Castable Sleeves for Gas Forge Openings?

[Steamboat]

I have just finished casting a couple of sleeves (liners? collars?) to protect the front opening and the rear pass-through port of a gas forge that I’m building. I opted to use Kast-O-Lite 30 LI, which should provide durability and some insulating value. This is the first time I’ve used this product (and the first time I’ve built a gas forge), so this is basically just part of an experiment, and NOT a recommendation for anyone else, although I hope it is of some interest to the community. I'm open to suggestions, since none of these ideas are "cast in concrete," so to speak.

I realize that there are easier and faster ways to protect the forge openings, but I’m not in a hurry, and I enjoy the design, fabrication, and experimentation aspects of my various projects. As long as I’m having fun and learning something, I don’t mind extra work. I'm building this forge as an "experimentation platform" to try out different insulating materials, burners, and other features, so I'm building it so that the front and back (the modified end-bells of an old tank) are both easily removeable. More about the forge itself later in another post. For now, this is just about the abovementioned sleeves.

For the rear pass-through port sleeve mold, I cobbled together some scrap wood, coated the inside with several coats of carnauba wax mold release (buffed a bit after each application), and for a sacrificial core I shaped a piece of XPS (extruded polystyrene) insulation, which I coated with silicone rubber. I didn’t want any taper in the passage through the sleeve, and the XPS was easily dug out after the refractory had set.

For the other mold, I used the front of the forge (the front end-bell of the old tank) for part of the mold, supplemented by three pieces of silicone-coated XPS and a doubled cardboard tube (Quik-Tube) temporarily adhered to the inside of the end-bell.

I allowed for a little expansion room between the castings and the steel openings of the forge. I also put a radius on all inside corners of the castings to help reduce stress risers. After the castings were removed from the molds, I radiused the edges that would be directly exposed to hot exhaust gases and high radiated heat (I might increase the radius on some of those edges later on). All other sharp edges were eased a bit. A diamond file worked very nicely for the "fine-tuning" work.

I’ve seen various types of “stainless-steel fibers” for castable reinforcement, such as needles, melt-extract fibers, hooked-end fibers, wavy fibers, etc., with needles being the type I’ve seen mentioned most often. However, instead of buying ready-made stainless fibers, I experimented with some DIY stainless fibers...about 2% in the mix. I don’t know if that’s an appropriate percentage for the fibers that I made, and don’t ask what the fibers look like...just yet, anyway. After I’ve used the forge for a while I’ll report on the success or failure of the castings and fess up about the DIY fibers I used. For now, suffice it to say that I used somewhat different fiber shapes for each of the castings. Frankly, in retrospect, I probably would have just purchased some off-the-shelf stainless fibers.

I tried to come close to the manufacturer’s recommendations for mix-to-water proportions, and I tapped and vibrated the molds to the extent that I thought was appropriate, based only on intuition. If I had more experience with this castable product, I might have more specific recommendations.

By the way, in anticipation of some questions, I’ve come up with a few workable approaches for supporting the sleeves in the end bells on all three axes while maintaining good insulation values and allowing for expansion/contraction, but I haven’t settled on one yet. I’ll post pictures when I do. It will probably involve the use of some ceramic insulating board, but that's about all I can say right now.

Next, I’m going to try to match the recommended dry-out schedule for the castings as closely as I can. I've also thought about applying a coating of ITC-100 to the castings after they are fully cured and have been through a few firings of the forge, but I want to research that possibility before applying the coating. Has anyone here used ITC-100 or equivalent directly on a castable refractory, and what are your thoughts?

 

Mold for the rear pass-through port sleeve:

 

Pass-through port mold after screeding (I didn't trowel the surface):

 

Mold for the front entry sleeve:

 

Mold for the front entry sleeve after screeding:

 

The castings:

 

Inside view of the front end-bell (made by welding a perimeter flange and a flat front plate on the end-bell of an old tank...and wearing out a few sanding discs). The openings in both end-bells are actually centered; the camera angle just makes them look offset.

 

Inside of rear end-bell (made by welding a perimeter flange and a square tube on the other end-bell of the tank):

 

Front entry sleeve as it will appear in the end-bell:

 

Inside view of front entry sleeve:

 

Rear pass-through sleeve as it will appear in the end-bell (I may shorten the sleeve about 3/4 inch):

 

Inside view of rear pass-through port sleeve:

Comments, questions, and suggestions are welcome!

 

[TFT]

Wow that looks great but i dont have any real input in the materials

[ThomasPowers]

Very impressive work. I'd probably sluiced the metal with a bit of kiln wash and then a layer of inconel foil; but quick and dirty is pretty much my secret middle name.

[Steamboat]

Thanks, TFT and Thomas.

