Some experience with paraffine oil as binder

[mabuse00]

Maybe may "lamp fuel" paraffine oil, or "Kerosine" as Americans seem to call it use different chain length than usual, but recently this phenomenon caught my attention, as I left a small bottle cap half full of paraffine and 2 days later it was dry...

 

Not even a greasy residue was left. So it's not just a fraction, but the whole stuff!

As it not only acts as a binder but als slows down the fuel, in my case whistlemix, I found this rather alarming.

 

I ignored that fact for long, but a fresh finished motor left standing upright on a table leaves a "wet" residue, like if you breathe against a cold window.

 

I never did a direct comparison oiled whistle vs. dry pressed whistle, but with BP the difference with 2% was severe.

 

A fuel that changes it's performance during storage is no good, think of hot setups and reliability, not to mention comparisons between different whistle batches are definitely made fuzzy. My older batches always seemed to be a little faster... This might be an explanation.

 

 

Do you have an opinion on that matter?

Edited December 14, 2014 by mabuse00

[dagabu]

Yes indeed, phlegmatizers are very important in whistle mixes. They act not only as a help for consolidation but also assist with grain flexibility and as you say as a retardant to the burn rate therefor controlling how quickly the fuel burns.

 

Because there are in all likelihood dozens of phlegmatizers that would be useful in whistle mixes to retard the burn and to help consolidate the mixture and aid in grain flexibility, we can choose any one of them and use them with great success... The limitations of each phlegmatizer can be realized over time as you have experienced.

 

Mineral oil, Vaseline, kerosene, Camping gas better known as white gas, paraffin wax, soy wax, carnauba wax,even diesel number one can be used has a phlegmatizer in whistle mixes.

 

Waxes, such as carnauba, soy and paraffin have proven to stay in whistle mixes for indefinite periods of time with little cracking or failure as they are not aromatic nor are they subject to evaporation. Any phlegmatizer that has volatile organic compounds is subject to evaporation and is prone to fissures, hardness of a grain, lack of flexibility, etc. Fissures vastly accelerate the burn which can result in the expulsion of sections of the fuel grain after the paper casing fails.

 

Mineral oil is also a phlegmatizer, it has no volatile organic compounds, is not a solid, does not evaporate, is not particularly different from hard waxes but is easily mixable in white gas or camping gas.

 

My suggestion would be to make one of each of the whistle rockets using phlegmatizers with volatile organic compounds, waxes and other phlegmatizers that you may have laying around, label them all, wait a predetermined amount of time, let's say 6 months, and then fire them all the same day. Keep a record of which rockets Cato and which ones do not, this should give you a very good indication as to which phlegmatizers will remain flexible and not evaporate versus the ones that do not remain flexible and Cato.

Edited December 14, 2014 by dagabu

[a_bab]

You clearly didn't do your homework properly.

 

What you seem to use in your whistle is kerosene, the stuff used by the jet engines meaning a volatile fraction, just above gasoline as it's fractionally distilled: http://en.wikipedia.org/wiki/Kerosene

 

Unfortunately it is called "parrafin" in UK and probably elsewhere in EU but not in USA, where parrafin oil is this: http://en.wikipedia.org/wiki/Liquid_paraffin_(medicinal), a clear, thick oil, with no smell at all, sometimes used as a laxative.

 

So as Dag said, you are only using a volatile compound which will eventually evaporate from your engine, leaving the fuel grain somewhat spongy. The rule of thumb is: if it smells, then it's still there. This is why the whistle fuel must be thorougly dried before pressing it, so you get rid of the volatile stuff (some use acetone to make the things faster)

 

What you should do is to mix the (real) parrafine oil with naphtha (it evaporates faster). Naphtha will work as a carrier for the parrafin oil whis is the phlegmatizer and it will stay in the fuel well distributed in the fuel.

 

If you can't find parrafin oil you'd better use baby oil which will smell better and is the same stuff plus some perfume in it.

 

So, to sum up:

Phlegmatizer examples: waxes and oils, vaseline such as motor oil/bees or candle wax etc. They are slippery and don't evaporate. 1-3% can be used.

Solvent examples: kerosene, acetone, laquer thinner, naphtha , white spirit, toluene etc. All volatile, flamable and will dissolve the phlegmatizer. Values between 150-200 ml are used for every kg of fuel. All will evaporate before the pressing !

 

 

As about the oil impact over the BP fuel, SLD once said: "For every 1% oil you add to the fuel, you reduce the amount of thrust about 12%".

