Alternate Binders

The Rocketry Forum

Help Support The Rocketry Forum:

Status
Not open for further replies.

Acaicia

Active Member
Joined
Oct 25, 2020
Messages
39
Reaction score
3
Howdy!
I'm making my own batch of solid fuel and need a good binder. PBAN in large quantities is either expensive or hard to come by, and other types of binders are, again, expensive or hard to come by.
Does anyone have an alternative binder? Like a flammable epoxy? Sadly epoxies nowadays are non flammable, but I'm sure some brands haven't made their products safe yet.

Edit: Preferably, not a rare item. Ideally accessible via Amazon in small qualities and AliBaba in bulk 👀

Cheers!
 
Last edited:

Rocket501

Well-Known Member
TRF Supporter
Joined
Feb 9, 2018
Messages
211
Reaction score
104
Howdy!
I'm making my own batch of solid fuel and need a good binder. PBAN in large quantities is either expensive or hard to come by, and other types of binders are, again, expensive or hard to come by.
Does anyone have an alternative binder? Like a flammable epoxy? Sadly epoxies nowadays are non flammable, but I'm sure some brands haven't made their products safe yet.

Edit: Preferably, not a rare item. Ideally accessible via Amazon in small qualities and AliBaba in bulk 👀

Cheers!
I'm afraid that according to the site's rules, we are not supposed to talk about specific engine making details outside of the research forum, which this is not. Mod's correct me if I am wrong, but I think most people who are in the know are probably avoiding responding for this reason.
 

heada

Well-Known Member
Joined
Jan 18, 2009
Messages
4,003
Reaction score
1,178
Location
Indianapolis, Indiana
Talking about formulations or processes are restricted but asking a very generic question like was posed shouldn't be restricted. Had they asked for binder, oxidizer and fuels with ratios sure but a list of binder(s) shouldn't be. Not when its common knowledge across the globe.
 

Rocket501

Well-Known Member
TRF Supporter
Joined
Feb 9, 2018
Messages
211
Reaction score
104
Talking about formulations or processes are restricted but asking a very generic question like was posed shouldn't be restricted. Had they asked for binder, oxidizer and fuels with ratios sure but a list of binder(s) shouldn't be. Not when its common knowledge across the globe.
At least from my personal perspective, these things are fundamentally intertwined. I agree we can share basics, but most alternative binder choices can only be used with extremely specific formulas. To share the binder alone is pointless without the remainder of the data, which would kick things to the research forum.

To go into what I am comfortable sharing, PBAN is for the most part no longer used by amateurs or professionals (excluding things like the SLS SRB's) which only use it for legacy reasons. HTPB has indeed replaced it, but it is not cheap and while it is easy to buy if you are TRA L2 or L3, you can't buy it from Amazon and I think it has export control as well.

Another popular, but low performance, options use modified forms of sugars as both fuel and binder. Many popular youtube tutorials using this fuel show extremely poor design and safety practices. However, people can make safe and reliable motors using this fuel if they follow good design principles.

Alternative composite binders exist, but they require special formulas and most have some fairly major associated issues.

Easiest thing to do is probably get your TRA L2 and accept that making rocket motors isn't cheap if you want to do it properly. If you want us to be able to answer in more detail, you could try to post on r/rocketry.
 

timbucktoo

Well-Known Member
Staff member
TRF Supporter
Global Mod
Joined
Jun 13, 2014
Messages
8,193
Reaction score
1,324
Location
Cocoa Beach
Howdy!
I'm making my own batch of solid fuel and need a good binder. PBAN in large quantities is either expensive or hard to come by, and other types of binders are, again, expensive or hard to come by.
Does anyone have an alternative binder? Like a flammable epoxy? Sadly epoxies nowadays are non flammable, but I'm sure some brands haven't made their products safe yet.

