Good: Got my 2252B, Bad: Bent Edge

dawgfan

Member
My long-awaited receiver came today, but the lower left front edge was bent in transit. Last time someone posted this happening the focus was more on shipping practices than repairs. Please advise the best results you've had in straightening an edge back. Pic attached to illustrate damage. Thanks.


2252Bcorner1.jpg
 
Tony, I don't know who feels more sick about this... you or me!:worried: Check your email. I want to do what I can to remedy this.

Dave.
 
I think it was merrylander, who described a repair procedure using a pair of pliers and cloth wrappings. Let me see if I can find it...
 
OK, here it is. Peculiar thing, it is about another 2252B, with a bent ear.

http://www.audiokarma.org/forums/showthread.php?p=995570&highlight=faceplate#post995570

merrylander said:
If you are very careful, you can use a flat jawed adjustable wrench on the bent corner. Fold some carboard, a business card will do, around the faceplate and adjust the jaws tightly over the cornet at the diagonal of the corner. Pull slowly in the outward direction. Don't overdo it as the faceplate material will sometimes create a wrinkle pattern where the bend is.

Rob
 
Thanks luvvinvinyl. I'm going to wait and hear all of the thoughts on this before proceeding. I'm in no hurry and certainly do not want to inflict any further damage.
 
I've had to fix a couple faces that suffered similar damage. Take the faceplate off, lay the bent corner down on hard, smooth surface, place a piece of leather over it and gently tap it flat with a smooth hammer. If you are patient and take your time, you'll hardly be able to see where it was bent.
 
Worse than mine! What a nightmare!

tarior said:
I've had to fix a couple faces that suffered similar damage. Take the faceplate off, lay the bent corner down on hard, smooth surface, place a piece of leather over it and gently tap it flat with a smooth hammer. If you are patient and take your time, you'll hardly be able to see where it was bent.

This is twice or three times worse than what happened to me!
 
Aluminum is soft and any hammering, even through leather, will leave dents.

Had a Kenwood KA-9100 with a bent face. Pulled it off, and took it to my machine shop guy. He used an arbor press and cardboard to protect the front of the face, and with the press and some steel squares on the backside pressed the dent out. Looked a lot better after he was done, but anytime you bend a anodized plate like that it's going to stretch and distort the anodized coating, so even it you get it perfectly straight (unlikely) it will be apparent that it has been bent.
 
I got a Kenwood KR 9600 with a couple of bent corners, and that was how I straightened it out, you do need to hold the hammer so it strikes flat, and don't try and take the bend out in one whack. An arbor press is probably better, but I no longer have access to one.
 
I just received a 2226B that had a corner that was bent and then straightened(not by me). It shows up as a wrinkle in the aluminum and like EW said you can see the defect in the anodized surface. I don't know what method was used on mine to straighten it, but I would be very careful on yours, or you could wind up with an unwanted wrinkle also. I would think if you could apply some kind of heat it might make it more malleable. Good luck.
 
Heating it will leave a heat mark, and may damage nearby silkscreen lettering. If there is a crease, no amount of pressing or hammering will remove it.
 
The anodized front surface of a Marantz panel is almost as hard as diamond.

I lay the front panel, front side up, on top of a pair of aluminum 3/8 inch thick by 1 inch wide bar. The bars are under the panel on either side.

Then, I take a short piece of two by four end and place it right on top of the apex of the bend. The aluminum bar is diagaonal across the entire bend.

Hold the far end down with your foot so it doesn't jump up (mostly just too loud but could snap the plastic window out of it's socket.).

Then, I use a 4 Lb hammer and wack the wood good and hard. Don't be shy about it. The wood is far softer than the anodised aluminum and leaves no mark.

The panel will be perfect, with virtually no sign of the bend.

I've even taken out waves in the panel this way.

DH
 
nukeme said:
I just received a 2226B that had a corner that was bent and then straightened(not by me). It shows up as a wrinkle in the aluminum and like EW said you can see the defect in the anodized surface. I don't know what method was used on mine to straighten it, but I would be very careful on yours, or you could wind up with an unwanted wrinkle also. I would think if you could apply some kind of heat it might make it more malleable. Good luck.

Wrinkles happen because the person tried to rebend it using a pair of pliers or other similar such method. That method does not work very well because it tends to stretch the aluminum under the anodization.

DH
 
Short of using a hydraulic press, I would trust whsh93a's method more than any others presented here.
 
whsh93a said:
Wrinkles happen because the person tried to rebend it using a pair of pliers or other similar such method. That method does not work very well because it tends to stretch the aluminum under the anodization.

DH

Will your method take out the stretch or is it too late?

Mike
 
I'm not sure - once the metal is distorted length-wise, it's awful hard to push it back together!

Aluminum is good for only one or two adjustments - then it tends to break.

DH
 
whsh93a said:
I'm not sure - once the metal is distorted length-wise, it's awful hard to push it back together!

Aluminum is good for only one or two adjustments - then it tends to break.

DH

yup
 
Yup, that's what I'm going to do. Hammer the hell out of it and see what happens. I don't think it will hurt it anymore than it already is.
 
Hi nukeme,
I received two days ago a 2325 with a slightly bent corner. Doesn't look quite as bad as your 2252B but still... :tears:

Anyways I have been checking the formability of aluminium and it seems that warming it up a little before hammering/forming can't hurt.

Reading this thread I get the impression that a hydraulic press is the least bad remedy, and hammering the riskiest.

If you intend to hammer your faceplate I would advise testing on some scrap aluminium first.

Keep us posted. I'll take pics of my 2325 and post them here as well.
 
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