# Cleaning a catalytic combustor



## Highbeam (Mar 7, 2017)

So as mentioned above my 2 year old steel cat stopped working earlier this year. I tried to tell myself that the white smoke was just steam but 14%MC wood and the dripping tar on my chimney cap told me otherwise. So did the constant smoke, reduced burn times, stalling cat, and low output. My cat was not doing its job and the BK design depends on a functioning cat to create low emissions, long burns, adequate draft, and heat output. The cat is the heart of this stove. The wood makes smoke, the cat eats the smoke to heat your home.

This is my second cat. The first one was the OEM ceramic and died in a less dramatic way after almost three years, replaced under warranty by BK with no hassle. That cat was just starting to let blue smoke by so the ceramic lasted longer in the same stove before failing. I burn 8-9 months of the year. Well over 5000 hours per year in my climate which is wet, dark, drizzly, cloudy, and muddy for most of the months. This amount of use will rack up the hours on a cat and cat life is rated by the manufacturers in hours. So if you are comparing, be sure to realize that my year is probably double your year based on hours.

So with this dead steelcat I first cleaned it in place per the manual and found that even with clear cells it was dead. Second step, really a last ditch effort, I decided to remove the cat and try the vinegar bath to clean, dissolve, melt off any junk that had deposited onto the cat cells and covered up the catalyst. The theory is that the precious metals that create the catalytic reaction with smoke are still there but are just being blocked by the hard remnants of previously burned smoke. You can't blow these deposits off. They are hard, thin, and preventing the cat from working. The deposits can be dissolved by acid and vinegar is acetic acid. Several different stove makers, catalyst makers, catalyst resellers, and even BK at one time have described the exact process of the acid bath. Each of the sources describes the same method so I felt like there was an agreed upon process and that's what I did exactly.

What follows are the photos of the acid bath process. I spent about 20$ on materials and about 4 hours of precious time. It was fun and I can probably do it faster next time. A new cat can be delivered to your home for 186$ in two days so if you value your time highly then you might be wise to just swap a new one in instead of the acid bath. I hate wasting stuff and want to revive the dead cat if possible and also as a learning experience for me and you folks. One gallon of distilled vinegar (used almost all of it) and 4 gallons of distilled water.

So I pulled the cat out with my fingers. Easy. The cat gasket is not reusable and fell out onto the firebox floor. I found a really wide 12" diameter, stainless steel, 5 quart pan in the kitchen with 3" tall sides to do the work. Make sure it fits. Once the cat is out of the stove you are kinda dead in the water. Make sure you have 36" of new cat gasket. That gasket is like 2$ per foot plus shipping. Note that I have a weird steel curtain behind my cat, supposedly this curtain is not present in all stoves. Looks to be just a baffle to prevent exhaust from shooting straight into the flue.

I fashioned a little handle out of some 14 gauge coated wire. You will use these handles a lot. I also installed a wire around the cat to keep it off of the bottom of the pot which will allow a flow of acid through the catalyst. If it just sits on the bottom then less acid will be able to flow through and remove deposits.

Getting long. To be continued.


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## Highbeam (Mar 7, 2017)

The last two photos in this post are the revacuumed "cleaned" cat front and back. Notice the rear has fuzzy white stuff. Weird.

So here is my work station. First thing to do is get a fire going in the non-cat NC30. The NC30 was laughing about the vinegar to clean cat, it must be a girl situation. Ha! Note that from a distance the cat looks totally invisible, a really odd effect.

I didn't know how much headspace to leave in the pan but I was ready to top off the pan after the cat was dropped in. The instructions specified dropping the cat into the hot vinegar and so I didn't drop it in until the vinegar was boiling. Then I had to top it up. I kept the pan full for maximum coverage and simmering so you can see bubbling.


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## Highbeam (Mar 7, 2017)

Here she is boiling in the acid. Yes it stinks, yes you will lose a lot to evaporation, and yes there is a brownish mud that is coloring the acid. Something is being removed from the cat. The stainless steel pan did not discolor or become damaged. The wife will never know.

Lots of dunking during all stages. You want maximum exposure of the cells to the liquid. If you are dealing with ceramic, no banging. Just lift it up and down every couple of minutes.


