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The Coleman globes arrived, and there is indeed a difference in diameter.

However, if the desired size is exactly 4 1/4" then the one is slightly undersize, but the other, due to having a rounded lip on the edge is slightly oversized.

Due to the narrow margin of error involved, I'll have to report later on which works out "better".

The casting, I notice, does have a slight taper to it, getting thicker, with reduced inside diameter further down, so the smaller globe would likely work.

There does not seem to be any difference in height.

I'm inclined to think the rounded lip on the slightly larger globe would be more durable and less likely to crack or break, but it's a toss up. Either one would probably work. I'm not sure which one I'll end up going with.

The larger one would mean more material would need removal from the casting, making an already thin wall, possibly too thin.

I took the castings to a local machine shop to do the majority of the clean up, so it may be a couple of weeks before I get them back.

It will be a few weeks before they can actually get started. I may take the globes over to their shop and see what they think.

As it turns out, a pickle jar is just right!

A perfect 4 1/4". OD

Maybe I'm looking at the grill bricks the wrong way.

I've only been considering it for a displacer up on end, but for the fan, the Coleman globe is only a little more than 4 in. tall. The displacer probably doesn't need to be more than 3 1/2 in. high.

So if the brick is laid down flat a plug could be cut out vertically, like this:

Still a loose fit, but probably close enough.

Might even be able to get two out of each brick.

The dark Kona bricks are also open cell and more fragile, (less heat resistant) than the closed cell hamster chew blocks, which are completely impervious, even if heated to a glowing red hot heat. The various "flaky" grill blocks will fall apart, but should serve the purpose in a stove fan, where they won't be subject to direct flame.

If not, I guess I'm back to making the thing from scratch in a kiln.

I DO want to experiment with that anyway, but ready made is nice.too.

Just got that return call from the Kona company about the grill bricks.

That don't have any that are an actual 4" x 4". Probably they are the same as any of the others being sold elsewhere, so I was told they will be adding the word "approximately".

I guess if that's good enough for dimensional lumber it's good enough for grill bricks. Maybe they are cut 4x4 hot off the conveyor but shrink as they cool off I guess.

It didn't sound like Kona actually makes the things, but sell them "as they come in", so apparently don't have direct control over the manufacturing.

The representative offered a full refund, if I return them, (undamaged, presumably, ha ha) and passed the information along that there is some demand for the full 4x4 size brick.

I guess I need to move the foam glass making research project forward on the to-do list.

I'm pretty sure all grill bricks of this kind were actually 4x4 when the Myers engine works first designed the stove fan, but like so many other things, everything seems to be shrinking. Cereal boxes, 1/2 gallons of ice cream are no longer 1/2 gallon. etc.

I got the stove fan castings back

https://youtu.be/ofJRLs3cGBI


Still a lot of work left to be done.

After posting the above video, this 2year old video of a Myers Stove Fan came up in my YouTube notifications:

https://youtu.be/O4DUivnPm_4

I found an old 10" Seneca Falls Metal lathe in good condition and that is just big enough to do the turning on the base of the stove fan. So now if I do any more, I won't have to pay someone else to do any of the machining

The lathe itself only cost $275 which is not much more than what I paid just to get a shop to do, maybe about 1/2 of the machining that needed to be done on this one small casting. ($210).

It's all there, but I had to disassemble it to get it out of the guys garage and onto the back of my pickup, where it still sits at the moment.

I still need to get it down into the shop and put it back together.

I received an email recently from Myers Engine Works advertising a sale.

But what I noticed is that the new website they had been working on the last time I contacted them is now up and running.

It includes, or will include, a page for FINISHED ENGINE PHOTOS

FINISHED ENGINE PHOTOS
Have you built a model engine? We are starting a new page with photos of your finished engines. These models can be ones you have made from scratch, from our castings, or from another supplier.

Currently that finished engine photo page still has no content.

I haven't had time to finish my fan casting project, or even get the bigger metal lathe down into the shop and set up, but I thought others here who have built engines might be interested. The new website is also generally a big improvement over the old outdated site.

Also the Lake Breeze fan kits are again available.