Vent fan still allows fumes

[Bill Kielb]

Yeah, it’s the only real way to capture though. Down drafts are generally fine but do spill a bunch for really tiny aromatics. We can never really design with them and comply with IAQ. Likely not as much as the steam in the video though. Or maybe molecule sized, just as much as the video if we could observe. With no perceptible breeze folks often smell wax burning off within minutes,  even 50 feet away. He could prop his lid or pull a port plug to help with oxidation.

I have laser augmented high speed video of scooping glaze materials from a prep table. Amazing how instant things begin to travel really far even with very careful scooping. Those are small measurable particles so I get it, but kiln aromas likely even much smaller.

[ronfire]

I increased the 2 holes in the bottom of the kiln to 5/16. I checked the kiln this morning just as it shut down on a cone 6, the kiln would still draw in air at that temp and the pipe to the fan was 86f.  I did not notice fume from the glaze fire  so the next firing will be a bisque and see if the small increase in hole size made a difference. I might then try to increase the mixing air until I get a good balance and not draw as much air into the kin as it does draw in a flame from a lighter to the inlet holes. 

The good note is I am happy with how the items look coming out of the kiln as long as I do not place large items on the bottom shelf. Guess I just like to try for perfection in how the kiln runs and vents.

 

[Bill Kielb]

Interesting 86 degrees but still sucks the lighter in? So not much air being drawn from the kiln actually. We know this for certain since the temperature of mixtures of air are a straight apportionment of the ordinary dry bulb temperature measurement.  It takes a very small amount of 2000 degree kiln air mixed with let’s say 75 degree room air to get 86. So definitely conflicting results. 86 degree exhaust pretty much means not much kiln air  or a lot of room air or a fan that is not performing well overall. I really don’t care about the lighter anymore actually, we pretty much know not much air is being withdrawn from the kiln, it’s the why and how much part that you will need to figure out.

[neilestrick]

I would expect the duct to be much hotter than 86 degrees. More like 120 in a larger kiln like yours.

[Bill Kielb]

I would agree.

I would suggest to adjust your room air till ya get in the 100 degree range with the kiln at 2000F. If my cypherin  is right 75 degree makeup air, 2000 degree kiln air means .994286 room air and .005714 kiln air. Your fan might be performing at 50 cfm but let’s assume it’s discharging 100 cfm which means prox 0.6 cfm of kiln air (at best)  to make the pipe 86 degrees.  All very approximate of course. I would at least get this up to 100 -120 degrees  with the kiln at 2000 degrees which will feel slightly warm @100,  to  getting hot @120 to the touch. Also check that your connection to the bottom of the kiln is not like Swiss cheese and leaking a bunch.

Temperature does not lie, smoke draw is often tough to figure. Often tuning these with temperature is easier. Ya just gotta be there when it’s hot is the only problem.

[Hulk]

Per parallel thread (temporal), wouldn't expect kiln vent to prevent any fumes/smell at all.

I'm happy with my kiln vent - it's a home made job, definitely pulls hot air from the kiln, hence oxygenated ambient goes in there, being the point, and also most of the wax smoke and other yuck out and away from the studio. My (similarly home made) overhead setup is back online, now featuring a somewhat overkill 400 cfm fan; now I feel comfortable being around the kiln whilst firing - both the waste heat and bit o' smell all wooshed out o' there.

[ronfire]

Well after increasing the 2 outlet holes to 5/16 seams to have helped with the issue.

 

[Bill Kielb]

How warm does the pipe get after the increase?  Might be good to know. Or how warm was it before and after the increase could prove helpful to others in the future.