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## Highbeam (Mar 7, 2017)

Dump the vinegar and then soap and water wash the pan. Dry with a paper towel, no smell remains, pan looks new. Distilled water bath twice. At this point there was snow on the ground and I needed to get the stove running. I don't know if there is any reason to dry a steel cat but I dried the cat on the NC30 for over an hour. Note how the cat cells dry out and lighten. Also notice that the white fuzz on the back dissolved! Pretty clean looking now. It was very apparent that water had soaked into the coating of the cat and that you should dry your cat whether it is ceramic or steel.


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## Highbeam (Mar 7, 2017)

At this point I gasket the cat. I used webby3650's method of overlapping the gasket and then cutting for a perfect butt joint. No overlap, the cat is a tight fit. The tape keeps the gasket from sliding off as you work it into the tight hole. Just work it into the hole slowly, a little on each side. It squeaks but you don't want to dislodge the gasket. I did cut off the tape from in front of the cat after installation but the rear tape just burns off. The 36" of cat gasket leaves you with the pictured remainder so don't cut it any closer when ordering gasket.

A tasty beverage to consume while the new fire starts.

So It's working great. The decline in cat performance was gradual and then near the end was rapid, a snowball effect. The wife asked, "has it ever worked this well?" There is no smoke at all after the initial warm up. It's only been three days but I removed the flame shield and find that the whole cat is staying grey now and not that brown color, also no deposits are accumulating on the cat face as they were before.

The drawback is that my window is now dirtier and less flames since I am able to run the stat much lower while the flue temps are up above condensing and stove output is higher. It seems I have been wasting a lot of unburned fuel just trying to stay warm.

Did I do okay? You'll notice that the durafoil cat block has buckled a little bit and come apart near the bottom. It is pushed in towards the cat chamber by under 1/8" and not welded there. No big deal in my opinion. It's not loose.


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## Highbeam (Sep 11, 2017)

Thank you mods for creating a new thread with this info. For an update, the cat did great for the remainder of last season which was 3-4 months of burning. I will be using it this season until it dies again which might be a few months or might be two more years. Folks that have done the vinegar bath with other brands have noticed that the time between the first vinegar bath and the second failure is much shorter than the time from new cat to first failure. In other words, I'm not getting another 12000 hours! At the first sign of a failing cat I will be ordering a new ceramic cat. They just aren't that expensive and the fresh catalyst will reward me with like-new performance.


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## begreen (Sep 11, 2017)

I figured that if it took me 10 minutes to find it buried deep in the bowels of the BK2016 thread that a newcomer would have no chance. It's good info and can now be more easily discoverable with a searchable title.


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## jetsam (Sep 11, 2017)

Those threads are big.  This was a good bit. (Yay for pictures!)

Highbeam, your process was vastly less rednecky than mine.   Gas burners, proper pans...  walls....

Can we have a new thread for The Dreaded Swoosh Sticker Wars too?


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## ohiojoe13 (Sep 12, 2017)

When you did the acid bath was it straight vinegar?


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## Highbeam (Sep 12, 2017)

ohiojoe13 said:


> When you did the acid bath was it straight vinegar?



Yes, but to be fair "straight" vinegar is already very diluted with water. There is a vinegar factory in my town and the straighter stuff is very dangerous. I used straight distilled white vinegar from the home depot for the acid boil.


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## WoodyIsGoody (Sep 12, 2017)

I would like to see instructions for achieving the same thing using muriatic acid. That's what I use in my hot tub to maintain optimum pH so I always have it around (and I imagine it is has less impurities than vinegar). Of course proper acid handling procedures need to be followed (which is why manufacturers probably recommend vinegar). Also, some "Muriatic Acid" is not pure but formulated for specific tasks. I always buy the pure stuff (diluted to 31.45%). I imagine a further dilution would be recommended.


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## redktmrider (Sep 12, 2017)

I would cation against using Muratic acid to clean a cat.
Vinegar is diluted acetic acid, which is organic in composition and not a very strong acid. Muratic acid is diluted hydrochloric acid, a very strong acid which is likely to attack the metal plating on the cat. I worked in a metals laboratory for a number of years and Hydrochloric acid was one the acids we used to dissolve metal into water solutions.


