Building a Round Door - PTJ 2024 Project, led by Sky Huddleston of Liberty Rocket Stoves!

Really intrigued and excited to see how this one is designed and made! I constructed a couple from scratch a few years ago and they became a very interesting puzzle to solve, the most important issue was figuring out how to deal with the massive weight of the wood because the diameter was quite big so I cut them in half. They give an amazing middle earth feel :)

There are 3 pages of ideas and sketches in this thread: Designing a round door - Hobbit house style

The plan that I have thus far is to use two layers of 2" X 8" boards, criss-crossed like plywood, that are rabbit jointed together via a table saw to form the joints, then glue'd and dolly's together to form a 8' X 8' giant square plank 3" inches thick, then use a string to mark out a circle, followed by sawing the circle out of the massive and heavy 3" pine door. We will have to have to HAVE TO use pressure treated wood. The hinges I will pre-fabricate and machine in my shop, made from 1" steel pipe and 5/8" steel rod with zirc fittings for grease, and the hinges will be welded to hydraulically formed bracket plates that will be bolted to the door frame, and the door will be carriage bolted to the bracket plates. The hardest part is the door frame, which I'm still thinking about. The simplest door frame I can think of at the moment is to build a decagon (12 sided) out of large 6" X 6" pressure treated and/or cedar beams, then cut the circle out of it. However, the decagon will need to have two circles cut out of it, to leave a 2" lip that the door seats against, this will have a compressible rubber gasket (garage door rubber seal or similar) to seal out the elements. Then comes the question of how to attach the door frame that the door seals against to the actual wall itself, and the best way I can think of thus far is to build another 6" X 6" square beam frame that is 9' X 9' or 10' X 10' effectively making it a frame within a frame, and using several sheets of 3/4" plywood with the outer profile of the dodecagon cut into it, and cut slots in the outer profile of the dodecagon for the plywood to fit into, and slots on thew square outer frame for the plywood to fit into, effectively making a strong, water resistant joint. There would be two layers of 3/4" plywood filled with spray foam for insulation and structure. The optimal size for the door is 7' in diameter, as far as I can tell, as this will minimize the amount of materials we need whilst still being tall enough that, fingers crossed, Paul wont bump his head on.

I'd get a quick green light from Paul before proceeding too far down the "pressure treated, glue, plywood and spray foam" path.  

Will the door open in or out?  With the huge overhang I doubt it will ever see any rain.

In the thread linked above, I had a suggestion for a potential approach (https://permies.com/t/80/41290/permaculture-projects/designing-door-hobbit-house-style#1364750)

Mike Haasl wrote:I'd get a quick green light from Paul before proceeding too far down the "pressure treated, glue, plywood and spray foam" path.  

Will the door open in or out?  With the huge overhang I doubt it will ever see any rain.

There are pros and cons to an inward vs outward swinging door. An inward swinging door will be more weather resistant long term, and the hinges wont rust. An outward swinging door makes for more usable interior space.

That illustration by Mike Haasl is pretty close to what I'm thinking.

Such an ambitious project!  I am excited to see this come together.  I have only made the rectangular kind of door myself an I thought that was challenging enough.  You guys are amazing!  

What is the purpose of the pressure treated wood?  I don't even like handling that stuff.  

Maybe instead of the pressure treat we could find some oak or black locust we could mill out into 2"x 8" boards.   Maybe the ends could be fire hardened and soaked with pitch while the are still hot.    

Osage orange or Yew would be sweet but hard to find boards that big.

could do old growth, fir or hemlock.    That old wood is really a different animal.  so hard and strong.  nothing like what they sell in the stores these days!

I think we need a small round door in our community garden for a hobbit tunnel...  

I suspect there might be an advantage to orienting the door boards at 45 degree angles.  One side slanted up and the other slanted down.  That just seems like it might resist racking even better than a horizontal face and a vertical face.

Putting a 7 foot round door on my Hobbit Home.

"undergroundandlovinit"

Did a test build on my shed.  7 feet across, 36 inch threshold with a 36 inch "hinge" line - so the door itself is not completely round.

