How much DOA to use? - Northern Colorado Rocketry

This topic has 10 replies, 5 voices, and was last updated 13 years, 7 months ago by James Russell.

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May 2, 2012 at 4:47 pm #41490
Tom Martin
So I am working on my first propellant formulation and have finally started getting all of the chemicals shipped. I will be using R45HTLO as my resin and the Desmodur E744 curative. These are easy to figure quantities by the equivalent weight, but I would also like to add some DOA plasticizer to the mix. I have been having difficulty finding info on how to figure a proper amount to mix in. Does anyone have any suggestions?
May 2, 2012 at 6:19 pm #55889
edward
Moderator
You don’t need DOA in your propellant. It just makes it mix better and you get a softer cure. Here is something I ran a while back:

79% AP 200u
1% Mg
13% HTPB
2% PAPI
5% DOA
1 drop silicone oil per 500 grams as a surfactant

Nothing fancy. Just a basic propellant. Still cured fine and tested well.

Edward
May 2, 2012 at 9:00 pm #55890
Tom Martin
Just looking to make things easier to cast. I will be trying something like this for my first batch.

60% AN
15% MG
4% AL
1% Lampblack (opacifier, I may not use this)
20% liquids (R45HTLO, E744, DOA maybee)

I am planning to start testing this in PVC motors on the test stand I just finished for characterization.

Thanks Edward. I am still out here and am still ordering up tubing from that source you gave me. Do I need to get graphite for nozzels, and aluminum stock for bulkheads on order or is that easily found locally?
May 2, 2012 at 10:04 pm #55891
Ed Dawson
Jeez,

What are you going to call it? “Heavy Metal”?

I’m just an amateur, but that seems a bit hot with the metals.
May 2, 2012 at 10:06 pm #55892
Ed Dawson
Jeez,

What are you going to call it? “Heavy Metal”?

I’m just an amateur, but that seems a bit hot with the metals.
May 3, 2012 at 1:41 am #55893
Anonymous
60/20/20 is a very common AN formula.

Tony
May 3, 2012 at 3:31 am #55894
edward
Moderator
ALRECO has plenty of hockey pucks for forward closures. Graphite is hard to source locally. I get it from NAC Carbon.

Edward
May 23, 2012 at 5:21 am #55895
James Russell
Major Tom, JamesR here. I have lots chemica for research and if you have any problems getting anything I do not have, I can help you get it. I personally like also but love the long burn time of the Ancon.

I have seen some formulas with 3 to 5% AP added to the AN to help with the burn and I would think it might help with ignition.

do you have a copy of John Wickman’s book? If not I could lend it to you.
May 23, 2012 at 5:29 am #55896
James Russell
Major Tom, JamesR here. I have lots chemica for research and if you have any problems getting anything I do not have, I can help you get it. I personally like also but love the long burn time of the Ancon.

I have seen some formulas with 3 to 5% AP added to the AN to help with the burn and I would think it might help with ignition.

do you have a copy of John Wickman’s book? If not I could lend it to you.
June 1, 2012 at 12:18 pm #55897
Tom Martin
James, I do have a copy of his book. In fact I went up and took his class a while back. I have been able to source most all of the items I have been looking for and have made a couple of small test batches to test my curing ratio and ignitability and such. the only thing I have had difficulty with is getting fine enough magnesium. Perhaps you know a good source. I can only get a hold of 325 mesh. I am also in the midst of finishing a test stand. I just need to build an insturmentation amp for my sensors and then calibrate the thing. I will then be looking to fire a few PVC motors to get burn times at various chamber preasures for my burn rate characterization. Any advice and tips are greatly appreciated.
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