I just recently went back to using sodium hydroxide instead of potassium because I feel as though I got a better reaction in a shorter period of time with it. this being said I wanted to know what you guys use and what you have found to be the pros and cons of each. with potassium I continually got a incomplete reaction at a base of 9 grams per litre and with sodium I get a good full reaction at a 5 gram base. What gives

 

I don't have a clue why your having problems with KOH, unless it's drawing moisture...............

I'll never go back to NaOH because of the problems with handling the glycerol. I recover the Methanol from my glycerol, and it's thick enough after the Methanol is removed. If I used NaOH I'd have to heat it up to get it in my recovery system, then recover the Methanol, then deal with the rock hard glycerol. No thanks! NaOH glycerol is highly toxic to plants, and animals, so I'd have a major disposal problem.

 

the glyceren disposal isn't a problem here because I give it to a guy who uses it to mold fiberglass as a release or something, he says it works great. I don't know what the deal is with the potassium but with a 2 hour reaction time at 140* F I keep getting unreacted oil and soap

 

It sure sounds like the KOH has absorbed some moisture. KOH is a lot more hygroscopic than NaOH. If it gets any moisture at all it turns into a chloride and will produce excess soap, and poor conversion.

 

my lye comes in small 2lbs containers that are sealed. I dont open them untill I'm ready to use it, where would it absorb moisture? how do you store this stuff ? I'm open for any suggestions as I would rather use the potassium it's not as dangerous and is a little more forgiveing to small amounts of water and high ffa

 

It could have been contaminated before you got it. I buy mine in 20 kilo bags (3 bags. one inside the other) and when I open one I put it in sealed 5 gallon pails. I had a bag once that must of had some moisture in it because I had the same porblems you are talking about. I opened a new bag and the problems went away.

 

I'll give it another shot from another supplier and see. thanks Don.

 

Just information.

I know this might sound nuts. But BE CAREFUL

I spent years working with Naoh on a professional basis. It is really dangerous in concentrate form. Please use the proper eye protection and NOT just safety glasses. Use goggles and a face shield at the minimum.

The shortest (at least in my professional research) of Naoh concentrate in contact with a human eye was 10 seconds which resulted in total blindness.

I just won't want you guys to underestimate the safety risk.

Never let your guard down with these caustic materials.

 

When I started making bio, I decided not to use NaOH because of the solidification of the glycerine. I only had problems when I tried using less methanol in order to save money. I use the 2 stage method as I get better reactions with it and it is just a little bit more work. I store my bulk KOH in 5 gal Homer buckets and tranfer to smaller one gal containers with tight fitting lids.

 

Koh, more forgiving on wet oil, and less soap production, disposal of the glycerin is much easier. only con is the current price jump.
i was paying 1.30/lbs, now 3.45/lbs.
i think yourt koh is less than up to snuff, some moisture in it, i use 8 as a base and almost always have complete conversion, only exception was very wet oil, not dewatered

 

Glycerin with KOH can be composted. Glycerin with NaOH cannot.