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Cracked firebox repair?

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    Cracked firebox repair?

    Hey all you ceramic chefs! I cook on a Primo oval XL - have been going on 10 years. I love it!!

    Been rolling with a cracked fire box for about the last 3 yrs with no adverse effects, until my last couple of low and slows. Getting some inadvertent 2 zone going on, even with deflectors in.

    I searched and searched for anything out there about repairing my firebox - found some folks that had used high temp furnace cement to "rebuild" them.

    I have some materials due in and will attempt a repair regardless, but I was wondering if anyone here has had experience with this???

    "They" want $360 plus shipping for a new firebox, I’m way too che….”ahem”…frugal and capable to warrant that kind of cash. I would rather spend that $$ on some premium cuts to cook.

    Thanks for any advice!!

    Aren’t you still under warranty? My BGE is lifetime on the firebox. If you are not still under warranty JB Weld might work.
    Last edited by LA Pork Butt; July 8, 2022, 10:30 AM.


    Primo's website says "limited lifetime warranty" on all ceramic parts. So while I can see them charging shipping, I think they ought to replace a cracked firebox, rather than you having to buy a new one.

    The exception might be that they state the warranty is to the original purchaser of the grill, so if you bought it used, they may have a loophole out of it.

    That aside, I would try the furnace cement, and not JB Weld. I don't think JB Weld is meant for the temperatures of charcoal.


    • Old Glory
      Old Glory commented
      Editing a comment
      JB Weld makes a high heat version that I have used in the past.

    • Allon
      Allon commented
      Editing a comment
      A JB Weld Smackdown!

    • Attjack
      Attjack commented
      Editing a comment
      I have a brand new firebox sitting in my garage. I only had to pay $50 for shipping thanks to the Primo warranty..

    Primo will send you ONE replacement firebox. The new one will; have an expansion slot cut into it. You will pay for the shipping though. Their website has all the info to submit a claim.


      Oh, nice!! I will check with Primo. I bought it before the ownership changed but it is worth a shot! Thanks


        No joy on the warranty, I can’t find my receipt. Pressing on with repairs, I’ll post the project when completed, in case anyone is interested. Thanks for all your input!


        • jfmorris
          jfmorris commented
          Editing a comment
          Well that stinks. I.e. that they require you to show them a receipt to honor the warranty.

        Still in procrastination phase. This Summer has been amazingly time consuming! Plus I got an SNS and a vortex for the kettle, so cooking has not been a problem. I will get this done though.


          I finally took the time. We have a couple more days of 80 plus this week. I figured I better get it done before we run out of summer. I started off by steam cleaning all my edges that needed to be cemented with my little handheld Bissel.

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          It worked out ok. The parts that were cracked the longest had quite a bit of carbon buildup that I could not get off. After the fact, it seems this did not affect the bond.
          My first attempt, I mixed up the cement pretty thick, think peanut butter. I buttered the edges of my pieces and tried to fit them together. Turns out, the extra material would not allow the pieces to go together properly and it turned into quite a mess. The cement, once on the pieces, began to set up very quickly and did not have any "glue" like properties I needed.
          If you’ve ever seen the kids movie "Inside Out" The little red guy blowing his top like a volcano pretty much sums up the next 5 minutes. (He was the incarnation of anger inside the main characters head) I’m sure it was pretty amusing to see…from a safe distance.
          Once over my grown-up tantrum, blood pressure restored to normal levels and dignity retrieved from the internal deep lake I threw it into – I pressed on.
          I cleaned the edges off enough to be able to fit the fire box back together reasonably well, then mixed a much thinner version of the cement. More like syrup this time. I worked the slurry into the open cracks of the assembled pieces with my hands. This was even more messy, but it worked great. Turns out, the partially cured layer from the first attempt grabbed onto the slurry and kept it in the cracks.
          With some wiggling, some light tapping and continuing to feed the slurry into the cracks, I was content with how it was looking. I let it sit for about 10 minutes. That furnace cement kicks off very fast.

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          I took my spray bottle and wet and smoothed, wet and smoothed all the areas. Trying to knock down any ridges, clean out the airflow holes and remove as much excess cement as I could without disturbing the joints. Then I walked away.
          I work nights so all this was finished up by 11:30 am, just in time for the sun to break over the house, warm up the back yard and bake that thing all day. I checked it tonight before leaving for work and I am very optimistic. The cement is nice and solid, the alignment for the broken pieces is close enough. I ‘ll start the final clean up and finish the detail work tomorrow!.


          • Allon
            Allon commented
            Editing a comment
            Wow, that’s quite the project. Great job sticking with it.
            It looks like you’re doing well now. Keep after it!

          I wouldn't recommend firing this up for another 2-3 days IMO. This is so you are 100% sure you get "ALL" the free water out of the cement used to attach these pieces together. Otherwise it will just turn to steam and crack again when you light it up.
          I would also recommend doing a forced dryout of the material. This is just a fancy term for saying do a 350-400 degree drying of the material. Ramp the temp up slow, hold for a couple hours at 350-400 then let it slow cool. This ensures all the entrained water molecules are removed and the material is cured and set. Heck throw some chicken on and kill two birds with one stone....LOL.....good luck and keep us posted on the outcome.


          • Philotius
            Philotius commented
            Editing a comment
            Thanks! I did see something about that on the cement instructions. That makes 100% more sense to me the way you explained it.

          • Allon
            Allon commented
            Editing a comment
            I would caution you about cooking when cement is curing. Never can tell what's in the exhaust gases

          Clean it up a little today. Joints feel very solid and well bonded.

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          Another skim coat to fill in a few missed spots and smooth out some unevenness

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          I think this is going to work out great. I should be able to fire it early next week and be ready for Labor Day cooking! Thanks for all the suggestions and info - I'll keep the updates coming until I get some ribs on.
          Last edited by Philotius; August 25, 2022, 05:14 AM. Reason: still trying to figure out the formating, also, the post has an extra attachment I can't seem to get rid of.


            Impressive. That there firebox is gonna look like new when all is said and done. As long as it holds up to the heat you should be good for years to come.

            This is a great thread for anyone with a ceramic grill.
            I have two, both purchased used so no warranty on either.

            Good luck when you fire that puppy up.



              I used the existing holes in the firebox and wired mine together. It's been going strong for years now.


                Day 3: Just a quick clean up with a 1" putty knife to knock any loose material off, took down a couple of ridges. I can really see where the cement still has a lot of water left in it by the color difference.
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                The putty knife with light pressure has done a great job taking loose material off finding any areas that have not bonded. Anything that doesn't scrape right off, I've been leaving alone. A quick rinse with the hose and it's looking good.

                I may do 1 more skim coat. I was thinking of screening some of the bigger chips out of the cement to make a nice smooth topcoat. I may be picking fly crap out of pepper though, probably doesn't need it. I might try wet sanding with some 400 grit drywall screen, see if that smooths things out. I just think that the roughness will attract more gunk build up.


                  This is awesome. How much time and money has this involved so far?


                    Another thing you can do to dry it out. Place it in the oven at 150 or 160 degrees for a few hours. Then bump up the temp 20 degrees every couple hours until you get to above boiling point. Start in the morning, plan to be done sometime that evening. Then let it cool overnight. Going slowly gives the ceramic time to heat soak, and water trapped will not turn to steam too rapidly.

                    Also if you can, add an expansion slot. My Primo firebox has a cut out that runs from the air intake all the way up. About 1/4 inch wide. Or less. Just enough to allow for some expansion.



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