Edit: Preferably, not a rare item. Ideally accessible via Amazon in small qualities and AliBaba in bulk 👀

Cheers!
If you want to discuss propellant formula, you must gain access to research forum. Must be L1 NAR or TRA certified & US citizen.
Here are the rules and the way to gain access to research forum:
 

prfesser

Lifetime Supporter
TRF Lifetime Supporter
Joined
May 7, 2017
Messages
1,821
Reaction score
1,890
Location
Murray, KY
That's one of those super hard to get or expensive binders I was talking about
So many of the newbies who get on this forum want to know about making rocket motors. Nope. This isn't the right place. If you're a US adult and L2 you can get on the "Research" forum and ask about almost anything.
 

dhbarr

Amateur Professional
Joined
Jan 30, 2016
Messages
7,166
Reaction score
1,585
So many of the newbies who get on this forum want to know about making rocket motors. Nope. This isn't the right place. If you're a US adult and L2 you can get on the "Research" forum and ask about almost anything.
Don't need L2 for research forum access, L1 is sufficient.

DO need L2 to fly them at any TRA EX launch.
 

Acaicia

Active Member
Joined
Oct 25, 2020
Messages
39
Reaction score
3
So many of the newbies who get on this forum want to know about making rocket motors. Nope. This isn't the right place. If you're a US adult and L2 you can get on the "Research" forum and ask about almost anything.
Damn now I remember why I don't like hobby specific forums. There's always one of these ^^
 

rharshberger

Well-Known Member
Joined
Oct 13, 2014
Messages
9,835
Reaction score
1,809
Location
Pasco, WA
Last edited:

Acaicia

Active Member
Joined
Oct 25, 2020
Messages
39
Reaction score
3
That particular "one of these" wrote the book on modern composite propellants, that is a reference for research rocket motors....

[/URL]
And I'm currently employed by SpaceX as a mission design engineer. Credentials don't mean anything. What your post SHOULD have said instead of blatantly disrespect is "Yeah we actually have a forum that's relatively hard to find unless you've been here a while, it's the research part and here's the link to apply"

If anything, your credentials should mean you are professional, not disrespectful.
 

G_T

Well-Known Member
Joined
Dec 29, 2011
Messages
2,311
Reaction score
383
Acaicia,

Generally people with knowledge that would be useful towards answering your question would not be inclined to. Sorry! Here are the reasons:

1) You are new here, we don't know who you are or where you are from.
2) For those in the know, open discussions about formulation of propellants generally falls under US regulations such as ITAR. It is even a specific line item in the regulations! Anyway a discussion on technical info that can be observed/obtained by a non-US citizen or dual citizen or a US citizen working for a foreign government or corporation or interest, is considered an export. Essentially the answer to your question may qualify as an arms export, legally, in the US. That requires major high level approval...
3) There are exceptions for research. There are lots of research papers online. Suggested background in physics, chemistry, engineering, math. And for binders, some knowledge of organic chemistry. It's an inter-disciplinary problem, and gets the label "rocket science" as overall it is fairly complex, and very non-forgiving of mistakes.
4) Mistakes can result in death and destruction. Very unfortunate for those involved. Also can be very unfortunate for those not involved, like the other people who enjoy this hobby. So we tend to get a bit protective on occasion.
5) So we don't like to get into propellant manufacturing discussions with those who have not already proven themselves capable of working safely and responsibly, through a track record of demonstrating competence with commercial motors.

Specifically when it comes to binders, before you go exploring too much, you should study up on it enough to know why the current binders are the current binders. That is, what makes them good for the job, and lots of other potential options not necessarily so good? When you can answer that, you might be ready for the research phase of your quest.

That's the short answer. I hope you stay around as rocketry really is fun and can be as deep as you want to make it.

Gerald

PS - Youtube is a good place to learn all the wrong techniques. It is full of dangerous idiots.
 

Acaicia

Active Member
Joined
Oct 25, 2020
Messages
39
Reaction score
3
Acaicia,

Generally people with knowledge that would be useful towards answering your question would not be inclined to. Sorry! Here are the reasons:

1) You are new here, we don't know who you are or where you are from.
2) For those in the know, open discussions about formulation of propellants generally falls under US regulations such as ITAR. It is even a specific line item in the regulations! Anyway a discussion on technical info that can be observed/obtained by a non-US citizen or dual citizen or a US citizen working for a foreign government or corporation or interest, is considered an export. Essentially the answer to your question may qualify as an arms export, legally, in the US. That requires major high level approval...
3) There are exceptions for research. There are lots of research papers online. Suggested background in physics, chemistry, engineering, math. And for binders, some knowledge of organic chemistry. It's an inter-disciplinary problem, and gets the label "rocket science" as overall it is fairly complex, and very non-forgiving of mistakes.
4) Mistakes can result in death and destruction. Very unfortunate for those involved. Also can be very unfortunate for those not involved, like the other people who enjoy this hobby. So we tend to get a bit protective on occasion.
5) So we don't like to get into propellant manufacturing discussions with those who have not already proven themselves capable of working safely and responsibly, through a track record of demonstrating competence with commercial motors.

