You do not need rigidizer, the ceramic wool hardens by itself?

[Toasty]

I have researched this topic (use of rigidizer to suppress ceramic particles ejecting from the  forge),  here, and elsewhere, but the  no need of rigidizer is new to me.

I purchased a new forge (devil-forge), and was concerned about the coating they provided for the forge, it appears to be a clay colored refactory coating.

 

Contacted the manufacturer re: rigidizer not included.  They said, the refractory coating they provided is adequate - you do not need rigidizer to prevent 

dissipation of ceramic wool particles, it will 'fuse by itself' when the forge is heated.

(their actual statement is: 'ceramic wool hardens itself when it is heated for the first time, so we don't think there is a necessity of spraying any additional substance before applying our rigidizer'.) They refer to their refractory coating as both refractory and a rigidizer.

 

 

This was a surprise for me - I have not read about the self-sealing ceramic wool, all I have read indicates a requirement to seal the ceramic wool by means of a

rigidizer (such as sodium silicate, or fumed silica), never by itself.

 

Can ceramic wool harden by itself without rigidizer?

I really do not want to get silicosis.

 

Thanks in advance.

[Buzzkill]

If the ceramic fiber blanket is completely coated with anything that can withstand the heat of a forge to the point where no flames are in contact with the blanket and there are no gaps where the particles can escape then it should be fine.   If you are applying the material yourself you will still want to wet the blanket surface before applying the refractory material.  If you want extra peace of mind then go ahead and spray rigidizer on it first.  All we are trying to accomplish is preventing tiny particles from becoming airborne, whether that be with rigidizer or other means.

[Toasty]

Thank you buzzkill,

I understand that the refractory coating will suppress ejection of fibers, provide that I am perfect, and do not puncture the coating.

 

I know that the very first chunk of steel I place in the forge, will miss, puncture the refractory, and send a cloud of fibers out of the forge (but that's me).

Conversely, the ceramic wool has 'solidified', as stated by devil-forge.

 

Have installed all items in accordance with manufacturers instructions.

 

Am contemplating - removing it all,

install new ceramic wool, rigidizer, kastolite30 (or equivalent).

 

Best Regards, 

 

[Frosty]

I'm now beginning to distrust Devil forge's word on anything. If your ceramic blanket refractory hardens without rigidizer or similar treatment it means it's ready to be replaced. 

Fumed silica is a much better rigidizer than sodium silicate. Sodium silicate has a lower melting temp, much lower than the operating temp of a propane forge with a layer of hard refractory between it and the flame.

Unless you misunderstood what the rep at Devil Forge told you, an easy thing to do when you're not sure what you know or don't know. If you haven't misunderstood I highly recommend you not take their word where matters of safety are concerned.

Rigidize the blanket then cover it with a hard water setting refractory.

Recently I've been talking to a member who was sold refractory CEMENT as a flame face liner by the manufacturer of a propane forge. The member asked me what HE'D done wrong because the "refractory" started flaking off the first time he lit it.

I'm beginning to doubt modern forge makers, especially the low dollar ones.

Frosty The Lucky.

[pnut]

8 hours ago, Frosty said:

I'm beginning to doubt modern forge makers, especially the low dollar ones.

It's pretty much the wild west out there when it comes to forge manufacturers. My advice to anyone is to do lots of research, understand what compromises you're willing to make, and don't rush in to a purchase because "It's what I can afford." I'm so glad I built a jabod first. It let me get started while I tried to accumulate enough knowledge to make an informed purchase. 

Pnut

[bubba682]

When i built my forge Toasty i did alot of research and everything said to coat the fibre blanket i over did mine lol,then i put the refractory cement on then i baked it so far 3yrs now and no major problems.I will say i ve had some chiping problems on the outside edges and its nice to see the blue rigidizer is there doing its job of containing the wool fibres.As for a quick fix i put  cheap 3000 deg chininy cement on the chips. When i redue the forge i'll fix that problem if your able you might want to replace that liner .

[Steven Lloyd]

This brings to mind two possible issues, the effectiveness of the coating and the identity of the fiber. Hardening does not provide safety. The rigidizer should glue the fibers together near the surface but not the inner material to retain insulating abiility. From the application and curing process, their rigidizer is closer related to Rutland 610 than a rigidizer. From what you posted, Devil Forge has acknowledged that it is not a rigidizer as non is needed. On searching thier site and the web, I have yet to find anything resembling an SDS which I understand is a requirement for international shipping. If the coating is only Rutland 610 then its service temp is limited to 2000F. Itself has silica fibers and emits toxic fumes. If the supplied wool is not just kaowool then it too may have other health concerns. I would recommend requesting SDS safety data sheet on both before using them. Note that any serious issues would have to be processed through Lithuanian law.

[JHCC]

Welcome to the forum, Steven! Feel free to write a post in the "Introduce Yourself" section, and make sure to READ THIS FIRST.

[Mikey98118]

On 7/9/2021 at 2:33 PM, Toasty said:

Can ceramic wool harden by itself without rigidizer?

