Fatigue cracking of hood inner structure

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   So, has anyone encounter fatigue cracking of the inner hood structure near the hinge mount points on a hood?
My GTS hood has suffered metal fatigue near the passenger side hood hinge mount surface, in front of the hood mount side of the hinge on the sheet metal. Looking into wanting to see if I can find a shop to waterjet some aluminum plates and roll the material if possible at this point, or worst case, get some 1/8" plate and having it bent to match the hood structure. 

Also, if you know of any shops capable, please drop me a message here, email, or message on facebook. 
Not exactly enthused but I'll make something look appropriate at this point.

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Eliteman76 Members Profile Send Private Message Find Members Posts Add to Buddy List Admin Group Joined: 20-March-2006 Location: Nebraska, USA Status: Offline Points: 4879	Post Options Post Reply Quote Eliteman76 Report Post Thanks(0) Quote Reply Topic: Fatigue cracking of hood inner structure Posted: 19-January-2023 at 3:33PM
	So, has anyone encounter fatigue cracking of the inner hood structure near the hinge mount points on a hood? My GTS hood has suffered metal fatigue near the passenger side hood hinge mount surface, in front of the hood mount side of the hinge on the sheet metal. Looking into wanting to see if I can find a shop to waterjet some aluminum plates and roll the material if possible at this point, or worst case, get some 1/8" plate and having it bent to match the hood structure. Also, if you know of any shops capable, please drop me a message here, email, or message on facebook. Not exactly enthused but I'll make something look appropriate at this point.
	Andrew:GTS.ORG admin, '72 Q code 5 speed Restomod Pondering: #99Problems

72 RS 351 Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: 04-September-2014 Location: Knoxville TN Status: Offline Points: 2445	Post Options Post Reply Quote 72 RS 351 Report Post Thanks(0) Quote Reply Posted: 20-January-2023 at 1:52PM
	I know that feeling about your hood, my 72 Sport hood finally began caving in years ago, that area where the force of pushing it down stresses it a lot. I have avoided opening the hood since then, knowing it needs to come off to do something about that.
	*Don* 73 Ranchero "Sport 72 front end", floor shift/console, planning EFI 7000+ rpm 351-4V &4R70W 73 Ranchero GT 351C-4V &4R70W for sale later. 92 Lincoln Mark VII SE GTC, OBDII 347/4R70W

californiajohnny Members Profile Send Private Message Find Members Posts Add to Buddy List Moderator Group Joined: 05-October-2013 Location: winlock, wa Status: Offline Points: 14512	Post Options Post Reply Quote californiajohnny Report Post Thanks(0) Quote Reply Posted: 20-January-2023 at 2:20PM
	for some reason the 72 hoods seem to be more prone to this! its caused by rusting from the inside out behind the bracing isnt painted and is bare metal
	JOHN 74 GRAN TORINO S&H CLONE 74 VETTE CUSTOM 90 S10 BLAZER 4X4 LIFTED 77 CELICA CUSTOM 75 V8 MONZA SUPERCHARGED 79 COURIER VERT. SLAMMED 75 VEGA V6 5 SPD 70 CHEV C10 P/U 68 MUSTANG FB CONVERSION

72 RS 351 Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: 04-September-2014 Location: Knoxville TN Status: Offline Points: 2445	Post Options Post Reply Quote 72 RS 351 Report Post Thanks(0) Quote Reply Posted: 20-January-2023 at 3:08PM
	Yes, I too noticed that the main surface paint was fine but there's visible rust inside the holes and behind the bracing. So over time on a hood that isn't being used(normal heat cycles help to reduce rust forming on the metal), the hidden areas start to corrode. Before the values went up many years ago, I figured I would find a better donor hood from a car that is beat up on the outside, and cut out the sections where the hinges attach. That may be the best way still, but it's more expensive now too.
	*Don* 73 Ranchero "Sport 72 front end", floor shift/console, planning EFI 7000+ rpm 351-4V &4R70W 73 Ranchero GT 351C-4V &4R70W for sale later. 92 Lincoln Mark VII SE GTC, OBDII 347/4R70W

Eliteman76 Members Profile Send Private Message Find Members Posts Add to Buddy List Admin Group Joined: 20-March-2006 Location: Nebraska, USA Status: Offline Points: 4879	Post Options Post Reply Quote Eliteman76 Report Post Thanks(0) Quote Reply Posted: 23-January-2023 at 7:16AM
	ok, in this case two thoughts: Would a brace waterjetted and bent to match the hood contour and then you have to drill holes, use a rivnut tool and install compression nuts in a few places be a way to resolve this? Or by drilling holes would I be creating potential failure points?
	Andrew:GTS.ORG admin, '72 Q code 5 speed Restomod Pondering: #99Problems

72 RS 351 Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: 04-September-2014 Location: Knoxville TN Status: Offline Points: 2445	Post Options Post Reply Quote 72 RS 351 Report Post Thanks(0) Quote Reply Posted: 23-January-2023 at 7:31AM
	The thickness of the metal all around that high stress area is the key. If you can make a brace section that extends beyond the critical area, and attach it very well, that should work. If the metal is thick enough, I'd weld it carefully around the perimeter, but only welding very short distances at a time. The support will be stronger if it's welded well, and if the base metal is still thick enough. I've thought of that but long ago figured I'd find a donor hood and make a larger project to use more of it. Making smaller bracing would be faster and easier no doubt.
	*Don* 73 Ranchero "Sport 72 front end", floor shift/console, planning EFI 7000+ rpm 351-4V &4R70W 73 Ranchero GT 351C-4V &4R70W for sale later. 92 Lincoln Mark VII SE GTC, OBDII 347/4R70W

californiajohnny Members Profile Send Private Message Find Members Posts Add to Buddy List Moderator Group Joined: 05-October-2013 Location: winlock, wa Status: Offline Points: 14512	Post Options Post Reply Quote californiajohnny Report Post Thanks(0) Quote Reply Posted: 23-January-2023 at 4:12PM
	12 or 14 ga. sheetmetal welding onto the structure should be plenty good
	JOHN 74 GRAN TORINO S&H CLONE 74 VETTE CUSTOM 90 S10 BLAZER 4X4 LIFTED 77 CELICA CUSTOM 75 V8 MONZA SUPERCHARGED 79 COURIER VERT. SLAMMED 75 VEGA V6 5 SPD 70 CHEV C10 P/U 68 MUSTANG FB CONVERSION