Jump to content
I Forge Iron

Question about lining.

Recommended Posts

So i need to build a proper gas forge. As anyone who has seen my other inquiry knows. I am about to get my lining and have a couple questions.

First i was  looking for the Kaowool and what i can find is Max-wool. There data says it is basically the same. Has anyone had experience with this stuff?

Second, they offer 2 different styles. one is 6 PCF and the other 8 PCF,  (PCF- pounds per cubic foot) both are rated the same.  Which is better and why would i pay for the heavier one when the lighter does the same job? Basically other than weight what is the difference? 

I am not a rich man and i am about to shell out $100 bucks for a roll and just want to make sure i dont just throw away money. 

Link to comment
Share on other sites

Billy: If you spend some time reading in the gas forge section here, Forges 101 is the most current but there is good info elsewhere that isn't really well covered in F 101.

If you want to know one product's properties vs. another that's on you brother, look up the MSDS and the company's  product info pages. It sometimes takes time and a few tries to get through the marketing department on the manufacturer's sites but the general info is there. Another place to look is on pottery kiln building info sites and or HVAC, glass manufacturer sites, etc. 

The industries that use this stuff rarely use it the way we do so their data is little help. However they're always back channeling looking for better, cheaper, longer lived, safer, etc. etc. That's where you have to look to answer a lot of your questions. I've read your other posts, you're looking for the best which just doesn't really exist in any objective way.

Frosty The Lucky.

Link to comment
Share on other sites

Maxwool is a Nutec trademark. Kaowool is a Morgan Thermal Ceramics trademark. Otherwise, you'd really struggle to find a difference between them. The Maxwool will be fine.

Going by the Kaowool TDS, the 8 PCF is a better insulator than the 6 PCF. It certainly seems stronger/stiffer in use. For us, it is definitely worth the extra money. I've not seen a full Nutec TDS, but I'd expect the Maxwool to be the same

There are 2 useful grades of Maxwool: HPS (2300 degF) and HTZ (2600 degF). The HTZ incorporates some Zirconia to achieve the higher temperature rating. If you are buying a roll and have any plans for welding in the forseeable future, the HTZ in 8 PCF is the stuff to go for. 1" thickness is probably the most useful.

If you are only ever going to be shooting for forging temperatures, the HPS will be fine.

It's worth noting that the rating temperature is usually based on permanent shrinkage, rather than a melting point or other catastrophic failure temperature, so the 2300 degree-rated blanked will not suddenly become a dribbly mess at 2301 degF. It will still work pretty well in a welding forge, even a hot one. 

I picked up a roll of the 1", 8 PCF, Nutec HTZ for cheap a few years ago and made several forges with it. None of them was perfect, but the HTZ was certainly not to blame for any of the shortcomings. I've been looking for more since my supplier closed down. 

As an aside, (Materials) Safety Data Sheets are not often particularly helpful when comparing products. They are usually written, by people who specialize in writing them, to provide only the legally-required safety information without giving away anything that might be commercially sensitive or useful to a competitor. Often they are all the information you have.

When dealing with refractories, even the Technical Data Sheets are limited. They will not normally tell you how prone to cracking on fast heat cycling a particular IFB or castable is for example. For that sort of information there is no substitute for real-world experience. 

If you can get hold of one of the real technical project guys/gals at a major refractory supplier and pick their brains, you can learn a lot very quickly. They get involved in the big-ticket industrial projects and tend to be well protected from penny-ante timewasters who only want one roll of blanket every few years (i.e. me and, probably, you), so getting to speak with them is seldom easy.

Otherwise you are stuck with either picking up whatever collective knowledge has been acquired on sites like this one, or doing the donkey work yourself.



Link to comment
Share on other sites

First thanks for the replies and my apologies. I forgot to hit that notify button at the bottom, so it took me some time to get back. Sundays are kind of busy for me. I am pretty active with my church so my time is taken. Sometimes i get an hour or 2 before Mass but thats about it. 

So onwards, 

Wayne, i shall look you up. 

Iron dragon, yup, looks like the way to go. 

Frosty, I did try and look up the MSDS and what i found was like i said almost identical. My real question was about the weight issue which i didnot find much in the threads. So i asked. 

Mikey, k28 brick. If i cant afford or get what i want i will keep that in mind. 

Tim, thanks. Very informative.

Thomas, i have not been to a SOFA thing. their last one i could have eve possibly been able to attend was Jan. 3rd. Which right after the holidays was blown out. Their next one is the 14th, i am going to try but that night will be up to the old lady. 27th is looking good though. I am also trying to make the time to make one of their blacksmithing 101 classes. Finances are preventing that however. 

Thanks again for all the help guys. 

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Create New...