Thinking - Vegetable stock

Risking yet more plagiarism I thought I'd mention an idea we had the other day. (although I have a funny feeling I may have already mentioned it...

if so...

To re-cap...

For some time now, we in the 120 things test kitchen have been saving and freezing the water left in the steamer after steaming some veggies to make stock at a later date. We have also been throwing our veggie peelings and scraps into the freezer for making vegetable stock at a later date. Apparently a common practice (I checked this time).

But now, we throw the veggie scraps into the steamer pan before we steam our veggies, and as a result, we get amazing stock every time we cook veggies.

If we don't use it on the day (but we generally do), we just freeze it (or freeze it by adding it to the ever growing container of veggie stock we now have in our freezer ready for the time we have enough to make a decent amount of stock).

The stuff makes an amazing soup base, and makes an even more amazing base to a chicken or whatever stock.

  • Peel your veggies. 
  • Put the peelings into the bottom steamer pan.
  • Add water. 
  • Steam the veggies.

BAM!

Mega-stock left behind in the steamer water.

Peta-stock!



Making smoked foods - Original rib ideas 0, Plagiarism 1

I just found out that my "Luxury cut ribs" idea wasn't original.

It seems that not only is there a competition BBQ circuit, but on it you might find something called "Hollywood cut ribs" which have an uncanny resemblance (being identical) to Luxury cut ribs.

Oh well.

I'm still holding out hope for Frenched luxury cut ribs as my one contribution to the carnivorous, and our deep-seated need to cook stuff on charcoal.




Making smoked foods - Frenched luxury cut ribs

I thought I was pretty clever when I came up with cutting ribs so that ever second bone was removed. I called it "luxury cut ribs". This is always enormously popular with people at a BBQ.

But now I think I'm even more clever.

Cleverer.

I frenched every rib, but at opposing ends.

Luxury cut, but with a handle.

A genuine meat popsicle.

Bam!


Fire - Tin can stove success

I decided to make another tin can stove with the new design, but this time I thought I'd make it work.

A major design flaw of the first attempt was not actually the bit where the tin ripped in two, but was actually the bit where I was thinking upside down.

The previous version had grooves that would only reach the bottom.

That was never going to work.









This time I made the grooves in such a way as they would still be grooves when they reached the top.

Much more likely.

So, the top (open ended) half of the can is bent like this, and made to sit into the bottom (still with the base on) of the can.




All up this process takes only 5 minutes or less.

The zig-zag bit is placed zig-zag down into the half on the left.

It doesn't even need to be a snug fit.

Just drop it in place.





The result is, that when you light the alcohol and wait a few seconds for the device to heat up, it vaporizes the spirit within the zigs and the zags of the two walls created by the can halves, and is emitted as gaseous fuel through the top of the (now inverted) zig-zag bits.

Like this.

Perfect!

And quick.

A quicker, more durable ethanol stove.

A total success.




Much better than the last attempt.

Thanks to whoever first thought of this method of making a little spirit stove, that enable the happy camper to knock out a stove within a few minutes of dumping a can's contents into a pot.

Now all I need is canned food that actually tastes good.

And perhaps the ability to make a tin can.

I have no idea how to make a tin can.

But I'm not going to make a can as a "Thing" because nothing good ever came out of a can.





120 Things in 20 years - No can was hurt in the making of this post.



And sweetened condensed milk comes in a can, and that stuff is delicious.

But I still don't want to learn how to make a can.




















Fire - Quicker, more durable ethanol stove

A while back I made a pretty convincing ethanol camp stove out of a coke can.

It worked well and looked like this when it was running.

I've used it a bit since then and it's definitely a practical addition to any backpack.

The problem is it's starting to show signs of aging. The can expands and contracts, and there is now a crease where extra gas flows giving an uneven flame.




In my model (also not my design) I used an inner sleeve with holes at the top to let the gas out. The result is that the trapped ethanol (spirit/alcohol/methanol) between the outside wall, and the inner wall boils the spirit, and creates a gas jet that looks a lot like a normal BBQ burner.

One of the problems was trying to get the top of a coke can to fit into the bottom of a coke can. It's tricky because (of course) they are the same size. It can be done, but involves gently stretching the outside one and it takes a lot of messing about.

Now I'm being pretty fussy here. The little burner works really well, but it did tend to leak fuel around creases that formed in the join between the top and the bottom sections.

Someone on a Stirling engine forum pointed me towards a different method of making one. This method involves no holes, but it just encourages those creases that mine developed by itself, and I think it might be a winner.

Their's also used a drink can, but I think it might make a more robust version if I used a tinned food can.

So, to start with, I peeled a normal, every day food tin.











The first step was to trim it to size.

I needed the top to fit into the bottom, so the first thing to do was punch a hole in it to enable a cutting tool to get in there.

I used that mystery tool that pocket knives have.

Probably a leather working tool or something.

Who knows, just punch a hole in the can.


Next jam in some tin snips or something to make a nice cut to separate top from bottom.

My tin snips are stupid, so I ended up using scissors.

This isn't the best way to use scissors, so don't do this at home unless you actually own the scissors.





One very good method of cutting a tin can, is to just tear it by grabbing a ragged tail of tin with a pair of pliers and twist. If there's a groove to follow, it actually makes a pretty straight cut.









As I said, I ended up using scissors to trip everything to it was nice and neat.

