Uses for old engine or cooking oil

[Western]

Is there anyone here who uses reclaimed engine or cooking oil.

I often wonder if I could get some cheap heating for my workshop in winter ... and if clean enough, for our home as well.

Our winters are pretty mild really, and the workshop is built inside a large shed ... lined and well insulated ... so don't really need much just to top it up.

Just occasionally I need more than my beanie and ugg boots.

Maybe even running a generator for some power hungry devices at times as well.

 

[Colin]

You need to start to get organised and have a number of people supply you with old oils. You can then see how to refine the oil by looking on the web. Simple refining and filtering is good enough for oil fired heaters and for diesel motors you need a little bit of "fiddling around."

 

[Les Jones]

I use old engine oil to heat a furnace for melting metal. This is the burner I use based on a Hago Delavan syphon nozzle. This is the blower that I use with the oil burner.

Les.

 

[Western]

You need to start to get organised and have a number of people supply you with old oils. You can then see how to refine the oil by looking on the web. Simple refining and filtering is good enough for oil fired heaters and for diesel motors you need a little bit of "fiddling around."

Yes, makes sense. I do have a friend with a mechanical garage who ends up with quite a lot. Oil fired heaters are not real common in Australia, but I'll do some research to see what sorts are available.

With winter just starting here ... heating's the first thing on my agenda. We're pretty well set up in the house with a decent wood heater ... it just gets a bit cold out in the workshop at nights.

 

[Western]

I use old engine oil to heat a furnace for melting metal. This is the burner I use based on a Hago Delavan syphon nozzle. This is the blower that I use with the oil burner.

That's a pretty cool set up ... I'll have to remember that in case I want to melt some metal. I just so happen to have a blower very similar to yours that we inherited when we bought this place ... was one of lots of stuff left in the sheds.

 

[tcmtech]

Is there anyone here who uses reclaimed engine or cooking oil.

I often wonder if I could get some cheap heating for my workshop in winter ... and if clean enough, for our home as well.

Our winters are pretty mild really, and the workshop is built inside a large shed ... lined and well insulated ... so don't really need much just to top it up.

Just occasionally I need more than my beanie and ugg boots.

I've been heating my place for about 5 years now on used oil of all types so how in depth do you want to get on how to do it?

Personally I use a oil fuel oil furnace burner with a modified nozzle systems that preheats the oil to~ 300F just before it exits the nozzle so that it will be thin enough to spray like normal fuel oil.

Here's the links to the threads I have here on what I work with.

https://www.electro-tech-online.com/threads/alternative-fuels-boiler-system-how-to-build-one.152957/ (thread totorial still in progress.)

https://www.electro-tech-online.com/threads/wind-generators-pros-cons.149508/ More indepth details of the burner and boiler its a part of.

As for finding used oil be careful on asking around. Word will get out and you will become overwhelmed with the stuff in a short time.

In ~ 5 years I went from barely getting 50 gallons a year from my own and families equipment to having to set up my flatbed truck to carry ~ 1200 gallons at time and am now setting up my second 3000 gallon storage tank (first ones full) on top of my existing 2000 gallon tank (Full) and 550 gallon tank (Full) plus 2500 gallons of tote tank capacity (near full) and at the rate the stuffs coming in I may pass the point of 10,000 gallons on hand by winter!

In fact I have a second 2000 gallon tank now I am going to set up for my brother so that I can start dumping my excess over at his place so that he can start burning off more of what I have coming in once I reach my goal of having 10,000 gallons on site, which as I have been burning the stuff, would be ~ 8 - 10 years worth of heating capacity.

Maybe even running a generator for some power hungry devices at times as well.

Regarding that, most old diesel engines that use mechanical injector pump systems will run on it just fine if you thin it out with ~ 20% by volume E85 fuel or preheat it to ~250 - 300 F just before it goes into the injectors.

Filtering wise for burner or engine use it just needs to be filtered to sub 20 micron levels first which can be done with a common whole house water filter and related cartridges if you want to get by really cheap on common easy to find off the shelf parts.

 

[large_ghostman]

Weee i do both! Bio diesel from cooking oil and heating oil from old 'other oils'. I process all mine though, its how i got into the alternative fuel thing

If your in oz you might have to clean it up like we do. I will grabbed you details and how we clean it. Getting a kind of system in place helps alot.

