What Have You Been Hacking/Making [2015-11-16 edition]

[remmin...@2xlnetworks.net]

This is a message from reMMinderbot.

Makers! It's time to share... what have you been hacking on or making?

Reply to this email with a brief run-down of whatever projects have
been keeping you busy, either at the space or elsewhere.


reMMinderbot thanks you!

[Custom Processing Unlimited]

Putting the brakes on my custom trike... (Literally).

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If "custom" was mass produced... it would just be a "product line."

Akai Coit
Custom Processing Unlimited

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[Tom Gralewicz]

I've been exploring magic smoke:

1) Let the magic smoke out of the Induction furnace high frequency transformer.  According to the guys at Pillar it was likely a plugged water passage, they are looking for a replacement .

2)  Replaced the blown transistors on the board in the Red Dragon, powered it up and smoked the new transistors.

Then I took the rest of the week off :-)

Tom Gralewicz

Chronic Maker

(414) 380-1716

milwaukeemakerspace.org

[the_digital_dentist]

I have been working on the heater for the the syringe for the chocolate printer.  I think I have it figured out and it is mostly assembled.  I will be mounting the heater, pump, controller, alarm beeper, and power supply on a board that will strap onto the syringe and will be more or less self-contained.  I am using a 300W aquarium heater with a bypassed thermostat.  It will be driven by a PID controller and SSR with a thermistor to monitor the temperature of the water.  The alarm output of the PID controller will sound if the temperature exceeds a set value (if that can be implemented without creating a lot of false positives- that beeper is LOUD!).

The frame design is done and I still have to cut a few more pipes to finish construction.

I still have to add limit switches to a couple places on the machine and do some wiring, but it is getting close to first operational test time which will occur at the makerspace.

[Pete Prodoehl]

I went to Pumping Station: One on Saturday to discuss the 2016 season and rule changes for The Power Racing Series.

Also, I took this photo of their bathroom door.






Pete

[Adrian Volden]

I have been working on a project for the next Makerfair Milwaukee Dark Arts Room, many of you saw the yellow balloon I had with me at last weeks meeting. Boy it as going great, right up to the point I popped the balloon about 24 hr to early and let the magic air out, now it is just a piece of desk art.

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Adrian Volden

Cell Ph (414) 379-8373 Anytime

Home Ph (414)-727-0539 After 5:00pm

Work Ph (414)-362-6373 7:30 - 4:00

[the_digital_dentist]

I picked up a block of dry ice to test the chocolate cooling system today.  There's good news and bad news.  The blower successfully gets air into the box (I have to put a heavy tool box on top to keep the top from blowing off!) and the hose delivers the cold air at -12C.  The problem is the exit nozzle hose coupler blocks up with snow very quickly.  I'll have to find a way to pre-dry the air going into the box (maybe a second cooler filled with water ice?) or a way to prevent the exit from icing up.  Maybe a resistor to heat it?

Here's how it works...

This thing blows!

[the_digital_dentist]

Maybe I need to increase the area and make it more like a funnel, but in the end, it has to exit the box at about 1/2" diameter, so it will always have that choke point.  Maybe adding baffles inside the box will give the moisture something to condense on before it ever gets to the nozzle.

It only reads this cold when the air is flowing.  Once the nozzle jams up, the air flow drops and things warm up a bit.

[ChrisH]

Where'd you get your dry ice from?

[Devin Ward]

You could try running the air through a column of silica gel before it goes into the box.

[the_digital_dentist]

On Friday, November 20, 2015 at 3:58:38 PM UTC-6, ChrisH wrote:

Where'd you get your dry ice from?

Continental Carbonic in Franklin

[the_digital_dentist]

I added some baffles, still jams up.  I tried putting a bunch of aluminum on top of the dry ice and using the baffles and it still jams up.

[Have Blue]

Reaction Engines also has had to deal with frost buildup as a major stumbling block in developing their SABRE engine: https://en.wikipedia.org/wiki/SABRE_%28rocket_engine%29

Recently they disclosed their secret sauce to eliminate icing:  https://www.reddit.com/r/aerospace/comments/3czys1/reaction_engines_reveals_secret_of_sabre_frost/

While injecting methanol into the airflow may not be a great idea for making foodstuffs, perhaps a spray of cheap vodka could provide similar anti-icing properties?

