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Scrambler82

Alumina Shelf Opinions, pls !

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I wanted to put an insulating layer under my Diamondback Forge while I am building the stand, was thinking Fire Bricks then I found an "On-Line Store for High Alumina Shelving" and thought the price was on the low side so wondered if there is more too it than I know about !

A piece 18x18x3/4" is $36, again I thought the price was good.

I haven't looked locally for Kiln Shelving or for standard fire brink but just wanted options on the product.

I was also thinking the 1/4" Shelf might make a good floor for the forge as time goes on, washed with Mertikote (spl).

Opinions please/thanks ?

 

 

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I would say it is about average. I get my high alumina shelves from Seattle Pottery supply, since they are in my town and have reasonable prices. But in the case of replacing the brick floor of a Diamondback forge, I wouldn't go with the shelve...moment of shock and surprise; Mikey would use something other than a high alumina kiln shelve for a floor1?! Yes; in this instance, I would go with an even better insulating high alumina castable (Kast-O-lite 30) From Wayne. I recommend high alumina kiln shelves in tube forges, where they are suspended in the shell, with only ceramic blanket underneath. Part of the reason for using an HA shelf is its strength, which is needed for a suspended ceramic part.

You will put the floor directly on the forge bottom, or on a ceramic board, which in term lies on the forge bottom. So, the part will be completely  supported. In this case you will save construction money, and fuel by purchasing castable from Wayne. Box forges have different needs than tube forges:D

Are you going to tell us what  "On-Line Store for High Alumina Shelving" so the rest of us can have a look see?

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Are you talking about inside the forge or outside the forge?  I believe Mikey is assuming the inside.

I read it as outside the forge:  I've used a slab of soapstone on top of my workbench when I put my propane forge on top of it to insulate the wood top from the forge and work pieces. Nice to have a place to set hot items near the forge and preferably one that won't contact quench high carbon.  Of course for blades I like an even more insulating surface to avoid quenching possibilities.

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Your right, Thomas. He meant outside, which simply needs something non combustible and somewhat insulating. How insulating would have to depend on how long at a time he plans to run the forge. I would go with something I could find other uses for after the stand is built.

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Most gas forges I've worked with a steel plate would be sufficient to "spread the heat" and keep it below combustion temps for wood.

My gas forge cart is just a propane grill cart with the grill replaced with a 3/16" steel plate. (about 10 years old now, I added an axle and better wheels as well as the cross bracing.  This is the shot from the back as I used the solid side as the front to prevent hot workpieces getting inside where the propane tank and hoses are. You can't see it but there are holes drilled in the plate matching the feet of my gas forge that is bolted down in use---with wingnuts to make it easy to dismount for transportation.

forgecart.thumb.jpg.65fcbbd7b2f7c330bce5e8b224946061.jpg

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2 hours ago, Mikey98118 said:

Are you going to tell us what  "On-Line Store for High Alumina Shelving" so the rest of us can have a look see?

I posted a picture of the Site Page and I guess it didn't show !

Here you go !

Thks for the input.

image.thumb.png.9fd846d0265d5a4fd2663339006bd4e4.png

2 hours ago, ThomasPowers said:

Are you talking about inside the forge or outside the forge?  I believe Mikey is assuming the inside.

I read it as outside the forge:  I've used a slab of soapstone on top of my workbench when I put my propane forge on top of it to insulate the wood top from the forge and work pieces. Nice to have a place to set hot items near the forge and preferably one that won't contact quench high carbon.  Of course for blades I like an even more insulating surface to avoid quenching possibilities.

The 18" X18" piece was going outside, under the Forge to reflect heat away from the lower shelves, but I was thinking a 1/4" thick piece for the floor inside too.  It would have been large enough to cover almost all of the floor but mainly I was thinking under the burners.

Thks Thomas

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I just use cement backer board on standoffs to keep the forge's heat off tables, benches, etc. A little dead air space makes a lot of difference.

Frosty The Lucky.

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Ok then, either a piece of steel or maybe even fire brick; I'll have to see what I can find.