I have two tanks, one i let sit for a few months and one ready to clean and process, then its into storage. But i get more used veg oil now, so its bio diesel mainly. Oil for heating is getting harder to get hold of.

We use a machine like this as first stage cleaning, then we fine filter

 

[large_ghostman]

my biggest tip is put your first settling tank at a slight slope angel, down that end stick some HDD magnets or whatever you can get hold of, most the waste engine oil we get is agricultural stuff, always has metal bits in it. So i settle it a min 4 months,save me a fortune in fine cartridge filters and nozels for the boilers (those are not cheap here and you have to have the burner tested each year for emissions ).

Once settle put it through a machine like that with o filters on, do it 3 times (two are just pure fun!! they are so cool to watch), first run stop it after you get every 5 ltr and clean the wall of gunk!! if your oil is dirty you get a huge amount of sticky gunk on the wall. The clean oil seeps over the top lip. my final steps are sometime magnetic biochar (home made) and fine cartridge filter.

I always know when there is alot of hydraulic fluid in the waste oil, the burner smells like bananas to me

 

[large_ghostman]

waste cooking oil keep separate if you got decent amounts, i got a kick ass recipe and fool proof way to make bio diesel with it. if your in oz, then are you in a humid area or dry area? I ask because bio diesel suck up water like a lady paid for those services. So if its humid or here as a normal precaution, we have 2-3 inches of clean veg oil on top, it does sort of mix after a while but use the diesel within a few months or dry it out.

I started with waste cooking oil bio diesel a good while back when it was a bit odd to do it. I titrate ALL oil batches and accurately weight out the Hydroxide (normally sodium) and methanol. I do slow careful washes and test small batches before putting it in the storage, i dont do more than i can erm give away or use in a few weeks. In winter i use it on the generator only but summer the tractor runs like a dream on it.

So does my mums car, she just dosnt know i put a few ltr in each day . she thinks it will damage her car, well for 3 years she been running on maybe 50-60% bio fuel and its her not me that tells people how good her car runs lol.

She thinks the fuel gauge is unreliable however.

 

[Western]

I've been heating my place for about 5 years now on used oil of all types so how in depth do you want to get on how to do it?

I'm weighing up my options really. I've been following the other threads and quite like the idea of generating bio methane.

I have plenty of shed space to set up a system. IBC's are readily available around here. I have several decent Rinnai gas heaters that with research have discovered can be converted from LPG to Natural gas ... which should allow them to run quite happily on methane.

I had no idea before of the operating pressures of either gas type ... but now am quite comfortable that I wont need any pump compression ... so it seems quite doable.


At the same time, I hear comments about oil burners and oil heating ... so figure I should weigh that up first before making my final decision.


I will read through your suggested links later today (I'm supposed to be working ) ... then ask more questions.


You don't hear of oil heating here in Australia nowadays. The main ones we used to have were built in ones that look pretty much like a standard radiant gas heater ... with a flue.

Most were turfed out after the energy crisis ... was that back in the 70's?

I never had one myself, though I do remember some in some school classrooms. They were rarely used ... and all I remember about them was that if all didn't go well ... they'd smoke the place out and we'd all have to leave the classroom.

I'll get to work and do some study tonight. Thanks you.

 

[large_ghostman]

You could do both. I am working on a log in for you, the IBC option is very good. You think you can get 4-5? 4 would need to be in a shed or in the ground and insulated? If so then you have options. The thing is no reason you cant use oil and gas, if you cant feed for digester enough then oil is a good back up.

Feeding mine is one reason i attached the septic tank plus add all the organic material i can get (alot with our acreage), but get them right and they produce alot of gas. pressure wise there is a nice easy trick to constant perfect pressure. I will pm you or email you on that

 

[tcmtech]

I've been following the other threads and quite like the idea of generating bio methane.

I have plenty of shed space to set up a system. IBC's are readily available around here. I have several decent Rinnai gas heaters that with research have discovered can be converted from LPG to Natural gas ... which should allow them to run quite happily on methane.

I like the principle but my issue is with the realistic scaling required to service a typical home.

In my area I need around 1 million BTU per day average for a winter season which with the bio methane approach at ~1000 BTU per cubic foot of gas that's ~1000 cubic feet per day just for what I am heating now which when the new house, and maybe someday, the big shop get added to the load that number will double or triple.

