All castor is not the same

[Russell Shaffer]

I have an unheated, separate garage where I store my fuel and do my dirty modeling work.  During a January cold spell the garage temperature was below 10 degrees F.  Well, it has warmed up but still hasn't got above 40 out there.  I had a quart of Morgan castor oil and one of Sig AA.  The Morgan looked  fine, just a little thicker but would still pour ok.  The Sig froze into a solid white chunk.  I moved the Sig to a warmer spot, about 55 degrees for several days and it stayed white and thick but was no longer solid.  Then I moved it into the house on top of my water heater and this morning it appears to be  100% normal.  Interesting.

[RandySmith]

I have an unheated, separate garage where I store my fuel and do my dirty modeling work.  During a January cold spell the garage temperature was below 10 degrees F.  Well, it has warmed up but still hasn't got above 40 out there.  I had a quart of Morgan castor oil and one of Sig AA.  The Morgan looked  fine, just a little thicker but would still pour ok.  The Sig froze into a solid white chunk.  I moved the Sig to a warmer spot, about 55 degrees for several days and it stayed white and thick but was no longer solid.  Then I moved it into the house on top of my water heater and this morning it appears to be  100% normal.  Interesting.

When using your  castor  check for  clear  waxy looking   "flecks"   or flakes  floating  around in the castor, these are very hard to see, hol d  up to the  sun or strong light, you can see them floating  if you look close
these will  kill you engine run, sometimes  your engine  as  they can stop up the  spray bar

Randy

[Tim Wescott]

When using your  castor  check for  clear  waxy looking   "flecks"   or flakes  floating  around in the castor, these are very hard to see, hol d  up to the  sun or strong light, you can see them floating  if you look close
these will  kill you engine run, sometimes  your engine  as  they can stop up the  spray bar

Randy

Is there a reasonable way to filter them out?  Shop rag?  Coffee filter?

[Lauri Malila]

Is there a reasonable way to filter them out?  Shop rag?  Coffee filter?

Yes, a coffee filter as emergency cure. But it's better to throw such fuel away, those flakes re-appear after a short time. L

[Steve Helmick]

Getting the fuel nicely warmed up seemed to fix the castor snowflake problem back in the '60's.  I'm surprised that SIG and Morgan did not act the same, but expect Morgan mixes in something with it to solve the problem. Maybe Amyl Acetate. What does it smell like, and any different than SIG, with the "whiff test"?  Steve

[Istvan Travnik]

Maybe the problematic castor oil was not "first pressed" quality brand.
(In FAI Sporting Code when the fuel mix is standard (F2A Speed models) it is compulsory to use "first pressed" quality, since 2011, to avoid this problem)

In the ancient times I made 1:1 mix of methanol and castor oil, enough for the next year in October, put into half gallons, narrow, clear plastic bottles, and in April I racked off the clear part. The muddled part spilled out.

Now (for 8-10 years I stopped castor oil, I buy 10 litre PAG based cheap synthetic (shared with a colleague), or, as luxury solution: Motul Micro (aesther based). I really hate cleaning engine and muffler of resin & carbonated residues...

[Russell Shaffer]

I'll do a sniff test tomorrow after the Morgan oil warms up.  I can barely smell it at all right now.

[Russell Shaffer]

Sniff test results - my wife, who has a much better nose, says the Sig smells like castor but the Morgan doesn't.  I can tell a little difference.  The Morgan is mostly used up and the Sig is full so maybe there could have been some oxidation or other change in the Morgan?  The oils look and feel identical when the Sig isn't frozen.  Still a mystery. I now have a request for information submitted to Morgan.

[SH Stunter]

Castor Oil isn't all that expensive, so throw it away, if you have doubts about it doing what you want, and buy fresh Castor Oil.
Stunt Guy in Florida

[Richard Logston]

Back in the sixties some of us mixed our own fuel. We used Bakers AA castor and methonal and would add a tad of Amyl Acetate as a blender, don't remember how much. We were running K&B, Enya And Super Tiger RC engines. I had left U/C to satisfy the RC bug. Now all these years back to building control liners again. I'm posting this because Steve brought back the memory of using Amyl Acetate. Richard

[Steve Helmick]

1% Amyl Acetate can be useful. It is (or was) a cheap solvent, and smells a lot like bananas. That's why I suggested a "sniff test".

Back in the olden days, nitro benzine was popular ("shoe polish smell"), but NB was designated as a carcinogen and banned completely, along with plain benzine. Amyl Acetate did the same thing at much lower percentages, plus it was cheap. Win/win. IF the castor oil came from China, there may be a chance that NB was "included".  Back in the '60's, "Blendzall" castor had the sweet aroma of Nitro Benzine...to make it mix with gasoline for racing motorcycles.  Steve

[Russell Shaffer]

I'll vote for the amyl acetate.  My wife says the Sig smells like castor and the Morgan does not.  Anyhow, Morgan is cheaper and doesn't freeze.

[bob whitney]

  can someone show me in the AMA rule book where nitro benzine is Banned

[Steve Helmick]

 can someone show me in the AMA rule book where nitro benzine is Banned

Banned by the EPA or some other goobermint agency. Ask them. AMA didn't have to ban it, because Uncle Sugar did it for them.

Tetra-nitromethane was banned by the AMA, and that should still be in the rulebook, although most glow speed/racing events are now limited to contest management provided fuel, as you well know.  Steve