My time frame for using the Forge will be small in comparison to someone making blades, but I don't want to take the stand apart after it is assembled.   I know you don't always get it right the first time but that's one of the reasons I ask too many questions and it take far longer than most to build something, it is called "DIRTFT", "Do It Right The First Time" !

Mikey, this castable product you mentioned from Wayne, can you make a form and cast it ?

The DB Forge can be opened completely up allowing retangular piece to be slid in place.

Thanks for the input.

6 minutes ago, Frosty said:

I just use cement backer board on standoffs to keep the forge's heat off tables, benches, etc. A little dead air space makes a lot of difference.

Frosty The Lucky.

Now that is a great idea, easy to come by too.

Thanks Frosty

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So you've encountered the 90/90 law, to paraphrase, "It takes 90% of your time & money to do it the first time, the other 90% to fix it."

I need some clarification. Are you talking about the forge floor or are you talking about the stand? We can talk about both of course but I think the two things are getting confused here.

Yes, you can make a form and cast Kast-o-lite -30. It's a water set castable refractory, just don't make it too wet. You want enough water to hydrate the calcium and cement everything together but not so much water molecules start replacing the refractory or it'll leave voids as the excess water dries. Think of it like touchy concrete and you'll have a jump on figuring it out.

Frosty The Lucky.

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Frosty,

I have the bad habit of writing about two things at once, my mind says I am doing it correctly but the understanding of the reader is another thing !

My Lit Professor in College always said I was writing two books at once, I think it is more like three or four, but he said my thought patterns are working double time and I needed to get them straightened out so people could understand what I meant to say, that is the real reason for my messed up ideas. (ADD / OCD)

To straighten this out some, my first intent of this thread was to determine if the Alumina Shelf in the attached picture above was a good quality, then I wanted to get an opinion on whether or not it would work as an insulating plate under my forge, sounds good so far, somewhere in between my mind told me if I used the ¼” shelf as a floor in my forge, mainly under the burners I would make the floor last longer and it all got mixed up.   Mikey answered the floor thought, Thomas came in reading the first idea and commented on the intent of the thread based on the…  as you can see the longer I write the more confused I get !

Now just to clarify…  I got most of my thought from reading too much, read one thread you get a thought, read another thread and a bubble breaks in the old brain and you put two and two together and you get another BRIGHT idea !

So…, from all of these good ideas mentioned above, which I appreciate because how can my mind work overtime without more than one idea going on at the same time, but what I am carrying away from this thread is, the Alumina mentioned above is an ok product and would work for the interior of the Forge but it is not suggested to be used on a flat bottomed forge like mine; it would be a better idea to use the Kast-o-lite -30 as a bottom plate.  Also, Fire Brick, Steel Pale with air space and the idea I liked the best is yours, the Cement Backer Board, used with spacers will stop a lot of the heat from the bottom of the forge transferring towards the second shelf and towards the propane tank area.

OK, in my mind we are all set but I hope this straightens it out…  on to another thought !

Frosty, when/if I form up the Kast-o-lite -30, what would be the best material to use as a form, thinking about sticking ?  Can it be cut after hardening ?   The floor of my forge is approximately 7.5” x 11”, thats off the top of my head, should I make the casting larger than needed and cut it for a tight fit or does it really matter.  One of the good points of the Diamondback Blacksmith Forge is the front and top can be opened up, allowing easier insulation relining.

Looking at the existing insulation, they are loose fitting, looser than I would have expected but still wonder about the loose fitment of the existing insulation.

Sorry for carrying on, I get carried away thinking of all of the things I still need to do.

Thanks for asking, hope this post doesn’t add to anyone confusion other than mine.

GrevB

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I get it, I tend to think of several things at once, especially if they're related.

Topic 1, What heat escapes through the shell of a forge isn't going to effect the propane tank unless they're in contact, even then. My concern for tank placement is to avoid trip hazards. Rolling a propane tank on it's side can send liquid propane down the hose and into the burner, this is a B-A-D thing, think 8' Dia fire ball shooting out the forge openings. Breaking a hose fitting is a BAD thing too. I place my tanks so nobody wants to walk between it and the forge minimizing trip hazards.