Trying too add pictures but not uploading...

Dave, the easiest way to do photos is to either link to them from elsewhere on the web using the IMG button above the text box or by using the Attachments tab just below the text box where we type.

Mike Haasl wrote: or by using the Attachments tab just below the text box where we type.

That is what i am doing, the status bar for the picture remains at zero - it just won't  upload.

Will try a different internet access point later in the day.

Sky Huddleston wrote:

Mike Haasl wrote:

Will the door open in or out?  With the huge overhang I doubt it will ever see any rain.

There are pros and cons to an inward vs outward swinging door.

Don't forget the weather....  i am looking at an outward swinging door for my Hobbit Home, 2 main concerns are wind - my 7' shed door has caught the wind twice now, almost ripping the door chain out of the frame...
Second concern is snow... hard enough to open a regular door pushing snow ... not sure how hard it will be on a 7' round...

Pictures of my round door build.

2 - 4x8 - t&g plywood on one side, 3 inch foam in center, 2 - 4x8- t& g on the other side.

Traced out the door i wanted ( hinge and threshold ) , removed the foam then cut both sides at one time to get the round door.
Mounted the entire thing ( round frame portion and round door ) to the front of the shed.
Covered the roumd door with black epoxy - which is now cracking - next door covered in steel.

Could not find the picutes, so these are right from my Facebook page "Daves Hobbit Home Build".

Hinges.

The black stuff is the epoxy, spread it around a bit for waterproofing...

Since this was a test build for the Hobbit Home door, i can say without a doubt - i will not be using straight epoxy on an exterior surface again...

Maybe some fiberglass would have helped...  it has been in use since 2019 though.

You will notice in these recent pictures, that there is a 1.5 inch step down inside the door....
I was limited by ground clearance outside by the plywood frame around the door - could have cut 1.5 inch off the bottom of the frame and lowered it, but then again, it was a test to see if it would even work...

Did not trust having screws only around the perimeter of the door, so there are 5 or 6 - 4 inch screws - screwed inside to outside - compressing it all together for a nice solid door.

And, finally, recent pictures of the sides of the door and frame, as well as the steel trim.
Bit of a "drip edge" at the bottom of the door, so water goes straight down, not inside.

That's  about it for now .

The round door is planned to go on cooper cabin - on the lab, which is pretty strict about what materials are allowed.

My guess is that Sky is worried about shrinkage and warping.  A good thing to be worried about.  And, at the same time, pressure treated stuff is not allowed on the lab.  So I wish to paint a picture that might help Sky feel comfortable.

RD3030 - the door will be a steel plate with wood and insulation mounted to the plate.  

RD3031 - The door is a truly round door with a hinge point outside of the door (no half door, or rolling door, or hinge point on the door to one side).

RD3032 - The door will have a bit of a conical shape to the edge.  There will be temptation to do magnificent engineering to have round cone door shape be a perfect fit into a counter-sink shape. But that would require materials that are outside the acceptable zone for where we are building this.  Instead there will be a bit of a gap (maybe a half inch?) between the door and the "counter-sink".  And then there will be a flat surface inside the counter-sink - maybe a one inch lip (maybe a little bigger) that the door touches.  Any attempt at sealing will happen there.  So this will be a flat-on-flat thing.  The good news is that allowing this "lip" will facilitate untreated woods.

RD3032 - the steel plate in the center, plus the rabbet edged wood will minimize the problems caused by woods experiencing interesting changes in the seasons.

RD3033 - the real engineering will be boring - the engineering in the wall.  

RD3034 - the beauty of this project is not in artistic flourishes, but in getting the door to exists, at all, without any cheats.  This means the door knob is in the middle of the door and the hinge point is entirely outside the door.  

RD3035 - although i am taller than most, I expect to have to duck (like gandalf) when passing through this door.  The design at the floor level will be rather interesting.  I am guessing that diameter of the hole will end up at 6 feet, or maybe as large as 6 feet, two inches.  And at this diameter, when the door has it's full wood and insulation, the whole door will end up weighing about 600 to 800 pounds.  The weight of the round door is what will make the engineering challenge the greatest.   And I think the deepest beauty of the final product will be experienced by the person moving the door and uttering "wow, that is really heavy."

