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My Propane Tank Forge Questions


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So I have read through more threads than I can remember here. I emptied and prepped a propane tank yesterday to use for a forge. I removed the regulator, have it all cleaned out, and am ordering insulation parts.

 

Here are my questions I am sure has been answered before. I have a 1" thick Ceramic Blanket rated to 2600F sitting in my shopping cart, plan on doing two layers, but dont want to buy more than I need for other supplies. I plan on casting over the ceramic blanket. I know rigidizer is recommended for the blanket, but should I rigidize the blanket before putting Kast-O-Lite over it? Does it matter? I have never rigidized ceramic blanket before, so I was not sure if it will make the blanket harder before I cast over it and make it last longer, or if it doesnt matter. Also, how much Kast-O-Lite and other materials should I buy for a 20lb Propane Tank Forge? If I need rigidizer (I think I do) is the stuff they sell in quarts on Amazon good enough quality? I know a lot of people here mention the same brand names for certain products. I am trying to figure out how important it is on certain things. For the castable I know it makes a huge difference, but the rigidizer you guys mention most (KAOWOOL) is $100 per gallon. Im not sure how much I need and dont want to buy that much.

 

I am always buying more than I need. I would rather not waste $100-$300 before Christmas on more rigidizer, more castable, and more IR coating then I need. I always seem to have way too much left over when I build stuff, which is usually ok, but all these extras are slowly building up on my property, and all I see when I look at some materials is money sitting on my shelves for things no one will ever buy from me. LOL

 

Thanks for any advice you can offer on buying. I know I am not the only one with unique project supplies I may not use for years accumulating.

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Yeah, I read that. According to him it takes 15lbs, IF you split it in two, which I do not plan on doing. I would assume that requires more casting to make the seam, and less ceramic insulation. He uses KastOLite, but does not mention rigidizer, or a lack of it. He does finish it with IR coating. Some quantities are mentioned in his write up, some are not.

 

So has anyone who put one of these together remember all of their quantities?

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If you were going to merely seal coat the insulation, rigidizing would be recommended to physically support the rather thin and fragile coat, as well as to help protect the insulation from damage through heat shrinkage.

But sense you plan to use a castable refractory for your hot-face layer, rigidizing the insulation is recommended  to transform the insulation into a working outer mold into which to cast the hard refractory, as well as to help protect the insulation from damage through heat shrinkage. and to physically support and cushion the hard refractory layer.

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Awesome. Thats is what I needed to know. I dont want to worry about fibers getting into the air, but also felt like I may be wasting money if I rigidized then cast over it. So I will do both.

 

Do you think 10lbs of KastoLite will be enough? Also, if I take my T-Burner and switch it to a NARB in 3-6 months, when I change the hole and cut back the cast mix and ceramic blanket, is that going to be a nightmare? Am I going to regret big time not going with the NARB from the start, or will enlarging the hole and cutting the shape for NARB not make a huge health hazard style mess? I have a plasma cutter and torches if it makes a difference, but my concern is what will happen when I cut through rigidized ceramic blanket and a couple inches of casting thats been heated and cooled repeatedly.

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FWIW, I'm building my first propane forge right now, and I'm going straight to NARB. It seems to me that the advantages are significant, and modifying the forge is probably a lot more hassle than it's worth. 

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Colloidal; silica rigidizer is merely fumed silica in water, with a little food coloring (which burns out during firing). A lifetime supply of fumed silica can be purchased through eBay for about twenty bucks (the shipping is free). The primary reason for rigidizing ceramic fiber insulation is to greatly increase its working life against damage from heat shrinkage, so exactly what "expense" are you referring to?

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2 minutes ago, Mikey98118 said:

Colloidal; silica rigidizer is merely fumed silica in water, with a little food coloring (which burns out during firing). A lifetime supply of fumed silica can be purchased through eBay for about twenty bucks (the shipping is free). The primary reason for rigidizing ceramic fiber insulation is to greatly increase its working life against damage from heat shrinkage, so exactly what "expense" are you referring to?

Expense is 2 things. One, I asked if it was recommended when casting since that should essentially encapsulate. Two, I dont want to buy a gallon of a product if I need a Quart, just to leave 3 quarts on my shelf. Going on bundles I see being sold of rigidizer and blankets together, I am guesstimating I will need about 2 quarts. If that could be confirmed that would be great.

 

I appreciate you including the active ingredient in rigidizer. I see a lot of brands, and was not sure if there was something about certain brands thats better than others.

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These options are what raised these questions BTW. I was buying things. Looking for the brands I see repeatedly mentioned pulled up a lot of comparable items. Some included with the blankets, some not. Not really the best descriptions when it comes to the details required to make a proper comparison. I take the ratings with a grain of salt. In my experience the manufacturers make sure they get good ratings, some times on sub par products I realized had BS ratings only after I use them.