On 11/20/2015 4:33 PM, the_digital_dentist wrote:

I added some baffles, still jams up.  I tried putting a bunch of aluminum on top of the dry ice and using the baffles and it still jams up.

[Brant]

Mark,
You could cycle the cooling on and off or heat the surface the frost is forming on.

http://m.contractingbusiness.com/refrigeration/defrosting-refrigeration-systems-keep-it-short-and-sweet

[the_digital_dentist]

I thought about adding a motor with a wiper to mechanically brush away the frost on a continuous basis, but the motor would probably frost up, too, unless it was located outside the cooler.  Maybe a puff of warm air every few seconds would be sufficient to keep it frost free.  Maybe a vibrator on the exit port would shake it loose so it would just blow out through the tube.

There are about a million things to try...

[Dont let google be evil]

I've got a mason jar full of zeolite you can play with (have) -I think this is similar to the stuff I've seen in air dryers for for truck air brake systems, and IIRC zeolite is used in nat gas processing to remove moisture.
https://en.wikipedia.org/wiki/Zeolite
Although zeolite is likely food-safe, the material I have -may- have bits of plaster, or sand from metal casting in it.

If it doesn't remove the water out of your air adequately, I'd try again after re-heating it (re-charge 600F) before giving up on it.
The only "field expedient" test that I know of is to put a little water on a spoonfull of the stuff, if it sizzles, and heats up -yer good.
There is no color change.
Sample tested "positive" a few minutes ago.

I imagine a kinda tight screen strainer thing on top of a pitcherish thing w/ a hole in the bottom to your fan might be something.

Ya know, I also wonder if piping source air from outside, once it gets a bit cooler out -might start you out w/ lower moisture to begin with.

FruitRollUp

[Eric Berna]

Can you recirculate the air? The air should leave the snow behind on the first time through and second (third, fourth, etc.) time through it should be dry. 

Eric Berna 

[the_digital_dentist]

I'm not sure how that would be done- since the exit coupler ices up there won't be any way to get the air back through the box.  I think either a zeolite or silica gel desiccant at the entrance to the thing might work, but if it doesn't completely dry the air it will only slow down the process of icing up the exit coupler.  If the air took a sufficiently circuitous route through the box it might deposit all the moisture as ice inside the box and not have any left by the time it reaches the exit.  I did try adding baffles and a bunch of odd shaped aluminum sitting on top of the dry ice to provide more surface area for the condensation to form but it didn't help.

Maybe dry ice is the wrong way to go with this.  Water ice might work fine and won't have the icing issues because it won't cause as large a temperature drop, and will be a LOT cheaper.

[Brant Holeman]

Have you tried looking at water-cooled PCs for inspiration?

On Mon, Nov 23, 2015 at 9:50 AM, the_digital_dentist <mark.r...@gmail.com> wrote:

I'm not sure how that would be done- since the exit coupler ices up there won't be any way to get the air back through the box.  I think either a zeolite or silica gel desiccant at the entrance to the thing might work, but if it doesn't completely dry the air it will only slow down the process of icing up the exit coupler.  If the air took a sufficiently circuitous route through the box it might deposit all the moisture as ice inside the box and not have any left by the time it reaches the exit.  I did try adding baffles and a bunch of odd shaped aluminum sitting on top of the dry ice to provide more surface area for the condensation to form but it didn't help.

Maybe dry ice is the wrong way to go with this.  Water ice might work fine and won't have the icing issues because it won't cause as large a temperature drop, and will be a LOT cheaper.

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Sincerely,

Brant Holeman

[Dont let google be evil]

Mason jar of zeolite is on the wire shelf in the 3D print area.

FruitRollUp

[the_digital_dentist]

Thanks, but I think I'll test water ice as the cooler next, and if that doesn't chill the air enough to solidify the chocolate, I'll make an air dryer using silica gel in the form of cat litter.  It's dirt cheap and readily available in large quantities.  I'll blow the air into a cat litter bucket full of the silica gel type litter and go from there into the cooler full of dry ice.

[Tom Gralewicz]

I wonder if you could mix a little alcohol with the chocolate and let it cool through evaporation as it comes out of the nozzle.

Tom Gralewicz

Chronic Maker

(414) 380-1716

milwaukeemakerspace.org

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