Stainless steel conical beer fermenter Pt.6

I decided to scrap the idea of using my ring burner shown in "part 5" of my conical fermenter series of posts. Instead, I started reading about home-built propane burners for use in small metal-working forges.

These sites were very helpful:
http://www.zoellerforge.com/sidearm.html
http://ronreil.abana.org/design1.shtml
http://www.backyardmetalcasting.com/oliverburner1.html

I decided to follow Mr.Zoeller's design, for which he was kind enough to post a PDF and provide great instructions.




I used an 1/8" NPT brass cap to seal the end of the 1/8" pipe nipple instead of a Tweco Mig tip. I drilled a .035" hole in the center of the brass cap after machining the sides and face smooth.


I used a 3/4" to 3/4" extender as a flare. I cut out the threads on the lathe, leaving a 1:12 taper on the interior surface. I tested the burner briefly before cutting the taper, and I'm not sure how much it really helped. I never tested it without the flare.


This is really a very good design. It can be built from parts found at any hardware store, and it only requires a couple holes to be drilled. The performance seems to be quite good. I do not have any other burners to compare it to, but I am quite pleased. It doesn't like to run at very low pressures. The flame will be drawn back into the tube, and it starts to sputter (as well as heat up the tube). Above 3 or 4 psi, it runs like a champ, and the adjustable air shutter is a critical piece. Without the air shutter, the flame is very lean and might blow itself out. I kept the shutter half-closed, and this seemed to produce a very neutral flame.

I fitted the conical with its valves and added 1 gallon of tap water. The burner is mounted by simply placing it between two short stainless pipes that I welded onto the frame rail. There is currently nothing holding the burner in place except gravity. I'll probably add a pin or strap to prevent the burner from accidentally falling.

Cool!


I achieved a full rolling boil in 20 minutes (1 gallon of water). I started out fairly low with the gas pressure, and gradually increased it, as I saw nothing bad happening.

Stainless steel conical beer fermenter Pt.5

I found a 0-10 psi adjustable propane regulator at Home Depot. It was a closeout item with a price of $4.99! I built a circular burner from 5/8" copper tubing and soldered in some "jet burners" from the ubiquitous 23-jet wok burner.


The 23-jet burner is available in natural gas and propane versions. I ordered the propane version from kitchensupplydirect.com (it was on sale for $20.03 a few weeks ago), but they might have sent me the natural gas version. I suspec this might be the case because the burner runs very rich. Take a look:


The yellow tips on the flames show that there is a lot of excess fuel. The flames are jumping off the burners probably because the mixture is too rich to start combustion inside the burner tube.

I ordered some hypodermic tubing from McMaster and made the jets smaller by press-fitting the hypodermic tubing into the existing jets. This changed the jet size from about .023" to .012". Now, the jets seem to burn too lean, and have a very hard time staying lit. The slightest breeze blows the flame out. When the burner was running too rich, it also could be blown out by slight breezes. I think the burners are not designed very well. The original orientation in the 23-jet burner caused a lot of turbulence to be generated -- it positioned the jets to aim into each other's path. This might have been a required design element to prevent the flames from being blown out.

Anyway, I'm considering a different propane burner design. More later.

Stainless steel conical beer fermenter Pt.4

Today I built a three-legged support structure to hold the beer fermenter. My original design called for welding three square cross-section tubes to the sides of the conical tank. I decided against this method because I wanted to ability to remove the tank from the stand, and I was also a little worried about having inadequate argon coverage on the weld backside (in the tank).



The three legs are only held together by the welds near the ground. The tank just rests on top of the legs. I may add some strapping to prevent the legs from splaying outward from the conical tank, but so far, this doesn't seem to be much of a problem. The legs are all 304 stainless steel - same as the tank.


I was surprised how little filler rod I needed for these welds. Next time, I will make my tack welds much smaller, because the weld bead itself was very tight, and the globs of filler from the tack welds were annoyingly large.


I welded some stainless nuts to small sheet metal structures, then welded the assemblies to either side of the copper heat block. The two nuts will allow me to sandwhich the Peltier between a large heatsink and the copper block. I'll use nylon screws to prevent heat transfer and also to make the compression on the Peltier more gentle and balanced.

Quickly tapping (threading) holes in plastic

For my day job, I often have to tap (cut threads into) holes in plastic that will receive screws. This can be done by hand with a standard tap wrench, but it's also possible to do with a hand drill. I bought a small 3/8" square drive adapter that has a 1/4" hex shank. This was intended for use in cordless screwdrivers which accept hex shanks, but a drill chuck will grab the hexagon just fine. I also bought a set of adjustable tap chucks that have a 3/8" square drive hole.
The smaller chuck goes from #2 taps up to about #10, and the larger for #10 up to 3/8".

For plastic, I use lots of distilled water as coolant. If I am tapping a blind hole, I usually just fill it up with water. The nice thing about using distilled water is that it leaves no residue after being blown clean with compressed air.

Tapping a hole with the hand drill works best for a certain range of sizes:

In ABS, I would use the drill for any size #2 through 1/4"

In acrylic or Delrin, I would probably only use the drill for #6 through 1/4"

The really small taps sometimes clog up, even with coolant, and the drill doesn't provide enough sensitivity to avoid snapping the tap. ABS is so soft, a clog would just be pushed away, whereas in acrylic or Delrin, it might jam.

For sizes larger than 1/4", I would probably use a tap wrench because they take a lot of torque, and it's difficult to keep the drill straight and have it deliver enough torque to spin the tap.

I like using the chrome-plated taps because the finish will not rust (a concern since I use water as a coolant), and the chrome is supposed to have a lower friction coefficient than bare high-speed steel.

For sizes smaller than 1/4", I would only use a bottoming tap in plastic. There is no reason to use a plug or taper tap because the bottoming tap makes a cleaner cut, and actually produces less friction and heat than plug or taper taps. In harder materials it makes sense to cut gradually, but plastic is so soft, it will just melt if the tap keeps making light passes that rub against the surface.

Google Checkout is making PayPal look good

This post is definitely off-topic for my blog, but I am extremely disappointed with Google Checkout's Merchant services, and I want to publicize the difficulty.

I have a customer that placed an order on my website and paid with Google Checkout. Her credit card was listed as "declined", so she called her credit card company to find out why. The credit card company responded that they had no record of the Google Checkout transaction at all, and there were no declined transactions on the account.

Of course, Google Checkout has no support phone number. Apparently they recently removed their support email address and online support contact form.

UPDATE: I found the "contact us" link at the bottom of the page, which allows merchants to enter an order number and request assistance, but there is no text entry box to actually describe the exact problem.



So now I am stuck with a very frustrated customer and perhaps a lost order. Worse, I have no way of fixing the situation because Google Checkout has no way of being contacted with details about the problem. Thanks, Google.


Here's some links to others who have had problems all stemming from the complete lack of merchant support.

http://www.shaftek.org/blog/2009/03/04/contact-phone-number-for-google-checkout/

http://www.google.com/support/forum/p/checkout-merchants/thread?tid=1c4ddc2e27f4ec72&hl=en

http://news.zdnet.com/2100-9595_22-341375.html

http://www.google.com/support/forum/p/checkout-merchants/thread?tid=67e6e5c02c6f3233&hl=en