Project "HUMPTY" — Kamado/BGE Restoration, Vancouver, Canada

Great ideas for the coal grate. Will check them out.

Thanks Waterloo. Didn't even occur to me to try home electrolysis. I removed the rust the old-fashioned way, with wire brushes, knives, files and a few skinned knuckles. A few curses too. Wish I'd seen the Rust Removal Using Electrolysis writeup before I painted all the other rusty bits.

May
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Project Humpty: SLIDESHOW, PHOTO ALBUM

Pardon my manners...

I'm forgetting my manners. Wasn't sure how to respond at the time, so am giving my belated appreciation for all the advice and encouragement EVERYONE gave (on and off this thread)....

• Waterloo - I may just do some electrolysis yet. Thx.
• Smokin Gator - Thanks for the Lodge trivet link. And yes, HE does look great! :wink:
• Swamprb - Brian, THANKS for all the great advice! Your Imperial Kamado Restoration posting was what I studied before jumping in to do my own repairs. Took a lot of the unknowns out.
• MostlySmoke - Yep, only one Copper Cooker out there; he's not part of any lemming pack! :wink:
• Brauma - Mark, still kind of wishing the copper to be that "new copper" color, but it still came out great. Humpty is looking quite dapper!
• Professor Salt - Thanks for the kind words. Glad you enjoyed the photo documentation and slideshow as I didn't want to overpost on the pics. The fish avatar is one of few allowed for newbies. As a newbie, I'm not able to post my own avatar (yet).
• Jonboy - One Wiggle Stick coming up this weekend! The Great Pumpkin is now one of Humpty's aliases.
• Crome - Glad you like the copper!
• Thillin - Ok, will be loading the firebox more. Was too timid before.
• Cabntmkr1 - Thanks for the pat on the back.
• CivilWarBBQ - The restore turned out better than I expected. A piece of cake compared to TomJax's Extreme Makeover. Even though I didn't use furnace mortar over the JB, everything is still holding together after the bakeout and first cook. Keeping my fingers crossed.
• Browser - When I first saw the Kamado, there was never any doubt in my mind that I would restore it. Some of my buddies did think it was an eyesore and better off in the landfill. :icon_shock1:
• CaptGrumpy - I'll be sure to watch my temperatures!
• FatDaddy - Hope you can get to your restore soon - I sure enjoyed mine.

You guys are all great!!!

May
Project Humpty: SLIDESHOW, PHOTO ALBUM
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Kamado/BGE
Cobb Barbeque

How Long to CURE Furnace Mortar?

swamprb said:

PLEASE DO NOT fire a clay Kamado like a Big Green Egg!

I can't stress enough for anyone with a claypot to download the manual for the pre 1976 BGE from the Naked Whiz!! You risk overheating and damaging all the fine work you've put into this. Start out with the suggested amount of briqs/lump and add as you cook.

I just got a Medium Sakura Hibachi Pot Kamado from my BIL's brother that will be my next restoration project and when he told me that he filled up the firebox EVERY time he cooked it was no wonder the thing is in pieces.

I would suggest using furnace cement over the JB-Weld joints. I only say this because I was using the claypot base mod in my WSM and it cracked-I pieced it back with JB-Weld and after a few cooks it cracked at the reapair. It was not in direct contact just the heat sink in place of the waterpan. A little insurance as I see it.

Click to expand...

Brian, FUEL OVERLOAD warnings duly noted. Thought I had overly skimped on lump for the initial bakeout and first cook. As suggested, will be referring to the original Kamado manual for fuel loads. Thanks for the extra emphasis.

Funny thing about the furnace cement.... I had actually returned the unopened product for a refund yesterday. Ok, it's back to the store to buy the stuff again. :roll::roll::roll:

Last week, I just got lazy and didn't want to go the extra step of furnace mortar. Sounds like I had better do it ASAP. However, will only be able to mortar the JB-welds on the inside, seeing how the outside is already painted. OK?

The Kamado was to star this weekend in 2 cookouts (Sat & Sun) with company coming over.... :icon_shock1:

1. If I apply the cement tonight, will I have enough time to let it dry and cure in time to use for tomorrow's dinner? !!!
2. What does curing involve? A low-temp bakeout?
3. How can I minimize cracking or flaking?

Thanks!

