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Hi-temp RTV (500 degree)

Discussion in 'Fridge/Freezer Builds' started by thedudeabides, Dec 9, 2010.

  1. thedudeabides

    thedudeabides Newbie

    Hi All, Fridge refurb is nearing completion - just a few more tweeks. Test fired unit today and started seasoning process. Temp got to 200ish and smoked like a peterbuilt. After several hours I let the unit cool down and opened up the door. It would appear the high temp RTV may have oozed from behind some rivets/joints or is that just smoke and water?  I have about 100+ hours on this project - please don't tell me I have to scrap her...[​IMG].

    Anybody ever had this issue - I'm hoping it's not the RTV but smoke/seasoning...
  2. tom37

    tom37 Master of the Pit OTBS Member SMF Premier Member

    I have cooked on rigs that have the rtv holding the gasket to the firebox door and the worst thing it did was fall off after the first year.

    It never ran or melted.

    How bout a pic or two of the guilty slimy goop you are refering to.

    Please I wanna see the smoker. Frig projects are starting to interest me.
  3. rbranstner

    rbranstner Smoking Guru OTBS Member

    I used some high temp food grade cocking last year on my smoker. I will have to go talk a look at the bottle and see if it the same stuff as you used. I have not had any issues with mine so far.  Yea some pics would be helpful.
  4. mballi3011

    mballi3011 Epic Pitmaster OTBS Member SMF Premier Member


    It looks like yu need to show us some pictures for sure. Now whats the worst thing that can happen?/ You have to scrap out the stuff and try it again. I would like Rbrans said and do alot of research and make the picking it out the last resort.
  5. thedudeabides

    thedudeabides Newbie

  6. Dude, that looks nasty, don't think I would trust it [​IMG]
  7. thedudeabides

    thedudeabides Newbie

    Yeah - I agree... My redneck sense was tingling so I lit it up today and seasoned with lots of peanut oil and kept it fired up A L L L day long. I'm using a brinkman elec converter in it and kept hickory in the cast iron pot for smoke. Even threw in some charcoal bricks to boost the temp a bit. Did not add any water today - just dry roasted the fridge (still going now actually...)  I'll take another pic tomorrow (after 12 + more hours of seasoning) and share...  I could've called NASA I guess but decided to stick to my old addage; grip it & rip it!
  8. tom37

    tom37 Master of the Pit OTBS Member SMF Premier Member

    Something isn't right!!!!  I am betting that maybe you used high temp automotive gasket maker,,,, maybe. The stuff I always use is the high temp RTV stove gasket silicon, like this.


    I did just a little bit of searching just now and the only thing I can think of is that some of the automotive stuff says up to 600 or 700 or what ever but it says intermittent temps on the high end.

    Even at that, most all of the auto stuff should hold up to at least 300 degrees.

    The above pic is what I have always used and never had a problem. I get it at westlake ace in the wood stove supply area.

    Here is 2 pics, one is of the old smoker from at least 6 years and the second is the RF I just put together this past summer, it has only two smokes on it now but looks as good as this pic from the day I installed it.


    Its a little tough to see but there is silicon gasket holding the stove door rope gasket in place. All four sides and also down the middle.

    Here is a little better pic of the one I just did this year.


    The red smoker gasket is black and the above pic is done with clear. I never never have seen one run and drip like in your pic.
  9. rw willy

    rw willy Smoking Fanatic OTBS Member

    I used red rtv on my UDS.  Its been alot of smokes and several high temp burns.  Stuff hasn't moved a bit.

    Note sure what that junk is in the picture.

    Good luck
  10. tom37

    tom37 Master of the Pit OTBS Member SMF Premier Member

    I guess we should have ask if the silicon is borken down where you removed the tin. Or has it turned mushy or gooey? If the first pic is where the tin is removed, it looks to me like the gasket is still intack.

