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Double kaowool and refractory in a furnace?


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Hey, gang. First time poster. I bought a propane forge. It just had kaowool in it, and it got real crappy after about 10 burns. I did some research, ripped it out, and installed new 1” kaowool. I rigidized it. I applied refractory cement. Now it won’t melt my copper windings (tried for 2.5 hours @ 28psi the other day). Would like to know if I can install another layer of kaowool OVER TOP of my existing refractory, and then add another layer of refractory, and finally IR reflective ceramic coating. I’d hate to waste the original refractory coating I have in there already. 

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I'm sure some of the more knowledgeable IFI members will be along shortly but a few things that pop into my head to check:

1. Did any of this re-lining process allow crud to get into the mix tube or even into the jet orifice?

2. Does everything you installed make a layer that is the same thickness, or thicker, or thinner than the original and:

                a)have you adjusted where the mix tube/nozzle sits accordingly in the new lining?

                b)does this significantly change the volume you are trying to heat up?

3.  How thick is the refractory cement layer you've installed? This will take more to heat up than just kaowool alone.

All of this long with: what was the original forge? what volume? What burner size and type? We need info to help you figure this out!

Cheers,

Jono. 

Also, the obligatory:

Welcome to IForgeIron! We won't remember where you're from after one post so be sure to add your location to your account profile so it shows up under your name when you post.

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Welcome aboard WallC, glad to have you. Jono pretty well covered things including adding your general location to the header.

Some pictures of your forge, a good exterior shot showing the burners and their alignment in the forge. Another in the opening so we can get an idea of how she looks and another couple of the interior, one right after you light it and one when she's as hot as she gets. 

If we can read your burner flame we can match it to how you lined it and help evaluate things.

When you say refractory "CEMENT" I get the hebe Jebes! until I remind myself everybody seems to be marketing refractories as cement instead of refractory. There is a REAL difference in the two. Cements and mortars are intended to cement things together and not to survive in direct flame contact in a furnace. Refractories on the other hand are.

What brand refractory did you get?

Frosty The Lucky.

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20 hours ago, Hefty said:

 

1. Did any of this re-lining process allow crud to get into the mix tube or even into the jet orifice?

2. Does everything you installed make a layer that is the same thickness, or thicker, or thinner than the original and:

                a)have you adjusted where the mix tube/nozzle sits accordingly in the new lining?

                b)does this significantly change the volume you are trying to heat up?

3.  How thick is the refractory cement layer you've installed? This will take more to heat up than just kaowool alone.

Ok, so no crud in the burner tube or burner nozzle, although it appears that the upper portion of my burner hole may be slightly covered by refractory, hence my flame sputtering recently.  I believe my 1” kaowool is thinner than the original kaowool that came with the furnace (hard to say as I threw it away, and this product has a very limited description on Amazon). I installed about 1/8-1/4” refractory over the new 1” kaowool; it’s slightly uneven in some parts. I did notice I don’t have a tight seal at the top anymore either, so I’m sure I’m losing heat around the lid. The original forge was…12.8kgs?  Here’s a link to Amazon where I bought it: 0-28lbs/12.8KGS Gas/Propane  Metal... Commercial link removed per TOS....interested parties can look it up.

Peninsula
Item Dimensions LxWxH 8.3 x 8.3 x 12.2 inches
Material Stainless Steel, Metal
Size 12kgs
Model Name MTG2

Also here are some pics of my red headed step child of a furnace…

Question still remains: can I put more kaowool over my refractory covered kaowool, and the put refractory over that?

CD2B133E-D00C-4DE0-89F4-190780563DFE.jpeg

C0086CCB-5FE3-471C-8E9E-7090394883A4.jpeg

DC10BA6C-2509-4472-A36E-CD8B02562843.jpeg

79F34DDB-504E-4230-9856-7ABF9C016B13.jpeg

3680F451-A1BB-44DD-82A8-FF5711978213.jpeg

72DF60AF-52FD-4503-B155-82474E865D65.jpeg

2D5B6D5D-4857-4CBC-B437-6A340F155689.jpeg

16 hours ago, Frosty said:

When you say refractory "CEMENT" I get the hebe Jebes! until I remind myself everybody seems to be marketing refractories as cement instead of refractory. There is a REAL difference in the two. Cements and mortars are intended to cement things together and not to survive in direct flame contact in a furnace. Refractories on the other hand are.

What brand refractory did you get?

Frosty The Lucky.

Hellcote 3000 refractory cement: Hellcote 3000 Refractory Cement for Ceramic Fiber Blankets to be Used on Any Brand Including All Hell's Forge Brand Propane Forge Units - 5 lbs

Edited by Mod30
Excessive quoting commercial link
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Uh . . . That's a Melter, NOT a forge. While similar they are two very different machines. See WallC? A picture is worth a thousand words.

I couldn't find anything useful about Hellcote refractory cement, only marketing hype. That the text is written in a foreign country and I couldn't find a MSDS for the product the stuff is made who knows where  and I don't know how far to believe anything they say. 

The related ads in the menu seem to be adhesives too. the links below are all for proven poor furnace refractory products. 

Angle the burner so the flame isn't grazing the bit of refractory sticking out in it's path. That might help. I'm not a caster but I know the flame dynamics in a melter is a lot different than a forge. The flame enters at an angle between the plinth and crucible and swirls around then up in the space between crucible and melter wall. The less space the better so long as there is space for the flame to move without interfering with burner performance. 

I can't tell anything about your melter. How much space does your crucible take up in the melter? How tall and wide is the plinth?

I need to let a caster handle this, I'm listing things I don't know enough about to evaluate let alone give a competent opinion.

Frosty The Lucky.

 

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I try but I'm out of my depth here. However, remember what I said we need to know about the crucible IN the melter? Hmmmm? If you put it in the melter and take a pic straight down we can SEE the space. Lay a tape measure across the center above and we can measure everything that matters. 

Frosty The Lucky.

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Isn't this considered a foundry? 

I'm no expert but I have a homemade one where I cast aluminum and brass. I think your walls are much too thin. You may want to chalk it up as a learning experience and re-lign it as well as the lid.  I don't know if placing another layer over what you've done would work or not. 

The burner tip shouldn't go past your lining either, just pointed in one direction to create that swirl effect.  Aluminum melts at 1221F, Brass at 1710F and Copper at 1984F.

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Good stuff!  Thank you. I have more 1” kaowool coming. I am going to try and layer it over the existing kaowool/refractory, then rigidize it, and apply more refractory with an IR liner. If it doesn’t work, I guess I’ll just rip it all out and start from scratch. 

Edited by Mod30
Excessive quoting
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Check first, measure how much space there is between crucible and the current wall. If there's less than 1" putting more in is a no go! Just put your crucible on the plinth and measure the gap. Take a pic while you're at it, eh?

Frosty The Lucky.

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Success with more kaowool and rigidizer. You guys were very knowledgeable. Thank you for all your input and suggestions!

7C0CFAF1-7681-4A5B-BFB0-CF0F2B6EF0E4.jpeg

FYI, gap between crucible and kaowool is now 7/8” at the top rim. Flame sputter has stopped as well after I removed the refractory (~1/8”) from burner path and installed new kaowool. 

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