Specifically when it comes to binders, before you go exploring too much, you should study up on it enough to know why the current binders are the current binders. That is, what makes them good for the job, and lots of other potential options not necessarily so good? When you can answer that, you might be ready for the research phase of your quest.

That's the short answer. I hope you stay around as rocketry really is fun and can be as deep as you want to make it.

Gerald

PS - Youtube is a good place to learn all the wrong techniques. It is full of dangerous idiots.
This is actually some pretty good info. Very good to know that this community isn't too large but also large enough to have tons of knowledge. Don't know who's going to read this (or where to post it), I'm a retired Air Force Mission Systems Specialist. Served for a while, got out and decided to work at SpaceX. I'm relatively familiar with the idea that some info needs to be confidential (My SpaceX job specifically requires a Top Secret/SCI clearance), but didn't really know binder alternatives are necessarily confidential. I can get specifically formulas and ratios need to be controlled though. Sadly I don't have L2 which is rather ironic now that I think about it. I'm really just here to get an idea of different solutions I can use for binders. After all, I'm not looking for pure efficiency, there's gotta be some sort of epoxy that can act as a replacement. Like a flammable glue with a relatively clean burn. I'm not necessarily new to SRE, just trying to gather info
 

Rocket501

Well-Known Member
TRF Supporter
Joined
Feb 9, 2018
Messages
211
Reaction score
104
This is actually some pretty good info. Very good to know that this community isn't too large but also large enough to have tons of knowledge. Don't know who's going to read this (or where to post it), I'm a retired Air Force Mission Systems Specialist. Served for a while, got out and decided to work at SpaceX. I'm relatively familiar with the idea that some info needs to be confidential (My SpaceX job specifically requires a Top Secret/SCI clearance), but didn't really know binder alternatives are necessarily confidential. I can get specifically formulas and ratios need to be controlled though. Sadly I don't have L2 which is rather ironic now that I think about it. I'm really just here to get an idea of different solutions I can use for binders. After all, I'm not looking for pure efficiency, there's gotta be some sort of epoxy that can act as a replacement. Like a flammable glue with a relatively clean burn. I'm not necessarily new to SRE, just trying to gather info
Just for your info, as someone who makes a large amount of experimental solid rocket motors, the binder itself is a fairly minor portion of my expenses. It's also not that difficult or expensive to get your TRA L2 in most parts of the US. I think you should seriously consider this option, as it will make your whole experience much easier.
 

Acaicia

Active Member
Joined
Oct 25, 2020
Messages
39
Reaction score
3
Just for your info, as someone who makes a large amount of experimental solid rocket motors, the binder itself is a fairly minor portion of my expenses. It's also not that difficult or expensive to get your TRA L2 in most parts of the US. I think you should seriously consider this option, as it will make your whole experience much easier.
I guess. I would say why I need an ungodly amount of propellant for but seeing how this forum is, I'm not sure it would go well. Not gonna lie if I'm going to continue, I will probably need at least my L2 or even L3. Ideally, I can use my current small stage testing to get my L1. Other than the ISP limitations, what does getting my TRA get me?
 

Maxwelljets

Well-Known Member
Joined
Sep 19, 2015
Messages
285
Reaction score
159
This is actually some pretty good info. Very good to know that this community isn't too large but also large enough to have tons of knowledge. Don't know who's going to read this (or where to post it), I'm a retired Air Force Mission Systems Specialist. Served for a while, got out and decided to work at SpaceX. I'm relatively familiar with the idea that some info needs to be confidential (My SpaceX job specifically requires a Top Secret/SCI clearance), but didn't really know binder alternatives are necessarily confidential. I can get specifically formulas and ratios need to be controlled though. Sadly I don't have L2 which is rather ironic now that I think about it. I'm really just here to get an idea of different solutions I can use for binders. After all, I'm not looking for pure efficiency, there's gotta be some sort of epoxy that can act as a replacement. Like a flammable glue with a relatively clean burn. I'm not necessarily new to SRE, just trying to gather info
Quite a few binders actually have higher theoretical performance than HTPB. HTPB is used because it provides a great balance of mechanical properties, mixing properties, long term storage, performance, and can cure at room temp (many alternatives require elevated temp cures, which obviously comes with a bit of risk).