Sometimes, old technology is the best technology.  Here, EVERY surface  coat used for protection, be it poly, paint or anything else, it will have to be tended at the first sign of failure.

Treated woods, often rot from the inside out, because the injected treatment only goes in so deep. As such, any cutting compromises the wood. Of course, the wood is anything but water resistant. You may have noticed this if you picked up a 2x and felt how water soaked it was from being stored in the elements.

And there is that the lower grades of wood are used for treated wood.

With surface coats, like paint and poly's, the expansion and contraction rate of the wood, as it gains and loses moisture, is, significantly, different than the finish. The results in the surface coat breaking loose from the wood, and cracking and splitting.  

Water will get in the cracks and the finish will hold it in, adding to the problems.

The problem of adhesion can be compromised by the primer used. For example, even with all the touting going on around waterborne primers, there is that they dry quicker than oil based, so may not get as much adhesion via soaking in.

If using a oil based polyurethane type finish, the choices are a long oil and a short oil finish. That's just a cute way of saying "more oil" or "less oil," long being more.

Short oil finishes, are most common in interior settings. Less oil means less flexibility, but more durability.  Their durability-less flexibility becomes a problem with that moisture gain/loss thing, and the expansion and contraction of the wood.

Long oil finishes are used in the nautical environment, because they do shift with the wood more than short oil finishes.

Oils are either hardening or non-hardening. Hardening oils would be oils like Tung oil, boiled linseed (treated flax seed) and walnut oil. Non-hardening would be like engine oil and mineral oil.

Whether hardening or non-hardening, oils are the least durable finishes.

Hardening oils are a bit like poly's, but lack the resins and U.V. protectants common to other surface coats.  And they do tend to be just surface coats, with a bit of penetration, except with some of the better, high end products, like Daly's Seafin and Profin, which penetrate more than they build.

Oil type finishes are the easiest to maintain.  Especially with the non-hardening oils, no stripping of the previous applications is ever required to add a new application.

Straight, non-hardening oils tend to wick in the wood. For example, straight mineral oil slathered on a end grain butcher block will soak in until it appears it wont. But hours or days later, more can be added.

It can look like the initial coats did nothing to protect the wood, after it's beaten on by the sun.  A few coats in, and the applications will be apparent, even a year later. This is because the applications are cumulative.

Once wood is full of oil, as from several aggressive applications over a few years, water will not soak in, because the wood is "full."  AND, as the oil soaks in, it will swell the wood, causing cracks and splits to seem to disappear (I had a badly cracked and split end grain butcher block that restored beautifully).

After a few years of treating wood with thinned oils, a seal coat can be added.  Primed paint would hold up far longer, because the wood is far less prone to gain and loss of moisture.

Sky Huddleston wrote:  [W]e will have to have to HAVE TO use pressure treated wood. . . .

Looking at the bottom, I assume there will be a minute angle to the "treadplate" area just back from where it would land on the plate, to the weather side, so any water landing on it will run off, and less likely to push in, even if hit by wind and rain. It would only take a degree or two,.  And that concept could even be repeated around the door. The wedge fit would make it more inclined to seal all around.

I use the slight bevel approach to deck railing and window sills (which was the norm generations before I came along).

When I can, I try to avoid screw or nail holes on top any horizontal surfaces. Those are the first places rot starts.  

paul wheaton wrote: [T]he round door is planned to go on cooper cabin - on the lab, which is pretty strict about what materials are allowed. . . .

paul wheaton wrote:
RD3031 - The door is a truly round door with a hinge point outside of the door (no half door, or rolling door, or hinge point on the door to one side).

RD3034 - the beauty of this project is not in artistic flourishes, but in getting the door to exists, at all, without any cheats.  This means the door knob is in the middle of the door and the hinge point is entirely outside the door.  

I totally agree with this.  I admit, i did cheat with the flat hinges, but, since this was a test run for the Hobbit Home located on a small shed, i did not want to spend the year or so it will take to weld up the hinges and door brackets needed for a true round door.