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## Highbeam (Sep 12, 2017)

WoodyIsGoody said:


> I would like to see instructions for achieving the same thing using muriatic acid. That's what I use in my hot tub to maintain optimum pH so I always have it around (and I imagine it is has less impurities than vinegar). Of course proper acid handling procedures need to be followed (which is why manufacturers probably recommend vinegar). Also, some "Muriatic Acid" is not pure but formulated for specific tasks. I always buy the pure stuff (diluted to 31.45%). I imagine a further dilution would be recommended.



I'm also a hot tub operator, was a pool operator in a commercial setting in my teen years, and I found that I never needed to add acid to lower pH unless I screwed up and added too much pH increaser. To this day I only keep sodium carbonate (pH increaser, soda ash) around for hot tub maintenance.


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## WoodyIsGoody (Sep 12, 2017)

redktmrider said:


> I would cation against using Muratic acid to clean a cat.
> Vinegar is diluted acetic acid, which is organic in composition and not a very strong acid. Muratic acid is diluted hydrochloric acid, a very strong acid which is likely to attack the metal plating on the cat. I worked in a metals laboratory for a number of years and Hydrochloric acid was one the acids we used to dissolve metal into water solutions.



What I know about acids is the metal can't tell if it's "organic in composition" or not. With acid it's all about time, temperature and dilution. I can make that muriatic acid weaker than white wine vinegar more quickly than you can say "I'm not so sure about that".


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## WoodyIsGoody (Sep 12, 2017)

Highbeam said:


> I'm also a hot tub operator, was a pool operator in a commercial setting in my teen years, and I found that I never needed to add acid to lower pH unless I screwed up and added too much pH increaser. To this day I only keep sodium carbonate (pH increaser, soda ash) around for hot tub maintenance.



I maintained swimming pools for a homeowners association with over 5000 residents while I was in college. I learned the method from an expert pool guy although I didn't fully understand the chemistry until years later. 

I'm fortunate to have almost ideal water for a hot tub/swimming pool right out of the tap. It has a very nice calcium hardness balance, no chlorine and is sourced from melting glaciers. This means much of it fell as snow over 10,000 years ago. I change it once every 12-18 months. Everyone who uses it comments on how nice it is on their skin and how it doesn't smell like typical "spa water". One of the secrets (besides the wonderful fill water) is borates (20 Mule Team Borax), about 1/2 box to a fresh fill. Then I need to add around 8 oz. of muriatic acid to make the pH ideal. The pH hardly fluctuates at all after that although I might add about 1 oz. of muriatic acid every 4-6 weeks if the aeration jets have been used a lot (I'm not gonna go into the chemistry involved).

I NEVER add "pH increaser" (which is soda ash) because it really depends upon the composition of your fill water. All water is not the same, obviously. The periodic addition of acid is not because I screwed up, it has to do with the minerals in the initial fill.

Do you use a salt water spa system? Because I notice you didn't list a sanitizer.


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## Highbeam (Sep 12, 2017)

WoodyIsGoody said:


> I maintained swimming pools for a homeowners association with over 5000 residents while I was in college. I learned the method from an expert pool guy although I didn't fully understand the chemistry until years later.
> 
> I'm fortunate to have almost ideal water for a hot tub/swimming pool right out of the tap. It has a very nice calcium hardness balance, no chlorine and is sourced from melting glaciers. This means much of it fell as snow over 10,000 years ago. I change it once every 12-18 months. Everyone who uses it comments on how nice it is on their skin and how it doesn't smell like typical "spa water". One of the secrets (besides the wonderful fill water) is borates (20 Mule Team Borax), about 1/2 box to a fresh fill. Then I need to add around 8 oz. of muriatic acid to make the pH ideal. The pH hardly fluctuates at all after that although I might add about 1 oz. of muriatic acid every 4-6 weeks if the aeration jets have been used a lot (I'm not gonna go into the chemistry involved).
> 
> ...



I'm a sodium dichlor guy. A little polymer if needed, and sodium carb for pH. It's so easy.


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## begreen (Sep 12, 2017)

This is a good chat topic for the DIY forum or the Inglenook, but way off topic here.  Can we keep the focus on cat cleaning? That's why this thread was created.


