In another life I designed a new diffuser for my Blaz'n Grand Slam. But when I sold the Slam I kept the mod cause it was a 10" by 10" by 3/16" piece of 304 stainless.  Have had the 590 for almost 3 yrs now and like many the diffuser has warped.  I have known that RT has replaced them when requested, but saw no sense in doing so, since the replacement would no doubt do the same. They have replaced the diffuser in the newer model with a cast iron diffuser but do not offer that one as a replacement for the original. So I took the mod and adopted it to the warped diffuser with SS hardware.  The thickness of the mod plate pulled the warp back out of the diffuser nicely.  Cranked it up to 400* for about an hour. Noted perhaps a bit slower to heat up but negligible IMO.  Cool down was slower but otherwise it worked well with no after-warp noted.  Just removed the long bolts and replaced with 1". Drilling the diffuser required getting the guide holes properly placed but was easy.

 This brings back fond memories of when I had my Traeger. Did the same thing. I also noticed longer warm up & cool down times with my 1/4" SS heat deflector reinforcement.  The temperature swings were

 also slightly reduced. That is what a heat sink does.

 I noticed the expansion rates of the two pieces were different due to their thickness differences. That led me to loosening the 4 pieces of 1/4" attaching hardware slightly to allow movement. This eliminated a

 slight creaking sound @ warm up and reduced any stress caused by temperature changes. Fussy I know - just me.

 This brings back fond memories of when I had my Traeger. Did the same thing. I also noticed longer warm up & cool down times with my 1/4" SS heat deflector reinforcement.  The temperature swings were

 also slightly reduced. That is what a heat sink does.

 I noticed the expansion rates of the two pieces were different due to their thickness differences. That led me to loosening the 4 pieces of 1/4" attaching hardware slightly to allow movement. This eliminated a

 slight creaking sound @ warm up and reduced any stress caused by temperature changes. Fussy I know - just me.

Wow! Deja Vu all over again!(ala Yogi)  I also noted the clicking sound but was at a loss to understand at that moment. Your experience and mine are the same!  Perhaps I should have the two pieces welded as others have done? How did your hold up over time?

I thought a few years ago they fixed or tried to fix the warp issue, by having a border the whole way around the top. Pretty much had a piece welded on both sides to connect the front and back. They billed it at the time as doing it for a place to put pellets for additional smoke. It much have been to costly o have that extra step done.

You should not have an issue with warpage any longer.

They always said it didn't effect the cooking of it but the past try to fixing it and now the cast diffuser make one wonder if it does effect the cook or if they were just tired of all of the complaints about them warping. I had seen some pictures that warped so much it pushed the drip tray up.

 This brings back fond memories of when I had my Traeger. Did the same thing. I also noticed longer warm up & cool down times with my 1/4" SS heat deflector reinforcement.  The temperature swings were

 also slightly reduced. That is what a heat sink does.

 I noticed the expansion rates of the two pieces were different due to their thickness differences. That led me to loosening the 4 pieces of 1/4" attaching hardware slightly to allow movement. This eliminated a

 slight creaking sound @ warm up and reduced any stress caused by temperature changes. Fussy I know - just me.

Wow! Deja Vu all over again!(ala Yogi)  I also noted the clicking sound but was at a loss to understand at that moment. Your experience and mine are the same!  Perhaps I should have the two pieces welded as others have done? How did your hold up over time?

I would NOT have the two pieces welded together.  Why? The uneven expansion will continue and could very well end up cracking the thinner material as it expands and cools faster in the thermal cycle. You will

 continue to hear noises. The creaking noise could very well develop into a rather loud pop. If one of the two pieces required replacing, both pieces would have to be replaced as they are now one.

 As far as holding up goes: I had a good two years of use from the set-up and off to my daughter it went when I got the Memphis.  She has had it close to three years w/o issues as far as I know. It doesn't get

 the use it did as when I had it.

 To allow for the different expansion rates, all the holes need to be slightly larger than the bolts, ~ 1/8 to 3/16" larger.

 To keep things together, double nutting is a good way to go. The first nut barely finger tight; with that being held along with the bolt, then firmly tighten down the second nut. This will allow the two parts to float

 or move independently from each other yet keep them together.   




 

You get the same even heat distribution you got in Blazn?

You get the same even heat distribution you got in Blazn?

In the Blaz'n I completely changed the shape from round to square, and thus the distribution was different. In the RT the added square is completely covered by the deflector, so no change in shape or size. 

