Kastolyte Thermal Cycling Issue?

[kraythe]

Greetings,

I am planning up a new forge since my old firebrick pile is being dissolved by borax. I had considered making the interior 7" high by 9" wide by 10" deep. The first inch on the hot face would be poured Kastolyte 30 with stainless steel reinforcing needles as 5% by volume. The remaining insulation would be 2300 degree superwool. This will all be powered by a 3x5 ribbon burner.

Since the roof would be flat, I am a tad concerned with thermal cycling cracking the roof and caving it into the forge.

So here are the questions I put to you.
1) Am I just fine with the flat roof being cast in one piece with the sides?
a) If not should I use an arched roof?
2) Do you think I need to put some ceramic fiber as an islator between the cast walls and roof to allow isolated expansion; such as between a poured patio and a house?

All opinions are welcome.

[WayneCoeArtistBlacksmith]

I suggest that you build your forge from a 20# propane bottle or a freon bottle (they are both readily available for free.
Use 1" of Inswool then cast over it about 1/2 inch with the Kast-0-Lite then paint with an Infrared product.
Go to my profile and send me an e-mail and I will send you an attachment showing how I suggest that you build a forge.

I too am in the process of building a ribbon burner and expect to have my new forge finished soon.

[Rich Hale]

If you are new to this and have not used a gasser much or any. I suggest you use one of the availeable how to build a forge instructions and follow the plans exactly. You we able to work with a proven design from the minute it is done. And as you use it you can see what works for you and think aboiut changes you may like. If you are used to a gasser and this is not your first rodeo then nevermind,,lol

[kraythe]

If you are new to this and have not used a gasser much or any. I suggest you use one of the availeable how to build a forge instructions and follow the plans exactly. You we able to work with a proven design from the minute it is done. And as you use it you can see what works for you and think aboiut changes you may like. If you are used to a gasser and this is not your first rodeo then nevermind,,lol

I am not new to this. I am looking for more expert information on the strength of castables. If I wanted to build another forge, I would. The question of the original post revolved around thermal cycling of Kastolyte, not alternative forging plans. I don't mean to be short but it's a pet peeve of mine when people post without answering the question in the original post. If you don't have that expertise then please refrain.

I suggest that you build your forge from a 20# propane bottle or a freon bottle (they are both readily available for free.
Use 1" of Inswool then cast over it about 1/2 inch with the Kast-0-Lite then paint with an Infrared product.
Go to my profile and send me an e-mail and I will send you an attachment showing how I suggest that you build a forge.

Cutting a propane bottle with a torch, plasma or even a saw is a short path to whatever deity you believe in. There is no way to make such a bottle safe after it has been filled and especially if it is old. Furthermore 1" of castable and 1" of wool will cost you a ton of cash in the long run. Not to mention the fact that the castable will press down the wool with weight and reduce the insulation power of the wool itself. Why would I go to the trouble of building a ribbon burner and shove it in a substandard forge?

I too am in the process of building a ribbon burner and expect to have my new forge finished soon.

Hmm ... if you are still at the stage of doing can forges, I would wonder about a ribbon burner. If you don't have those welds gas tight and a good seal with the Kastolyte, you will be in deep trouble. Also did you consider the volume of the area in a propane tank, the enclosed back and the dragons breath? Ribbon burners put out a crapload of BTUs on blowers and I'd hate to see you get cooked by the dragon's breath.

[MattBower]

Great caution is definitely appropriate when cutting propane bottles, but this exaggerates the danger. I don't know where you get the idea that it is *impossible* to make them safe to cut.

Expansion joints in your forge are probably a good idea, but I have not built one as you describe.

[prburner]

I would not recommend a flat roof. Go with an arched roof. If it is supported on the edges, even if it cracks it won't fall in. I would also go thicker than 1". 1 1/2" minimum

There are photos of how I build forms for Kastolite 30 roofs on Facebook. http://www.facebook....77315?sk=photos Look at photos of "small forge 1"

Tom

[WayneCoeArtistBlacksmith]

"I don't mean to be short but it's a pet peeve of mine when people post without answering the question in the original post. If you don't have that expertise then please refrain."


WayneCoe, on 07 December 2011 - 08:15 PM, said:
I suggest that you build your forge from a 20# propane bottle or a freon bottle (they are both readily available for free.
Use 1" of Inswool then cast over it about 1/2 inch with the Kast-0-Lite then paint with an Infrared product.
Go to my profile and send me an e-mail and I will send you an attachment showing how I suggest that you build a forge.

Cutting a propane bottle with a torch, plasma or even a saw is a short path to whatever deity you believe in. There is no way to make such a bottle safe after it has been filled and especially if it is old. Furthermore 1" of castable and 1" of wool will cost you a ton of cash in the long run. Not to mention the fact that the castable will press down the wool with weight and reduce the insulation power of the wool itself. Why would I go to the trouble of building a ribbon burner and shove it in a substandard forge?


WayneCoe, on 07 December 2011 - 08:15 PM, said:
I too am in the process of building a ribbon burner and expect to have my new forge finished soon.

Hmm ... if you are still at the stage of doing can forges, I would wonder about a ribbon burner. If you don't have those welds gas tight and a good seal with the Kastolyte, you will be in deep trouble. Also did you consider the volume of the area in a propane tank, the enclosed back and the dragons breath? Ribbon burners put out a crapload of BTUs on blowers and I'd hate to see you get cooked by the dragon's breath.

Well, I will try to address each of your concerns as relates to my response to your request.

1. From reading your post I thought that you said, “I am planning up a new forge…”
   

I interpreted that as you were planning to build a new forge, therefore I thought that my response was approprate.

1. I have built many forges; all except the first one have been made from either propane bottles or Freon bottles with never a problem. Therefore, I feel that I do have the expertise. Since this is not a private message I felt that the information might be useful to others as well as you.
2. Anytime when opening a closed container, whether originally filled with flammable or non-flammable contents open all valves and empty any remaining contents. Some valves will not vent by just opening the valve so then drill a hole in the container. When I do this with a bottle I do it in the end. This serves two purposes. 1. It will allow any contents to be vented or poured out and 2. It gives a place to insert the saber saw blade for cutting out the doors. I certainly would not suggest cutting into a closed container with a torch. Straight cuts can be made with a reciprocal saw or a cut-off wheel on an angle grinder. I cut the doors in each end then cut the container in two lengthwise to aid in casting and add household hinges to hold the two parts together after casting. By building this “clam shell” design you can also take out one of the hinge pins and prop open that side of the forge allowing you to heat forgings that will not fit through the doors. I would not use a torch because you need straight, even, uniform cuts so that when the parts are put back together they fit well. When you first drill into a propane bottle you will probably smell what you may think is propane. It is probably the oil which is put in the bottle to give the gas the odor as a safety feature. After you have cut into the bottle you may want to wipe as much of the oil out as possible.
3. I suggested 1” of Inswool (or other ceramic blanket) and ½” of Kast-0-Lite (not 1”). Ceramic blanket’s insolating properties are not the same as fiberglass insulation used in your home. Ceramic blanket actually insolates better when it is compressed. When installing it the blanket should be spritzed with water and pressed into position, then the Kast-0-Lite cast over it. The Kast-0-Lite is a light weight, insolating castable that is resistant to flux. For the blanket, castable and Plistix for a 20# propane bottle forge expect to spend $61.00 plus shipping. That is for 2 feet of 1” X 24” blanket, 3 6# bags of Kast-0-Lite and one pint of Plistix for a total weight of about 20# plus the weight of the shell, burner and whatever leg system used. This is anything but a “substandard forge”.
4. As to your comments about the ribbon burner, it goes without saying that the burner, or any burner, should be well built. There should be space between the ribbon burner and the forge casting to allow for expansion/contraction (see http://www.pineridgeburner.com/ ) Your forge should have both a front and back door. This allows longer forgings to be put in the forge and to allow for needed back pressure(see http://ronreil.abana.org/).
5. Now to go back to your original question, as I understand it. I feel that you would be better off to cast a dome or arch to have a monolithic pour and to hold everything in place. I would not use the stainless steel pins because they would be causing a thermal break in your casting, even if they do not go all the way through the casting. As I said earlier, Kast-0-Lite is a light weight, insolating castable. This means that it will moderate the thermal swings by keeping the heat inside the forge, then with the Plistix it will be even better. My present forge is made of a 30# propane bottle with 2 1” T-Rex Burners and after the forge has been running all day I can reach out and touch the outside. Now that does not mean that I hug it or grab hold of it but I can touch it and not leave my finger prints behind.
   

I had not intended to write a complete tutorial but hope that this answers your questions and helps others.If not I apologize.If anyone has questions or would like to discuss this further please do not hesitate to call me, e-mail me, pm me or post on this thread and I will try to help however I can.After all, isn’t that what we are all about as blacksmiths and bladesmiths?

[kraythe]

Great caution is definitely appropriate when cutting propane bottles, but this exaggerates the danger. I don't know where you get the idea that it is *impossible* to make them safe to cut.

Expansion joints in your forge are probably a good idea, but I have not built one as you describe.

ASME welding standards. Its not impossible of course but not recommended. And why take the risk if there is no need.

I would not recommend a flat roof. Go with an arched roof. If it is supported on the edges, even if it cracks it won't fall in. I would also go thicker than 1". 1 1/2" minimum

There are photos of how I build forms for Kastolite 30 roofs on Facebook. http://www.facebook....77315?sk=photos Look at photos of "small forge 1"

Tom

Thanks man. Very helpful.