 

This is the point where my $50-$100 plan is morphing into a $200-$300 plan. No biggie, I just dont want to spend $300, then realize I used the wrong brand trying to save a few bucks and it falls apart after a year.

 

I will buy the products recommended from Wayne Coe's site. I would rather my money go to a smaller business then the empire the screenshot came from. I am just someone who does a lot of research, and doing that on this subject only raised more questions I realized I needed clarification on before spending more money.

Edit: Copyrighted catalog list and images removed.

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There are two permanent threads (Burners 101, and Forges 101); if you peruse them, stopping to pay attention when something of especial interest come up, they will answer all your questions. Otherwise you could wonder in the wilderness of advertisements for years and come out as confused as when you entered. Even if you buy a commercial forge, you will need much of the same knowledge as to build one. Sorry, but there is no practical way around this.

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I read both, and many other threads from this site and others. I even copy and pasted pertinent info into a word doc to reference.

 

This is a case of, LESS IS MORE. Too much info. Its like if my son asked me what a largemouth VS smallmouth bass look like, so I make him read a book on all species of freshwater fish. There are many solid points made about burners and forges in there when it comes to info people are looking for. The problem is referencing it, indexing it, finding it again. Its like you can go through and read the evolution's of the burners and forge conversations, and why people arrived at the conclusions they did. I have not found a reference for all of the conclusions reached though. Where are all the things people agree on apart from the conversations that got them there? A bullet-point doc or PDF would be nice of probably 50-100 common things people ask across the borard. I see these same questions repeatedly with the same answers "have you read this thread, that thread". Thats why I started copying things into a doc myself. Even then, there is still too much. I cannot imagine trying to navigate all this info if I didnt weld, do masonry, understand thermodynamics, etc. It would be pretty discouraging. Especially on top of all the other things people are trying to figure out.

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5 hours ago, SharpPotato said:

A bullet-point doc or PDF would be nice of probably 50-100 common things people ask across the board. 

I attempted this but you are talking about many hours of work, my "summarized" version of the two threads was a 150 page word document and that wasn't even 60% of the information. There really are very few simple explanations that answer question about building forges, or forge burners.

If you need specific information from the site try a Google search starting with "iforgeiron" then the info you need, it often will take you to the specific pages with in the threads of this expansive forum that have the info you need.

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5 hours ago, SharpPotato said:

I started copying things into a doc myself. Even then, there is still too much. I cannot imagine trying to navigate all this info. It would be pretty discouraging. Especially on top of all the other things people are trying to figure out.

A bullet-point doc or PDF would be nice of probably 50-100 common things people ask across the board. 

 

2 hours ago, VainEnd84 said:

I attempted this but you are talking about many hours of work, my "summarized" version of the two threads was a 150 page word document and that wasn't even 60% of the information. There really are very few simple explanations that answer question about building forges, or forge burners.

Some topics on IForgeIron can have lengthy discussions and a very large amount of material recorded. Anytime a topic is researched you distill the information down so you can understand it.  If you would like to submit these condensed versions, I would be interested in putting them on the site as reference material for others to read. And not for just the propane tank forge questions, but for most any popular subject on the site.

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I’m a noob, trying to get the lay of the land and build a workable propane tank forge without killing myself in the short or long term. Still doing my research and I really appreciate this discussion!  I can absolutely understand the idea and eventual value of processing an entire convo thread, but it would be nice to have some of he very basics collated into a one stop shopping doc. 

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Just throw in with the rigidizer discussion, since I've just been recently making sure stuff I ordered should work:

Be careful when ordering fumed silica, as many sellers on ebay don't specify the exact product name which can clue you into whether it's hydrophilic or hydrophobic.  Of the more commonly available varieties Aerosil 200 is a hydrophilic fumed silica.  In fact, if there's a letter before the number for Aerosil products (ex: Aerosil R 200) then it is one of their hydrophobic varieties (like what gets used for floatants for fly fishing).  Didn't dig far enough to see if Cab-O-Sil had any such conventions. 

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20 hours ago, Glenn said:

If you would like to submit these condensed versions, I would be interested in putting them on the site as reference material for others to read

If I can get the file off of my old PC I will send it to you, but that a big IF.

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I will create a build if no one beats me to it once I finish. I have found a few different ones, but when I read things like, 'drill a hole in the propane tank to drain it, then you can light the hole if you want and flames will come out', I start to question if other things are the best way to go more than I should. I know that's pretty safe BTW, and from a guy who knows a lot more on this subject than I do, but if you drill a tiny hole like 1/8" it WILL explode like a bomb if you light it. 1/2" hole will just give you a poof. But the best way is to just unscrew the regulator.