    I am very courious as to the results of todays test.
  11. thedudeabides

    thedudeabides Newbie

    Nice rig Tom.  Sorry for the delayed test results guys - wanted to hickory smoke roast the fridge for a few days straight...  I started off with low temps 150 - 175 and slowly cranked it up to 275 - 300 over a 2 day period.  I used high-temp RTV 500 degree fireplace door gasket sealant and temps never got above 350 tops.  Below are updated pics just took this morning - seasoning is coming up nicely - liberally applying oil before each cycle and I threw in hickory every few hours...  I'm on the fence on if this is safe for food or not...?


  12. justpassingthru

    justpassingthru Smoking Fanatic OTBS Member

    Hey Dude,

    Nice looking build, I've seen those kind of results at the drag strip when we used gasket sealer that didn't have time to dry, but you used the correct stuff, may I ask if it was dry before you fired it up, second thought is all of the silicon products here have an expiration date, I've tried using them after the expiration date and they never set up, maybe yours was old (I don't know if that is applicable for the silicon in the States)? Silicon has a definite smell when it is wet, do you still smell it?

    Maybe you could contact the manufacturer and show them these pics and see what they have to say.

    I used the red hi-temp in my GOSM to seal the seams and it didn't run like that, after all of that work I hope it is a simple solution.

  13. thedudeabides

    thedudeabides Newbie

    Thanks Gene,

    Yeah, it was applied weeks before I fired it up the first time.  I'm thinking it may just be built up cooking oil around all the rivets and it left some residue as it warmed up and dripped/ran...  I never even thought to check for expiration - I usually bought a few tubs and used them up within a few days.  As I discarded used tubes I won't be able to tell.

    I too hope it's just oil residue with the 100 + hard hours and money I didn't have to blow on it...


  14. beer-b-q

    beer-b-q Epic Pitmaster OTBS Member

    Did you try cleaning it off and seeing if it does it again?  I would say worst case scenario would be having to clean and reseal the silicone...
  15. thedudeabides

    thedudeabides Newbie

    Thanks Beer B Q - it's smoking right now so I'll try that tomorrow.  Any tips on what I could use to strip the old RTV?

    Hi All, I wanted to share this with everyone - may have discovered the problem...

    Part I

    Multiple and intermittent 4-alarm fires!!!  BEC is no joke - 1500 watts of unadulterated, uncontrollable, rage.  First seasoning attempt, entire fire box area (lower fridge unit) A B L A Z E.  Santa could've used it for runway approach here in the Northern Rockies during winter storm...

    Here's a hint - don't ever, never, ever never ever use wood to support insulation in fire box area.  I had a steel tank 15" wide that I dropped into an isolated, and insulated 'box'.  Yes aluminum burns...ok no, but it sure as freggin' melts...I have the proof.  I walked outside to check on the seasoning and to strut around the yard - proud of my work.  With my p.j.s tucked into my boots, and two jackets on (snow and cold), I walked into a mini-forest fire and could only see about 5' in front of me.

    With a sinking feeling I slip over to where the garage was - or maybe used to be I imagine, and find my beloved fridge smoker, again, ablaze.  It looked like a NASA rocket reached take off stage (blast off) but was chained down.  I frantically begin shoving snow into the fire box - only to my amazement - more smoke than I've ever seen in my whole life...  Still holding my breath after just coming outside, I wasted no time and nearly picked up the now 1850 pound fridge smoker (rivet weight) and thank God it was icy - slid the fridge out of the garage and into the yard about 20 feet.  I open all hatches, doors, exhausts, and all door gaskets immediately slid off the doors and onto the ice.  So much for strutting around.

    I managed to slow the destruction to a slow burn - went inside, took ANOTHER shower (smoke damage) and went to bed...disgusted.  The next day I sucked out my previous work with the shop vac - and started again, with steel.

    Part II

    Having repaired all the damage and replaced the melted; aluminum, wood, insulation, wood...I moved on with the seasoning process.  Prior to every session I've been applying cooking oil - like any good redneck, very liberally.  All was well until I started to notice black streaks in the food chamber that I thought was just oil at first.  More and more I, and others on this forum, believe it to be the high - temp gasket silicon that's been M E L T I N G due to extraordinary temperatures.  Funny, my temp gauge never got/gets above 350.  Looking back I suppose that's the ambient air temp, NOT the surface temp levels usually found at the base of most lightening strikes.