 This brings back fond memories of when I had my Traeger. Did the same thing. I also noticed longer warm up & cool down times with my 1/4" SS heat deflector reinforcement.  The temperature swings were

 also slightly reduced. That is what a heat sink does.

 I noticed the expansion rates of the two pieces were different due to their thickness differences. That led me to loosening the 4 pieces of 1/4" attaching hardware slightly to allow movement. This eliminated a

 slight creaking sound @ warm up and reduced any stress caused by temperature changes. Fussy I know - just me.

Wow! Deja Vu all over again!(ala Yogi)  I also noted the clicking sound but was at a loss to understand at that moment. Your experience and mine are the same!  Perhaps I should have the two pieces welded as others have done? How did your hold up over time?

I would NOT have the two pieces welded together.  Why? The uneven expansion will continue and could very well end up cracking the thinner material as it expands and cools faster in the thermal cycle. You will

 continue to hear noises. The creaking noise could very well develop into a rather loud pop. If one of the two pieces required replacing, both pieces would have to be replaced as they are now one.

 As far as holding up goes: I had a good two years of use from the set-up and off to my daughter it went when I got the Memphis.  She has had it close to three years w/o issues as far as I know. It doesn't get

 the use it did as when I had it.

 To allow for the different expansion rates, all the holes need to be slightly larger than the bolts, ~ 1/8 to 3/16" larger.

 To keep things together, double nutting is a good way to go. The first nut barely finger tight; with that being held along with the bolt, then firmly tighten down the second nut. This will allow the two parts to float

 or move independently from each other yet keep them together.

Good advice John, I think I have enough bolt length to do so.  Will look into it. I wonder if the second nut is really necessary since the heat and soot pretty well locks the nut in place anyway?  Really took some tork to get the original nuts to move when removing the bolt/legs. A little research is in order---.

I had made a lot of mods to my Blazn' GridIron when I had it.
Posted them back on the PH forum.
Don't know if I have any pictures around, I'd have to look.  Have some drawings I think.
I made a funnel for the hopper for easier filling, Extra weight on lid (was always worried about wind blowing it closed), new heat deflector, new grates (the roller grates sagged), New longer handle for opening lid, shelf for side to set thermometer(s) on, and added a Smoke Daddy.

I also ditched the roller grates. Surprised they still use them after all the complaints, i.e. sagging and not rolling. I replaced with custom 3/8" 304 SS. I also put insulation on the floor because a hot spot there kept the paint peeling on the bottom. Otherwise the pit was a good one. Online service was also good. All USA made.

I also ditched the roller grates. Surprised they still use them after all the complaints, i.e. sagging and not rolling. I replaced with custom 3/8" 304 SS. I also put insulation on the floor because a hot spot there kept the paint peeling on the bottom. Otherwise the pit was a good one. Online service was also good. All USA made.

You jogged my memory, I put metal plates in the bottom for same reason.
Tim was always great with helping out.

Yes Tim was helpful.  I had no trouble selling the pit.  Someone came up from Oklahoma City and carried it away. I got a good price for it as well. Never heard again from the buyer so assume he was happy.
Except for the warped deflector, I am satisfied with the RT products and service. 

Just had email exchange with RT Service. Got an immediate response as follows:
1. Warp is common and does not affect the cooking characteristics
2. They don't replace the diffuser any more since it will just warp again.
3. He did not respond to my comments on change made by the mod.  i.e. Slow cool down, and altered high temp.
4. Said he would remove the mod and ignore the warp.

Conclusion: Will think on it. 

Just had email exchange with RT Service. Got an immediate response as follows:
1. Warp is common and does not affect the cooking characteristics
2. They don't replace the diffuser any more since it will just warp again.
3. He did not respond to my comments on change made by the mod.  i.e. Slow cool down, and altered high temp.
4. Said he would remove the mod and ignore the warp.

Conclusion: Will think on it.

  RT service is correct. Traeger says the same thing...  I feel any warpage in a pit is due to poor design based on cost. In this case, thicker, more expensive material shouldn't warp. RT as well as others have

added no cost stiffener ridges to to reduce warpage of their heat deflectors. Their effect is minimal @ best.

 The reason I reinforced the heat deflector on my Traeger is I didn't want it getting worse (warpage) and felt straight & true just felt better to me.  Much like well organized lines(ropes) on a sail boat. Neat and

tidy wins.

Wow, that is not what one would expect to hear from the best customer service out there.

 I can not imagine wanting to remove you plate, you just upgraded your cooker and made it better.

I have to believe that warping depending on how bad would throw temps off some side to side.

If that is their stance I wonder why they ever replaced any of them under warranty.