May
Project Humpty: SLIDESHOW, PHOTO ALBUM
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Kamado/BGE, Cobb

Humpty's Got New Cracks :<(

Didn't notice this before, but apparently the previous 2 fires (bakeout & 1st cook) caused some thermal stress. The JB'd bottom, firebox and fire ring are all fine. But new cracks have propagated from the original ones that were JB'ed in the dome.


Crack growth in dome - close up.


DRAT!!! I thought the two previous firings were low and slow. Maybe not?

This calls for new JB-epoxy application PLUS FireStop furnace repair cement ! ! !

However, Humpty has been committed for tonight's dinner (and tomorrow too)!!! Invitations have been issued and accepted. Food has been bought and prepped. :icon_shock1:

*** So, I'm going ahead and cooking on Humpty anyways. ***

As precaution, the dome will be reinforced with wire around the neck so that it doesn't collapse. Will also be careful to keep the temperatures below 400F.

There will probably be more crack growth due to thermal stress from the additional firings. If the dome cracks right to the edge, JB application next time should work better because the epoxy can then be applied INTO the cracks (instead of on the surface).

I will deal with all this AFTER the weekend, after all the guests have left.

Moral: Look at things in the day(light).
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Project Humpty: SLIDESHOW, PHOTO ALBUM

First of all, thank you both, as I used your experiences and photos to restore an ancient #3 last week. It was a craigslist score and even has the Japanese stamp!

I'm kicking my self for not documenting the process, but it wasn't much different from yours, just less work. The only crack in the egg itself was in the bottom and I JB Welded it and covered it with furnace cement. The firebox had several cracks which I gave the same treatement, but it appears that the cement doesn't adhere well to the JB Weld. When heated, it appears to bubble up. Did you do anything to prepare the surface? I let the JB Weld dry for 24 hours and did the same with the furnace cement.

Anyway, it's a really good cooker. Surprisingly, very little lump, draft and time was needed to get it over 400. The wife wasn't too pleased with the addition to the family, but the beer can chicken in an hour won her over. I'm really impressed with this 20+ year old cooker.

Jim_Beam said:

First of all, thank you both, as I used your experiences and photos to restore an ancient #3 last week. It was a craigslist score and even has the Japanese stamp!

I'm kicking my self for not documenting the process, but it wasn't much different from yours, just less work. The only crack in the egg itself was in the bottom and I JB Welded it and covered it with furnace cement. The firebox had several cracks which I gave the same treatement, but it appears that the cement doesn't adhere well to the JB Weld. When heated, it appears to bubble up. Did you do anything to prepare the surface? I let the JB Weld dry for 24 hours and did the same with the furnace cement.

Anyway, it's a really good cooker. Surprisingly, very little lump, draft and time was needed to get it over 400. The wife wasn't too pleased with the addition to the family, but the beer can chicken in an hour won her over. I'm really impressed with this 20+ year old cooker.

Click to expand...

Congratulations Jim! Good on you. I'm glad this postings thread was able to help you with your restoration. Swamprb's Imperial Kamado Restoration posting did the same thing for me.

I took a lot of pictures because it's my first Kamado and serious barbeque cooker. Also, wanted to prove my naysayers wrong. Besides, pictures paint a thousand words, and digital pics are free.

About the furnace cement, I'm going to follow Swamprb's advice to clean the area well before application. In my case, I let the JB cure inside the house for a whole week before firing up the Kamado. Maybe that's the difference with the JB.

All the best. Keep us posted on your restoration!

Humpty Survived 3rd & 4th Firing - Repairs Planned

swamprb said:

I know the feeling! When I rebuilt my Large Imperial Kamado it developed a crack in the dome after I painted it also.

I'm repairing the cracks in my BGE and you've really got to have a clean surface for the furnace cement to adhere to, the edges I've feathered flake of very easily, unlike the claypots.

Click to expand...

Thanks Brian. I'm feeling slightly dejected about the new cracks. :icon_sad
The good news is that the Kamado held up to an intense weekend of BBQ activities (food pron later), WITHOUT showing additional crack propagation other than the ones noticed earlier.


However, some parts of the JB-welds look like they're melting, as a couple of weld pits have shown up. JB Cold Weld is "temperature resistant" only to 500F.