That's a good question. Ron Reil used to explain it with the assertion that "it takes a set" in response to readers who worried that screwing it in position to the forge shell would not work out, becuase it's so fluffy.

Ceramic wool starts out by being very springy, but Ron was right; it definitely takes a set, becoming much firmer after a few heats. However, fumed silica rigidizer one-ups this advantage, and costs very little money to do so.

[Demne]

Hi Toasty, 

I'm new here and would really like to hear your experience with this.  I have encountered the exact same thing at the moment.  I bought a Devil-Forge DFPROFK2 recently and applied the coating it came with.  I was concerned that maybe I hadn't installed it correctly, because when I mixed it according to the directions, it still seemed really thin and watery, not really a paste but more like melted icecream. 

On 7/9/2021 at 7:58 PM, Frosty said:

I'm now beginning to distrust Devil forge's word on anything. If your ceramic blanket refractory hardens without rigidizer or similar treatment it means it's ready to be replaced. 

Fumed silica is a much better rigidizer than sodium silicate. Sodium silicate has a lower melting temp, much lower than the operating temp of a propane forge with a layer of hard refractory between it and the flame.

I called them up and asked if I should have used rigidizer, and was told the same ... it was all I needed, and I also mentioned that I would put a coat of ITC 100HT on top of that and he said it was fine.  

Fast forward to now, I finally got it all sorted and over the last couple of days I have been running the forge in small intervals.  The coating is REALLY thin, but it is pretty complete as far as I can tell.  I put on the ITC 100HT with no issues, waited for a few days and have now started using it.  For the first 5 minutes or so, the forge runs amazing but then starts to emit an absolutely awful smell.  Is that the ceramic wool burning?  Does it have a distinctive smell?

I have COPD and my 10 year old son has asthma, and I'm genuinely concerned that I have done something incorrect here and am going to make our health problems worse.  If everything is fine, it would be nice to have some reassurance that maybe that smell with burn off or go away, and then it will be safe/fine to work with.  If not, do I need to now take all of that apart and start over?

[Frosty]

Welcome aboard Demne, glad to have you. I've never heard of a forge liner emitting a strong smell. I can smell The Kastolite 3-0 I line mine with when I fire it the first time but it smells like concrete setting and goes away shortly. The orange flame from the calcites oxidizing never seems to go away completely but I don't k now anybody in our club who's had ill-effects from using it. 

I'm sensitive to bad air myself, I react to low levels of carbon monoxide and nitrous oxide is like breathing fire. Other people will be giving me funny looks as I leave the room but I notice bad air like most folk notice cigar smoke. I'm an ex long time heavy smoker and am coping with COPD. 

I haven't used ITC-100 in probably 30 years and I understand it's much improved since. I've been in the same shop when a Mr. Volcano was running several times and didn't notice more than the general smell of a propane forge burning. I can feel the nitrous oxides and CO buzzing my gums. 

I wish I had a more useful answer for you but I'm afraid I don't. Maybe someone here will know there's quite a spread of skills and professions represented here.

Frosty The Lucky.

 

[Demne]

On 7/10/2023 at 7:39 PM, Frosty said:

I'm sensitive to bad air myself, I react to low levels of carbon monoxide and nitrous oxide is like breathing fire. Other people will be giving me funny looks as I leave the room but I notice bad air like most folk notice cigar smoke. I'm an ex long time heavy smoker and am coping with COPD. 

 

Thanks Frosty, this is me as well ... probably body's defense mechanism since our lungs are already compromised.  The smell is still there, even after running the forge a few times ... I cant really run it for more than about 10-15 minutes before the fumes are really overwhelming, I can smell it through the respirator, and I can smell it afterward presumably either on my clothes or my beard or both, though it doesnt seem constant ... I just get a whiff of it here and there. 

Just in general, as maybe you might know, if the forge liner was actually burning somewhere, does that emit a strong smell?  The layer of refractory/rigidizer does not seem really substantial, maybe 1 mm thick at best and the insulation is soft behind it.   I think if I had this to do over again, I would have done it differently despite what the manufacturer suggests (they say just use the rigidizer/refractory powder it comes with and that's it, as mentioned in this original post).  There was no kind of spray on rigidizer, so I would have started with that and I might have used a thicker refractory that at least feels a bit more substantial before applying the ITC 100 HT.

This was the response I got from Devil-Forge when I mailed: 

 

Hello XXXX,

 

It is hard to tell where the smell is coming from. If the wool is sealed under two layers of rigidizer, the smell should not be coming out of it. Our ceramic blanket can withstand a temperature of about 1450 C (2640 F), so I don't think it is burning under the rigidizer. There might be a smell coming out of the paint of the furnace - they can only withstand 650 C (1200 F) (they are the highest temperature-ranked paint we could find), so they might be fuming a little. Whatever it is, I believe it will stop fuming eventually, but we still recommend you to work with a face mask even if you have the insulation perfectly sealed with a rigidizer.

