My 7.5 foot Fisher blade rotted all along the upper edge due to it being stored with the A-frame pointed skyward..
I ran over the dam thing backing up in my driveway one dark night ,and the part with the 3 holes you pin to the truck mount destroyed a near new tire one day when I left it sitting on the ground in its normal position.

...I stupidly left it close to the driveway edge...
So I tipped it up,left it like that over a year..next time I went to use it I could see thru it all along the top..and another spot where the trip spring mount was welded to the skin too..
I used pieces of a 275 gallon oil tank as patch panels,it was thicker than the original metal and already curved,it worked perfect...used my arc welder with 6011 rods and 75 amps to melt it together..
During the last storm in 2015 when we had 12 feet fall between the end of January and April,the plow came off when I was backing away from a snowbank,stopped just in time to not rip the hydraulic hoses right off it..
The A frame on this blade is just 3" channel iron,which was just butt welded to the center pivot point bushing housing,cracked at the welds--I was able to weld it back together,and I wrapped a piece of 1/4" thick flat stock 3" wide around the channel iron and bushing and welded that in good to reinforce it,also added two angle iron cross braces to the triangle part to beef it up better..
This blade has only 3 trip springs--the previous one I had on my '77 GMC had 4 springs,and had a very beefy A frame made of 3/8" angle iron and was braced much better..I'd have kept it,but it was a wider spacing than the mount is on this truck 25" vs 22"..
The Diamond plow on my Suburban is built like a battleship--it has 3/8" angle on the A frame and also has an upper pivot arrangement that is super thick,the blade weighs a lot more than a Fisher too..