Franken-Cooler

My sous vide adventures have sometimes been serious mis-adventures.  Case and point was the Easter Brisket Saga.  I wanted something sturdy, large, and well insulated for large and longer term cooks.  Something that would be efficient and not heat the house as much.  There are some guide out there that recommend drilling a hole in a 24 quart coleman stacking cooler.  They don’t sell those in my area any more, and I didn’t want to online order one.  A local sporting goods store did have 48 quart coolers on sale for 16 bucks though!

Most guide recommend a 2-3/8″ hole in the lid.  The sous vide cooker will slip down the hole, but stop before the electronics get submerged because of a shoulder on it.  The larger cooler meant the device would sit much higher, and it comes out of the water every time you lift the lid to check on things.  Instead I printed a bracket to get it clipped to the side and held much lower than the stock bracket would allow.  I started in orange PLA to get the dimensions all worked out, then printed in black PETG.  It is a higher temperature material and should withstand the cooking temps.

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I cut the bottom section off the orange test part and used it as a tracing template for cutting the lid as tight as possible to the bracket.

A little sanding cleaned up the edges, and everything was looking nice.  The only trick being that the lid hit the top of the cooker when opened.  I was considering taking the hinges off anyways, so I just did that.

It turns out the lid on these cheaper coolers is hollow.  Not too shocking.  Instead of leaving it that way I shot it full of foam.  I don’t think I got every square inch, but it should be an improvement.  Either break off the excess or cut with a sharp knife once fully cured.

With that all setup I was able to start my first ambitious project.  I did an 8 hour run at 179F for barbacoa.

It was a really high temperature for sous vide, and right around the limit of PETG.  Though the cook came out well the bracket had a few issues.  The bottom had a little bubbling from the heat.  That wasn’t the issue though, there was a crack started where the outside of the clip sat on the cooler rim.  I played with it a bit and got it to break off.

When printing, that segment is printed as a bridge (filament free hanging out in space), so ends up being kind of weak.  To compensate in the second bracket (top in right and picture) I increased print temperature for better adhesion, increased number of bottom layers to make sure the bridging didn’t compromise strength in that area, increased thickness of that bridge, and the thickness of that outside clip area.

Even though it broke I am happy with this design.  It went for hours at a really high temp and only broke when I started prying on it heavily.  Anything that asks for a sous vide temperature this high can probably be done in the crock pot on low (~190F typically).  Still, the lid didn’t get too warm, and the sides of the cooler were room temp to the touch.  It was a great stress test.  This thing can sous vide anything!

One thought on “Franken-Cooler

  1. Pingback: June 2017 3D Prints | Kilted Craft Works

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