I have sludge about a .25 thick left on the bottom of the barrel after CF'ing the oil and pumping it out, is this normal( I have processed about 200 gal.)? Am I not prescreening enough or maybe not settling long enough? I have not heard of anyone else addressing this. The oil I finish up with is like dark ice tea and passes the pan test.

Where on the barrel are drawing from?
If you're not drawing from the very lowest point then you're not processing all the oil, and once stuff has settled lower than your pickup point it's going to stay down there.

Easiest way to set up an an oil drum like this to put it on legs to raise it off the ground a little. Then, using a fence post or something similar, give the center of the bottom a whack or two from the inside.
This won't exactly give you a cone, but it will dish out the bottom and put the lowest point at the center, where you can then weld your take-off.

With a CF you want to process everything in the barrel. Pre-filter the big lumps out then remove all the rest with the CF.
It's not as though you're going to be blocking expensive filters with the thick stuff!

I get that sludge on the bottom of my barrel too. My barrel is off the ground and has a bit of a cone bottom.

One important thing I do when final filtering is not drain the oil in the barrel all the way to the bottom, if you do you will end up sucking up the sludge and plugging up your polishing filter when transferring it out into a clean barrel or vehicle.

I get rid of the sludge every 5 batches or so when I begin centrifuging a batch. After the batch is heated, and after I start the centrifuge, I take broom handle, hockey stick or whatever can reach to the bottom and stir it up. In an hour you centrifuge will be pretty plugged up, so clean it and finish processing your batch like you normally would.

quote:

Originally posted by Grease gun:
..... I take broom handle, hockey stick or whatever can reach to the bottom and stir it up.......

Good idea. A stiff brush on the end of the stick would probably help too.

Thinking about it, you could probably automate the process by extending the bypass outlet to the bottom of the drum to let it wash the bottom clean.

Maybe I'll try that.

I get that. I am thinking it is because my heating element is off the bottom of the barrel so it does not get real warm could be as much as 50% of the drum temp but that is just a guess. I tip it on the site and clean that crap out and put it in the turk burner. I draw off the top down to the top of my half inch pickup. Hopefully I can afford a cone bottom tank soon. I don't have the ability to cone a drum. It's been workign for me but is around 90% efficient.

yes I have the barrel tilted, I think the stirring idea is a good one so I will start doing that. Thanks guys

I have my barrel tilted up on a piece of 2/4. I have a stick that I drag across the bottom of the barrel as I run the CF. After I get most of the stuff filtered from the oil I drag it to stir up the stuff that drops to the bottom which is very little. I get as much oil out as I can then tilt the barrel to get the rest and don't see anything except the bottom of the barrel.