I have no idea what size of digester would be required to keep up with that but I doubt that a few tote tanks is anywhere close to enough.

Plus beyond that, how much feedstocks would it take to reliably produce that amount of gas on demand and how much labor would be involved in making the system stay functional all winter?

I know how to handle solid fuels and liquid fuels in my boilers easily and efficiently enough but a biological based fuel source that cant be shut off when not needed seems problematic to me.

Also as I get older the labor part seems to be less and less favorable. ~16 - 17 years ago gathering and cutting the ~15 - 20 cords of wood for a winter and spending 15 - 20 minutes a day feeding and cleaning it was no big deal but now it rather sucks compared to bringing in a years plus worth of used oil in a few hours time and spending 10 - 15 minutes every other week servicing and cleaning out the boiler.

 

[Western]

Personally I use a oil fuel oil furnace burner with a modified nozzle systems that preheats the oil to~ 300F just before it exits the nozzle so that it will be thin enough to spray like normal fuel oil.

Here's the links to the threads I have here on what I work with.

https://www.electro-tech-online.com/threads/alternative-fuels-boiler-system-how-to-build-one.152957/ (thread totorial still in progress.)

https://www.electro-tech-online.com/threads/wind-generators-pros-cons.149508/ More indepth details of the burner and boiler its a part of.

Ok, thanks ... I've had no experience with them ... so that was very helpful seeing what they consist of ... and what's involved in building the oil burner and boiler ... and the extent of your work ... that's pretty amazing.

As for finding used oil be careful on asking around. Word will get out and you will become overwhelmed with the stuff in a short time.

Mmm ... I'd have to keep a pretty low profile with that quantity of oil storage ... the EPA would be around in a flash ... someone would spot it and dob me in.

I like the principle but my issue is with the realistic scaling required to service a typical home.

Yeah ... I spent a lot of time trying to understand the scale of a practical, workable system ... to see if might be worth doing here.

In my area I need around 1 million BTU per day average for a winter season which with the bio methane approach at ~1000 BTU per cubic foot of gas that's ~1000 cubic feet per day just for what I am heating now which when the new house, and maybe someday, the big shop get added to the load that number will double or triple.

That's something I have to study up on for our region. Volts, amps, current are part of my everyday vocabulary ... but BTU's, Degrees Farenheit , kPa etc are like a foreign language.

I'm certain our requirements are probably an order of magnitude lower than yours ... weather here is pretty mild. It's newsworthy if there's ever any snowfall in the state ... maybe once or twice a decade and I've never seen any here.

I have no idea what size of digester would be required to keep up with that but I doubt that a few tote tanks is anywhere close to enough.

From the amount of oil you use, I'd be surprised too ... but I need to start somewhere.

Even a few hours a day, methane supplementing the heating in our house and in my workshop would be worthwhile.

Plus beyond that, how much feedstocks would it take to reliably produce that amount of gas on demand and how much labor would be involved in making the system stay functional all winter?

Yeah ... I'm pretty lazy when it comes to some of that stuff ... especially when you can just flick a switch to make most things happen ... at least until I get the bill !!! We have quite a bit of grass and sheep manure in the paddock alongside ... though the grass drys off over summer. Certainly have some dairies close ... but that would be worse than cutting firewood !

I know how to handle solid fuels and liquid fuels in my boilers easily and efficiently enough but a biological based fuel source that cant be shut off when not needed seems problematic to me.

I wondered about that too ... but supposedly you just stop feeding it ... and the generation slows down pretty smartly. Depending how it's stored ... a lot of users let it burp off if it gets full ... and claim that's a legit and safe enough way of handling it.

Also as I get older the labor part seems to be less and less favorable. ~16 - 17 years ago gathering and cutting the ~15 - 20 cords of wood for a winter and spending 15 - 20 minutes a day feeding and cleaning it was no big deal but now it rather sucks compared to bringing in a years plus worth of used oil in a few hours time and spending 10 - 15 minutes every other week servicing and cleaning out the boiler.

Haha ... yeah ... sounds like me. I just bought a new chainsaw for smaller stuff ... about 5kg ... the old McCulloch I inherited from my dad is 55 years old and weighs 15.5kg. That's hard work ... but it still works fantastic. And I just busted it with the last load we got ... the dogging spikes came loose ... rotated across and busted off half the teeth on one side of the chain.