If you'll pardon the analogy, I'm the sort of bloke who avoids the freeway and takes the scenic routes and back-country roads, even though it takes a lot longer to get from point A to point B, and that aspect of my personality probably crosses over into my approach to my projects. I don't get things done very quickly (ask my wife), but I try to have some fun and learn (sometimes by mistakes) along the way. I'll try to ignore the gnawing urge to extend the analogy any further.

I always seem to have a long list of ongoing parallel projects. Fortunately, I occasionally finish one now and then, so there's at least some closure once in a while. I've noticed a tendency for the completed projects to be the ones that were assigned a high "spousal priority" level...lol...but I must say that my better half is surprisingly tolerant of my little idiosyncrasies, and as I mentioned in another post, is actually becoming quite interested in blacksmithing and will probably join the forum at some point.

Steamboat

 

[ThomasPowers]

I really am VERY IMPRESSED;  your work and methodology is awesome.  It's not for me; but I can appreciate it!  Just wanting to keep reminding people that there are more than one way to skin a cat:  or as Kipling put it:

"There are nine and sixty ways of constructing tribal lays,
"And every single one of them is right!"

[timgunn1962]

I'm also very impressed indeed.

I've not tried ITC100 myself as it's very hard to find over here and the price in the UK is way over the US price.

If you do try it, could you be persuaded to tune and run the forge without it first, then apply it and try to get some quantitative data relating to any improvement?

Could you also let us know the dimensions and what burners you are intending to try?

 

[Steamboat]

Thomas, I really appreciate your remarks. And as to foil, I've had a few items heat treated that were wrapped/crimped in stainless foil for the process, but I hadn't yet given any thought to the possibility of using any of the various high-temperature alloy foils in this environment. I'll have to look at some of the specs.

Steamboat

[Steamboat]

2 hours ago, timgunn1962 said:

I'm also very impressed indeed.

I've not tried ITC100 myself as it's very hard to find over here and the price in the UK is way over the US price.

If you do try it, could you be persuaded to tune and run the forge without it first, then apply it and try to get some quantitative data relating to any improvement?

Could you also let us know the dimensions and what burners you are intending to try?

Thanks Tim! By the way, I read your post about the Amal injectors...very interesting and informative. 

I'd eventually like to try several different burners on this forge over time, and I'd be happy to post any results (no specific list of burners yet...that will depend on budget and available time). I'll probably experiment later on by building a couple of burners myself. I'd like to learn as much as possible about gas forges. Of course, the forge isn't just for experimenting with burners and insulation, etc., since I plan to put it to use for some practical reasons, such as making reproduction hardware for our Federal Period house that we're gradually restoring.

As to the ITC-100, I plan to fire the forge a few times to season it and fully cure any substrate materials before applying the ITC-100, so I should be able to get at least some rudimentary before-and-after data, although I can't guarantee how 'scientific' the testing will be. 

I think I might have a type K thermocouple probe for my Fluke IR thermometer, and if not, I should be able to get one. It will probably be a couple of weeks before the first firing, but I plan to post more information about the forge on IFI pretty soon.

Steamboat

[Mikey98118]

Steamboat,

Nice work! Also, I'd like to give you special thanks, as I was beginning to fear that I was the only compulsive personality on the Gas Burners forum

I never mixed stainless needles into refractory, because I stumbled unto Kast-O-Lite 30 LI (previously called Kast-O-Lite 3000) right off the bat; it is such a tough refractory that I've never seen a single crack in anything built from it.  Combining the two products should see your sleeves through anything.

 
 

[Steamboat]

10 hours ago, Mikey98118 said:

Nice work! Also, I'd like to give you special thanks, as I was beginning to fear that I was the only compulsive personality on the Gas Burners forum

I never mixed stainless needles into refractory, because I stumbled unto Kast-O-Lite 30 LI (previously called Kast-O-Lite 3000) right off the bat; it is such a tough refractory that I've never seen a single crack in anything built from it.  Combining the two products should see your sleeves through anything.

Thanks, Mikey! And yes, my wife says that I do tend to be a bit, uh, "detail oriented," shall we say?   And I'm gratified to hear your positive opinion about the Kast-O-Lite 30 LI.

On the subject of things like sleeves and liners: Regarding the lining of the forge itself, I mentioned that I designed the forge for quick access to the liner from both ends for easy replacement or maintenance. This is part of my plan to experiment over time with several different approaches to insulating liners, some of which are considered "recommended" and others that might fall into the "questionable" category, since the latter should provide a good opportunity for learning more specifically about what makes them fail or perform poorly, and perhaps with luck, to devise some modification/improvement for better results. So, if you see me employ some odd combination of insulating materials in the forge, just remember that I'm merely experimenting, and not ignoring what I consider to be very sound advice from experienced and knowledgeable people like yourself and others. And I do plan to share information about failures or poor results...not just the good results.

