Frosty Posted December 12, 2015 Share Posted December 12, 2015 Disappeared this reply 3x and discovered I was timed out to edit the backdoor try in about 10 seconds. Johnson Appliance forges don't usually develop enough heat to need more than 2,600f refractory. They're pretty well known for being hard to get to welding temps. I believe they were originally intended for heating to bend rather than heavy forging let along welding. I've only used one briefly back a couple decades or more, Heck I ended up with one I don't want more than 20 years ago so maybe 3 or 4 decades ago. Yeah, I have a Johnson Appliance 122A out behind the shop I've never fired or even brought inside. If anyone close by wants one, make an offer. I wouldn't try casting the contact surface, it'll be a LOT more likely to heat check unless you plan on lighting it and leaving it running till you're ready to reline it. If you're running it on propane you'll want a higher temp refractory, 3,000f hard fire brick minimum. How you back it can make a real difference in overall efficiency. I don't know what Johnson used but there are certainly better options available. Even fuel air ceramic kilns use a hard brick on the contact surface and back it with light brick or ceramic blanket. I"m thinking a zirconia kiln wash might provide a flame resistant surface but that's speculation. Frosty The Lucky. Quote Link to comment Share on other sites More sharing options...
natenaaron Posted December 31, 2015 Share Posted December 31, 2015 You keep your Johnson out behind the shop? Had to be said. Simple question. Why would leaving it on until relining it keep it from heat checking? Quote Link to comment Share on other sites More sharing options...
jeremy k Posted December 31, 2015 Share Posted December 31, 2015 It would not be going thu heating and cool down cycling. Quote Link to comment Share on other sites More sharing options...
natenaaron Posted December 31, 2015 Share Posted December 31, 2015 Well, duh. Pretty xxxxxx obvious now that you said it. Thanks, Jeremy, for not calling me an idiot. Quote Link to comment Share on other sites More sharing options...
Frosty Posted December 31, 2015 Author Share Posted December 31, 2015 6 hours ago, natenaaron said: You keep your Johnson out behind the shop? Had to be said. Simple question. Why would leaving it on until relining it keep it from heat checking? Yeah. I didn't want it in the first place but it was an all or nothing sale so I hauled it with. I have no use for something that large nor inefficient. I'll let it go cheap. Frosty The Lucky. Quote Link to comment Share on other sites More sharing options...
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