    So once again, ego having recovered, I seasoned the smoker for a few more days - adding oil every morning.  I achieved a good deal of success in this regard.  Mistakenly, I depended upon my Ambient air temp gauge to judge my success.  Maintaining a nice warm temp I was pleased with myself - notice the trend here?

    After going through 2 full bags of sweet hickory in a 3 - 4 day period, things started to smell...well, cockeyed.  Now I'm one who abides (no pun intended) by smoke legend/law, never open the door so as not to waste that elusive and desirable smoke level and temperature.  Until this morning that it.  Dressed this time, I walked outside and took a nice big sniff - hoping to smell that ole hickory roasting away.  What filled my nose was not what I anticipated.  Instead, a rancid, black, used diesel fuel stench permeated the mountain side.  Like any good redneck, I immediately examined the smoker exhaust and there was B L A C K smoke rolling up and out.  Then I looked at the temp gauge and it read around 275.  I thought that was ok so the next thing that popped into my head was...wait for it, wait for it, snatched open the door and crammed my head inside with my eyes wide open as fast as possible.

    So, I still have my eyebrows but...I have seen hell.  Faster than a democrat can raise taxes, all that thick black smoke instantly, and all at once I think, exploded into a raging inferno on every side of the food chamber, my head prominently placed in the dead friggin' center.  After screaming like a school girl and convulsing my head out of harm's way, I slammed the door closed - thanking God for sparing an idiot and taking note if anyone actually saw what just happened.  Now on my third life of nine, ok, I'm not a cat but I'm just sayin' - I unplugged the Brinkman and slowly cracked open the door and let it all cool down to about 800 degrees.

    So, here's the point - if you decide to go with the Brinkman, go into it with your eyes open (no pun intended).  It's a LOT of juice so be prepared to vent, or something...

    Merry Christmas everybody.  
  16. tom37

    tom37 Master of the Pit OTBS Member SMF Premier Member

    Did I read correct that this all has happened in the life of the frig??

    Is there any chance that someone pulled a switch-a-roo and got diesel in you cooking oil jug. 

    I think at this point I would pressure wash the whole thing, season with one light coat of coconut oil, and go for a small burn. And see what it does.

    My very first smoke ever was a thanksgiving turkey. [​IMG]  About 2 or 3 in the AM I could hear a bubble noise coming from inside the rig.

    Well, just like stated above I open the doors to see whats up?????  What was up was the FLAMES!!!!!! In an instant I slam both doors.

    I zip up, and tie my hoodie real tight, and put my sunglasses on (at 2 something in the AM) and go back in to save the turkey.

    I rescued the bird and waited the 1 hour plus for the flaming grease to quit burning. No way was I going to loose that bird.

    The point of that story is that you have triggered a flashback.

    After all the grease burned there was a terrible nasty black substance inside my smoker. It actually looked pretty close to whats in your pic.

    I wonder if the goo is from to much cooking oil??? And possibily had some sort of reaction with the silicone.

    As far as striping the RTV, I have always been able to use a sharp putty knife.

    BTW..... any chance there is a pic of you running around the yard with your pj's tucked in your boots. Sorry man I can't help but to sit here and laugh, that is since you are allright.

    OMG..... was the smoker really inside the garage??

    Oh yes just so you know that I am not making fun, I make frequent trips to the home depot with my shorts and boots on. Funny thing is no one will ever go with me.
  17. flyboytr

    flyboytr Fire Starter

    I have just started a refrigerator build...will be posting pics, etc as I go along.  For misc. sealing and applying the door gasket/rope, I plan to use SU5005 RTV, Food Grade adhesive/sealant.  It is available in several colors, good for up to 400 degrees constant...and is safe around food.  I've used this product on various projects over the past few years, including some smokers.  Never had any problems or issues.  There is an eBay seller that has it in a 10oz tube (for a caulking gun).  ...I think about $8 with shipping.  I just ordered two tubes.   An eBay search for SU5005 will bring up all the results. 

    FlyboyTR  :)
    Last edited: Apr 11, 2011