how to widen the return hole (AGA)

[bayareaquarist]

<a href=showthread.php?s=&postid=10550889#post10550889 target=_blank>Originally posted</a> by boviac
It is common for reef ready tanks to be drilled on the bottom plate, then tempered, and then assembled.

And once they're tempered, I wouldn't mess with it.

I like the idea of griding down the threads on the insertable part.

Really?? I mean if its tempered dont even think about trying to fix the problem there...but drilled then tempered?? How do they keep the hole from compromising the entire piece?? do they treat the edge of the holes with something??

 

[bayareaquarist]

<a href=showthread.php?s=&postid=10550963#post10550963 target=_blank>Originally posted</a> by Reefugee
I would NEVER grind down the threads. You don't want to risk the chance of weakening your bulkheads. Save yourself some headache and purchase the right bulkheads.

Minh

Not "grind" down the threads...just take off enough material so that they sqeeze into the holes...tephlon tape em and tada~!

I do believe in the mantra of using the right material for the job but this hobby can be quit pricey so DIY mods are awesome~!

 

[boviac]

I don't know the exact science or manufacturing technology on how one tempers glass. But I understand that the sides (front & back) are made stronger than that in the middle. Yes the holes do weaken the glass somewhat and a circle or radius is the best to minimize stress risers, but generally the thickness of the glass and the following tempering increase its fracture strength to an acceptable factor of safety. - Hey a BS in mechanical engineering and I know just enough to be dangerous.

 

[bayareaquarist]

LOL @ Boviac~!

BS In mech Eng...nice~!!

From what I undestand they heat up the piece near its softening point and then cool it down rapidly with jets of air focused more towards the edges of the piece to increase internal stress within the glass and that stress is what makes it "stronger"...The outside edges posses the highest level of tensil strength.

Heres a readable link about tempered and heat-treated glass...

http://www.alumaxbath.com/tech/tgp.htm