I went in to buy a new chain a few years ago and the guy literally laughed at me ... prick! I think I've found some secondhand stuff ... just waiting to find out for sure. The rest of it's not worn out yet.

I'll look more into the how I would use an oil burner. If I were to build one it would have to be out of the house ... but then I'd have to install a heap of water heaters (hydronics?) around the house ... with the associated plumbing. Still sounds easier than collecting sheep manure and grass everyday like you said.

 

[Western]

Weee i do both! Bio diesel from cooking oil and heating oil from old 'other oils'. I process all mine though, its how i got into the alternative fuel thing

If your in oz you might have to clean it up like we do. I will grabbed you details and how we clean it. Getting a kind of system in place helps alot.

I have two tanks, one i let sit for a few months and one ready to clean and process, then its into storage. But i get more used veg oil now, so its bio diesel mainly. Oil for heating is getting harder to get hold of.

We use a machine like this as first stage cleaning, then we fine filter

Looks interesting. I do have a centrifuge almost that size ... but it is designed for large test tubes. I probably could modify it in some way. Just something I picked up at a government auction 20 years ago ... in case it ever came in handy.

my biggest tip is put your first settling tank at a slight slope angel, down that end stick some HDD magnets or whatever you can get hold of, most the waste engine oil we get is agricultural stuff, always has metal bits in it. So i settle it a min 4 months,save me a fortune in fine cartridge filters and nozels for the boilers (those are not cheap here and you have to have the burner tested each year for emissions ).

Once settle put it through a machine like that with o filters on, do it 3 times (two are just pure fun!! they are so cool to watch), first run stop it after you get every 5 ltr and clean the wall of gunk!! if your oil is dirty you get a huge amount of sticky gunk on the wall. The clean oil seeps over the top lip. my final steps are sometime magnetic biochar (home made) and fine cartridge filter.

I always know when there is alot of hydraulic fluid in the waste oil, the burner smells like bananas to me

If I do end up going this way ... all these sort of suggestions will be invaluable ... thank you.

waste cooking oil keep separate if you got decent amounts, i got a kick ass recipe and fool proof way to make bio diesel with it. if your in oz, then are you in a humid area or dry area?

We don't have much issue with humidity down south where we are ... up in Queensland and up north they certainly do.

So does my mums car, she just dosnt know i put a few ltr in each day . she thinks it will damage her car, well for 3 years she been running on maybe 50-60% bio fuel and its her not me that tells people how good her car runs lol.

She thinks the fuel gauge is unreliable however.

Haha ... I wish one of my kids was doing that for me.

 

[Western]

You could do both. I am working on a log in for you, the IBC option is very good. You think you can get 4-5? 4 would need to be in a shed or in the ground and insulated? If so then you have options. The thing is no reason you cant use oil and gas, if you cant feed for digester enough then oil is a good back up.

A log-in would be great thanks ... the more educated I can get should raise my chances of making it work.

I'm certain I could get 4 or 5 IBC's without much trouble. There's plenty of room in the lean-to shed ... and I have a heap of cool room insulation that was in the shed when we bought the place. My wife wanted me to throw it out ... yeah right !!!

There's a solar heater for the pool on the shed roof too ... I could divert that to warm the tanks up as well.

Feeding mine is one reason i attached the septic tank plus add all the organic material i can get (alot with our acreage), but get them right and they produce alot of gas

One thing I spotted in my research was the people using a stainless sink with an Insinkerator in it ... mounted up high and with the outlet straight into the tank inlet tube. Might need a platform to step up and use it ... but should speed up the process of feeding it.

I don't have one of them ... I'd better start researching.


There's enough room in the lean-to shed ...



Solar Heater



Spare Insulation ...

 

[tcmtech]

Mmm ... I'd have to keep a pretty low profile with that quantity of oil storage ... the EPA would be around in a flash ... someone would spot it and dob me in.

On that aspect I would dig into the actual rules a bit. Contrary to what some wish everyone to believe the EPA regs have a lot of loopholes and grey areas to play with on the private end that the commercial doesn't have.

Around here there is not a defined limit on storing fuel or oil if its declared to be for your own private and personal use and its kept in a reasonably maintained and orderly fashion.

Its how larger farmers here can have 1000's to 10's of thousands of gallons of fuel, oil and toxic farm chemicals all just sitting around in tanks, barrels and totes on site and not be hassled about it whereas a commercial business would be held to far higher standards and regulations.

