Special Request

[wideasleep1]

If someone happens to have a spare thermocouple handy, I'd appreciate knowing something: how hot the VENT BOWL gets during a typical roast session..be it a single roast or back to back.

My thinking: I want to use a a standard metal flexible duct (ubiquitous availability at hardware stores) at 3 inches diameter. With the vent bowl outlet at 2.5 inches diameter, I'm entertaining options.
Options: 1) Cut down a standard (cheap) silicone hot pad into a 3/4 inch strip and wrap/secure to form a silicone 'gasket' for the duct, secured with a standard hose clamp. Drawback is once secured and stable, is not modular enough to quickly disassemble.
2) Masters-Carr has a silicone
bubble tape with appropriate hardness to seal well, but the adhesive on the tape is only tolerant to 250F. Does the bowl see these temps in heavy use? Advantage is can quickly remove tubing from bowl for storage. Many thanks!

[edtbjon]

I recon I can give that a try. I have a spare Center 301 with the TC's that came along. I guess that the temp reading we're interested in is inside the exhaust pipe.

I bought 2 meters/ 6.5' of 60mm duct intended for heating systems in cars. I cut a 2" slit in the end  to taper it a bit and wound thin aluminium tape around it to make it leak proof. It works very well and have no signs of burns or even staining. (That brown color of the inside is the same at the other end of the duct, 6 feet away.)

[wideasleep1]

(posted this in the wrong thread originally-doh!)


Thanks a ton, edtbjon! It dawned on me that even a quick shot with a laser thermomoter on the vent bowl, near the duct connection, would be revealing, if you have one of those. Cheers!

[Gregr]

I did the same thing. With the same kind of tape (I think):
http://www.homedepot.com/p/Nashua-Tape-1-89-in-x-50-yd-322-Multi-Purpose-HVAC-Foil-Tape-1207792/100030120

[dynamiteid]

I use a 3" vent pipe attached with the same foil tape. So far so good. The tape and pipe are fine after two extended burn-in sessions and 4 roasts. I can touch the vent bowl during the roast. It is warm, but not overly hot.

[Gregr]

I should've added that I did that foil tape/vent rig about 50 roasts ago 

[edtbjon]

I made a max value metering today with a thin and very responsive TC placed in the middle of the exhaust pipe part of the bowl. I.e. just in the center of where you attach the duct. The max temp I reached throughout warmup and two consecutive roasts were 70.8C (163F). Touchable but not at all comfortable. Anyhow, no high temps to deal with.
Just a word about my setup... Pretty much standard, with the standard long J pipe into the funnel/sieve/fan/exhaust bowl.
I was planning to connect the TC to Artisan via my Phidget 1048, but I didn't have the patience to go thorugh a new setup again.  As my current setup havn't shown any signs of even getting a tan I don't feel I have to worry and this metered value is a good proof for that it's cool enough. (Cars get hotter inside when parked in the sun at summertime...)