ajdelange

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As I said in an earlier post they dump heat by ablation which is orders of magnitude more efficient than black body radiation.
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preliminary tests just with mirrored and brushed#4 finishes (looks like what CT is, or maybe 2b)

1st test is showing:
After 1 hour in direct sun, no wind ambient temp about 85F on 12x12" 304 stainless
Mirrored finish is 128F (warm barely hot to touch for 10 secs)
brushed finished #4 is 138F (uncomfortable to touch for 10 sec)
 
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ajdelange

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I don't know how you are measuring temperature but I will point out that IR thermometers don't work with stainless steel (or at least 300 series - emissivity isn't 0.95). The fix is to stick a piece of black electricians tape onto any stainless article you want to measure and shoot that.
 


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I don't know how you are measuring temperature but I will point out that IR thermometers don't work with stainless steel (or at least 300 series - emissivity isn't 0.95). The fix is to stick a piece of black electricians tape onto any stainless article you want to measure and shoot that.
Yea, I figured that would be a problem, especially with the mirror. The IR gun I have u can adjust emmisivity(I trying a couple from an emmisivity chart, but not very reassuring and mirrored might not work start all) I just tape a temp prob to them.
Thanks for the tape tip, I was afraid the black tape would get hotter then The metal creating a hotter than actually is issue
 

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Yes, that could happen if the sun hits it so you would want to put it on the side away from the sun.

The polished stuff is a mirror to visible light - not necessarily IR.
 

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Please tell me how ferromagnetic it is. Qualitatively.
 


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Please tell me how ferromagnetic it is. Qualitatively.
We dont know exactly what Tesla will be using, so telling u if this metal is magnetic seems useless. the 1 im using is 304 series cold worked, but not hardened. EDIT FYI it actually is VERY VAGUELY magnetic, a small neodinium magnet just barely attracts to it. able to hold just itself up when the plate is held vertically

all we know is Tesla is using "30x ultra hard cold worked stainless steel" so I would think theirs is at least partially hardened. I will probably get a hardened 301 plate to do tests on also, at a later time.
 
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looking up 30x stainless steel plates on McMaster Carr today. 301 6” by 6” plates $26.29; 303 6 x 6” $162.65; 304 6 x 6” for $13.17; 321 6x6 for $18.47. different thicknesses, a bit confusing. But seems like 30x will be close to 304.
 

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I have been wondering a couple things, mostly how hot the CT will get in direct sun all day. (Also just thought of will it elongate or do temps need to be higher for that?)

I'm going to get a couple 6x6 .12inch( or as near 3mm as possible)pieces of a 300 series stainless. Paint a piece black, do nothing to 1, near mirror polish 1. Maybe paint 1 white,test the temps. Also I'll shoot a piece with a 9mm.

Any thing else y'all would like to have tested?

Of course this is just for fun and a bit of info. we don't know the alloy or if its heat treated,or do we? Elon does say "ultra hard 30x steel"
I guess I'll get a hardened sample to test, depending on what I can find (Unless some1 wants to let me in on the secret Sauce. I wont tell)

1st test is showing:
After 1 hour in direct sun, no wind ambient temp about 85F on 12x12" 304 stainless
Mirrored finish is 128F brushed finished #4 sitting at 138F
2 questions, what does it take to make it rust and How magnetic is this SS? I was going to use high strength magnets to attach lights for camping but I do know the more it doesn't rust the less magnetic it is.
 
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looking up 30x stainless steel plates on McMaster Carr today. 301 6” by 6” plates $26.29; 303 6 x 6” $162.65; 304 6 x 6” for $13.17; 321 6x6 for $18.47. different thicknesses, a bit confusing. But seems like 30x will be close to 304.
yes 304 is the most common and thus cheapest.
But there's also different finishes that change the price a bit
as well as whether they are hot vs cold rolled
and of course thickness. We are looking for 3mm or about .112 inch

but i havnt been able to find a 304 thats hardened, Elon said "ultra hard" so i would assume that means its hardened . I can only find 301 series hardened
 
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2 questions, what does it take to make it rust and How magnetic is this SS? I was going to use high strength magnets to attach lights for camping but I do know the more it doesn't rust the less magnetic it is.
Thats not necessary thru, the grain structure (how the metals molcules are aligned, basically) also effects it. This metal is VERY VAGUELY magnetic, a small neodinium magnet just barely attracts to it. able to hold just itself up when the plate is held vertically

i can probably get a simple rust test going too.
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