Keeping the forge off a table keeps the heat from warping or singing table tops. I like isolation rather than insulation, if the forge shell gets too hot it can warp and that's not good.

Topic 2, inside the forge I don't think it makes a lot of difference which you use, for the flame face so long as it's up to the environment. Kiln shelf or high alumina cast refractories are both up to the task. If you lay ceramic blanket under the flame face floor then some rigidity is necessary or the physical abuse it will take is going to try flexing the inflexible face and it'll want to crack and break up. alumina kiln shelf is more than up to the task but it's a pita to cut, rent a tile saw is a better course of action than the scribe and break like you would cut glass, it takes practice.

The castable refractories like Kast-O-Lite-30 can indeed be cast in any shape you'd like with simple forms though it needs a little more thickness to bridge the flex of the blanket under it. Its no gig thing, 1/2" is good and 3/4" is more than enough. This castable is a concrete hard at 3,000f high alumina so it's proof against the temp, mechanical abuse and welding flux it'll encounter. It has the added benefit of being a better insulator than kiln shelf so it'll help extend the working life of the ceramic blanket under it.

When I'm casting the burner blocks for the NARBs I use 2" x 2" for the form, screwed into two L shaped segments. They screw onto a 2" x 8" with the holes to hold the crayons. Sand it smooth and paint it with something shiny, I used a can of Krylon enamel from my paint cabinet. I discovered grease works a lot better for a release agent than oil or wax, I just grabbed an OLD tub vegetable shortening out of the fridge. It worked a treat.

Do NOT make it large, it's not going to "trim" easily, you'd have to grind it down and that's likely to chip it. Make is a little bit small, model it on what comes in the forge. Don't adjust what works, you're already modifying it, do that one thing at a time. Eh?

Frosty The Lucky.

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Yes I did, not thinking about the walls of the forge though.

Tell me... How would you adhere the 1/4" sections to the walls of the forge ?

I like that idea, will have to keep it in mind.

Just looked it up the measurement for the Diamondback Forge are:

Interior: 13.5" L X 7 1/8" W X 3.5" H, there has to be something there I can mod to fit !

Thanks

 

----------------

Mikey, 

Please tell me again about the Alumina Shelf Material, i.e. 3/4" thick, being used as a floor, I just don't get it, why won't it work as a floor on a box type gas forge ?  Maybe over a good insulating solid material ?

If I use the Alumina Tile, on the interior walls, it is still necessary to use the Metrikokte ?

I was under the impression that the Metrikote should be used no matter what material is already in place.

One more question, from what I have read about the DB Forge's insulating material, it calls out a dense ceramic floor, is anything needed on it, replacing it, or just something under it to add to insulation ?  ( Is that more than one question ? LoL !)

Thanks for your time and the effort you put in this Site !

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just place each tile to overlap one end of the next tile, to trap it; that leads only one stainless steel screw needed to reach from the forge top, down far enough to trap the last edge of the fourth tile in place, locking all four of them in position.

It isn't necessary to use a heat reflective coating over the tile, but it is smart to do so; this doesn't mean you have to add the coating immediately. You do need to check which coating is going to be best over a hard ceramic surface.

To the best of my knowledge, the forge originally comes with a half brick floor. My recommending Kast-O-lite 30 is only for its greater insulating value. But, a high alumina kiln shelve has seven times the insulating value of hard brick, soooo...take your choice; you are going to do well either way :D

I don't think you want parts that has to come out, to eventually the change the ceramic board to adhere to anything :P

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Contacted the Ceramics Store Posted above and asked about custom cut Alumina Shelves.

I asked about cutting the following: "3.5" X 13" tile my back wall, 2 - 7.5" X 3.5" tile my end walls, and a 7.5" X 13 tile for my floor,  these are the wall/floor pieces for a Diamondback 2-Burner Blacksmith Forge", I didn't mention the thickness but they are willing to custom cut those sizes in 3/4", out of a 16 X 16 X 3/4" piece ($56.00 stock piece), for an addition $20.00 !

