Show us your Door Thread

[Sixto]

That makes perfect sense! Thank you for your detailed response David!

[fox]

I use a very similar solution to David but use vermiculite board for the backing, I use vermiculite and metal for the inner door and vermiculite and wood for the outer door.
vermiculite board is used to line wood burning stoves and is readily available at associated stores.

[MarkJerling]

That sounds great for the Stainless or Aluminum, Thanks Mark! Any suggestions about the insulation material if I can't get calcium silicate???

The aluminium is only for my outer door. Aluminium does not play that nicely with heat. For insulation, encapsulated in the steel box on the inside of my wooden door, furnace blanket works really well.

[Sixto]

The aluminium is only for my outer door. Aluminium does not play that nicely with heat. For insulation, encapsulated in the steel box on the inside of my wooden door, furnace blanket works really well.

Got it. thanks Mark! I'll probably do two doors, a stainless steel sheet with no insulation and a perlite/refractory cement like what David described.

[dfhood]

Stainless pieces upcycled from junked commercial cooler, stainless rivets and handles (may need to use potholders -_-), ceramic glass, ~2.75" ceramic insulation, 5" thermometer from forno store inset into 2" hole, and probe guard on back. Would've been nice to weld this door together, but did what I could with what I had. Hoping it will help to retain heat decently, despite the amount of glass. Looking forward to using it later this month. Planning to also make a simple separate door (thin, lightweight) for easier airflow control if desired.
Door pictured is intended for retained heat baking, with visibility using a flashlight.

[UtahBeehiver]

Great job on repurposing SS and use of ceramic glass.

[david s]

Very nice job. I’d be very interested to know how it operates. Not sure of the thickness of stainless you used, but it is notorious for warping from heat. The thinner the stainless the greater the problem. This can cause sealing issues against the rebate which can negate any gains in heat retention from the insulation.

[rsandler]

Lots of great doors on here. A question for folks--thoughts on having the door go through the entry arch (like a plug) with a small lip of something to sit against the reveal, vs the body of the door sitting against the reveal? Seems like a majority of the door builds in this thread do the plug version, but a few do the other way, and I if I follow the pictures, there are some hybrids, with most of the door outside, but a small bit going into the arch. I also saw a build thread where david s specifically recommended not doing the plug approach. My first oven had the door built plug-style, but getting that to fit snug-but-not-too-snug was a pain in the neck. Trying to think through what to do on my current build.

[david s]

No, this is a bad idea IMO. For my first oven I thought I was being clever and made the oven mouth and door slightly conical so that the door fitted nicely. The mistake was not to account for the shrinkage on oven cooling, when placing the cooler door inside the oven mouth. The result was the door jammed so tight in the oven mouth it was extremely difficult to remove. It is far better to have the face of the door sitting against the face of the oven mouth. For the same reason, this method is superior to a hinged door.

[rsandler]

Inspired by a post I saw somewhere (I thought in this thread, but a search doesn't turn it up) of using kevlar skids to make a door easier to slide, I thought "why not make the whole door casing out of Kevlar?" I used to do fire spinning back in college (still do occasionally), and we used kevlar for the fire wicks. If you can soak it in camp fuel and light it on fire, surely it could stand up to oven heat, right? It would be a lot lighter than metal, wouldn't conduct heat, and has a little bit of give, such that it would serve as its own gasket.

After doing a bit of research, I found that if you're going to use aramid fabric for a heat resistant application, you want Nomex, rather than Kevlar--it doesn't have as high of tensile strength, but has much better heat resistance. We're stopping heat loss, not bullets, after all. I found a source online (thefeltstore.com) that sold Nomex felt for a reasonable price, and ordered a small bobbin of Nomex thread from a seller on Amazon. Total materials cost about $50 for the fabric and thread, including shipping.

My door is made of two 2" thick pieces of leftover CalSil from my oven build, with a single piece of 1/8" Nomex felt wrapped around. I cut small wedges out of the top edges of the felt to let it fold down smoothly, and sewed a pretty rough seam with a curved "upholstery" needle. I then glued a wood facade (walnut with a spar urethane finish) onto the outside with a bunch of Liquid Nails Extreme. The door sits against the reveal of my inner arch, rather than going inside.

Total weight is about 11 pounds, most of that from the insulation (the CalSil boards are 7lbs by themselves), which is pretty good for a 4" thick door, I figure.

So far the Nomex is holding out great--soot covered on the inside, of course, but no sign of degradation in the fabric or the stitches after half a dozen full pizza fires. Heat retention is fantastic--I get 425F the next morning after a quick <1hour firing for just a couple pizzas, and had over 550 the one time I added a few more logs after finishing with pizzas in expectation of baking bread.

I think there's real potential for using Nomex as door exteriors. One could probably eschew the wood facade, and just sew on heavy duty straps (leather, perhaps) if you don't mind the look. One could even embroider the outside if you had the skill (I sure don't). Although you'd need to think more carefully about sewing good seams, I also think you could essentially sew a cushion cover out of Nomex felt and stuff it with CF blanket instead of CalSil, as if it were a pillow. That would reduce the weight substantially, and the additional give would probably make a tighter seal. Just would need to make sure it's stiff enough to hold it's shape.

Thanks for looking!

[AJH]

Looks like you should call that Franken-door =)
It does make me wonder if a "beanbag" approach would work using Nomex with perlite/vermiculite as filling... you could push it partway into the doorway and it would mold itself to the shape and still be loose enough to remove. You could use it to plug the opening and still have a wood face to give it some rigidity to block the vent landing as well.

[rsandler]

Looks like you should call that Franken-door =)
It does make me wonder if a "beanbag" approach would work using Nomex with perlite/vermiculite as filling... you could push it partway into the doorway and it would mold itself to the shape and still be loose enough to remove. You could use it to plug the opening and still have a wood face to give it some rigidity to block the vent landing as well.

Worth a shot--might be tough to keep it from sagging, especially if you have it relatively thick. But, as long as it stays upright enough to block the whole oven mouth, doesn't really matter how it sags. And you might not need it that thick. I think David S has pointed out on other threads that loose perlite/vermiculite is actually a better insulator than CF blanket (although the concrete versions are significantly less efficient).

Worst case, cut the stitches with a seam ripper and fill it back up with something else. Small as it is, the little bobbin I got off Amazon has enough thread for a dozen doors.