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## redktmrider (Sep 12, 2017)

I have a BS in chemistry and 20 years of lab experience, I would NOT put a cat in any ionic acid (HCL, H2SO4, HNO3). pH is only one part of the acids chemistry.


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## Highbeam (Sep 12, 2017)

Okay, vinegar it is! Cheap, available everywhere, and recommended by all cat manufacturers and stove manufacturers that provide cat cleaning instructions.

Plain old off the shelf distilled white vinegar. I'd better not hear about anybody using apple cider vinegar!


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## WoodyIsGoody (Sep 12, 2017)

redktmrider said:


> I have a BS in chemistry and 20 years of lab experience, I would NOT put a cat in any ionic acid (HCL, H2SO4, HNO3). pH is only one part of the acids chemistry.



OK, maybe citric acid would be better for catalytic converters?


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## jetsam (Sep 12, 2017)

I used balsalmic. Tangy!


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## ohiojoe13 (Oct 1, 2017)

I tried the vinegar bath and I can still see some stuff in the cells. Did I do it wrong or is that normal to still see some stuff.


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## jetsam (Oct 1, 2017)

You should be able to see catalyst adhering to the ceramic substrate, but no calcification/soot/ash.


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## ohiojoe13 (Oct 1, 2017)

jetsam said:


> You should be able to see catalyst adhering to the ceramic substrate, but no calcification/soot/ash.


Ok thank you.


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## SCOTT S. (Mar 30, 2018)

Highbeam said:


> Dump the vinegar and then soap and water wash the pan. Dry with a paper towel, no smell remains, pan looks new. Distilled water bath twice. At this point there was snow on the ground and I needed to get the stove running. I don't know if there is any reason to dry a steel cat but I dried the cat on the NC30 for over an hour. Note how the cat cells dry out and lighten. Also notice that the white fuzz on the back dissolved! Pretty clean looking now. It was very apparent that water had soaked into the coating of the cat and that you should dry your cat whether it is ceramic or steel.
> View attachment 195715
> View attachment 195718
> View attachment 195720
> View attachment 195721


Where did you buy your gasket?


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## Highbeam (Mar 30, 2018)

SCOTT S. said:


> Where did you buy your gasket?



The only place that seems to sell them is firecat.


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## SCOTT S. (Mar 30, 2018)

Great thanks for the great thread I’m going to give it a shot.


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## Highbeam (Mar 31, 2018)

SCOTT S. said:


> Great thanks for the great thread I’m going to give it a shot.



It’s fun and made a noticeable difference but it only bought me a few more months. In my case, the cat was just past the rated service life. If your cat is still young but coated with “stuff” then you may get more bang for your vinegar buck.


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## SCOTT S. (Apr 11, 2018)

My cat was 80% plugged. Did the acid bath last night. I did the distilled water rinse four times before it was clean. I think my cat probably won’t last much longer as we burn starting in September until early June and this is its third year. I wish I would have taken pictures, I never seem to think of it in the middle of a project. I haven’t seen this much glow in a while.


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## Highbeam (Apr 12, 2018)

SCOTT S. said:


> View attachment 225687
> 
> My cat was 80% plugged. Did the acid bath last night. I did the distilled water rinse four times before it was clean. I think my cat probably won’t last much longer as we burn starting in September until early June and this is its third year. I wish I would have taken pictures, I never seem to think of it in the middle of a project. I haven’t seen this much glow in a while.



After the vinegar bath process my worn out cat was rejuvenated significantly but it did not last. Got a few good months out of it before the cats age again became apparent. Really, it wasn’t worth the time, cost, and effort to do an acid wash when a new cat is so cheap.


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## SCOTT S. (Apr 13, 2018)

Highbeam said:


> After the vinegar bath process my worn out cat was rejuvenated significantly but it did not last. Got a few good months out of it before the cats age again became apparent. Really, it wasn’t worth the time, cost, and effort to do an acid wash when a new cat is so cheap.


Did you buy your new cat from firecat?


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## Highbeam (Apr 13, 2018)

SCOTT S. said:


> Did you buy your new cat from firecat?


Yes! Through their amazon store mid mountain or whatever. 186$ shipped! It's running at 1400 right now.


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## SCOTT S. (Apr 14, 2018)

Highbeam said:


> Yes! Through their amazon store mid mountain or whatever. 186$ shipped! It's running at 1400 right now.


