I’ve long been aware that some folks use welder’s blankets to cover the Main Chamber (MC from now on) to help protect the CG from the effects of cold and windy weather. I wrote a blog entry back in October called COLD WEATHER SMOKING-PART 1, where I mentioned I hadn’t been able to find a source for welder’s blankets close by. Somebody wrote a comment that welder’s blankets were available at Harbor Freight. The last time I had checked, about a year ago, the nearest Harbor Freight was in Connecticut. When I looked this time around I found that a Harbor Freight had opened in nearby Amherst, New Hampshire. There were also 2 new stores now in Danvers and Natick, Massachusetts, both slightly farther away than the New Hampshire store. This was a no-brainer since New Hampshire has no state sales tax and the drive would involve far less traffic. Harbor Freight has 3 sizes of blankets: 4’ x 4’ (1.25 x 1.25 m), 6’ x 6’ (1.75 x 1.75 m), 8’ x 8’ (2.5 x 2.5 m) priced at $22.99, $29.99 and $39.99 respectively. The blankets are made of a fire retardant fiberglass and are said to be rated up to a temperature of 1,000 degrees (537 C). The blanket I bought weighs about 9 pounds ( 4.125 Kg) and is a light beige color with a slightly glossy finish plastic-like outer cover. The outer cover reminds me of the blue poly drop cloths sold for camping ground covers. The padding is fairly thin in the range of 1/4” - 3/8” (0.635 - 1 cm) thick. The blanket has metal grommets spaced 12” (30 cm) apart. I need to give the grommets some more thought since they might help hold the blanket in place but what do you use to tie it? An elastic bungie cord would melt and metal cables would scratch the CG.
I bought the welder’s blanket the week before Thanksgiving and selected the 8’ x 8’ (2.5 x 2.5 m) version. I figured this would allow me plenty of flexibility and I could fold the blanket over on itself and get multiple layers covering the MC. I don’t plan on placing the blanket over the Side Fire Box (SFB from now on), but I am going to measure the temperatures of the SFB to see if I might want to rethink this. After starting the winter off with a large snow storm in late October, we have been having unseasonably high temperatures since then. Now in mid-January we finally got our second measurable snow of the wInter. It started off as rain Thursday night and finished off as an inch (2.5 cm) of snow Friday. The snow was over by mid-afternoon, but the problem was the predicted winds. There were high wind warnings out for 40-50 MPH (64 - 80 kph) winds. I was trying to make a smoked lamb stew for Saturday which I wanted to have spend an overnight in the fridge on Friday. I needed to get in a one hour smoke for the lamb and ideally an additional hour to smoke a head of garlic. When I heard about the predicted winds, I figured this would be a good test for the welder’s blanket. My only real concern was whether I’d have problems keeping it from blowing off the MC.
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The welders blanket was placed so as to overhang the back side of the MC by about 6” which kept the blanket from contacting the SFB (left). At the chimney side of the MC the blanket was wrapped around the chimney and the two 18” flaps were folded over & I tucked the bottom ends of the blanket into the gap between the side table slats and the MC. I also used a pair of tongs to help secure the seam. I also tucked the bottom of the blanket into the gap between the slats of the front table and the MC (right).
When I lit the CG at 1:30 PM, the winds were starting to pick up. I was able to use a sheltered area between my gas grill and the CG to light the charcoal chimney. I have a weather app on my iPhone and the nearest weather station it monitors is 1 mile (1.67 km) away, so I figure the conditions they are pretty close to what I am experiencing. The temperature at the nearby weather station was 33 degrees (1 C) and the steady winds were 18 MPH (29 kph) with gusts to 24 MPH (39 kph). I had great trouble lighting my butane lighter and once lit the wind was pulling the flame away from the slots in the charcoal chimney. This happened no matter where I placed the lighter. I finally did get the chimney lit and I headed inside to get the lamb cubes ready to go on the smoker. I decided to put the lamb and garlic on the smoker at the same time I added the charcoal to the SFB. This way I could use the blanket to cover the CG and help it warm up faster.
The cubed, rubbed lamb & the garlic cloves are on the CG. The lamb will smoke for an hour after the CG hit 250 (120C) and the garlic will stay on for an additional hour.
After placing the lamb and garlic on the CG, I folded the blanket into a 4’ x 4’ (1.25 x 1.25 m) square. This meant that I would have 4 layers of blanket covering the MC. I placed the blanket over the MC so that about 6” of the blanket was overhanging the end of the MC closest to the SFB. It didn’t actually fold over and hang down, it curved down at about a 45 degree angle. This kept the blanket from direct contact with the SFB. At the chimney end of the MC there was about 18” of blanket extending beyond the end of the MC. I had wrapped the blanket around the chimney and folded the two pieces of the blanket over to cover the end of the MC. I was able to tuck the bottom of the blanket in under the gap between the MC end and the first slat of the side table. This put the bottom of the blanket an inch (30 cm) below the gap between the lid and bottom half of the MC. I used an old pair of tongs to help pin this seam down. I also tucked the bottom of the blanket in along the seam between the front side of the MC and the slats of the front tray. This meant this side of the blanket also covered the seam at the lid by an inch (30 cm) or more. The blanket hung down about 6” below the rear seam of the MC lid. So I now had the top half of the MC and the lid seam covered with 4 layers of blanket on 3 of the 4 sides. The SFB side of the MC was not covered but I had the CG facing into the wind. This meant the uncovered part of the MC was facing away from the wind.