The maximum temperature did briefly exceed 550F (T-gauge limit) as the coals were ashing up, but I brought it back down. :icon_blush:


TODAY'S REPAIR PLANS

1. Clean out the Kamado. Degrease and de-soot.
2. JB over old welds.
3. JB new cracks.
4. Mortar over JB.
5. Let dry and cure several days before baking out.

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Project Humpty: SLIDESHOW, PHOTO ALBUM

JB-Weld Does NOT Survive in the Firebox!

BACKGROUND
Upon reincarnation as The Copper Cooker, Humpty has only had 4 firings so far:
---1. Bakeout #1. Low and slow. Overnight. T < 500F.
---2. Cookout #1. Low and slow. 7h. T < 500F.
---3. Cookout #2. 4h total. T < 500F.
---4. Cookout #3. 4h total. T > 550F briefly, 500F 1h, 400F 2h, 300F 1h.

Recent repairs consisted of 1 coating of JB-weld on all visible cracks, but NO application of furnace cement. New cracks appeared on the dome after the first 2 firings, but no further damage to the dome were noticed after 4 firings.

Disassembly of Humpty showed ADDITIONAL DAMAGE to the firebox and base.

JB Weld does not hold up in the firebox. Coal temperatures are too high for the material to withstand (500F temperature rating only). On the firebox, most of the JB has flaked off and/or turned into white powder. As a result, the JB no longer bonds or seals. :icon_frow


Close-up of JB deterioration.


JB has flaked off and broken down completely INSIDE the firebox.


Firebox came apart in 2 pieces. Most of the JB-weld has turned to powder wherever it was applied, so all the other old cracks will need to be dealt with again. See JB powder residue where the firebox has completely broken off.


CONCLUSION: JB WELD CANNOT BE USED IN THE FIREBOX.
(To repair the firebox again, I will use High-Temperature Furnace Cement only.)

JB seemed to hold up OK inside the dome. For today's repairs, the new cracks were sealed with JB and a second coating was applied over the old JB-welds.


JB also seemed to hold up ok inside the base. However, there were new cracks at the bottom of the pot (propagation from old ones). For today's repairs, the new cracks at the base were JB'd on the inside only, but not on the other side where the JB had flaked off. The old JB-welds near the inside top rim also got a second coat of JB.



TOMORROW'S PLANS

1. After curing overnight, all JB-welds will be covered with High-Temperature Furance Cement.
2. The firebox will be repaired with furnace cement only (no JB).

To be continued....
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Project Humpty: SLIDESHOW, PHOTO ALBUM

TysDad said:

Have you thought of reinforcing the JB Weld with some fiberglass tape? Apply some Weld, put a strip of tape on and rub it in so that the Weld works its way into the weave and then rub another coat of Weld over it. Use a plastic baggie as a glove...

I don't know if that will screw up the expansion/contraction of the rest of the cooker and cause more cracks elsewhere, though.

The drilling the hole at the end of the crack to stop propagation is a really good, really old trick. Do you want to drill all the way through to stop the crack and then fill and touch up the paint on the outside at this point? Hope someone else has tried it on something like your cooker and can give you some first hand advice...

Click to expand...

Thanks for the suggestion, but I don't think fiberglass reinforcement will help at higher temperatures (great for lower temps). Above 500F, the JB-weld will still break down from the heat and turn into powder despite the fiberglass support. :sad:
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Project Humpty: SLIDESHOW, PHOTO ALBUM

Hole at the End of a Crack Reduces Crack Propagation

Swamprb and TysDad, you are both correct that drilling a hole at the end of the crack will help stop the crack from growing. The trick is to make sure that the hole is drilled AT the end of the crack! :wink:

Essentially, the stress at the end of the crack is inversely proportional to the radius of the end of the crack. By drilling a hole at the end of the crack, you increase the radius, which effectively reduces the stress on the crack, so that it will have less chance to grow (Griffith's Theory, Unstable Crack Growth, 1920).

For example, in the early 1950's, a lot of de Havilland aircraft were falling out of the sky. The planes split in half in midair from stress cracks that started at the corners of the square windows that were in use at the time.

For the mathematically inclined, this is all explained here: Stress Concentrations & Griffith Crack Theory, where "a" is related to your crack geometry.

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Project Humpty: SLIDESHOW, PHOTO ALBUM