Ok , I looked at them on amazon the ceramic one for the princess is the same size as the steel one for the Ashford is there any reason I can’t use the ceramic in my Ashford?


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## Highbeam (Apr 14, 2018)

SCOTT S. said:


> Ok , I looked at them on amazon the ceramic one for the princess is the same size as the steel one for the Ashford is there any reason I can’t use the ceramic in my Ashford?



Oooh, excellent question. I can use either on my princess but I am unsure about the newer ashford that was only ever manufactured ant tested with the more expensive steel. 

That’s a great question for bk. I’m sure their official answer is steel only but would the ceramic work? After having gone back and forth I’m perfectly happy with the ceramic.


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## Todd (Dec 8, 2018)

Soaking my Keystone cat now in a 50/50 solution, no boil, I'll just let it soak for a couple hours then rise with distilled water. Ive gone 3.5 years with this steel cat and i wanted to replace but Woodstock is having problems with their supplier so they've been out of stock for quite some time and cant give me a date on new ones coming in. I'm hoping to get it will rejuvenate and give me another month or two.


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## Highbeam (Dec 8, 2018)

Todd said:


> Soaking my Keystone cat now in a 50/50 solution, no boil, I'll just let it soak for a couple hours then rise with distilled water. Ive gone 3.5 years with this steel cat and i wanted to replace but Woodstock is having problems with their supplier so they've been out of stock for quite some time and cant give me a date on new ones coming in. I'm hoping to get it will rejuvenate and give me another month or two.



Sorry about the supply chain problems. Deep down I think all of us cat stove guys worry about that. 

I didn’t reread the whole thread but I recall easily getting a month or two of excellent cat activity after the full cat boil. The Woodstock guys have been known to use a spray bottle of vinegar and then a spray bottle of distilled water for rinse it so I’m thinking the boiling may not be required.


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## Todd (Dec 8, 2018)

Yeah, I usually do the spray bottle thing once a year, hoping a longer soak will help. Woodstock told me they are waiting on some equipment then they will start making their own cats so they never have this problem again.


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## Todd (Dec 9, 2018)

Looks like I have some new cat life this morning, how long is yet to be determined. I was having problems getting the stove temp up to 500 with a full load of Black Locust before the soak now she's cruising along nicely at 600+. I soaked the cat for 3 hours occasionally lifting it out to flush out the loose deposits and it came out looking brand new. It left lots of junk in the bottom of the soaking tub, a lot more than I thought there would be.


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## Rockey (Dec 9, 2018)

Anyone ever tried an ultrasonic cleaner? I bought one for my business about 5 years ago and does a great job cleaning circuit boards. The unit we have is controllable on duty cycle and frequency. I could try a low setting and hope the substrate integrity is not compromised. May have tot ry it at the end of the season this year and see what happens.


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## jetsam (Dec 9, 2018)

Rockey said:


> Anyone ever tried an ultrasonic cleaner? I bought one for my business about 5 years ago and does a great job cleaning circuit boards. The unit we have is controllable on duty cycle and frequency. I could try a low setting and hope the substrate integrity is not compromised. May have tot ry it at the end of the season this year and see what happens.



I think you should try it.  I understand there are 3 layers- substrate (ceramic or steel), then a high surface area wash coat (aluminum oxide), and then some catalyst (palladium?).

I don't know anything about how the catalyst is made to adhere to the wash coat, so no speculation as to whether the ultrasonic cleaner will be harmful.  I do suspect that if the cat has ever been overheated, you will lose a lot of substrate in the cleaner.

Ultrasonic cleaners are good at decalcification, which is basically the goal of the vinegar bath, so maybe it will be awesome!


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## Woody Stover (Dec 9, 2018)

Todd said:


> I soaked the cat for 3 hours occasionally lifting it out to flush out the loose deposits and it came out looking brand new. It left lots of junk in the bottom of the soaking tub, a lot more than I thought there would be.


Was the catalyst peeling or coming loose, that you could see by looking through it? I guess not if " it came out looking brand new."


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## Todd (Dec 9, 2018)

Woody Stover said:


> Was the catalyst peeling or coming loose, that you could see by looking through it? I guess not if " it came out looking brand new."