I plan to post more pictures of the forge project soon in the Gas Forges section. It will probably be after I return from a little vacation that we're planning for next week.

Steamboat

[Mikey98118]

Sounds great; we all love photos, and we all love experimenters. We only get crabby when we see guys run off in all directions sans any planning at all. My personal favorite thing is to hear a report on something, either new or old, that is full of his personal views on what he experienced, good or bad; I think that a thoughtful even handed report does more to encourage beginners than anything else they can read about.

[Steamboat]

2 hours ago, Mikey98118 said:

Sounds great; we all love photos, and we all love experimenters. We only get crabby when we see guys run off in all directions sans any planning at all. My personal favorite thing is to hear a report on something, either new or old, that is full of his personal views on what he experienced, good or bad; I think that a thoughtful even handed report does more to encourage beginners than anything else they can read about.

That's good to hear! You've seen a bit of a preview, and the main "feature" should be "coming soon to a forum near you." I hope it gets reasonably good reviews, but at least it should be a learning experience for me, and maybe for others.

Steamboat

[Steamboat]

I've given some additional thought to how I might support the sleeves in the end-bells. As far as the X- and Y-axis support goes, it will probably be from a combination of the end-bells themselves and a circular slab of one-inch Insboard HD fitted into each end-bell, with cutouts for the sleeves. I'd probably pack the area behind the Insboard with ceramic blanket. I'm not sure yet as to the coatings I might apply to the Insboard (colloidal alumina? Satanite? ITC-100?). I want to make sure that they would all be compatible with the Insboard and with each other, and also applied in the correct manner and sequence. Any opinions or recommendations? 

As to the Z-axis support, that should take care of itself, since the sleeves should be secured between the end-bells and the insulation system inside the main forge body. At least that's how it appears to my little gray cell (cells on a good day) at the moment. This is all tentative. I guess we'll see how it actually transpires.

Steamboat

[RandyScott]

6 hours ago, Steamboat said:

... a circular slab of one-inch Insboard HD fitted into each end-bell, with cutouts for the sleeves. I'd probably pack the area behind the Insboard with ceramic blanket. I'm not sure yet as to the coatings I might apply to the Insboard (colloidal alumina? Satanite? ITC-100?). I want to make sure that they would all be compatible with the Insboard and with each other, and also applied in the correct manner and sequence. Any opinions or recommendations? 

I have used 1" Insboard for the end enclosures on my freon tank forge. I painted the entire surface with Rigidizer, cured same with my Mikey burner, then several thin wash coats of Satanite (with extra coatings around the openings for protection from tong/work piece abrasion) also heat cured between coats and the hot face coat of ITC-100. Pretty near bullet proof.

[Steamboat]

1 hour ago, RandyScott said:

I have used 1" Insboard for the end enclosures on my freon tank forge. I painted the entire surface with Rigidizer, cured same with my Mikey burner, then several thin wash coats of Satanite (with extra coatings around the openings for protection from tong/work piece abrasion) also heat cured between coats and the hot face coat of ITC-100. Pretty near bullet proof.

Thanks, Randy. That is more or less what I was considering for the surface treatment of the Insboard HD. It sounds like your coatings are holding up well.

I happen to have some colloidal alumina rigidizer (rather than colloidal silica rigidizer), and I'm wondering how well it will bond, not just to the Insboard, but also to subsequent coatings of either Satanite or ITC-100. I'd rather not have to buy more rigidizer if I don't need to, and I like the high temperature rating of the colloidal alumina. So far, I haven't found much in the way of user reports on how well it would work for what I have in mind.

Steamboat

[Mikey98118]

It should bond just fine to the board, if you first coat it with silica rigidizer. If you have trouble bonding to the other, mix it together with just a little of the colloidal silica, as silica is the most common form of binder for ceramic formulas.

[Steamboat]

13 hours ago, Mikey98118 said:

It should bond just fine to the board, if you first coat it with silica rigidizer. If you have trouble bonding to the other, mix it together with just a little of the colloidal silica, as silica is the most common form of binder for ceramic formulas.

Sounds like a very good suggestion Mike, although when I installed the sleeve castings in the end-bells several days ago, I didn't have any colloidal silica rigidizer on hand, but I did have a bottle of colloidal alumina rigidizer, so I forged ahead and applied that to some insulating board. I figured it might at least add another item to my overall experiment. So far, it looks encouraging, but time will tell as the forge moves in fits and starts toward operational status.

I'll add more details and photos soon.

Steamboat

 

[Frosty]

Have a brand name for the colloidal alumina rigidizer? It will go with products like ITC-100 like hotcakes and syrup. ITC is zirconium of various screen sizes a Kaolin clay matrix. Kaolin is a high alumina ceramic Heck, I'd be tempted to try adding a little of the rigidizer to ITC or see if it will mix with Zircopax as a kiln wash.