Lots of plans for the new house, since the effort will be worth it.... a truely round door with a fancy hinge that i will fabricate on site (hopefully come out with something that looks like the movie  ( attached picture )) and yes, having a door handle in the middle of the door, by extending the door pin that extra 3 feet into the door jamb...

The hinges and door mounts will also add structural strength to the door...

I see this is probably going to be based on a metal plate, but just for kicks -

there has been some really cool work in homestead-scale CLT (cross-laminated timber) that prevents shrinking/twisting/checking incredibly well.  

CLT is being implemented in commercial architecutre to build wood-based structures with unprecedented strength, stability, thermal performance, height, and span.

Here is a thesis with from some students at Harvard GSD, probably worthy of its own thread.  This project shows that CLT is achievable at a homestead scale, and hyper-local paradigm. Lots of great images and description of their process and findings in the video.

https://www.gsd.harvard.edu/project/the-littleton-trials/

I think it would work well for a labs-standards worthy, wood-based door format.

I didn't know that pressure treated was not allowed, the good thing is that I have recently secured a very inexpensive source of very tight grained white oak, which after long deliberation I have decided to go ahead and tongue and groove 1" thick boards rather than rabbet them, and then use dowel rods 3" into each side of the boards along the joints, and laminate in two layers of alternating grain direction to form a 2" thick door. This will absolutely minimize warpage due to seasonal changes and make for a door that is literally bullet resistant. This is also a good opportunity to try an organic method of treating wood to be rot resistant thats in one of my old books. This will take more time on my part but it will be worth it in the long run, and create a true heritage piece that I anticipate will last at least a few centuries if well taken care of. I was planning on using steel hinges and brackets of my own design. This effectively means the workshop will be mounting the door and building a doorframe, as the hinges and door itself I will make in my personal shop. The hinges and brackets are a must to be made here, assuming I'm not incorrect in my assumption that wheaton labs does not have access to a large milling machine. I was originally planning on making the door 7' in diameter, as oak boards come in 8' lengths and thus this would maximize materials usage, (and also for Pauls sake) however I could reduce the diameter if Paul wants. But I will not be using a large metal plate for the door itself, it will be a genuine solid core round door, using only metal to reinforce the section the welded hinge bolts to.

I was originally planning on using a hybrid conical/lip door and joint, however now knowing that a small gap between the door and doorframe is acceptable and that conical sections arent allowed, that actually makes my job a lot easier and relieves stress off me. Should there be a slight conical taper like a subtle frustum, or no taper at all? A specific number or range of degree's would be best. 90 degree's? 85 degree's? Between 72 and 95 degree's? etc.

What kind of steel plate in the center do you want? In the center of the door for the knob? And by "outside hinging" you mean you want the door to swing outward rather than inward? And you want the hinges to be

Whilst we're on the subject of privisions and conditions, is there anything else that Cooper Cabin specifically needs or precludes? These provisions that I recently became aware of made me glad I didn't get too far in the design process, lmao.

As far as attaching the door and doorframe to the hinges, I was gthinking a combination of carriage bolts and lag bolts, if those are acceptable hardware choices. If need I can use square headed lag bolts to give it a more 19th century aesthetic.

I also have to thank kelly craig for chiming in, as my knowledge of wood trating is rather lackluster by comparison. I have a drum of used motor oil I can bring with some brushed to keep near the door, for convenient periodic re-coating. After a few years of use and daily brushing, we can then go ahead and coat the wood. Makes sense to me. Given that used motor oil is just mineral oil with suspended carbon particles this should be an economical and effective way to upcycle and otherwise completely wasted material.

Frankly, it looks like Dave Lotte has more experience with designing round than me. In fact, given that photograph, I know he does. I'm going to have to step my game up to the next level lest I look like a buffoon, lmao. The amount of competency and knowledge on this forum never seizes to impress me. I look forward to designing and fabricating the hinges, which will be the hardest part, next to mounting the door and frame into the structure itself. The creation of the door itself is kind of trivial by comparison (though still difficult!)