Odds are you could have quite a bit sitting in a common bulk fuel tanks and tote tank containers and nobody would say a word as long as it's kept reasonably organized looking.

That's something I have to study up on for our region. Volts, amps, current are part of my everyday vocabulary ... but BTU's, Degrees Farenheit , kPa etc are like a foreign language.

They work on the same principles. Just different physical units and applications. Pressure is like Volts, flow rates are like Amps and the rest sort of fall into similar comparative equivalents.

I'm certain our requirements are probably an order of magnitude lower than yours ... weather here is pretty mild. It's newsworthy if there's ever any snowfall in the state ... maybe once or twice a decade and I've never seen any here.

If you know how much fuel you use now in a given time frame you can extrapolate that out to get a rough idea of what you would need to make a secondary heating system worth it.

Downside is the initial setup can get to be fairly labor and cost intensive (trial and error fine tuning is the hard part) but the long term savings for having near free fuel is what pays for it, if you can use it enough to balance out the financial end.

Where I am at to heat what I do to the comfort levels I like would take 2500 - 3000 gallons of propane a year which at typical winter prices of $1+ a gallon that would get pretty spendy.

That's where my motivations to go with an alternative fuel type heating system was justified.

Mostly it just a matter of spending some time doing the numbers and seeing what you come up with and if it financially justifiable or more academically justifiable as learning experience, that just sort of saves a little money as a after effect to the education you got for having played with it.

I'll look more into the how I would use an oil burner. If I were to build one it would have to be out of the house ... but then I'd have to install a heap of water heaters (hydronics?) around the house ... with the associated plumbing. Still sounds easier than collecting sheep manure and grass everyday like you said.

If you have forced air heating and or cooling like my house does all you need to do is add a heat exchanger in the ducting.

 

[Western]

On that aspect I would dig into the actual rules a bit. Contrary to what some wish everyone to believe the EPA regs have a lot of loopholes and grey areas to play with on the private end that the commercial doesn't have.

Yes, makes sense. The other thing around here is to keep a low profile and not talk too much about what you're doing.

They work on the same principles. Just different physical units and applications. Pressure is like Volts, flow rates are like Amps and the rest sort of fall into similar comparative equivalents.

Yeah, I understand what they are and how they apply ... where I have trouble is in relating to the actual amounts easily. If you tell me something is 17.5 metres 45 degrees from the corner of that shed ... I don't have to think about it ... that computes.

But when you said you might need 1 million BTU per day average for a winter season ... I don't have a standard to relate that to. Something I'll have to learn pronto.

Same goes for pressure ... I've always worked in PSI ... I know what pressure to put in my tyres ... what's safe to run the compressor etc ... but researching methane and lpg heaters ... people are bandying about kPa and inches of mercury ... I can't translate that in my head yet.

Australia went metric when I was in my late teens ... so imperial and metric are easy for me ... I can translate that in my head ... but my wife on the other hand is 10 years younger. If I ever say yards or feet and inches ... I just get this blank stare.

Downside is the initial setup can get to be fairly labor and cost intensive (trial and error fine tuning is the hard part) but the long term savings for having near free fuel is what pays for it, if you can use it enough to balance out the financial end.

I recall reading years ago about anyone who went off grid and had to look after batteries, generators etc ... that they were really just taking on a hobby ... coz it was going to be a lot of extra work. Looks like same goes here.

Where I am at to heat what I do to the comfort levels I like would take 2500 - 3000 gallons of propane a year which at typical winter prices of $1+ a gallon that would get pretty spendy.

That's where my motivations to go with an alternative fuel type heating system was justified.

That makes sense. Our house is comfortable enough .. but I would like to keep it a couple of degrees warmer in winter. If I've got cheaper options, I could do that.

If you have forced air heating and or cooling like my house does all you need to do is add a heat exchanger in the ducting.

Of course ... I never thought of that. We do have a ducted reverse cycle aircon that can be used on fan only ... that would be relatively easy to do. Thank you for that one.

 

[large_ghostman]

Forget most the systems you see on the net for biogas, they are at best 30-50% efficient. The tank or chamber you fill into first is aerobic in a good system, once we sort a log in i can discuss out the outflow side. Most the web types are really batch systems that have been modified, a 4-5 chamber without microbe cell on should be hitting 80% efficiency for gas conversion, with some work and a tune up you should really be getting ~90% conversion or something is wrong.