Frosty The Lucky.

[Steamboat]

6 minutes ago, Frosty said:

Have a brand name for the colloidal alumina rigidizer? It will go with products like ITC-100 like hotcakes and syrup. ITC is zirconium of various screen sizes a Kaolin clay matrix. Kaolin is a high alumina ceramic Heck, I'd be tempted to try adding a little of the rigidizer to ITC or see if it will mix with Zircopax as a kiln wash.

Frosty The Lucky.

Frosty, here are a couple of different brands you could look into:

Wesol D30. Links: http://www.wesbond.com/      http://www.wesbond.com/wesol_d30.htm

Zircar Alumina Coat. I think you can get this product in a one-quart size. Links: http://www.zrci.com/    http://www.zrci.com/zrci500.pdf

Both websites have links to MSDS sheets for the products.

I suggest contacting both of these companies to see if they have more complete or updated information available.

Steamboat

[Frosty]

Excellent, I'll check them out and see what's to see. Thank you.

Frosty The Lucky.

[Mikey98118]

Steamboat,

You might want to look up Ron Riel's burner pages, and review his comments on how ceramic fibers "take a set" in his mini-forge section; it should give you some interesting ideas about using stainless screws to securely mount ceramic board to other things

[Frosty]

I tend to have to run SS screws into the kaowool from the shell side to keep it from sagging or falling out but I tend to put large area flat roofs in mine.

Frosty The Lucky.

[Steamboat]

15 hours ago, Mikey98118 said:

You might want to look up Ron Riel's burner pages, and review his comments on how ceramic fibers "take a set" in his mini-forge section; it should give you some interesting ideas about using stainless screws to securely mount ceramic board to other things

Thanks for the reference. I read about his use of stainless screws to connect a piece of Kaowool board to a horsehoe, and I've noticed how ceramic blanket material can be formed into shapes to some degree.

14 hours ago, Frosty said:

I tend to have to run SS screws into the kaowool from the shell side to keep it from sagging or falling out but I tend to put large area flat roofs in mine.

Frosty The Lucky.

I was initially thinking that I might secure the insulating board in the end-bells with some kind of stainless fastener, but it wasn't necessary in this case because of the design of the forge. When the forge is assembled, the board should be held securely between the curved end-bell and the insulation material in the forge body itself, so it shouldn't be able to move in any direction. At least that's my theory.

Here's a photo of one of the end-bells (the one with the vent/pass-through port). The end-bell is entirely filled with insulating material, with no open areas. I used a bit of Inswool Moldable caulk around the edges of the rigidized board as part of my experiment, and I'm also experimenting with a thin coating of refractory mortar on the board. I think it was Derby 3000 Hi Temperature Mortar that I used on this end-bell, but I'll have to check my notes. Before installing the board in the end-bell and coating it with mortar, it was heated to drive off any binders and also to set the rigidizer. All exposed insulating surfaces will be coated with ITC-100. As usual, I followed the manufacturers' instructions and safety guidelines when using these materials, including the use of personal protective gear, and I'll add my 'experiment' disclaimer below.

Disclaimer: The methods and designs presented here are intended only as an experiment and not as a recommendation for their use. I do not warrant the safety, efficiency, applicability, or any other characteristic of these methods or designs, and their use is entirely at your own risk.

Steamboat

[Frosty]

I love watching a "mechanic" experimenting. Sure it's a complex design but everything has a well thought out reason and the execution is outstanding. I can't wait to see how this baby performs!

The term I used above, "mechanic" is something an old long passed friend used all the time to mean someone who can and does figure out how to do things whatever they may be. Turned out it's been around a lot longer than what we might think of as Mechanical machinery. Anyway, I re-read the post and realized it might confuse folk who didn't know Bill Trent so "I esplain." If I'm quoting people why not throw in Ricky Ricardo?

Frosty The Lucky.

[Mikey98118]

Zirconium oxide is the "active ingredient" in ITC 100. When used strait out of the jar, this product isn't all that effective, and certainly not worth its price. But, you can take a small amount of it, and separate its colloidal content by placing it in a clear container, and then add water until the cruder particles drop to the container floor, leaving the colloidal content still in-solution. Coat a small area of the forge with the untreated product, and see how bright that area gets. Then, coat another area of the forge with the treated product and compare the orange color in the first patch with the yellow incandescence in the second patch. Yes, you lose a minor amount of the formula this way, but what you are actually losing isn't anything you wanted in your forge. Anyway, that's how the experiment worked out for me sixteen years ago. Someone else sells the product now, but I doubt they have improved it.

One; rigidize. Two; finish coat. Thee; separate and coat with ITC 100; it's as simple as...well, you get the idea.