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Unread 26-06-2004, 18:36
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dlavery dlavery is offline
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Re: Tapping broken taps (a.k.a. I'm all tapped out)

Quote:
Originally Posted by patrickrd
So, I'm thinking of two possible errors:
1) I didn't put in enough alum (what are the correct proportions of alum to water?)
2) The water quickly cooled to room temperature... Maybe I should keep it boiling like the instructions say.
You want the alum solution to be pretty well saturated. The last time I needed to do this, I dumped the entire container of alum - one of the little ones from the spice rack in the grocery store - maybe three ounces? - into about a pint of water. Heated it up to simmering, dumped in the part and walked away. It worked just fine, and after a few hours the part was tap-free.

Quote:
Originally Posted by sanddrag
I saw this thing on a show called Trucks! that was like a big bowl of nut shells or something and it vibrates a lot and you put your parts in there and they come out real nice after like a day. I think it was pretty expensive though.
That is exactly what it was. Vibrating bowls are used to provide a number of finishing operations for metalworking. A number of different materials are used, based on the finish desired or the rust/scale/crap to be removed. Ground walnut shells and fine playground sand are two of the more common materials. Left in the vibrating bin long enough, ground walnut shells will provide a nice polish to most metal parts.

[EDIT]There is a simple tumbler design here that will work very well for cleaning and polishing small parts.[/EDIT]

Quote:
Originally Posted by Astronouth7303
An ultra sonic cleaner. Usually used with jewely. The problem with mechanical means of removing R&C is that you actually remove material. They won't fit together as well any more.
Ultrasonic cleaners will work real well to remove grease, oil and even old paint. They ususally don't do so well will rust and scale.

If you are specifically looking to remove rust, there are several ways. For small parts, or light rust, several methods already mentioned (Naval Jelly, steel wool, sandblasting, etc.) work quite well. If you have a lot of items to de-rust, or it is very deep into the part, you can try rust removal by electrolysis. For this method, you place the iron/steel part in an alkaline solution, pass an electric current through the solution, and blast some of the ferrous oxide back into good metal (you hope). There are good instructions on how to do it here and here. I have used this method once, and have a friend who does this a lot when restoring old machine tools, and it works quite well. And, yes, the resulting solution really is as nasty looking as that crud in the second link...

-dave
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Last edited by dlavery : 27-06-2004 at 09:33.