I made 4 test batches from one 2-liter Dr Pepper bottle and thought I would get a new bottle since the one I was using became a bit worn from repeated squeezing out wash water.
This time I tried a Shasta Cola bottle cuz I didnt have Dr Pepper. I added the methoxide and waited 20 min. to give it a second shake.
Luckily I didnt shake the bottle since I noticed a hiss when I picked it up and thought I didnt tighten the lid.
When I tried to tighten the lid it came off easily with ½” of threads still inside the lid.
I think the methoxide must have weakened the plastic.
On the bottom, both bottles have the recycle triangle with the number 1 inside and PETE written below it so I don’t think it was the type of bottle or the Dr Pepper/Shasta Cola brand that caused the problem.
I think the problem was switching from a long skinny-necked funnel that reached down closer to the WVO to a wider-necked funnel that allowed the methoxide to directly contact top of bottle when added. I say this because I noticed that around the threads there are many hairline fractures where straight methoxide came in contact.

Basically I got lucky since I could have easily doused innocent bystanders, my dog and myself.
PLEASE BE CAREFUL FOLKS!!!

Clint

The Dr Pepper method is inherently dangerous, and repeated use can lead to house fires. Ask it's inventor, one of the world's foremost champions of why not to make biodiesel.

John,

I wont go as far as saying not to make biodiesel. More like improve the process is what I would say. Perhaps mixing methoxide with WVO in a red gas can then adding it to a soda bottle. Or just process in the sealed gas can or sealed thick HDPE container that is said to be safe for mixing methoxide.

Clint

Hello Tripseven

Did you mix the methoxide in the Shasta bottle? I have found that that will quickly result in holes in the plastic.

NaOH will attack PET plastic over time. I have found that if you pour the methoxide into a pet bottle and allow it to sit, crazing will start to occur over the space of a few hours.
That is why I have in the instructions:
"As NaOH/KOH will degrade the plastic used to make soft drink bottles over time, these bottles should never be used to make more than one batch of biodiesel."

However, once you shake the contents of the bottle you can leave the biodiesel/glycerine in the bottle for years with no apparent deterioration of the bottle.

Any further information on this is most appreciated as I am contiually upgrading the instructions to the Dr Pepper Procedure as new information comes to light.

Hi Tilly,

Sorry...I should have gave more info.
I mixed methoxide in glass mason jar, poured it on top of 1-liter of WVO using funnel. What I didnt mention is 13.5g NaOH, 250ml methanol, which Im sure added to the problem.
I was trying to push the NaOH to see if it would produce more Bio.
This is why I titled the thread "2-Liter Bottle Test Batch" rather than the DP Method.

Clint

quote:

More like improve the process is what I would say. Perhaps mixing methoxide with WVO in a red gas can... just process in the sealed gas can or sealed thick HDPE container that is said to be safe for mixing methoxide.

Now that's good thinking. Play safely.

After the mix reacted in the 'gas can', it would be simple to pour it into a 5 gal polycarb water bottle to observe separation.
Turn the water bottle upside down and you've got a handy separatory funnel 'cone bottom' tank.