repairing perforated cutting decks

well, i had pulled the deck off the tractor couple weeks back, and have been replacing the bearings in the spindles, pulleys etc. this weekend i got around to sanding the deck in prep for painting, when i found some pinholes - odder part is they weren't obvious from the top side, just from underneath

and this is the second deck i've refinished with the perforations in the same spot, in the "tunnel" above the blade with the high lift wings, on the discharge side (sorry, but in the photos, i forgot to take one of the whole deck, but you can figure out where it's located

the perforations (about 5) were all in or near the turn or corner in the deck, where it turns from flat surface (what would be the "ceiling" above the blade) to the side wall of the shallow round well the blade resides in. And as that section is the last part of the path debris, cuttings etc follow before going out into the discharge chute, i suspect it's just a matter of abrasion from the debris, sand etc flying thru there

anyway, i figured i'd try to start a weld from the flat part of the deck, where the metal still has some thickness to it, and walk the weld over to the pinhole (for those that don't weld, welding paper thin metal is difficult and i couldn't be rustier at it). anyway first attempt, the welding wire coming out of the mig welder shoved a 1/2" circle of metal up, not burnt thru, just literally popped it out

i started my repair, that in the course of it, a better and easier approach would have served as well.

i took a short section of a 1" diameter wooden dowl just to see how it fit the radius of the turn in that "ceiling" to sidewall corner, it fit near perfect so i knew what i'd need for a forming tool.

I had some 1.5" wide strips of mild alloy carbon steel (wish i'd had some 4140 chrome moly but it was sunday) - cut some 1.5 - 1.75" long pcs from one of those strips on the chop saw, and formed them in the vice (opened the vice about a 1" spread between the jaws), heated em with a torch to soften em a little, and used a 1" steel pipe i had for the form tool, laying it on the short pc and tapping with a hammer till i got what looked like the radius turn i needed. When they cooled i checked em against the actual spot they'd be welded into and adjust em as needed.



(Please don't judge the welding - the argon bottle on my MIG welder was real low and i was getting a lot of sputter / splattering from the wire but it was sunday and i wanted to get it done.)



Then it hit me -instead of welding anything, i could have just used some stuff i'd bought to repair the 4514 muffler i had (it had a small 1/8" diameter hole). I'd tried this stuff for the hey of it, and it actually works **** well. I tested it on a pc of scrap metal - not sure what the bonding agent is, but it looks like 50W motor oil with a bunch of metal ground dust mixed in. When it cures fully (it takes some heat), it will not sand but you can use a grinder or file to shave it down if you want. You can drill it, drill & tap it, machine it, you name it. It has the durability, and fixing pinholes in metal is exactly what it's intended for. JB Weld has some similiar qualities but doesn't have the abrasion resistance this stuff has.

it comes in small bottles (approx 2 oz volume) but it seems to go a good ways - but it doesn't spread or apply like sheet rock mud, more like dry mixed concrete, but it is strong.

what i should have done was to abrade the pinhole areas with a grinder, degreasing and spreading a thin skin of this stuff would have been a heck of lot easier and as durable. Next step is to sand it down with some heavy grade sand paper i've got for the metal grinder, then after rustproofing, i'll smooth that surface with a heavy coat of the pickup truck bed liner material

before skinning the welded in pcs with this stuff, i used the grinder to bring the welds down to the level of the small pcs welded in - target is or was to keep that surface as smooth for air flow as possible.

here's a shot of it (i bought two bottles, used less than 3/4s of one)





in case this helps someone or gives em an idea for a better solution
but this should extend the life of my perforated deck.