hydrive
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disolving a steel screw from an aluminum frame
Hi, I was wondering the best chemical to use to dissolve steel from aluminum. *Note- I am pretty sure the metals are steel vs aluminum, but I am not
100% sure.
Basically the aluminum item is a cell phone frame (Motorola droid). I believe the screws are steel (they are magnetic I know). The screws were
loctghted in (loctite was used on a few of the screws when the manufacturer assembled the phone) so the ones that have loctight are in place pretty
good. The screws also strip very easily. I figured I would use some acid to see if that’s strong enough to dissolve the screw fragments that are
remaining. The trick is I want to disolve the screw, not the aluminum frame. I have sample materials to test the chemicals on first, incase it does
disolve the aluminum frame.
I also tried using a screw extractor to attempt to remove the screws that are stripped but the screws are so small that the head of the screws broke
off upon extraction so I cant put another screw back in place till I remove the broken fragments of the original screw. I looked some chemicals up
and the following were suggested: hydrochloric acid, Nitric acid, and Sulfuric acid. What would be the best chemical to try in hopes of only disolving
the screw?
PS- all electronics (LCD, circuit board, etc) are able to be removed prior to the disolving because when the screw heads break off, it allows me to
remove the LCD and other electronic components. My problem is putting the phone back together because I cant put it back together if the screw
fragments are stuck inside the screw mount holes. Any info would be appreciated!
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m1tanker78
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Acids will dissolve the aluminum long before the steel screws. If you're able to remove all of the non-metals and electronics then hit the frame with
gentle heat from a torch. The thread lock should loosen (unless they used the red stuff).
Tank
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blogfast25
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There's already another thread on that subject in this section. Use the search facility (top left of dashboard).
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LanthanumK
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A non-chemical way: Drill the screws out.
hibernating...
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barley81
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Concentrated nitric acid passivates aluminum but will dissolve whatever the screws are made of (I haven't actually tried this) Here's a video from
NurdRage where this property is applied:
http://www.youtube.com/watch?v=d6hPgGV_qAg
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Intergalactic_Captain
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Soak a q-tip in chloroform or DCM - rest it on top of the screw, replenish if necessary until you can remove the screw... I found this one by
accident a few years ago, with long enough exposure the cyanoacrylate will start to gel and lose its grip, though it might screw with the plastic and
painted parts of the phone if you're not careful.
If you see me running, try to keep up.
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ScienceSquirrel
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Mood: Dogs are pets but cats are little furry humans with four feet and self determination! 
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If you use a Dremmel type tool and a micro drill bit of the right size this is possible.
I have broken off a screw in the back of a SCSI card and I drilled a hole through the core of the screw. I then inserted a jeweller's screwdriver and
removed what was left of it.
A new screw bedded down very nicely in the unharmed hole.
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