I will start designing hinges next week and post some 3D models. Right now I'm thinking a pair of bored steel tubes with pressed in bronze bushings on each end for a total of four bushings, and tapped for grease fittings. designing them to be adjustable will be the biggest challenge.

I'm pretty sure used motor oil wouldn't be approved either.  But bare oak or a bit of tung or linseed oil might work.  

How would you laminate the oak boards together?  If glue, that might also need to be approved by Paul.  Bolts through the door pinching the two slabs together would be a decent option I think.  And look "old timey".

I think when Paul says "a hinge point outside of the door" he means that the pin of the hinge is to the side of the door, not at the edge of the door.  Maybe a few inches away from the edge of the door or a foot.  That way as the door closes against the flat lip, the side closest to the hinge is still able to compress a gasket/seal.  

It's a great question to wonder if the door needs to open in or out...

Mike Haasl wrote:I'm pretty sure used motor oil wouldn't be approved either.  But bare oak or a bit of tung or linseed oil might work.  

How would you laminate the oak boards together?  If glue, that might also need to be approved by Paul.  Bolts through the door pinching the two slabs together would be a decent option I think.  And look "old timey".

I think when Paul says "a hinge point outside of the door" he means that the pin of the hinge is to the side of the door, not at the edge of the door.  Maybe a few inches away from the edge of the door or a foot.  That way as the door closes against the flat lip, the side closest to the hinge is still able to compress a gasket/seal.  

It's a great question to wonder if the door needs to open in or out...

Yeah I was planning on using glue. And thats also my interpretation of "hinge point outside the door" which I was planning on doing anyway, as designing a complex machined and welded hinge with grease points and adjusting nuts is frankly less intimidating to me than carpentry. I'm kind of backwards in that sense.

Just keep in mind, tung oil and BLO are build coats, like paint or poly, though they're at the bottom of the list when it comes to protection from the elements, until they get played with, such as with the addition of resins and UV blockers, at which point they, essentially, move into the poly category.

You can get significant penetration by thinning. And the longer you keep the surface wet, the more you keep catalyzing oxygen from sealing the surface, giving more time for penetration.

I don't know what all you can and cannot use for protection, but there are products like Daley's Seafin that penetrate and protect.

Just curious on the dowels, the idea which I like, since it's akin to butterflies in cracks, to stop splitting, or in this case, separation. Will the end toward the exterior be exposed? If so, special attention to treating the dowel ends may be appropriate, since all such holes are invitations to the evils of the elements. Another option (hey, it's a complicated project, so what's a little more of YOUR labor     ) might be blind holes that stop, say, 1/8" of the exterior side.

I've used a lot of used motor oil for fences and things, but only because it was free, versus buying motor oil, or something like Chevron Shingle Oil.  

Interestingly, even dark black oil out of a hard worked diesel engine does not turn wood black. And, sun grayed wood just becomes back in beautiful red and gold hues. Of course, unused motor oil works fine for the stated purposes, AND you are guaranteed "less friction and better gas mileage. . . ."

Anyway, what kind of limits do you have on the finishes you can use?

Dave Lotte wrote:i will not be using straight epoxy on an exterior surface again...
Maybe some fiberglass would have helped...  it has been in use since 2019 though.

Fiberglass cloth would have helped some, but epoxy can't be left exposed to ultraviolet light. Best to epoxy it then paint it black or, better yet, add an overhang to protect the door from rain and sun.
Another way to get a black door and strengthen the epoxy (together with fiberglass cloth, which adds tremendous strength and surface integrity), is to mix in graphite powder. I do this for the bottom of my wooden boat, it stands up to grinding on a beach.
Also, plywood is not a good choice for the exterior skin. Lumber will not crack or check as much.

Nice shape!

Sky Huddleston wrote:I didn't know that pressure treated was not allowed, the good thing is that I have recently secured a very inexpensive source of very tight grained white oak, which after long deliberation I have decided to go ahead and tongue and groove 1" thick boards rather than rabbet them, and then use dowel rods 3" into each side of the boards along the joints, and laminate in two layers of alternating grain direction to form a 2" thick door. This will absolutely minimize warpage due to seasonal changes and make for a door that is literally bullet resistant.

