Blaze King Door Gasket Replacement

[Highbeam]

It turns out that door gaskets are very important on blaze kings, responsible for 95% of the small number of early catalytic converter failures. I've been using this original door gasket for the last 3.5 years and decided to replace it and document it for anybody that wants to see how to do it themselves.

So remove the door and pull out the old gasket. Easy enough, mine was glued in place well with black silicone from BK. Not too much silicone but plenty to glue it in place. Scrape out the old silicone with screwdrivers, wire wheel, whatever you have since new silicone doesn't stick to old silicone.

Now for the interesting part. All those nuts hold down a series of brackets that squeeze the glass in place and also provides the door gasket channel. An odd design for sure since the door gasket covers the nuts and the studs protrude way up into the gasket which limits the effective crush of the gasket but whatever. Check the door glass for tightness. It shouldn't wiggle left to right or in and out. Mine wiggled in and out, as in away from the door frame. The glass was actually flexing more than moving. I checked the tightness of the 3/8" nuts and found all of them at least slightly loose and snugged them up. Didn't fix the problem and one of the brackets would rock even though the nut was tight. I removed that bracket and found a big old chunk of slag/plating/crap under it which prevented that bracket from ever squeezing the glass. With that rock gone, the glass is now snug and back to the door gasket.

I then bought the ultra copper permatex RTV that is rated for 800 degrees. Same 7.50$ price as the black RTV that is only rated for 600 degrees. "Sensor safe". Notice the rather heavy application of RTV. I was shooting for 3/8" bead and it took almost 2 tubes of the stuff. In a pinch, you could probably get away with a single tube and a smaller bead. None of that spooged out so I'm glad I went heavy. Might regret it next time when I have to clean it out.

I tried my best not to twist the gasket but you can see that last section I got a small twist. Word of warning, don't cut it too short or too long. The amount of gasket on the hinge side of the door seal is the most important since it is not affected by the adjustment at the latch side(so you can't fix it if you cut it too short) and since shutting the door is difficult if you cut it too long and have to bunch it up which makes the door feel tight but really you are just smashing the gasket at the hinge.

The new gasket shows a defined groove where the door frame knife edge digs in. My old gasket was very much shot to heck. I'm not even sure if it was ever as thick as this new BK gasket.

Oh and get an OEM gasket from BK. They are not expensive at 35$ delivered, and they are special.

 

[begreen]

Good info, thanks. 3 yr old gasket shot to heck? What killed it so soon?

 

[Woody Stover]

nuts hold down a series of brackets that squeeze the glass in place and also provides the door gasket channel. An odd design for sure since the door gasket covers the nuts and the studs protrude way up into the gasket which limits the effective crush of the gasket

Indeed.

Notice the rather heavy application of RTV. I was shooting for 3/8" bead and it took almost 2 tubes of the stuff. In a pinch, you could probably get away with a single tube and a smaller bead.

I think I said one tube would do it but I think you did right going heavy on the bead, with those nuts in the channel.

Might regret it next time when I have to clean it out.

Indeed.

The new gasket shows a defined groove where the door frame knife edge digs in

Did you do the dollar-bill test, or isn't it dry enough yet?

 

[Highbeam]

Good info, thanks. 3 yr old gasket shot to heck? What killed it so soon?

I bought the stove new but I suspect the door may have been used on a floor model. I never realized how big and full the gaskets are supposed to look until I saw a new one on a new stove at the showroom recently. My old gasket NEVER looked like that. After my second year I had used up all available adjustment on the latch. I had also never gotten that full groove cut into the gasket from the knife edge door frame like I have now. There's always the chance that somebody at BK installed the original gasket with a stretch which dramatically reduces the diameter. Maybe they cut it too short and were trying to make ends meet. It was the right color and after I removed it I could scrunch it up and it got fatter like the new gasket.

This new gasket is better than the original ever was.

 

[Highbeam]

Did you do the dollar-bill test, or isn't it dry enough yet?

I waited an hour between when I shut the door on the wet silicone and when I fired the stove. None of this 24 hour stuff. BKVP didn't wait at all.

Didn't do the dollar bill test but have an actual three sided indentation all the way around so I believe it's sealing. I never really liked the dollar bill test on a knife edge gasket design. There will always be resistance to pullout and nobody seems to think you need to rip the paper.

I was so nervous to do this gasket that I stalled by sweeping the chimney and cleaning all ash. Even cleaned the glass! Heck, I even lifted the double wall pipe off and lubed the bypass mechanism.

The big news is that rock I pulled out. That thing was likely causing me a leak.

 

[tarzan]

Interesting. For what it's worth my door gasket was started "and ofcourse ended" on the bottom, latch side.

 

[Woody Stover]

I was so nervous to do this gasket that I stalled by sweeping the chimney and cleaning all ash.

Once I did one I felt a lot more comfortable going forward.

The big news is that rock I pulled out. That thing was likely causing me a leak.

Yeah, nice 'get,' finding that.

 

[BKVP]

I waited an hour between when I shut the door on the wet silicone and when I fired the stove. None of this 24 hour stuff. BKVP didn't wait at all.

Didn't do the dollar bill test but have an actual three sided indentation all the way around so I believe it's sealing. I never really liked the dollar bill test on a knife edge gasket design. There will always be resistance to pullout and nobody seems to think you need to rip the paper.

I was so nervous to do this gasket that I stalled by sweeping the chimney and cleaning all ash. Even cleaned the glass! Heck, I even lifted the double wall pipe off and lubed the bypass mechanism.

The big news is that rock I pulled out. That thing was likely causing me a leak.

No rocks at either plant...perhaps a hardened piece of cement/silicone? Also, very interested in your burn times. When I recently did my overhaul, I found I have restored slightly longer burn times.

 

[Highbeam]

No rocks at either plant...perhaps a hardened piece of cement/silicone? Also, very interested in your burn times. When I recently did my overhaul, I found I have restored slightly longer burn times.

It was weld slag or plating slag. It looked like a chrome crystal. You know those chunks of ground metal that accumulate under the grinder wheel? It was crystalline like that but obviously chrome colored like the door. Right at the base of that stud.

I switched to 100% red alder which burns much longer and cooler than Doug fir due to the ash shrouding effect. Burn times are excellent at a solid 24 hours with full split reloads.

 

[webby3650]

I have seen gasket cement and silicone fail if the stove was fired up right after a gasket replacement. What will save you is the large channel that the gasket rests in. The old models didn't use any sealant, the big 1" gasket just tucked into the channel. It takes very little silicone to keep a BK gasket in place. Looks like you got plenty on there!

 

[Highbeam]

So unlike the original gasket, this new one actually formed a groove where the door frame digs in. It's not too tight, I can latch the door with one finger. I'm doing some low burn experiments so the glass was particularly sooty.

Looking back, I could have probably gone easier on the silicone. I wanted a good seal over that irregular channel.

 

[Highbeam]

Also, very interested in your burn times. When I recently did my overhaul, I found I have restored slightly longer burn times.

After several fireboxes have been burnt I have noticed a trend. It is not what I expected but the superior door seal has resulted in lower possible thermostat settings, lower possible burn rate, and longer burn times. Significantly more fuel remains after 24 hours and the stove can be throttled to a lower burn rate.

The debris pattern on the glass is very symmetrical and stays lower on the glass but is darker than before as though more of the air is coming in through the airwash.

Perhaps coincidence, slightly dryer fuel, I don't know. Weather hasn't changed. Still above freezing overnight.