Ulma Doctor, Scraping Mentor

Just a partical from an "old Engine Guy"........after the bloc, casing, cover,or other
part was chipped, scraped , sandblasted, or whatever,it was primed and dumped
in the backyard for a few months to "settle down"before machining; and that is why
those ancient parts you are refurbishing are painted even in utterly inaccessible
corners. ..........BLJHB
 
Yea, I would drive up for that, Between work, and stuff it would be a nice break.
Jut learning how would be nice.
Then I would have a good reason to get more tools and stuff. :rolleyes:
 
I was reading the other night on about cast iron stress relief on certain grades needing temperatures to be brought up to 1500 degrees then down to 1000 slowly... after which keeping it there for sometime before slowly bringing it down to room temps. If they are suggesting it takes that much heat to do this how would such low temperature changes of outside weather make enough difference? Maybe a hundred degrees max over a year? Most swings being 20-30 degrees per day? I know Bridgeport and I believe south bend did a similar "outdoor" approach. I just wonder if there are any supporting cases of machining the same product after a normal cool down period vs. a few months or a year outside? Same batch castings of course.

Paul
 
I was reading the other night on about cast iron stress relief on certain grades needing temperatures to be brought up to 1500 degrees then down to 1000 slowly... after which keeping it there for sometime before slowly bringing it down to room temps. If they are suggesting it takes that much heat to do this how would such low temperature changes of outside weather make enough difference? Maybe a hundred degrees max over a year? Most swings being 20-30 degrees per day? I know Bridgeport and I believe south bend did a similar "outdoor" approach. I just wonder if there are any supporting cases of machining the same product after a normal cool down period vs. a few months or a year outside? Same batch castings of course.

Paul
I think it is an issue of time, and one of settling. Something in a stressed condition wants to move toward relieving that stress. Time can and will do that. The molecules of metal will subtly shift in the matrix toward a less stressed condition. It is always moving 'toward' the low stress condition, never actually reaching it completely. We would like to hurry the process up. Heating it to 1500 degrees will let the stresses out, but some new ones will form as it cools. In the production and use of metals, a lot of time and energy goes into relieving stresses. Some of it is science, some of it is pragmatic (whatever seems to work best.) If you brought the subject up at a place like a foundry workers or steel mill workers convention you could probably raise a 'heated' discussion...
 
It's very interesting to me. Odd how the stresses of molecules closely resemble the human condition! :)
 
Hi Nez,
i'd love to come back down to Austin and San Antonio, it's been a long time.
I'd be proud to show y'all what i have learned!!

At the Rongero Inn "we'll leave the lights on for you" And I will stock up on San Miguel beer.

We'll make this little jewel near perfect. Do you remember it passing through Ulma Doctor's shop for certification?
20170302_003817.jpg
 
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Then there is cryogenic treatment process as further help to get castings, or just about anything to remove stress.
I hope I am allowed to put in a link here. At http://www.cryotron.com/index.html under the solutions tab are three articles, Cryogenic Stress Relief, Wear Solutions, Thermal Stresses in Castings, that provide some information. They gear it to automotive type products but reference other industries.
I have experimented with cryogenic treatment using styrofoam containers and dry ice. I think it worked for me. Time will tell.
Also striking metal with any instrument is a form of shot peening another form of stress relief.
 
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