No peeling I could see just some hard light colored deposits mostly on the cat face that wouldnt come loose with a paint brush.

My take on these new steel cats is they need a little more maintenance than the ceramics since the holes are much smaller. I tend to brush mine about every two weeks or so. Also need to brush that scoop as well. Im tempted to go back to ceramic for a little better flow as well as a little more heat. I always had a hotter stove with may ceramic cats but I'm not sure they last as long as the steelies?


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## jetsam (Dec 9, 2018)

Todd said:


> No peeling I could see just some hard light colored deposits mostly on the cat face that wouldnt come loose with a paint brush.
> 
> My take on these new steel cats is they need a little more maintenance than the ceramics since the holes are much smaller. I tend to brush mine about every two weeks or so. Also need to brush that scoop as well. Im tempted to go back to ceramic for a little better flow as well as a little more heat. I always had a hotter stove with may ceramic cats but I'm not sure they last as long as the steelies?



If you take care of a ceramic, the service life is the same. End of life happens when not enough catalyst is exposed- through washcoat collapse, washcoat delamination, or masking. Could be other stuff I've never heard of.

BKVP says he's been burned one cat 24/7 for 10 years, and it didn't get any special treatment.. I got 2.5 out of my first one. I expect the user's definition of 'dead' plays into that heavily.


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## Woody Stover (Dec 9, 2018)

Todd said:


> My take on these new steel cats is they need a little more maintenance than the ceramics since the holes are much smaller. I tend to brush mine about every two weeks or so. Also need to brush that scoop as well. Im tempted to go back to ceramic for a little better flow as well as a little more heat. I always had a hotter stove with may ceramic cats but I'm not sure they last as long as the steelies?


Yeah, I need to brush the cat and screen and clean the glass as well but it's too cold to let the stove go out right now.
I'm not sure about how long the cats last. I think I had the first steelie (diesel-foil) for about three years before I bought this one. I also have the original ceramic that came with the stove, which still works OK. Hard for me to say how many hours I have on anything; I was switching cats back and forth, and switching the Fireview and Dutchwest in and out since 2010.


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## heavy hammer (Dec 9, 2018)

What is the average life of a cat?  The ones who have done he acid bath is it worth the time or would you just purchase a new cat?  How long after the acid bath would you say the cat lasted?


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## Highbeam (Dec 9, 2018)

heavy hammer said:


> What is the average life of a cat?  The ones who have done he acid bath is it worth the time or would you just purchase a new cat?  How long after the acid bath would you say the cat lasted?



Pretty consistent across all brands and forum members on this and the other forum to get 10-12000 hours before a significant decline in function. Just as the cat manufacturer rates them.

It is ridiculous to use “years” as a time frame in this application because a cat can last for 1000 years if the stove never gets used. 

I tried to summarize in the thread but since I only got a few more months and since a new cat is under 200$ I will not be doing another vinegar bath unless I run into an emergency where a new cat is not available for some reason.


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## Todd (Dec 9, 2018)

heavy hammer said:


> What is the average life of a cat?  The ones who have done he acid bath is it worth the time or would you just purchase a new cat?  How long after the acid bath would you say the cat lasted?


Average life of a cat is 12,000 hrs give or take and that number probably has a lot of variables with it. Maybe you can extend that life if your not burning low and slow all the time and keep a little flame going that would keep the cat from doing all the work?


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## jetsam (Dec 9, 2018)

Burning low and slow makes the cat do more work over the course of the load, not less. A catalyst (by definition) isn't consumed by the reaction that it encourages, so that doesn't matter. On the other hand, keeping it low reduces the chances that you'll get the cat white-hot and sinter the wash coat.


On the cat bath thing, I am kind of using this as scratch paper to do my thought process...

Consensus seems to be that we get 2-3 months out of a cat bath. Say that's 1/3 of a 5000 hour burning season for a full time burner, or 1666 hours.

A cat costs $200 and lasts 12000 hours, or $0.017/hr, so a bath gets us $28 worth of cat lifespan back, less $10 for the gasket and vinegar.

If masking is the primary issue, I should be able to keep one cat going indefinitely for $30 a year (3x gasket + 3 gal vinegar).
If substrate sintering is the issue, performance should not be impacted by the bath and the cat will function in a degraded capacity.
If substrate delamination is the primary issue, time for a new cat.