[ddewees]

If you organize common petroleum distillates by their evaporation rates from fastest to slowest, you come up with the following:

 

Methane: already evaporated to a gas at room temperature

Propane: also a gas at room temperature

Butane: almost a gas at room temperature

Heptane and octane used in gasoline: very fast evaporating liquids

Naphtha: reasonably fast evaporating

Mineral spirits: fairly slow evaporating

Kerosene: almost no evaporation

Mineral oil: doesnt evaporate at room temperature

Paraffin wax: a solid at room temperature

[mabuse00]

Well it said paraffine oil, so I used it

It's very confusing, it never sais exactly what you get in a chemical sense.

 

Mine does not smell, it only has a very faint odour.

 

Next try:

I'll go to the pharmacy and ask for medicinal paraffinum liquidum - any objection?

 

 

PS:

I like to use liquid oil for obvious reasons, if you make many small batches for comparisons it saves a lot of work.

However once the favorite mix is found, I would not hesitate to use a phlegmatiser/binder that has to be melt, and make larger batches.

 

My question here is, which binder gives the strongest fuel grain and best pressing behaviour and has the lowest influence on the burn rate?

[dagabu]

Solid paraffin wax will give you the most flexibility and the strongest grain when compressing. Lacking that, use mineral oil better known as baby oil but without the fragrance if you can find it. Your pharmaceutical should have it listed as laxative, USP.

[schroedinger]

Mabuse have a look for white oil sold for wood treating, if it says paraffinum (per) liquidum in medical grade you get the sam estuff but propably much cheaper then at the pharmacy a litre is about 11

[dagabu]

Well it said paraffine oil, so I used it

It's very confusing, it never sais exactly what you get in a chemical sense.

 

Mine does not smell, it only has a very faint odour.

 

Next try:

I'll go to the pharmacy and ask for medicinal paraffinum liquidum - any objection?

 

 

PS:

I like to use liquid oil for obvious reasons, if you make many small batches for comparisons it saves a lot of work.

However once the favorite mix is found, I would not hesitate to use a phlegmatiser/binder that has to be melt, and make larger batches.

 

My question here is, which binder gives the strongest fuel grain and best pressing behaviour and has the lowest influence on the burn rate?

 

Keep in mind that the phlegmatizer has to stay in the comp, if it whets the tube, evaporates etc, it is of no use and the propellant will likely crack.

[Col]

Mineral oil is the easiest one to find usually. I dont know about long term storage but a few months doesnt have any noticeable effect on the performance compared to a freshly pressed motor. How you store them could make more of a difference.

[dagabu]

Looking at the hundreds of posts on Passfire, Fireworking and here, I would have to say that the tube, pressure, solvent, temperature, lighting position & humidity all have a significant roll in the success of a whistle propelled motor. I for one have sacrificed power for reliability (so I thought) by using slower whistle propellant, using mineral oil, not pressing as hard and using less dwell time on the comp. All of the motors I made in 2010 with this in mind flew exceptionally well, no CATO's in that batch. I had this beast whipped!

 

Like, I said, or so I thought.

 

Winter 2013, same batches of chems, same method of workflow, same everything including tubes and tooling and only one year later a full 20% of them CATO'd just after launch, about 50' up.

 

Good luck and keep us in the loop as to what you find.

[ddewees]

I have a similar experience...

 

Great motors last year, zero Cato with whistle (well maybe one or two). Now this year, not so fortunate. I use Vaseline in whistle... but prefer canning wax for everything else. The only thing I've changed is the kclo4... trying to use up some dirty stuff I got from Firefox.

 

I've never used mineral oil, but may start... it seems like the easiest method.

[MrB]

Not that this is much of a help, but, paraffin oil, used for treating wood, "should" be available on any IKEA store. Kitchen supplies. I bet it's not the cheapest place to buy it, but nobody looks at you in a weird way when you walk out through the register with it, and IKEA is pretty much everywhere these days. I read you could go around the world and only eat "swedish" foods by going to IKEA, so the odds are that you might have one near... Good luck.

B!

[mabuse00]

I've never had any problems in practice. The motor may dry out over time, but they never failed me, I used several different tools in 10 and 15mm calibre over the last years and there was not a single unexpected CATO.

 

In fact it just bothered my that my comparisons are spoilt that way, because one batch my drier than another.

 

 

I'll change the method next year, thanks for your replies.

 

 

Another question:

I recently made some motors for NYE and I found salicylate sticking to my (steel) spindle like hell, on the other hand benzoate came off without trouble, MUCH more pleasant to work with.

Just curious, is that a common experience?

[a_bab]

Yes, salicylate stickiness is the reason many hate it. Rubbing your spindle with some parafine before pressing makes the difference though.