I can't rent a wet-saw for $20.00 so it is not a bad price.

Also, their 18 X 18 X 1/4" is only $36.00, so now it gets even cheaper, $56.00 plus cutting and shipping; I haven't asked about shipping !

If someone can't find a local supply for their Alumina Tile, this could be a good alternative location, sized for their use, buy it, get it, slip it in !

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Contacted the Ceramics Store Posted above and asked about custom cut Alumina Shelves.

I asked about cutting the following: "3.5" X 13" tile for my back interior wall, 2 - 7.5" X 3.5" tile for my end interior walls, and a 7.5" X 13 tile for my interior floor,  these are the wall/floor pieces for a Diamondback 2-Burner Blacksmith Forge", I didn't mention the thickness but they are willing to custom cut those sizes in 3/4", out of a 16 X 16 X 3/4" piece ($56.00 stock piece), for an addition $20.00 !

I can't rent a wet-saw for $20.00 so it is not a bad price.

Also, thre was a 18 X 18 X 1/4" for $36.00 (which I can't find again), so now it could gets even cheaper, $56.00 plus shipping; I haven't asked about shipping !

If someone can't find a local supply for their Alumina Tile, this could be a good alternative location, sized for their use, buy it, get it, slip it in !

–------------------------------------

Additional Info:

Here is where I sent the cutting question: euclids.com, but I got. Response from "The Pottery Supply House" !   I will have to check this out first ! 

Shipping would be $12.50 for most orders, larger order will be addressed as needed.

They are located in ON, Canada

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I have also tried to contact Euclids to get more information.  One thing that concerns me is the composition of what they are calling a high alumina kiln shelf.  Their site says it is Cordierite - Mullite.  According to other research on refractories I've done this material combination may only be rated for 2,150 deg. F, which may be an issue in some forges, and certainly for flame impingement.  Of course, what the material is rated for doesn't necessarily mean we can't use it for a forge floor at higher temperatures, just that it may not be able to be used as a wall or ceiling element at elevated temperatures.  This is the site I used for additional info: http://www.usrefractories.com/products/prod04.htm

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Will be interested to hear the feedback from the manufacturer.  From my limited experience with high alumina castings I think you may end up having a problem with the relatively rapid thermal cycling potentially cracking the high alumina tile, depending on your installation details, use and forge design.  The high alumina castings I've used didn't like any kind of quick temperature changes. A crack is not as big a deal for a forge floor as it might be for the walls or ceiling, if either are used for the forge structure support.  

If you do try to line your forge interior with the shelves I'd love to hear how it works, but I'd suggest you make a kind of ceramic fiber blanket "gasket" to allow differential movement of the shelf at any ends that rest against other hard substances (other shelves, forge frame...)

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Latticino,

Just came in...

"Greville,

 These shelves would not be considered high alumina in many refractory applications but for potters' use, the alumina content is high enough to ensure good, repeated performance at cone 10.

 High alumina is a relative term used to distinguish them from shelves that are lower in alumina and higher in cordierite. The higher alumina content (from the mullite) allows them to be fired to cone 10 with very little tendency to slump.

 Jon Walls

Euclid's Elements

The Pottery Supply House

1-800-465-8544 ext.223

www.euclids.com

www.psh.ca"

 

In in other words this is what we sell in Brazil, called Alumina Tile !

 

I in turn asked if he had any "alumina tile" that has a melt point, if you will, of 3000 degrees F !

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3 hours ago, Irondragon Forge & Clay said:

If I recall cone 10 in the kiln is 2381 degrees.

In a fast firing, yes. For medium or slow, slightly lower.

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4 hours ago, Scrambler82 said:

I in turn asked if he had any "alumina tile" that has a melt point, if you will, of 3000 degrees F !

Latest response !

"No, I'm afraid we don't know of anyone producing it in this area.   - Jon/PSH"

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