I made the inside sleeve (the one on the left), slightly taller than the other so the pot could sit on the rim and let the gas escape from the gap between the outside sleeve.






I bent a series of grooves in the base of the inner sleeve so that they would allow the flow of gas, and also allow the inside sleeve to fit inside the outside sleeve.

This was simply a case of grasping with pliers, and twisting them to the left, and slightly down toward the centre.





Next I inverted the inside sleeve and carefully positioned the outside sleeve over it so that I might press the two together by stamping down with my foot.









Which failed completely.

Stirling engines - Ball bearings

From what I've read, shiny wire does a better job of being a bearing on a tin can Stirling engine, but I want to see just how much extra friction a proper ball bearing race or two would add to the mix.

The friction levels are very low on these little engines.

They have to be or they just don't work.

But I want to try to make a more robust version, and perhaps even make one that is capable of doing some work.

Perhaps.

But probably not.

Any attempt to make a bigger tin can Stirling engine would also involve a lot more weight. And more weight means more wear and friction. Ball bearings will be the solution, as long as there is enough power left over to overcome the extra friction that bearings have.

That sounds a little contradictory, but bearings are really good at dealing with extra load on the rotating surfaces, but they involve a little extra friction than say... hovering in space.

So, with this in mind, I looked into small bearings.

They cost a lot.

A 12mm (internal) ball bearing race is a very standard thing that industry makes. They cost around $2 each retail, and are a weighty, very strong thing you might find in a motor bike, or in the centre of a bicycle wheel. They carry a lot of weight, and last for ever. But they have way too much friction.

The little bearings I want that are only around 1.5mm in diameter (internal) all seem to cost around $20 each. They are nothing like the robust 12mm ball bearing races I looked at.

Tiny.

Fragile. (actually not really, but compared to the 12mm version...)

Fragile.

And expensive.

But my fishing real has a dozen of the things. They cant really cost that much. It must just be that there is no real retail trade in them. I need three or four, so I thought of buying a $20 K-mart fishing reel, and pulling it to bits, and that's probably what I'll end up doing. But in the mean time, I really want to know if a bearing will be too costly in terms of friction.

I found a little computer cooling fan in my electronics junk drawer. I figured that should have at least one bearing.

These little fans don't put a lot of stress on their little bearings, but they last for ever and spin really fast, with little friction.

Last for ever, fast.

Perfect.

I started by removing all the bits that didn't look like a bearing.

How hard could it be.

Very, it turns out.

That's the little bearing inside the small brass tube.




I spent a lot of time and energy trying to get it out.

I started by trying to knock out the pin by gently placing a centre punch (made of thick wire) on the centre axle, and smacking it with a hammer as hard as I could.

That didn't work so well.

Actually that didn't work at all.

I finally got it to give some ground by taking a hacksaw to it, and cutting through all the hard plastic surrounds that held the coils to the little motor.








This left me with a much more manageable bit of kit, that even looked like it might finally surrender it's bearings.

In fact, this would be perfect if I could just get the pin out of the centre, so I could put the Stirling engine's wire crank through the centre.

Centre.

Difficult
I put one end in over the opening of a little socket so the punch could get through and hit it hard.

Nothing happened, so I turned it over and hit it again.

That's my trusty hammer at the top of the frame.

Camera shy hammer.



This time it worked.

There's a little flange on one end of the pin that was making it impossible to tap out.

An amazingly strong little flange.

I hit it hard.

A lot.



Now that the shaft was out, I needed to knock out the bearings. I tried inverting the socket so it's outside fit inside the brass sleeve, and rested against the bearing. I hit it again.

And again.

And some more.

In the end I just kept cutting.

The hacksaw was the only thing making any progress.

Who would think there would be a time where a hammer failed me.

There's no real danger of damaging the little bearings here, as the brass sleeve is soft and bearings are made of insanely tough... stuff.

The bearings came out with ease, once the brass was cut through.

It turns out that the brass sleeve is really a brass sleeve with a divider in the middle.

No amount of hammering was ever going to get the bearings out.





Oddly, after all that hammering, the bearings still roll reasonably.

Reasonably.

The reason the little fan was part of my electronics junk drawer in the first place, was because it no longer turned. I think it was the cooling fan that I replaced on my rectifier, so it was never going to work perfectly.

The bearings spun freely enough after rotating them for a while with my drill. but there was a little bump in each revolution.

This pic is of the new ball bearing raced tin can Stirling engine running on my stove-top at around 200rpm.






200rpm is around the same speed on the same heat setting as it ran before, but it no longer runs from the heat of a single candle at only 36rpm, so the bearings have increased friction a little.

The brass sleeve was replaced with a cable tie for each bearing, and it turns out that cable ties fit nicely into my adjustable screw in bearing mounts.

Having the adjustable wire crankshaft I made turned out to be worthwhile, as I would never have been able to make just this one change. The smallest change in the crank shaft, in either the displacer crank, or the power piston crank makes a lot of difference as to how well my little Stirling engine runs, so it would be very hard to tell if it didn't work because of the bearings, or because of the different crank I would have been forced to make.

So.

A success as far as this little engine up goes. The bearings are small, but should be more reliable than the a plain wire on wire bearing. And it seems the friction loss is only around a quarter of a candle.

An interesting addition to this learning thing.





120 Things in 20 years measures the amount of friction in a tin can Stirling engine in "candles". I think I just invented a new metric.

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