Science

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Plain to Pretty: Rubber Band Gun #6 Anodized

Gord over at Gord’s Garage has been busy with home-based anodizing.  It’s some amazing stuff he is doing. I sent him one of the rubber band gun assemblies, and he did an amazing job on it.

In an incredible amount of detail, Gord has written up and photographed the whole process:

http://gordsgarage.wordpress.com/2011/11/21/the-full-monty-part-1/

http://gordsgarage.wordpress.com/2011/11/22/the-full-monty-part-2/

In summary, it went from this mill finish:

To this polished finish:

To this anodized finish:

Amazing!

 

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Designing a better Lime Squeezer

From time to time we host a get-together or party where we feature fresh squeezed limeade as the main beverage.  We have universally heard 5-star feedback from people who have had this simple but good drink.

The problem is, squeezing enough limes for a party of 60+ people takes a lot of time (and limes).  After about the fifth lime the first time… I had enough!

I went down to the shop and built a simple but powerful hinged wooden squeezer about 3′ long.  It looked like two canoe oars with a hinge holding them together.  With this contraption, a suitable helper (Eli), and a big stainless steel bowl, we could really crank out the lime juice (gallons).

Since using that a number of times, I’ve thought of some improvements I’d like to make, eventually ending in a fabricated stainless steel mechanism that is easy to use, powerful, and helpful.  The force applied to the lime should be compounded at the end of the squeeze cycle, taking full advantage of maximum leverage to get the last drops out (less waste, less fatigue).

Using the power of four-bars, I’m working up a Solid Works model which should meet most of the above criteria.  I think we will soon build a prototype out of maple, which is a very hard wood.

Here is a picture of it “open”:

Here is a picture of it “Closed”:

 

 

 

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Making a punch; heat treating tool steel

About Tempering Metal  (how I explain it to kids):

The little metal guys normally stand at attention in rows — millions of them (molecules).  When you heat them up red hot, they start dancing and get all mixed up and out of order; not in rows any more.  When you cool them down, they get back into nice neat rows.

However, when you cool them off really fast by dipping in cold water, they get frozen before they can get back into nice neat rows!

If the metal guys are in nice neat rows, and you push on a row really hard, they can all move sideways.  But if they are all mixed up, it’s hard for them to move any way.  

This makes the metal really hard.

 

As part of Ezra’s box project, he needed to countersink the nails into the plywood.  I should have one, but I don’t have a countersink handy that would do the trick.

So we made one!

1/4″ diameter W1 tool steel rod (water hardened) was cut down to about 3.5 inches long.  Being that I don’t have a metal lathe, I improvised by chucking the metal into my drill and grinding it on the grinder – while spinning.  This resulted in a fairly uniform (albiet scratched) conical point.   We wire brushed it a bit on the grinder to smooth it out, and then took it over to the other side of the shop for heat treatment.

This casual approach to tempering worked well for our purposes.  We heated the metal red hot (just the end) and dunked it in cold water.  Then we polished it up a little bit.

In informal tests, this made it REALLY hard.  If I placed a nail against the top end and banged it, it would scratch the punch.  If I placed a nail agains the bottom (hard) end and banged it, it would flatten the nail without even marking the surface of the punch.

Also, the punch would reliably put small holes in a cast-iron vice and other metal without any noticeable deformation.  Nice!

Here is the pictures:

(Fire extinguisher was about 2 feet to the left, in case you were wondering!)

 

 

 

 

 

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Two birds and an egg

We’ve been watching this bird’s nest for some time in our shed which is in construction.  The mother, would always fly around the clearing watching and waiting…  Maybe having a panic attack?

The little ones finally came.  Sadly, the third egg never hatched.  A few days later, the nest was empty (except the 1 egg).  Little birds are a bit ugly I must say, but I’m sure the will pretty up in a short amount of time.

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1,000 Sparklers — at once!

Sparklers are fun, right?

Well, if you multiply that fun times 1,000 in a pile, then it gets really fun, and hot, and somewhat dangerous.  From my observations, sparkelrs burn much faster when grouped together.  If a normal sparker takes 60 seconds to burn, 1,000 of them might take 6 seconds to mostly burn.  This means there is TEN THOUSAND times more light and heat being released.

Wow!

(Quick way to burn $40.00, proverbally speaking)

Also, if you are not well versed in, and professional about, safety considerations of very hot metal and bright light, then it is my advice that you do not even consider this.

Here is a washed out picture of the glowing metal after it is done.

Chemistry Photography
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Chemistry Photography

[Charcoal + Potassium Nitrate + Sulphur] when ground together in the right proportion, make … great photos!

Here is a scene from chemistry class.

 

First, we made charcoal by heating hardwood without oxygen.  This produces a lot of smoke, but in the end, all that’s left in the test tube is charcoal sticks.

Second, we ground the charcoal to a powder, and added a some potassium nitrate and sulphur.

Here is a spoonful of the fresh made black powder

Upon touching a hot coal to it, it ignited and combusted with a lot of smoke!

Quite bright!  This is a neat photograph (taken with Droid X)


 

(Proper safety precautions were taken during this class, including fire prevention and eye protection.  Do not repeat without appropriate knowledge and safety precautions in place)

 

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Arduino, Transistors, Motors, and LEDs

Well, the fun is increasing with Arduino.  We hooked up some circuitry which enables a transistor to switch a fairly large 12V load via a very small 5V digital pin on the Arduino board.

This has been a great learning resource: http://www.kpsec.freeuk.com/trancirc.htm

Basically, we have 12V power going through a motor circuit (protected by a signal diode), and then to the collector of a transistor.  The emitter of the transister is connected to ground.

Lastly, the Arduino ground is joined with the emitter, and the transistor is switched by a 5V digital output pin on the Arduino board.

Now, just need to find something useful to do!

 

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Melting table salt in a red hot spoon.

We were using a bunsen burner hooked up to a propane tank to heat a spoon, and the salt in the spoon, red hot in order to melt the salt.

According to the wikipedia article on salt, the melting point is 1474 °F.  See further comments after this picture…

Melting salt in a spoon over a propane burner

It took a while, but we did get it to melt.  I “poured” it onto a metal surface, and you can see it still glowing here:

And for reference, here is what a Sodium Chloride crystal looks like up close: