Flattening old HHL chips (2 Viewers)

[AK Chip]

Having success with flattening out old school HHL chips!!

Using the 43mm ceramic blanks with clamp, place in cold oven set temperature at its lowest 350 then set timer for 10 minutes. Almost on the dot the timer will go off right when the oven hits 350. Pull them out wait 30 minutes to tighten the clamp just a smidge and let cool.

 

[ekricket]

Watching closely, I’ve got a bunch.

 

[AK Chip]

Watching closely, I’ve got a bunch.

My fist batch I left in quite a bit longer than 10 minutes but even those don’t show much if any pinching
Here is a couple of pics of the ones I’ve finished, looks pretty decent and no more wobbling in stacks.

 

[ekricket]

Pull them out tighten the clamp just a smidge and let cool.

I’m my experience with other chips, this is where the “pinching” or “bulging” happens. I think the chips are in a state of equilibrium with the internal pressure, and that last tightening is where I “feel” them squishing into undesirable deformity.

 

[AK Chip]

I agree but I've found if this isn't done, during the cooling they will kind of go back to being warped when released from the clamp.

These HHL chips are the first ones that i couldn't make just a couple of slight twist on the clamp before it was tight again, these it felt like I could just keep turning them until they were completely smooshed.

 

[AK Chip]

estimating 30% have returned to warped condition.

I just did a batch without tightening at the end and have let them cool down longer than the others.

 

[AK Chip]

They came out just as flat,

 

[AK Chip]

So far the only ones staying flat are the ones I let cool down for a long time while clamped.

 

[Colquhoun]

So far the only ones staying flat are the ones I let cool down for a long time while clamped.

Wait, you’re un-clamping while they’re still warm?

 

[AK Chip]

Wait, you’re un-clamping while they’re still warm?

No, but on these last few that are holding I tightened the clamp when they were cooled off and let them sit about another hour.

 

[AK Chip]

 

[ekricket]

View attachment 1203981

Looks great!!

 

[AK Chip]

It looks like they will all hold flat; I was starting to get worried.

So, into a cold oven, set temp for the lowest possible 350 degrees. I then pulled the chips out as soon as the oven reached 350 approx 10 minutes. Let cool for 30 minutes and tightened the clamp a touch and let sit an additional hour.

 

[AK Chip]

More success!

 

[GreekRedEye]

Thanks for documenting. I have some HHRs that I need to flatten.