 

Regards,

Sales manager Ben

 

On Mon, Jul 10, 2023 at 8:12 PM xxxx wrote:

Hi there, 

 

I have my forge set up and running now for the last couple of days.  I had called a while back regarding the refractory coating (I was concerned that maybe it was too thin when I mixed it) and was happy that you were able to talk to me about it and assured it was fine.  I bought some ITC 100HT as well and applied that over that layer as well.  The issue I am running into now is that after the forge has been on for a bit (maybe 5-10 minutes maximum), and gets to a high temperature, there is a really noxious smell. I've checked the coating coverage, and the coverage is complete (there is no kaowool exposed that I can see anywhere).   Is that normal and does it go away?  My concern is that maybe the kaowool isnt sealed and is burning under the coating. 

 

Thank you! 

[LeeJustice]

Where or what is the forge resting upon?  When I was first running my Mr. Volcano and running it hot, I thought that I smelled paint burning.  But the Mr. Volcano forge is mad of stainless, and so it is not painted.  However, it was resting atop my table saw, the extension part was painted.  It was, in fact, burning that paint.  I put vermiculite boards atop the table saw, then hard firebrick.  No more burning paint from then on.

[Demne]

On 7/13/2023 at 11:33 AM, LeeJustice said:

Where or what is the forge resting upon?  When I was first running my Mr. Volcano and running it hot, I thought that I smelled paint burning.  But the Mr. Volcano forge is mad of stainless, and so it is not painted.  However, it was resting atop my table saw, the extension part was painted

Thanks for the question Lee.  It's sitting on a stainless steel workbench, definitely not paint or so there that could produce the smell, but that was definitely a good thing to check. 

[Jimw3326]

You mentioned a respirator and a beard. Unless your respirator is of a PAPR style I doubt it is doing much good and the fumes will be filtered through your beard, path of least resistance.

[Demne]

11 hours ago, Jimw3326 said:

You mentioned a respirator and a beard. Unless your respirator is of a PAPR style I doubt it is doing much good and the fumes will be filtered through your beard, path of least resistance.

Yeah, I have been finding this is the case.  I literally (as in yesterday) ordered a positive pressure one after reading on the forums here a bit about respirators that work with beards.  Tbh, I knew the seal wasn't perfect (I served in the military, so I know the importance of being clean shaven for a seal) but figured it was still decent enough for dust, just not for fumes.  Biting the bullet on it now because I know I wont shave my beard and there are more fumes than I anticipated with these processes. 

[Candidquality]

On 7/13/2023 at 10:08 AM, Demne said:

There might be a smell coming out of the paint of the furnace - they can only withstand 650 C (1200 F) (they are the highest temperature-ranked paint we could find),

Just an fyi for anyone actually interested, you can buy a ceramic paint good to 2000f..cost about $10 online and $15 in the big box store sold by Rust-oleum.  Just used some on my muffler rebuild for my lawn tractor.  Just needs a few heat cycles to process properly, which would add cost.  I cycle mine in a convection oven I keep outside 30 min at 200, 30 min rest. 400, 600.  Then a cycling process in installed heat, but for a forge body, I would just let it run normally to finalize the cure. 

[Frosty]

A couple thoughts for you. I'm not familiar with Satanite so I don't know how it smells in use. 

The smell of burning calcite binders in hit temp refractories is reminiscent of the smell of Portland cement concrete wet and later curing. Not the same but similar. I use a different type of ceramic refractory blanket and flame face refractories. The dragon's breath is an orange especially when the liner is fresh and it dims down in a while though doesn't go away. The orange is the calcite binders in the refractory oxidizing. (technically burning but don't let that bit confuse you) Eventually the liner will degrade and require replacement, it's just a fact of life nothing a person did wrong. Unless it burns out quickly, say as fast as a plaster of paris and vermiculite or sand liner does. That IS maker error!

Here's my thought. What did you use that SS cart for before? Is it brand new and so burning off mill lubricants and finishes? If it's been around a while, how well did you clean it before putting a propane furnace on it? What's on the underside of the top? Burning labels can be nasty and the adhesives don't necessarily go away quickly. I've tried burning labels off rather than scrape and clean with solvent back in the day.

What do you have between the cart top and the forge? I use a piece of concrete backer board, the stuff used to make sure tiles STAY where it's put especially if it's being exposed to high temps say behind a wood stove or a kitchen range top. I cut some small pieces to keep the piece of backer board off the steel topped cart, the small pieces provide an air space and my cart top hasn't warped from the heat.

We have a number of guys in the club using Mr. Volcano forges and they work very well though some of us have considerations other than effective heat generation to contend with. 

What works best for me it to take a walk outside regularly and especially if I start getting the "feelings" I'm getting gassed. People who have been exposed to much CO become sensitized to it and are effected more than, Oh say . . . non-smokers, even being an ex-smoker for almost 2 decades hasn't brought me back to my old resistance levels.

Frosty The Lucky.