# Getting rusted snapped screw out of aluminum **URL:** \ **Category:** Factual Questions\ **Created:** [March 3, 2013, 2:14am UTC](https://boards.straightdope.com/t/getting-rusted-snapped-screw-out-of-aluminum/651873 "2013-03-03T02:14:18Z")\ **Posts on this page:** 9\ **Page:** 2
**Author:** ![Napier](https://avatars.discourse-cdn.com/v4/letter/n/ce73a5/32.png) [@Napier](https://boards.straightdope.com/u/Napier)\ **Post date:** [March 5, 2013, 3:28am UTC](https://boards.straightdope.com/t/getting-rusted-snapped-screw-out-of-aluminum/651873/21 "2013-03-05T03:28:19Z")
> [@Rick](#): > > The OP said it is a #8 screw which would indicate a sheet metal type screw not a machine screw. So unless he can convert to a machine screw, heli coils are off the table. > #8 is kind of small and I doubt that even with my rather extensive collection of easy out I have one small enough to fit. > If the material is thick enough it could be drilled almost the full depth using a drill press then either use a larger sheet metal screw (#12?) or use a blind hole tap and use a machine screw. Could be an 8-32 machine screw. ---
**Author:** ![Rick](https://avatars.discourse-cdn.com/v4/letter/r/9f8e36/32.png) [@Rick](https://boards.straightdope.com/u/Rick)\ **Post date:** [March 5, 2013, 5:00am UTC](https://boards.straightdope.com/t/getting-rusted-snapped-screw-out-of-aluminum/651873/22 "2013-03-05T05:00:37Z")
Yes but I have always seen machine screws listed as 8-32 and sheet metal screws listed as #8. In any event using an easy out on an 8-32 screw? I have never seen an easy out that small. ---
**Author:** ![Crafter\_Man](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/crafter_man/32/458_2.png) [@Crafter\_Man](https://boards.straightdope.com/u/Crafter_Man)\ **Post date:** [March 5, 2013, 5:20am UTC](https://boards.straightdope.com/t/getting-rusted-snapped-screw-out-of-aluminum/651873/23 "2013-03-05T05:20:05Z")
> [@Mdcastle](#): > > I’m not that concerned about scratching the aluminum since it’s inside something and not normally visable The inside of a large, grid ball, perhaps? :eek: ---
**Author:** ![CalMeacham](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/calmeacham/32/35_2.png) [@CalMeacham](https://boards.straightdope.com/u/CalMeacham)\ **Post date:** [March 5, 2013, 1:38pm UTC](https://boards.straightdope.com/t/getting-rusted-snapped-screw-out-of-aluminum/651873/24 "2013-03-05T13:38:49Z")
> [@Kevbo](#): > > Nitric acid is the true nerd solution. It will attack iron but not Al. Precautions are in order if you take this approach. When I broke off a screw in an assembly one of our Experimentalist Gods told mre the solution. He told me to make a cofferdam around the hole with a cut-off piece of large diameter glas tubing and RTV, then to put an acid solution in the cup thus created and heat it all with a hot-air blower (basically a hair dryer). It dissolved the screw remains in no time at all. He asked about the material of the fixture and the screw before recommending an acid, so it makes a difference. But nitric acid sounds OK. I suspect you can cofferdam with clay or something else, too. You can get RTV at Home Depot. Wear safety glasses if you try this. ---
**Author:** ![Mdcastle](https://avatars.discourse-cdn.com/v4/letter/m/958977/32.png) [@Mdcastle](https://boards.straightdope.com/u/Mdcastle)\ **Post date:** [March 5, 2013, 1:41pm UTC](https://boards.straightdope.com/t/getting-rusted-snapped-screw-out-of-aluminum/651873/25 "2013-03-05T13:41:34Z")
It is a machine screw. ---
**Author:** ![bobot](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bobot/32/21622_2.png) [@bobot](https://boards.straightdope.com/u/bobot)\ **Post date:** [March 5, 2013, 1:53pm UTC](https://boards.straightdope.com/t/getting-rusted-snapped-screw-out-of-aluminum/651873/26 "2013-03-05T13:53:00Z")
I’ll drill it out, and if necessary heli-coil it for you. I’ll have to bring it to work with me. I live in the south suburbs of Chicago. How soon can you get here? ---
**Author:** ![johnpost](https://avatars.discourse-cdn.com/v4/letter/j/f17d59/32.png) [@johnpost](https://boards.straightdope.com/u/johnpost)\ **Post date:** [March 5, 2013, 2:55pm UTC](https://boards.straightdope.com/t/getting-rusted-snapped-screw-out-of-aluminum/651873/27 "2013-03-05T14:55:23Z")
if you try a chemical solution to this problem you should have more than enough chemical to neutralize the acid you are using. if it is a through hole then creating containment on the reverse side might be good or knowing the interior won’t be damaged by some acid. ---
**Author:** ![figure9](https://avatars.discourse-cdn.com/v4/letter/f/f0a364/32.png) [@figure9](https://boards.straightdope.com/u/figure9)\ **Post date:** [March 5, 2013, 11:46pm UTC](https://boards.straightdope.com/t/getting-rusted-snapped-screw-out-of-aluminum/651873/28 "2013-03-05T23:46:16Z")
If it is in a not visible place can you just drill another screw hole nearby? ---
**Author:** ![DWX\_9929](https://avatars.discourse-cdn.com/v4/letter/d/ba8739/32.png) [@DWX\_9929](https://boards.straightdope.com/u/DWX_9929)\ **Post date:** [March 7, 2013, 12:01am UTC](https://boards.straightdope.com/t/getting-rusted-snapped-screw-out-of-aluminum/651873/29 "2013-03-07T00:01:32Z")
The best penetrating oil is a 50-50 mix of transmission fluid and acetone. Best way to remove broken bolts is to weld a slightly larger nut onto the broken bolt. You can do this with bolts broken fairly deep (I have done this as far as 1/4" deep). The heat from welding helps to break the corroded bond. Work the nut back and forth, like a tap. [Previous page](https://boards.straightdope.com/t/getting-rusted-snapped-screw-out-of-aluminum/651873.md?page=1)