Better sealing for better temp control


 
H

Hank B

TVWBB Pro
I'm getting a bit frustrated by the lack of ability to control temps due to air infiltration. This is particularly true if there is any wind at all. I think the lower vents seal well so I'm going to work my way from the bottom up.

I got some Permatex "HIGH-TEMP RED RTV SILICONE GASKET MAKER" from a local auto parts store. Yes, not food grade and yes, I'm aware of the warnings that it produces formaldehyde at higher temps.

In this application it will not have contact with food, so I don't think food grade is important.

The formaldehyde issue does concern me. I did lookup the MSDS for the food grade product and it carries the same warning, so that is no solution. After this cures, I will run one empty smoke with the thought that it will release the bulk of any formaldehyde that will eventually be released. I will then follow this by airing out the WSM and I might even use oven cleaner to remove the coating inside the shell in case any material has been absorbed into that.

Needless to say, I appreciate any further information anyone can provide regarding this concern. I also plan to contact Permatex to see what they say.

I applied a small bead along the bottom groove on the middle section. When this is set into the base (after curing of course), it should provide a good seal between the two parts.
DSC_1315-PP.JPG


I used the handle of a silicone brush - slightly modified to increase the radius - to form the bead after squeezing it into the groove. Anything that can be appropriately shaped could probably be used.

DSC_1313-PP.JPG

(Foreign readers - the US penny used for scale is about 3/4", 19mm diameter.)

After giving the silicone about 20 minutes to firm up, I gently scraped the extra off.

Comments and questions?

-walt
 
Walt,

I had the same air issues with my WSM.

Here is my solution:

Make a "gasket" for the lower-middle section.

I took a piece of HD aluminum foil that was approx. 58" long*. Then I folded in half several times until I had a strip 58" long by 2" wide. Finally I formed this strip around top of the charcoal bowl, curling it over the rounded lip. For a neater appearance, tuck the excess under the lip with a popsicle stick (or even a credit card).The result is a somewhat squishy gasket to help seal the gaps with the middle section. It is hardly noticeable on the assembled WSM, and had lasted for over a dozen cooks so far.

*58" is the approx. circumference of the charcoal bowl.
 
Thanks for the suggestion Bradley,
That sounds like another good solution. I was casting about for what to use to seal and came up with high temperature RTV, but it sounds like aluminum foil works as well.

I just got off the phone with a tech service rep at Permatex and he told me that formaldehyde would be released if the product was in flames. It seems unlikely to experience that in this application.

thanks,
walt
 
first thing i would do is check all sections for an out of round situation. You would be surprised how a tweak here and there will close up gaps.....
 
I'm running an empty smoker with the coals left over from a previous smoke. Temp shot up to over 300 degrees so I closed all bottom vents. It continued to climb slowly.If I close the top vent, it drops slowly.

This is not the result I had hoped for. I do not think the bead of silicone I laid down is thick enough to make contact all of the way around.


And...

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by DAVIDMICHAEL:
first thing i would do is check all sections for an out of round situation. You would be surprised how a tweak here and there will close up gaps..... </div></BLOCKQUOTE>Great point. My cooker came in an unmangled box and I have handled it carefully. Nevertheless, I put a tape measure to it and measured 1/2" out of round on the bottom section which surprised me. I would have expected it to be the least susceptible to being deformed. I did not see the same problem on the middle section which I would expect to be more susceptible to getting wonky. I also noticed that when assembled, the middle can rock on the bottom section. When the charcoal has burned down and the smoker is cool, I'll have to take a better look at that.

I presume I just need to bend the pieces until they measure the same diameter at all points. Let me know if there are better strategies.

thanks,
walt
 
doesn't it take like over 10 minutes for the coals to stabalize with any adjustments ? are ya giving it this time or are you expecting immediate changes ?
 
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by george curtis:
doesn't it take like over 10 minutes for the coals to stabalize with any adjustments ? are ya giving it this time or are you expecting immediate changes ? </div></BLOCKQUOTE>
Hi George,
When I initially loaded hot coals and saw the temp shoot to 300° F in less than ten minutes, I did not wait. This is an empty smoker so the only thermal mass is the shell and charcoal grate. At that point I closed all bottom vents and it did respond by continuing to creep up. I'm not sure I waited ten minutes before closing the top vent, but I'm confident that I did see the response. Later on I opened the top vent and the temps did start to come back up before the charcoal started to burn out.

thanks,
hank
 
Make sure you have the water pan at least partially full, then the temp should settle down... the water serves as a heat "sink" as well as a humidifier. Sometimes 3-4 hrs into a stable smoke the temp may begin rising ...usually a sign that you need to refill the water pan. Cheers, Rondo :)
 
If the charcoal goes out in a couple of hours when you close all vents, your wsm is tight enough to control temps. If not, look for out of round and the seal around the door. I understand out of round, but some of that can be fixed just by spinning the middle to find the best fit with the bottom. You're kind of matching two ovals. Then put a little weight on it and seat the middle into the bowl. A gasket beyond some foil, seems more than should be necessary.
 