Ive been planning on setting up a hot work area in my shop for over a year to expand my railing work and stop relying on torches. Now that its time for me to start spending all the money, I am having a really hard time finding all the info I have read in the past. So I google to find it, then I find these threads I have read through that are like books. I knew I was going to hear, read this and that if I created this, but I dont know how many more hours I can devote to finding these needles in haystacks if I want this running before 2019.

Anyway, I have two Frosty T Burners built and working. I'm going to go with a ribbon burner, but am curious as to how that will affect the forge if I want to make it smaller a lot of the time to conserve fuel. I may go with a blower on the burner, but I am having a hard time finding actual numbers comparing efficiency and figuring out if they are worth it. Again, I have read many threads, but I would be so happy if I found something like this with a burner comparison.

 

Burner Type:

BTUs:

Fuel consumption per hr @ _____ PSI

Different sizes for same burners

etc_____

etc____

I know its a pain to figure out this info, and a lot of it may not be written anywhere, but when I know I am going to use this thing many many hours every week and burn lots of propane, its going to affect my overhead. Thats why I am playing flamethrower into a pile of bricks in my shop and watching how big of a fuel difference were talking about on these. Just trying to figure out whats what exactly. A lot of what I read is guestimation, which I am perfectly comfortable with if I am the one making that guestimation. I am wondering if I should do two small ribbon burners, maybe two NARB burners with a partition to save fuel when I dont have to run pieces all the way through.

 

I know a lot of guys on this site do the same type of stuff already, Im just trying to get there. The build will take no time compared to the research and screwing around Ive already done.

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Do not buy commercial rigidizer. Sodium silicate works and is sold in a gallon for 30 bucks by rutlands. Instead of itc 100 make the mix i posted about which is high zirconia kiln wash kaolin and zircon flour. I just coated my forge today and its fantastic. Tip for rigidizer is to put it into a spray bottle and add food coloring. That way it tells ya where ya sprayed.

 

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On 11/20/2018 at 8:32 PM, NateHMirage said:

Do not buy commercial rigidizer. Sodium silicate works and is sold in a gallon for 30 bucks by rutlands.

Sodium silicate is a completely different thing than colloidal/fumed silica.  While it does rigidize the fibers, it does so through  curing (like a glue, just requires CO2)... and at high temperatures can break down or act as a flux (eating away at your fibers).  Fumed silica rigidizes the fibers by vitrifying the microscopic silica and causing it to bind the fibers together (like brazing). That's why the recommended procedure is to apply rigidizer and fire each layer as they're applied.

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I once attempted to write down only what knowledge was needed for beginners to make a first class gas forge; the result was a 216 page book that put my own family to sleep. This result wasn't discouraging, as I was interested in helping college art students to create one of the tools needed to translate their degrees into a living. How-to books are about helping the determined to get an important goal accomplished; not competing with Gone With The Wind; unfortunately they may end up being just as long. Trying to summarize that knowledge ends up in a pamphlet; these are fine as helpful hints for tradesmen who have a strong background in related fields, and a trap for everyone else.

There are safe shortcuts to acceptable results; they all depend on believing the experts, and following their directions EXACTLY. As one of them, I have noted the tendency of the same independent minded people who want to do things their way, to be impatient about the learning curve doing that requires.

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On 11/21/2018 at 1:34 PM, HojPoj said:

Sodium silicate is a completely different thing than colloidal/fumed silica.  While it does rigidize the fibers, it does so through  curing (like a glue, just requires CO2)... and at high temperatures can break down or act as a flux (eating away at your fibers).  Fumed silica rigidizes the fibers by vitrifying the microscopic silica and causing it to bind the fibers together (like brazing). That's why the recommended procedure is to apply rigidizer and fire each layer as they're applied.

What is the likelihood it eats at your fibers? I just applied it

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Not a chance, I never allow MY fibers to go unescorted in public! :o

Melted sodium silicate won't dissolve ceramic blanket, that isn't an issue though it's not as effective a rigidizer as fumed silica. 

Both substances leave a layer of silica, one more akin to glass but both the same element which glues the intersections together. Without being able to slide past each other a fiber blanket becomes stiffer, more rigid. According to the numbers set sodium silicate has a lower melting temperature than "pure" silica as in fumed silica. 

Sodium silicate sets up hard with exposure to the CO2 in air as said already where fumed silica needs a little heat. I don't think it needs red heat but red won't hurt a thing. It just needs heat to set up, don't get hung up trying to figure out what the exact or best, or . . .whatever time/temp is. Eyeball estimation is fine.

Frosty The Lucky.

 

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I think the most important difference between colloidal silica and and sodium silicate is that the silicate tends to be thick and glue like, while colloidal silica  will run along the ceramic fibers of the insulation, doing a cleaner and much easier job. There are other differences too, but I think this is the practical one.

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