I am so glad to hear you are not going to build a 3" thick door. Would have been too heavy, and overkill. 2" of oak laminated of 1" boards will be plenty stout. I doubt that Paul would want to buy rigid foam board for an insulation/thermal break layer, but if there is some to be repurposed a 1" layer between the oak skins would make a big difference in the winter. Then you would have the additional step of banding the edge with more oak.

NO used motor oil as a finish! Toxic fumes for quite a while, and again each time you add a coat. My expertise is in finishes. I would start on the outside with a colorless, penetrating wood treatment that is basically silicate. Never any rot that way. Everwood https://evercrete.com/products/everwood-ew/  or  TimberPro internal wood stabilizer https://timberprocoatingsusa.com/products/internal-wood-stabilizer/ (both made in USA).

Next, you can use a water-base stain with some color (the more pigment, the better the protection). Other non-toxic alternatives are Teak Guard (easy to use, water base, does not form a surface film, easy to apply, has a burnt-red, almost maroon coloring to it), or any of the TimberPro finishes at the link above (made in Portland, Oregon and I have used their products on many projects) or Envirolast https://envirolast.com/product/envirolast-stain-and-seal-5-gal/ . Not inexpensive, however.

As for sealing, for the lab I'd think you'd probably go with a multitude of layers of raw linseed oil.  I use cold-pressed flax oil from the health food store thinned with citrus oil. Nothing synthetic nor additives or unnecessary processing.  You can start by thinning 5:1, and build up to an undiluted linseed coat.  I have read that flax/linseed oil have 4 molecular reactive sites which is why the are so effective and sealing and binding when made to penetrate and layer, both on wood and earth.  Whereas mineral oils and poly's will more like sit on top of the surface.  And they're not allowed anyway, so . . .

You could also consider charring the exterior and edges.  

I think Paul would not be opposed to having a *very* heavy, very thick door.  It will more than compensate for the omission of unacceptable rigid foam.

Here's a time lapse and some screen shots of the laminating jig from the video I linked above.  Another part of their project was to thermal transfer across laminated layers.  I'll have to watch again,  but I think they did 5 layers, of site-milled 1x, alternating directions, and achieved good thermal qualities.  They used some red maple and some black locust, but white oak should be superior in every regard.  

2 inches of oak would be a good start but not excessively beefy for a 6-7' disk.  Especially if they're actually 3/4"?  I do like how stable it would be.  How about 4 layers?  1 vertical, 1 horizontal, 1 45 degrees up, 1 45 degrees down.  Through bolted to hold it all together.

They've managed to make wooden doors for centuries without steel cores so I'd love to see one made from primarily wood.

Better insulation might be possible if the central layers of the door were cedar (reportedly higher R value) but that wouldn't help the strength of the door as much.

If you came to WL with all the 8' boards milled/edged/routed, the assembly could happen on site.  Depending on how much of the 2 weeks you have for the project.

Mike Haasl wrote:2 inches of oak would be a good start but not excessively beefy for a 6-7' disk.  Especially if they're actually 3/4"?  I do like how stable it would be.  How about 4 layers?  1 vertical, 1 horizontal, 1 45 degrees up, 1 45 degrees down.  Through bolted to hold it all together.

They've managed to make wooden doors for centuries without steel cores so I'd love to see one made from primarily wood.

Better insulation might be possible if the central layers of the door were cedar (reportedly higher R value) but that wouldn't help the strength of the door as much.

If you came to WL with all the 8' boards milled/edged/routed, the assembly could happen on site.  Depending on how much of the 2 weeks you have for the project.

I'm going to be dedicating 1 week, so the door and doorframe, and hinges, will be built in my private shop, and then trailered to Wheaton Labs. Like Paul said, the real engineering will be in the wall.

Sizes and dimensions are all nominal, actual sizes.