Well, OK. I started a smoke this morning, full load of briquettes and smoking wood with a gallon of hot tap water. Ordinarily I have at most one grate open and frequently I wind up with all three closed and temps a bit higher than I'd like.

This time I rotated the middle section for best fit before starting. Visually, it looks like the bead of silicone I laid down should do the job. When I put the lit coals in the middle and closed it up - cover on, that is, all vents were wide open. Temps climbed to 170 within about 5 minutes so I closed two bottom vents. By the time I got back inside to check temperature, it was up to 188°. Within 3 minutes the temperature was back down to 185°! I went back out and opened one bottom vent (two open now) and the temperature started to ramp back up again, but more slowly.

Ambient conditions are 24° with 11 mph wind. While it's a bit nippy, I'm sure that amount of wind would usually cause me grief trying to keep temps down.

At this point I'm cautiously optimistic that the bottom seal has reduced air infiltration to the point that I can easily control the smoker using the bottom vents. In fact at this point - 20 minutes loading the meat - the temperature seems to be settling at 204°. I may need to open a third bottom vent a bit.

Thanks all for your suggestions and help getting this sorted.

-walt
 
I had a similar question. I noticed my WSM was leaking at various places. I was thinking of getting a set of gaskets sold for Big Green Eggs.
 
During my first 2 years of owning the 18 inch WSM, I noted an "out of round" condition and sloppy fit on my stock aluminum door. It didn't seem to make any difference at all in quality or temp control. As a matter of fact, I could start a full load "minion" method with a full water pan using 12 briq's and still get up to temp in a little over an hour. When I hit 235 and increasing, I could adjust the vents one time and nail it at 250 for the next several hours.

I then bought the new SS aftermarket door that so many owners are talking about. Totally new dynamic and noticeable from the very first cook after installation with repeatability ever since. My WSM runs tight.....almost too tight. The time to come up to temp has increased by probably 30 minutes and to compensate, I've had to start the minion method with twice as much lit. And even then, in some cases, I've had to open the door to get the cooker climbing in temps at the start of a cook.

The door looks good, it feels good, but I'm not convinced the overall effect is positive. In hindsight I'm suspecting, the WSM was designed to maintain smoking temps and function with "out of round" middle sections and leaky doors.

I'll stick with the new door after making adjustments to my routine, but it's really only a cosmetic improvement at best.
 
When I first assembled my 22.5 I noticed the out of round. My bowl was out by a quarter inch. The middle was out a little less than quarter at the bottom and a quarter inch at the top in the other direction. The lid was round.

I set the bowl sideways on some carpet and gave it a nudge, it moved real easy, perfectly round now. The middle I did by hand, just push and the pull in the direction it needs to go. The metal is thin so it moves pretty easy. The door moves way easy so you have to be carefull not to crease it, just work the radius of the door a bit, I rounded the bottom of the door a little more and that really did the trick as far as getting a tight fit. (Sit in a chair and use your thigh as form)

I am sure the porcelin does not like being stretched, but I have not noticed any damage, and I have done this to kettle bowls in the past with no ill effects. I would rather spray some touch up paint then deal with inconsistant temps every time the wind blows. (pretty common in New England!)

(I work at an aerospace place and used to straighten thin walled aluminum castings, so moving metal isn't difficult for me. Please use this advice with caution, creases do not come out easy!)

Jamie
 
I understand that the ceramic cookers use some sort of felt as a seal. Has anyone tried to locate some of this high-temperature felt and attempt to use it on the WSM?
 
Whether you use the original door or the cajun bandit door there still will be leaks. Top left and right. At least that was my experience. A sure fire solution is buying a couple extra compression latches from south co latches, ebay or amazon and installing them so you have three going across the top. Also use some nomax seal tape around the door to secure a tight fit. My 22 inch wsm leaked like a faucet but now it seals like a vault. No smoke leakage anywhere. Tighter fit means better fuel efficiency, better heat retention and better tasting food.
 

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Wow. Never seen three latches on a WSM door. Seems like overkill, but if it works for you that's all that matters. Thanks for sharing the photos.
 
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