Brand New Damper Design - "The Macro Damper" - For Large Pits


 
SteveCK

SteveCK

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Howdy all. I have a new damper design for everyone. It's called the MacroDamper.

The MicroDamper has been successful on pits all the way up to UDS and large cabinet smokers (similar in size to the Backwoods Cabinet Smokers). But this leaves a gap for those with larger pits. The MacroDamper was designed for these people.

The MacroDamper was designed to utilize 80mm fans and boasts an intake size of 2550 square millimeters (4 square inches). 80mm fans are what most people associate as computer case fans, however there are many many choices of fans to be had from Mouser or DigiKey that are able to obtain high static pressures and CFM airflow - these are not your wimpy computer case fans, see photo below comparing the MicroDamper fans to a MacroDamper fan. It should be noted that this design has not been tested (as I don't own a large pit, yet). Because the MacroDamper is large, I incorporated an opening for a RJ45 adapter that you can pick up at Lowe's/Home Depot. I have made two version, one accepts the SG90 servo, and the other accepts the MG90 servo.

Please contact me at MicroDamper@gmail.com if you have a pit that you'd like to use this on. I'd be more than willing to assist you with fitting a fan to your pit.

Here are the files - MacroDamper

And now some photos:
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Awesome design, Steve. Keep us posted on how well it does. What's the largest CFM available for an 80mm fan?
 
Thanks Will. The fans with an appreciable static pressure output top out around 75-85 CFM. They also only cost around $20-$25.
 
I added a SG90 servo model to thingiverse and a 80mm to 40mm fan reducer for those who wish to run the MacroDamper with a 40mm fan.
 
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Just upgraded to a Humphrey's Down East Beast, and while I have been using a Heatermeter for years, I've always been a fan only guy. As the DEB is much better insulated than my UDS, I feel it would perform better with a servo controlled intake damper + fan. Humphrey's come standard with a 2" nipple (and ball valve), and I currently have a 25cfm Delta Blower attached via a 2"-to-1.5" reducer. I had a hard time getting up to 350 with all vents open 100%, though this may be due in part to the fact the coals were getting low, and I was using briquettes vs lump.
After reviewing the various Servo Damper threads, I think the best fit would be the Macro Damper. Looking at the pics here and on Thingyverse, I am unable to determine what kind of connection it has on the grill/smoker sife of the unit. What is the standard connection on the Macro Damper?
 
I've got a UDS with 2" black pipe intake. You wouldn't happen to have a version of the MacroDamper with 2" female NPT on it? I'm trying to find something on Thingiverse I can grab the threads from, but no luck yet.
 
WillD said:
Hey. I built one. It's going on an Old Country BBQ Pecos. Will post updates after the first use.
Click to expand...

Have you had a chance to use it yet? If so, how did it work? Most importantly, what fan did you use?

I am thinking of building one for my home built off-set smoker built from a 60 gallon propane tank.

Thanks!
 
B Frame said:
Have you had a chance to use it yet? If so, how did it work? Most importantly, what fan did you use?

I am thinking of building one for my home built off-set smoker built from a 60 gallon propane tank.

Thanks!
Click to expand...

It worked out pretty well and I'm impressed for the most part. I printed with PETG and attached it to the smoker using some ductwork as shown below. There were a few issues that came up during the build and on the first use:
1. The leads on the fan were too fat to fit into the punchdown block on the keystone jack, so I ended up soldering them to the tips of the punchdown contacts.
2. The servo I got won't rotate a full 180 degrees, so I had to choose whether to give up either full close or full open. I gave up full close.
3. During operation, the little screw that holds the servo arm to the servo kept working itself loose and the "top" would fall off. When I would check on the smoker to see why it was getting so dang hot, I'd find the reason laying on the ground. A little bit of Loctite fixed this.
4. When I had the top-falling-off-runaway-temp situations, the PETG melted just a little right where it meets the duct. It actually seems stronger now.

The parts I used were:
80x25 12VDC Axial Fan
PF80251V3-1000U-F99

MG90D Servo
1143

RJ45 Jack to IDC Connector
DN-93601-U/R

IMG_20200517_102617.jpg
 
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