The lamb is ready to come off & during this 1 hour smoke in the strong winds, the temperatures only varied 3 degrees total.
I was happy to see the temps rose steadily right from the start. The winds were getting a bit stronger but they seemed to have absolutely no effect on the temperatures in the MC. With the blanket securely tucked into the slats of the side and front table of the CG I felt safe monitoring the temps remotely from the comfort of my Kitchen. The blanket was not likely to blow off. I made a point of looking at the receiver of the thermometer about every minute to see the grate temps. I also looked when a big gust shook the house and was very surprised to find the temps never went down. It took 30 minutes to hit 225 (110 C) which was my minimum desired temperature and another 10 minutes to hit 250 (120 C), which was my ideal temperature. This was a bit faster than I would have expected for a calm day at this temperature, but with the winds involved that was excellent. Now here is the surprising, almost shocking part: For the next 2 hours, despite the gusty winds the temps never went lower than 248 or above 251 degrees. That would be exceptional on a warm, wind free day. During this two hour period the air temps never got higher than 35 and the winds got up to 22 MPH (35 kph) steady with gusts over 30 MPH (48 kph). Normally I would expect temperature drops of 20 degrees (11 C) with those kind of wind gusts. I am absolutely amazed at this performance: A 3 degree variation? That is crazy!! I can think of at least 1/2 dozen cooks with bitter cold temperatures and/or strong winds that I barely limped through and how easy they might have been if I had used a welder’s blanket.
When I went out to add more pecan wood chunks, I brought out my infra red thermometer to shoot the surface temps of the SFB. The highest temperature I ever recorded was 634 degrees (334 C).
I still have some learning to do and decisions to make. The first decision is whether to cover the SFB or at least cover the SFB end of the MC. In the latter case this would mean some of the blanket would come into contact with the SFB. Several times after the CG had reached 250 (120 C) in the MC and I went out to add wood chunks, I also used my infra red thermometer to measure the temperature of the SFB. The highest temperature I measured was 634 degrees (334 C). While this is well below the 1,000 degree (537 C) rating of the blanket. I am still inclined to think I will not completely cover the top of the SFB. This might raise the temps of the SFB by not letting the heat escape. I do think I won’t fret if a small area of the SFB near the MC comes into contact with the blanket. The method I used to secure the blanket via the slats of the side and front table seem to work quite well. This may mean I don’t need to make use of the grommets to run cables to secure the blanket onto the MC. I’d need to come up with a cable that wouldn’t melt and wouldn’t abrade the painted finish of the MC. A suitable cable material hasn’t come to mind yet, but I may not need it with the method I used to secure the blankets,
The last decision is what to do about rain or snow. As I mentioned earlier, the cover of the blanket has a plastic like feel to it. The manufacturer made no comments about getting the blanket wet. I would think they would not expect a welder’s blanket to get wet. I have a feeling the blanket may be damp proof, but is not waterproof. Actually as for rain, I don’t want to get the blanket wet with rain. Fiberglass insulation works by having lots and lots of little air pockets that gives the fiberglass it’s insulating qualities. If the fiberglass gets wet, the air pockets aren’t there and you lose the insulation properties. If it is raining the temps would be above freezing and I could struggle along without the blankets as I have been doing for seven years now. Snow I will have to think some more about. Unlike rain, the snow won’t all go into the blanket. Much of it will pile up on the surface of the blanket and can be brushed off. I may try and find out more from the manufacturer about the water resistance properties of the out coating of the blanket.
So there you have it. A VERY VERY successful first run of the CG with welder’s blankets. It will be real interesting to see how the welder’s blanket improves cold weather fuel consumption. For this cook I only needed the warmup time plus 2 hours for the garlic head, so I only added enough charcoal into the SFB to give me 2 hours of cooking time. This was about 2/3 of a full SFB. I should mention that at the 3 hour mark the temps were still at 247 (119 C). So I have a feeling I will get great “fuel economy” on long cooks. It was funny because I had myself mentally braced for a hard cook where I’d be constantly running outside to tweak the temps. Instead I only had to run outside to add wood chunks. When I was done I kept thinking: “Is that it? It can’t have been that easy could it?” Well it was that easy and I am really happy about what this portends for future cold weather and windy cooks. If you use your smoker year round, a welder’s blanket will certainly make your life easier too.