As far as the dowels go, they wont be all the way through like re-bar. Instead the holes will be drilled 5" deep on each side of the boards, before the tongues and grooves are cut on the tablesaw, and then dowels will be glued and inserted into one side, following by the final assembly. The cross grain of the dowel will provide added structure for the joint

Sky Huddleston wrote: I look forward to designing and fabricating the hinges, which will be the hardest part, next to mounting the door and frame into the structure itself. The creation of the door itself is kind of trivial by comparison (though still difficult!)

I will start designing hinges next week and post some 3D models. Right now I'm thinking a pair of bored steel tubes with pressed in bronze bushings on each end for a total of four bushings, and tapped for grease fittings. designing them to be adjustable will be the biggest challenge.

Have fun with your round door project.  Some of the challenges i found along the way ...

1.  Asking peoples opinions on how to build it - lots of opinions - some good suggestions - a few heated - " you should do it this way !"  But when asked - absolutely no practical experience ...
2.  Fitting the round door - you would not believe how hard it is to get that thing lined up, and my door is light weight - with a couple of flat spots !  1/32 of a turn either way, and the darn thing don't  fit ! 😁.  You definately notice the difference between round and rectangle !  Good luck with a 300 lb door.

I now have a supplier for 10 inch insulated wall panels.  The plan for my Hobbit Home, is too pour the concrete walls, waterproof the front wall, then stand these steel clad - R 40 panels all along the front wall making a continuous insulated, steel sided outer wall.  Then all i need to do is cut out the 7 foot round and use that piece to make the actual door - with the proper round shape and heavy duty hinges.

Also have to install the home made round window as well at some point.

ANOTHER SIDE NOTE:

Regardless which protectant you use, remember a main purpose is, to stop weather checking caused by the wood loosing moisture.


I'm not familiar with the Everwood products, but they appear worth looking into and adding to the arsenal of things to protect wood.

I did note they used the penetrating Everwood on cedar, for their example.  I've treated oak, cedar, maple, pine, sycamore, mahogany, and a host of other woods. The cedar was the best at taking on [replacement] moisture in the form of protective coat.



Many things determine how well a given coating will protect wood. For example:

* Time:

As the wood looses moisture, it becomes more possible to add moisture back.

NOTE:  That lost moisture is what makes our fences and decks look horrible. The shrinking causes wood cracks and splits.  




* Scuffing planned surfaces

The smoother the surface, the slower the penetration of oil, water and finishes or protectants, and the less top coats tend to adhere.




* Wood type:

About forty-five years ago, I got in on the burl table craze.  I took a bit more time than most and would apply deep, penetrating finishes.  I used a lot of what was called Flecto Varithane Plastic Oil, which is of the poly family of protectants.  I used them even on a LOT of redwood cedar, though many, erroneously, claim the oils in the wood prohibit such (my hold-my-bear moment was, oil is oil and if it mixes, or plays with with certain thinners, it's fair game).

On a four inch thick cedar top I made for a table, I'd keep adding thinned poly for as long as it would soak in.  When I'd get to one end of the, roughly, two foot by four foot piece, the part I started at was ready to take more. So I kept starting over.  

When the absorption slowed way down, I left a bucket of thinned oil at the burl and would pick it up and add more, where needed, to and from lunch and coffee breaks, or any other time I walked by.

Well into the project (about 1-1/2 gallons of Plastic Oil), I dropped the brush. When I kneeled down to pick it up and looked up at the underside of the slab, it was sopping wet from the hardening oil and solvents that I'd added to it.

SIDE NOTES:  I did turn the wood over and repeat the process; and wood treated this way has sat in front of a well used fire place without any cracking and splitting, from drying, over about forty years.

More dense woods, like maple, will still take penetrating products, but do not begin to compare to porous woods like cedar, in how fast they will absorb them.  That said, end grain maple will respond VERY well, as will many dense woods, when the finish is applied to the end grain (actually a problem woodworkers have to address, when staining and such.

I bought an end grain, maple butcher block, which was split and cracked. It was so cheap I couldn't pass it up, even though it was obvious it had been neglected for a long time.  To play with it, I bought several bottles of mineral oil at WallyWorld.  I used the time honored approach of adding it wherever and as long as it would soak it in.  I'd tend it each time I walked by during the day.