As to amounts, 3-4 people and 1/4 acre grass a week should give you around 6 hours of cooking gas a day for a 4 burner gas stove. Add in all kitchen scraps, all waste paper like flyers through the door (staples out except once in a while (Trace Iron is good) and you should be getting 9-10 hours of gas a day minimum. The more diverse the mix the better, if you go the hooking into the septic tank route then it goes before the septic tank.

Nothing but pee,poo,paper down the toilet!!! If you put a macerater on the toilet then gas will increase ~15%. Not in amount but in production rate, its alot like composting, you need to get tuned in. Its easy with practice. The biggest issue with human waste is potential Hydrogen sulphides and disulphide and maybe siloxanes. But this should not be an issue on a well run multi chamber system. And should require little work as most of it can be automated

 

[Western]

Haha ... you guys must just be getting up ... and I'm supposed to go get some sleep ... it's 1am here.

Forget most the systems you see on the net for biogas, they are at best 30-50% efficient.

Yes, I picked that up thanks ... have been downloading all the latest patents I could find. Multi stage systems etc ... interesting stuff.

a 4-5 chamber without microbe cell on should be hitting 80% efficiency for gas conversion, with some work and a tune up you should really be getting ~90% conversion or something is wrong.

That sounds worthwhile aiming for. Marked improvement over 30%

As to amounts, 3-4 people and 1/4 acre grass a week should give you around 6 hours of cooking gas a day for a 4 burner gas stove.

Unfortunately our stoves are electric ... but I'm sure I could swap one of them to gas ... plus extra heating would bring me more brownie points.

Nothing but pee,poo,paper down the toilet!!! If you put a macerater on the toilet then gas will increase ~15%.

Cool, 15% is worthwhile too. An extra toilet down at the shed for the pool and the workshop is on the cards ... but levels already require a macerator/pump ... so I could feed that one in easily.

And should require little work as most of it can be automated

Haha ... that's sounds like my style ... did I say I'm lazy. The idea of automation is something I could get my teeth into also. Sounds like a fun project.

You're right ... I might have to do both.

 

[tcmtech]

But when you said you might need 1 million BTU per day average for a winter season ... I don't have a standard to relate that to. Something I'll have to learn pronto.

Think of it like Kilowatts and kilowatt hours. If you know what your heating system uses in a hour and how many hours it runs a day, week, month or season you can figure out how many BTU hours per time frame you need. The rest is just a matter of learning the conversion factors between the different units of measure.

It's one of the dream crushers of doing long term energy usage calculations were rather smallish quantities add up to big numbers that may be rather hard to achieve reliabilly.

Even more so if you have peak usages that are way above the statistical average number that may be hard to hit when needed the most. Where I live it's not uncommon to hit -30F with wind chills to -50+F on a bad day or night which can push my peak BTU usage way past 1 million BTU hours a day then have a +30 F sunny calm day shortly after that uses less than 1/4 the average for that day.

That wide range of heat usage was one of my peeves with burning wood. On a bad day (when I really didn't want to be outside) I was loading the old wood burning boiler every 3 - 5 hours and on good ones twice just to keep the fire burning and the water up to temperature. With the used oil everything is automatic and all I have to do is wait until the boiler tells me it's time to service it because either the nozzle plugged, the filter needs changing or it sooted up and needs cleaning which can be 50 - 300+ burner running hours depending on how clean the oil is.

I recall reading years ago about anyone who went off grid and had to look after batteries, generators etc ... that they were really just taking on a hobby ... coz it was going to be a lot of extra work. Looks like same goes here.

That's where determining the realistic value of having the system comes into play. How much will it cost you in time, labor and money to build and fine tune and use to where it's reliable and how much normal heating costs does that equate to. For me, where this sort of endeavor is worth $2000+ a year in offset costs, there's a lot of financial motivations to pursue it even if it takes a 200+ hours of learning and building plus a $2000+ to just get it all to a bare minimal working level the first year.

However at 1/10 that annual cost avoidance numbers it may not be worth it unless its more of a academic/hobby type knowledge and skill building experience. It may not pay for itself in cost avoidance in any short time frame but when you have a new set of knowledge and skills, that few others have, that can save you time and money elsewhere then it's well worth it!