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Repairing bent or broken external heatsink fins?

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Pageplayer

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Happy Thanksgiving!
I tried searching different terms but got no hits.
So, does anybody have a technique for repairing bent or broken external heatsinks like those found on the Pioneer 1280 etc. ?
Are they made from pot-metal or aluminum?
Thought about bringing it to a fabrication weld shop to see if they could repair something like this.
 
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Usually they are die cast aluminum. Bent fins can be heated and carefully straightened, but would require refinishing afterward. Broken fins could be welded (TIG) and machined to match, then refinished. There's no really easy/effective alternative unless you have a replacement part. If you have a shop nearby which can successfully repair aluminum boat propellers, that's a good parallel to repairing the thin cross sections in these castings.
 
"aluminum boat propellers" is a great tip Watthour!!
The last fin towards the rear of a 1280 is bent in and slightly cracked.
I'm thinking it would possibly need to be broke off, straightened and Tig'ed back on and refinished.
You have gave me hope!
I'll document what I find out.
Thank you.
 
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got a pic?? I'd say air flow is more important and just a couple of bent vanes won't affect heat transfer 'en masse' Broken chip off a corner? glue it on.
 
I'm thinking that some heat at that corner to anneal the aluminum, bend it straight, then sand and fill over teh crack with epoxy. Re-sand and refinish. Of course. it will have to come apart for that.
 
That's an aluminum extrusion, most heat sinks are made with the extrusion process, think Play Dough Fun Factory. Aluminum in it's plastic state is forced through an extrusion die.
 
I know the smaller ones are typically extrusions, and I'm not sure about this SX-1280, but many larger units had castings. The G-9000 comes to mind.
 
my thoughts are its cracked from just one bending . that crack needs welding before anything .then the correct heat applied and eased back very slowly .
 
I suggested a boat propeller repair specialist since they are accustomed to welding on heat sinks (and an aluminum prop makes a great heat sink). Many smaller weedless props have cross-sections nearly as thin as this, and they are repaired routinely (and essentialyl invisibly) and hold up to use as a propeller once again. I've had entire blades replaced after leaving one in a log or next to a rock.

The welder would most likely pack it in a sand bath and lay the tungsten to it. A really good welder would probably add very little filler. And then there would be work to do after the repair and before refinishing.
 
Honestly, I'd leave it alone, probably not going to cause any problems. It just looks ugly.

You could straighten it and solder it, but the finish is anodized, so you'd have to send it out. Any paint would probably reduce efficiency. If it bothers you that much, find a replacement.
 
I'm going to remain positive and see this through. I see no reason why this can't be repaired.
Why bother? Because I love bringing these classics back from the brink. When I do these restorations I go above and beyond to bring them back better than new. Not just functionally, but cosmetically.

What will it hurt to try? If I fail repairing this heatsink, then I will look for a replacement. If If I'm successful then I'll pass on what was learned.
I currently have three 1280's in my possession. One of which is my keeper that I refinished with exotic veneer due to extensive case damage.
For the record, the heatsinks on these are not anodized. They come painted from the factory.
 
Those are thin and should bend back, personally I would put a rag on it so I do not scratch it and starting from the top down bend it back with some needle nose. I am betting the original point of Impact was closer to the crack versus the end of the fin. Fill the remaining silver in the crack with a black sharpie. Buff off the extra sharpie as it will look a little shinier than the original black.
with a little work you can blend sharpie well.
 
Yes, it's almost certainly a crack, but disassembly, heating to about 750°F, then bending it backnear the point where it is still attached should work if caution is exercised. It would still need to be reconnected somehow, either by weld, epoxy, or whatever. My choice would be weld.
 
You can not weld the pot material.
I bought a single 1980 heatsink as a spare.
The fin profile works in all the similar Pioneer models with some shaping.
You cut the material from the donor HS and graft it on the broken HS, attaching it with JB Weld. Using body working technique's (Sanding and some leveler) and a few coats of Satin bomb makes it perfect.
Only graft the damage not the entire fin. Use a 45 degree angle from the lateral attach point to help ease the transaction.
It's worth the effort.
 
Are you saying the 1280 used die cast zinc instead of aluminum? That would be a greater challange.
 
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