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5110 Days of genuine trouble-free motoring on veg oil from 18th June 2008 to 16th June 2022 - read more

Biodiesel - What is it?

A Look At The Dangers Of This Homemade Fuel

A few years ago very few of us had heard of Biodiesel. Now it's becoming more and more popular, though as can happen in such situations it is receiving mixed press.

In theory Biodiesel is a good guy! It's a fuel based on vegetable oil but mixed with certain chemicals to make it less viscous and therefore more suitable for unconverted diesel engines. The main problem with Biodiesel is that some of the chemicals used are downright deadly (more below) and the whole concoction needs to be thoroughly cleaned to remove substances like methanol and glycerine from the mix before it can be safely used.

Personally I think this is why Biodiesel gets bad press. Done properly it is an excellent fuel, has lower emissions and is largely sustainable (except for a few fossil fuel additives). The problem is the unscrupulous amongst us want quick bucks and can't be bothered to do a thorough job, leading to poor grade fuel. Either that or the DIYer simply isn't up to the job and either badly injures himself or produces a porridge like sludge which he's stupid enough to try and run his car on. Personally I suspect that eventually the DIY production of Biodiesel will be made illegal, simply because it is so dangerous.

Biodiesel Viscosity & Corrosion

The real problem for me with Biodiesel is that it's still too viscous for the modern engine. In terms of viscosity it sits somewhere between pure vegetable oil and standard diesel, but it's thickness has led to reports of injector troubles. As such, if you're going to try and use Biodiesel on a modern engine, you really need to heat it first, and my logic is if you're going to go to the trouble of heating it, why not just use vegetable oil?

Biodiesel is also famed for its corrosive qualities on rubber and certain plastics. The problem is engines often contain rubber and plastics, so those running on Biodiesel often need to replace engine parts with synthetic materials. Fortunately vegetable oil has no such corrosive qualities - another tick in my box.

Biodiesel Dangerous Chemical Nasties

In the past I have tried to manufacture my own Biodiesel. I started the novice way, with pure virgin vegetable oil, poured this into my food blender (oh yes).

I added to this methanol, which is basically rocket fuel - but is poisonous and odourless, can be absorbed through the skin or through inhalation, and can cause blindness and even death.

Then came the sodium hydroxide - which can cause severe burns and again, death.

Now when you mix sodium hydroxide and methanol together, you get a substance that is highly dangerous. You cannot breath it in and respirators don't work. You can't afford for it to touch you because it's so corrosive it's painless - because it actually kills nerve endings, so you don't feel the pain, then it gets on with doing some real skin damage.

I remember reading one book on the subject. The author was describing the cleaning process (where water is run through the Biodiesel to remove the leftover nasty chemicals). He stated that he walked across his lawn with a bowl of this waste water and accidentally spilled some on his grass - which NEVER grew back. The crazy thing is he poured that waste water down the drains and into the water system. Mad! And he called it a green fuel?

DIY Biodiesel Brewing - Precautions To Take

Needless to say, I was always VERY cautious when making Biodiesel; no kids, no pets, no distractions, no naked flesh and a face turned blue through not breathing. But many people are not so cautious and I'd hate to think what could happen to a child around that stuff.

I did a spint as a handyman once and was amazed at the stupidy of people. I saw radiators nailed to walls, bare electrical cables forced into outlets with matches, are burst pipes repaired with chewing gum and cellotape. Needless to say that if you are this kind of DIYe, do not even try it. Someone will get horrible hurt or worse!

As I said above, I really believe sooner or later the DIY production of Biodiesel will become illegal and it's because of this kind of DIYer. The process is highly dangerous and, let's be honest, very, very few of even the good DIYer brwers dispose of the toxic waste products sensibly. Most, I fear, flush them down the drain.

Given these hassles, I peronally don't think the DIYer should touch the stuff. Buy it professional brewed by all means, but don't brew it yourself. And that, in a nutshell, is why I opted for veg oil motoring over biodiesel.

Still Going To Brew Your Own...?

If you've read the above and you're still going to brew your own, then please look for expert guidance for other websites than this. There are many forums on the subject and "Best Practice" is a common theme due to the dangers involved - so research well!

Biodiesel, Vegetable Oil or Diesel?

So, which fuel should it be? Let's have a look...

Fuel Cost Most expensive Slightly cheaper than standard diesel Least expensive
Sustainable No Yes Yes
Fossil Fuel Content Most of it A small part None
Emissions Loads (boo hiss) Some, but better than LPG Few, the best of the bunch
Older Engines Run fine Run fine Run fine
Modern diesel engines (without conversion kits) Run fine Some, but can be injector problems. No. Too viscous
By-product? All manner of nasties Toxic waste, dumped down the drains by most DIYers I fear None

Weigh up the above however you wish, but for me the answer was obvious.

  • Standard diesel - smelly, poisonous, planet killing, expensive.
  • Biodiesel - greener, but with fossil fuel content, emissions and still too viscous
  • Vegetable oil - cheap, cheerful, biodegradable - liquid sunshine - but viscous.

As both Biodiesel and vegetable oil are too viscous for the modern engine, both need a converter system, and if you're fitting a converter system, why use Biodiesel? For me vegetable oil motoring makes much more sense.

Useful Biodiesel Links

Please don't let me put you off Biodiesel. I am a fan of it. It's just that quite simply my car won't run on the stuff without conversion, so I may as well use the best stuff - vegetable oil. However, for those interested in a little more detail about Biodiesel, below I've included a few useful links.

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