, reliable in terms of producing a solid grain, and much less susceptible to water than other powdered fuels. It would also be physically very strong, so much less likely to experience an early cato. Not only that, you might be able to replicate some of the concentric solid fuel grains of different speeds that you find in military missiles such as the Rapier SAM.

A google search produced a link to a <a href="http://www.geocities.com/infiltrationweb/propmixes.html" target="_blank">Resin fuels and other propellants</a> page, which seemed to support my theory.

</font><blockquote><font size="1" face="Verdana, Arial, Helvetica">quote:</font><hr /><font size="2" face="Verdana, Arial, Helvetica"> You will also find fibreglass resin. This is a
liquid made from polystyrene and polyester resin. It is catalysed with a few drops of hardener. PVC plastic can be dissolved in tetrahydofuran to make a thick paste. This can be mixed with an oxidizer and allowed to dry for an extended time to form a propellant grain. </font><hr /></blockquote><font size="2" face="Verdana, Arial, Helvetica">But I wonder if anyone out there has experience or comments on this type of fuel. :)

[DarkAngel]

I've been interested in the idea of cold castable rocket fuels my self but never try'd it.
This site has some good info about them: <a href="http://members.rogers.com/rnakka2/knepoxy.html" target="_blank">http://members.rogers.com/rnakka2/knepoxy.html</a>

[Kriegsminister]

You are right, there are some rocket fuels that contain resins.
Maybe this link might help you.

<a href="http://come.to/pfp" target="_blank">http://come.to/pfp</a>

It's a site about pyrotechnics and they have a nice collection of composition including rocket fuels.
Currently the site seems to be down because they are moving...
But I copied that site once so I can list some of the fuels containing resins or some sort of 'plastic', though I never tried one of these:

80% Ammonium perchlorate
20% Resin (Epon 815 Epoxy & Curing Agent U)
+1% Copper chromite

70-80% Potassium perchlorate
20-30% Methyl polymethacrylate

85-90% Ammonium nitrate
10-15% Urethane plastic

72.79% Ammoniumnitrate
1.99% Ammonium dichromate
9.79% Genpol A-20 polyester resin
12.22% Methyl acrylate
2.22% Styren
0.49% Methyl ethyl ketone
0.25% Cobalt octanoate (1% in styrene)
0.25% Lecithin (10% in styrene)

And last but not least the Space Shuttle Boost Fuel:

69.9% Ammonium perchlorate
12.04% Polybutadiene
1.96% Epoxy curing agent
16% Aluminium powder
0.07% Red iron oxide

[Sparky]

Sadly, the PFP database has been "moving" for quite a long time. It has been abandoned because of legal troubles that the owner had over it. Supposedly someone hurt themselves with one of the formulas. But enough with rumors. There are a few places you can download the pfp database. Here is a link to a friends site that has it:

<a href="http://pyropage.cyberarmy.ca/" target="_blank">http://pyropage.cyberarmy.ca/</a>

[Mr Cool]

Today I tried a few fuels, not in rocket engines, but didn't have very good results :(.
I started with a 65:35 ratio of KClO3:polyester (for fibreglass), and it burnt relatively slowly, and with a lot of grey smoke.
I had similar results with ratios between 80:20 and 60:40, nothing I tried looked suitable as a propellant.
What I intend to try next is something like 40% AN, 30% KNO3 and 30% polyester, to try to get a better gas output.

Has anyone actually had success with polyester based fuels, but without all sorts of catalysts and burn rate enhancers?

[Arkangel]

One thing to be cautious of when casting a polyester resin/oxidiser fuel is to only use a tiny amount of catalyst and mix it well. Use too much and it will heat up dangerously when curing, and will start to crack the grain. This might lead to a premature ignition, and if it doesn't the fuel grain will be full of voids, meaning you're likely to suffer a CATO at some point. It'll take a while to go off, but when it does it will be slow and cool - a bit like me <img border="0" title="" alt="[Wink]" src="wink.gif" />

[DarkAngel]

Keep in mind that when a fuel is burned without a container and it burns slowly it still could be a suitable rocket proppellant.
I read that propellants containing NH4NO3 sometimes don't even burn without a container.

[xoo1246]

No problem with the peroxide in the catalyst and the oxidisers beeing used(chemical reaction between them)?

[Arkangel]

Hmmm, possibly, it's generally MEKP, although I generally only use 1-2cc per gallon of resin, so there's not a lot of it. However, that's a good reason to be cautious of the heating.

[Guerilla]

First.. I was wondering could it be possible to use zinc powder as a metal fuel in the AN based composite fuels (something like AN/Zn/Epoxy), even though it is rather low-energy fuel compared to Al and Mg?

Second, has any of you ever tried chlorate based composite fuels? I know, it is not recommended to use chlorates in rocket fuels but they can be used. At least I have read of successful rockets that have used NaClO3 with epoxy or urethan resins. I would consider these far better than chlorate/sugar or any other porous fuel that is likely to CATO without proper confinement (I'm not gonna ram any chlorate fuel). I don't have NaClO3 and I don't bother making it, so I stick with KClO3, should be better anyway.. I have already made some test batches with KClO3/Epoxy, it burns very fast with bright flame, adding small amount of CuO makes it burn slightly more faster.

I don't know yet how big nozzles should I use, but I will probably use the same 20mm diameter pvc-pipe that I've used to play with KNO3/sucrose.. I let you know if I will have any success, could take some pics too. Now to the bed...

<small>[ April 12, 2003, 05:02 PM: Message edited by: Guerilla ]</small>