When it got to where hours would go by and no more was soaking in, I slathered on one last, generous coat of mineral oil and walked away, forgetting about it for a few weeks.  When I came back, the oil had all soaked in, and had wicked to other dry areas. The result was, much of the wood swelled back to near or at the state it was in, when the butcher block was built, leaving ALL the cracks and splits gone to the naked eye.



* Treating all six sides of each piece :

Every side or edge of a piece of wood left untreated is one more place for moisture to enter and leave the wood.  

The better you can slow down the gain and loss of moisture, the less chance of shrinkage of the wood, which will cause unwanted cracking and splitting. Too, there is less likelihood of gaining moisture, which can cause swelling and result in buckling.



AGAIN, when using any hardening finish intended to penetrate the wood, the longer you can keep the catalyzing oxygen away, the more chance it has to penetrate, before hardening.

For this reason, I used generous flow coats on poly type floor finishing projects.  This allowed the finish to seep down and seal the sides, as well as to work under the wood (usually well seasoned oak).  

When I thought it time, I stopped, removed excess finish, and walked away.  At that point, the hardening process really started getting down to business.

Yes, I used more product, but that spot in front of a fridge, where the air exhausted over the wood floor, went decades longer, without showing signs of aging (drying, etc.).

And, these techniques do not apply to two part mixes, like epoxies, or lacquers, or shellac, or. . . .

Sounds like a perfect reason to look into the possibilities of making it the equivalent of a pre-hung door,

Dave Lotte wrote:

Sky Huddleston wrote: [ 2.]  Fitting the round door - you would not believe how hard it is to get that thing lined up, and my door is light weight - with a couple of flat spots !  1/32 of a turn either way, and the darn thing don't  fit ! 😁.  You definately notice the difference between round and rectangle !  Good luck with a 300 lb door. . . .]

The door will be on the front of cooper cabin, which has a five foot eave.  In country where the humidity level is generally low and the annual precip is relatively low.  

So there is no need for wood preservatives.

Sometimes when wood will be exposed to rain, we put a bit of raw linseed oil or tung oil.  

assuming I'm not incorrect in my assumption that wheaton labs does not have access to a large milling machine.  

Correct!  But I think there is a fella within about five miles that has one, and it is sorta his business.

conical sections arent allowed,

I think conical sections are very wise.  It's just that you don't have to go through 20 hours of math to get a perfect fit.  A bit of gap is fine.

Should there be a slight conical taper like a subtle frustum, or no taper at all?

I think a taper is wise.  Without the taper, the hinge stuff is gonna get too interesting.

What kind of steel plate in the center do you want?

Excellent question.  I think 1/4 inch would be too thick.  How do you feel about 3/16.  I think the primary function of the steel plate would be to hold the massive weight without the door changing shape.

And by "outside hinging" you mean you want the door to swing outward rather than inward?

In my head, I keep imagining the door swings out. Yet our normal house doors swing in.  Does the hobbit book say anything about which way the door swings?

I was gthinking a combination of carriage bolts and lag bolts, if those are acceptable hardware choices.

Those are great.  

Mike Haasl wrote: If glue, that might also need to be approved by Paul.  

Glue is generally out.  But if somebody wants to use pine tar - or a mixture of heated pine tar and wood ash, that's fine.

Generally wood glue is allowed if it is less than 1% of conventional.  But we do take some pride if we can build things without any glue.

As a general note, we tend to never use stains or paints on the lab.  Some buildings at basecamp require it.  At the lab, we have used raw linseed oil from time to time, but we try to minimize that too.  

Insulation of the door:  odds are that we are gonna go with wool - from sheep.  But if the stars align just right, it could be worth exploring beau's mycelium insulation (I doubt there will be enough time for the two projects to overlap).

At about 17 minutes in, this video describes joinery for doors. He tells of his first door using pegs... the first season, the pegs were working themselves out. He suggests using square pegs, with rounded corners on one end.