Additionally, the reason epoxy resins are not typically used isn't because they're not flammable. If you mixed them with AP and lit them on fire you'd find that they all will burn, unless they're so loaded up with inert fillers (but the epoxies that have such a high concentration of inert fillers they can't burn will be such high viscosity you'd have lots of trouble mixing them anyway). Epoxy resins are not used because their curatives are typically liquid polyamines. AP will react with these polyamine hardeners, which will result in a bad cure. That, plus the fact that epoxy will produce a very brittle final product compared to a liquid rubber like HTPB or PBAN, means that epoxies are not a great choice.
 
Last edited:

Maxwelljets

Well-Known Member
Joined
Sep 19, 2015
Messages
285
Reaction score
159
I guess. I would say why I need an ungodly amount of propellant for but seeing how this forum is, I'm not sure it would go well. Not gonna lie if I'm going to continue, I will probably need at least my L2 or even L3. Ideally, I can use my current small stage testing to get my L1. Other than the ISP limitations, what does getting my TRA get me?
You can read all about the cert process and benefits here.

Certs can only be done on commercially manufactured, certified rocket motors. You can't cert on a homemade motor.

Tripoli membership gets you access to local flying clubs and fields as well as a multi-million dollar insurance policy in case something goes wrong related to (some of) your rocketry activities (only related to flights, not manufacturing of motors).
 

Acaicia

Active Member
Joined
Oct 25, 2020
Messages
39
Reaction score
3
Quite a few binders actually have higher theoretical performance than HTPB. HTPB is used because it provides a great balance of mechanical properties, mixing properties, performance, and can cure at room temp (many alternatives require elevated temp cures, which obviously comes with a bit of risk).

Additionally, the reason epoxy resins are not typically used isn't because they're not flammable. If you mixed them with AP and lit them on fire you'd find that they all will burn, unless they're so loaded up with inert fillers (but the epoxies that have such a high concentration of inert fillers they can't burn will be such high viscosity you'd have lots of trouble mixing them anyway). Epoxy resins are not used because their curatives are typically liquid polyamines. AP will react with these polyamine hardeners, which will result in a bad cure. That, plus the fact that epoxy will produce a very brittle final product compared to a liquid rubber like HTPB or PBAN, means that epoxies are not a great choice.
Fantastic. And now I'm back to the part where I need my L2 to know what these higher performance binders are, don't I.
 

Acaicia

Active Member
Joined
Oct 25, 2020
Messages
39
Reaction score
3
You can read all about the cert process and benefits here.

Certs can only be done on commercially manufactured, certified rocket motors. You can't cert on a homemade motor.

Tripoli membership gets you access to local flying clubs and fields as well as a multi-million dollar insurance policy in case something goes wrong related to (some of) your rocketry activities (only related to flights, not manufacturing of motors).
Gotcha. So I just have to build the body and integrate an Estes motor? Then, of course, launch it at some sort of event.
 

Maxwelljets

Well-Known Member
Joined
Sep 19, 2015
Messages
285
Reaction score
159
Fantastic. And now I'm back to the part where I need my L2 to know what these higher performance binders are, don't I.
None of these binders have so much higher performance that they're worth pursuing. The ones I know of were experimented with by professionals and then abandoned in favor of HTPB. PBAN is one such binder, but it requires elevated cure and is a specialty product. HTPB actually has non-rocketry uses as well, so it's cheaper than many of these options. Another potential binder is PPG (polypropylene glycol), which also has slightly higher theoretical performance than HTPB, but unfortunately it is hygroscopic (absorbs moisture), doesn't wet out solids well (so takes forever to mix), and doesn't age well at all. Others, with worse performance, include polysulfide rubber (some of the earliest composite propellants used this, but it was quickly abandoned) and asphalt (melt-casted).

HTPB is used for a reason.
 
Status
Not open for further replies.
Top