Still curious to hear how the ultrasonic cleaner does. That would be neat if it works well. (I am basically looking for an excuse to buy a new gadget here. Found one that fits my cat for $130 on Amazon.  )


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## Highbeam (Dec 9, 2018)

Wouldn’t it be great if the ultra sonic cleaner blasted the catalyst off?


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## jetsam (Dec 9, 2018)

Highbeam said:


> Wouldn’t it be great if the ultra sonic cleaner blasted the catalyst off?



That's a possibility, since the washcoat can delaminate from the substrate, and possibly the catalyst can be removed from the washcoat. Not sure how easy the latter is.


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## georgepds (Dec 9, 2018)

You could always use vinegar as the bath in the ultrasonic cleaner


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## Woody Stover (Dec 9, 2018)

Todd said:


> Maybe you can extend that life if your not burning low and slow all the time and keep a little flame going that would keep the cat from doing all the work?





jetsam said:


> keeping it low reduces the chances that you'll get the cat white-hot and sinter the wash coat.


Yeah, I figure it's easier on the cat if I don't glow it real brightly, like bright orange or yellow. So I'll either run a bit of flame in the box, or if I want no flame I'll cut the air to where the cat isn't glowing real bright. I don't run it at the point right under where the flame goes out and the cat is bright.


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## georgepds (Dec 10, 2018)

from woodstock

https://www.woodstove.com/images/editorial_support/209 PDFs/209 Catalytic Combustor 171011.pdf



"VINEGAR & WATER CLEANING HOW TO: 

The vinegar & distilled water cleaning is recommended 1-2 times during the heating season. The vinegar is just acidic enough to remove any ash within the cells that may be masking the catalytic coating. Materials needed: (1) work gloves and safety glasses; (2) spray bottle; (3) white vinegar; (4) distilled water. 

1. Be sure the fire is out and the stove is cold. Remove the top stones from the stove. Lift the cast iron cook top and stand it up in the rear channel. 

2. Slide the combustor forward and out from under the cast iron surround. Place the combustor onto 21 newspaper or an old towel. In the spray bottle prepare a 50/50 white vinegar & distilled water mixture. 

3. Spray the 50/50 mixture through one side of the combustor and allow it to drain onto the newspaper. Flip the combustor over and spray through the other side and allow it to drain. 

4. Rinse the combustor with 100% distilled water to remove any remaining vinegar, allow the combustor to dry before returning the combustor to the stove. 

5. Return the combustor to the stove. Be sure that it is seated properly to the gasket behind. 

6. Close the top lid."


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## heavy hammer (May 27, 2019)

Highbeam I ended up replacing my cat while cleaning out my stoves and chimney's today.  Your pic's helped out a lot.  I'll post some in a bit, thanks for posts.


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## heavy hammer (May 28, 2019)

Removing the old cat  was more difficult than putting the new one.  I used scotch tape to hold the gasket together and on the corners for a smooth slide in.  The dogs supervised since the stove room is their hangout.  Three years and not bad, the old cat looks worse than it was from pulling on it with needle nose and regular pliers.  Appreciate the old pics Highbeam!


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## Kevin Weis (May 30, 2019)

Okay, what about the metal cats?


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## jetsam (May 30, 2019)

Kevin Weis said:


> Okay, what about the metal cats?



Same deal, can be handled less gingerly. Thermal shock isn't an issue if you're boiling it.


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## kennyp2339 (Dec 23, 2019)

Quick question, I’m boiling off the cat now in distilled vinegar, how long does it stay in this bath? 30min an hour? Just wondering


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## kennyp2339 (Dec 23, 2019)

So I’m answering my own question, I let the cat sit in the vinegar bath for 2hrs, multiple times I brought the vinegar to a boil, then let cool off to just steam when I opened the lid, I gently dunk the cat all throughout the process, rinsed it off with distilled water twice and then put it in my kitchen oven in a disposable backing pan at 300 for 30 min to dry off.
I re-installed the cat with a new gasket and made a fire, 20min in I closed the bypass, the needle climbed to 1pm, cat is glowing happily T stat is set at 2:30 position, just have ghost flames above the wood.. let’s see if this holds


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