Repairing bent or broken external heatsink fins?
- Thread starter Pageplayer
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Pageplayer
Active Member
Zeb, Are you offering to fix my heatsink?
PM me with details.
CoastinHome
Well-Known Member
Beat me to it. That's the stuff.
I worked at a small hardware store 45 years ago and one of the samples to show the strength of JB Weld was two Chevy intake valves glued face to face. Hard as I tried, with cold chisel, sledge hammer and a rock-solid vise, I could not separate the two. I was sold and have used the product many times over the years - always with success. I've also used the newer fast setting version with the same success -- but I think you'd do better with the slow setting stuff because of the clean-up time.
If you've broken off the fin and have a good fit, I would hold the fin in place and adhere some strong tape to one side of the fin. Then bend the fin back using the tape as a hinge, fill the gap with this thermally conductive steel epoxy, hinge the fin back into place, then clean up the excess with lacquer thinner or acetone then place tape on the cleaned surface. Make sure it's straight and let it dry. Do your best to avoid excess unless you are able to file or grind the area. It's a bit of work to remove once dry -- just like filing steel.
That should give you a strong-as new fin. If you did a clean job you might be able to get away with touching up the repair with a Sharpee (assuming black fins).
I'd leave it. Any attempt to fix, short of replacing whole thing could get uglier. You won't lose any appreciable heat transferability. If in doubt, use a small fan. Once cracked, bending back will leave a hunk of metal in your hands. If just bent, probably ok to unbend. My experience with things like this. Ymmv...
Probably JB Weld...
And a coat of paint. That is what I would do.
That's good shiite, just mixed up a dab 2 days ago to cover a coolant tank crack in my beater money-pit volvo wagon.Probably JB Weld...
OP& owner of that repaired finnage still will have to be diligently cautious in handling that thing from this day forward, however.
petehall347
the brandy coffee man
that jb weld doesn't work for me . tried it on an engine block crack and it peeled off . ended up cold stitching it .
You really need a donor heatsink to repair severe damage.
You can't weld the pieces back together. I had a pro at the Trane (Lacrosse, WI) HVAC company's maintenance welding department give it a shot. If Brian can't weld it, no one can.
JB Weld is the best route, plus a regular guy can sort it out using a Dremel, EZ406-02 metal cutting kit. DigiKey has them.
You can't weld the pieces back together. I had a pro at the Trane (Lacrosse, WI) HVAC company's maintenance welding department give it a shot. If Brian can't weld it, no one can.
JB Weld is the best route, plus a regular guy can sort it out using a Dremel, EZ406-02 metal cutting kit. DigiKey has them.
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Nice work @zebulon1 .....I have worked with all kinds of metals for most of my life....would have been the way I would have picked to fix it!
Pageplayer
Active Member
The Amazing Zebulon1 !
I'd like to give that a try next time I need to repair on a similar heatsink but the epoxy bonding method works for most of us, and it's pretty foolproof. Mostly for cosmetics, which helps us OCD types sleep.
I had to buy some fresh Filler and Leveler. Got about $20 plus the donor heatsink I've been using. Less than a used heatsink if you can find one.
Just an update, there actually IS a way to repair that heat sink fin and not lose functionality. As an example, many small engine carburetors are die-cast zinc ("pot metal") and lower-refined aluminum castings. There is a relatively low-temperature alloy filler rod which can be used to successfully repair these provided the proper cleaning and flux are employed.
The alloy has a tensile strength of around 22KSI, which was really important for this since the fuel tank actually hangs onto the carb body with no other support. This one cylinder thumped away for many hours after the repair without a problem. I'm thinking a moderately abused heat sink fin probably wouldn't place that much stress on the repair.
The alloy has a tensile strength of around 22KSI, which was really important for this since the fuel tank actually hangs onto the carb body with no other support. This one cylinder thumped away for many hours after the repair without a problem. I'm thinking a moderately abused heat sink fin probably wouldn't place that much stress on the repair.
That's just about what I'd do. Had some bent aluminum rack handles on a piece of gear that I refurbished that way.