Blueing contraption......

Harold Visser

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Here is a little contraption I made for effortless blueing of screws and hands. A good friend of mine made one and I knew I had to copy him. It uses a temp control that can be set to hold a certain temp closely on a brass block. A ten buck thermocouple, 200W heater, brass block, $25 dollar PID controller, 6x6 electrical box, relay and some wiring. Dark blue (570F), plum (540F) or gold (450F), easy as can be, just set the temp. I drilled a number of different sized holes for screws and milled a larger hole for hand hubs so they lay flat. No more watches a blueing pan intently, or having hands overblue at the tips....
 

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Ralph B

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Looks like a great idea Harold.

Any chance of a basic circuit diagram, and where the parts were obtained, for the non techies like me ?

Cheers
Ralph B.
 

Harold Visser

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Ralph, Most came from Amazon, PID control $18 to $36, SS 20A relay $10, Ktype thermocouple $3. The 120V 150 or 200W cartridge heater Ebay around $10. The brass block I already had, 6x6box came from Home Depot. Even though I have the brass block an inch and a half off the base , the base still gets really hot. Someway to heat isolate it would be nice.....
 

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Ralph B

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Thanks a lot Harold, this is definitely something I'll have a go at.
The occasional small screw is one thing but I recently had a hand off an English regulator to blue that was about 6 inches long by 3/16 wide. Bit of a mission that I'm sure a machine such as yours would make easier.

Thanks for going to the trouble.

Cheers
Ralph B.
 

Harold Visser

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Doug, the 2"x1.5"x1.5" brass block is solid. The only reason I used that size is because it was something I already had in my scrap pile. Any size brass block would work, but wouldn't recommend any smaller, mass is important so temp can be kept stable by the PID. I drilled a 10mm hole clear thru for a snug fit of the cartridge heater, drilled & tapped for the thermocoupler, and four 10/32 tapped holes for the mounting legs. The small holes on top are for the various screws sizes to be blued, the screws and hands could just as easily be loosely laid on top of the heated brass block. It just keeps them from rolling off if the unit gets bumped.
 

doc_fields

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Harold;
Great idea! But, what is a PID control? Could you elaborate? And, was the thermocouple the type used in furnace heating or hot water heaters? Those I am familiar with. Thanks!........................doc
 

cazboy

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Doug, the 2"x1.5"x1.5" brass block is solid. The only reason I used that size is because it was something I already had in my scrap pile. Any size brass block would work, but wouldn't recommend any smaller, mass is important so temp can be kept stable by the PID. I drilled a 10mm hole clear thru for a snug fit of the cartridge heater, drilled & tapped for the thermocoupler, and four 10/32 tapped holes for the mounting legs. The small holes on top are for the various screws sizes to be blued, the screws and hands could just as easily be loosely laid on top of the heated brass block. It just keeps them from rolling off if the unit gets bumped.
Harold, OK, I think I see! That block isn't a box that opens, it's a large mass to hold a steady temperature. The principle is totally solid - mass retains heat easily, where air would disperse it.

Harold;
Great idea! But, what is a PID control? Could you elaborate? And, was the thermocouple the type used in furnace heating or hot water heaters? Those I am familiar with. Thanks!........................doc
Hey Doc, I was wondering the same thing so I looked it up. Apparently PID stands for "Proportional, Integral, Derivative". I found a couple of informative websites, and one of them says that car cruise controls and house thermostats are two examples of PID control. PID controllers are made to eliminate the need for constant operator attention. Read more here: http://www.expertune.com/tutor.aspx and the Wikipedia entry here: https://en.wikipedia.org/wiki/PID_controller

Harold, that's a BRILLIANT idea! Congratulations on making a working prototype, and especially for sharing!
 

R.G.B.

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That's a great idea. Way better than my binding wire laying over the toaster and holding the handle down. :)
 

Ralph B

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My bits are on the way.
Bit of a hunt around on Ebay found that you can buy the controller, relay, and thermocouple as a complete kit for about 40 bux. A heater about $7.

I now have a use for the 2" X 2" X 6" lump of copper bar that's been lying around the workshop for years.

Ralph B.
 

R.G.B.

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RGB, that's not such a bad idea, really! Wire over the toaster and holding the handle down - hmmm... I can see how that would work pretty good.
It does work well for clock hands, certainly better than a torch. This fabrication looks like it would be much better for watch hands and screws. Thanks Harold.
 

jhe.1973

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Thanks for sharing this Harold.

I really like the idea of a PID controller and I'm going to add this to the big box store hot plate I have been using. I added a 1/2 inch aluminum plate over the element to more evenly distribute the heat.

Here I was monitoring the temperature w/a K type thermocouple for a critical welding job:

Weld18a.jpg

I know it ain't horological but it seems to me that your idea will apply here too and the hot plate offers a ready made stand.

:thumb:
 

jhe.1973

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Harold;
Great idea! But, what is a PID control? Could you elaborate? And, was the thermocouple the type used in furnace heating or hot water heaters? Those I am familiar with. Thanks!........................doc
Hello Doc,

I just noticed that your question about K style thermocouples wasn't addressed.

The K refers to the temperature range the thermocouple is accurate for. Here is a close up of the digital thermometer I was using above:

1.jpg

Here are 2 styles - both K's - and the thermometer:

2.JPG

Close up of the simple one showing the end where the two dissimilar wires are welded together at the tip. The thermometer measures the tiny current generated when the tip is heated:

3.JPG
 

doc_fields

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Thanks Jim! I have a Simpson meter used for readings in stoves, dryers, etc., and have the same thermocouple as your last picture, just didn't know they were called K-style thermocouples. Thanks much. BTW, at the Erwin Sattler site, I ran across a brief mention of their blueing of hands, and they mentioned the temp. at which they blue their hands. Maybe they have a similar device to blue with like this one mentioned here.............................doc
 

Ralph B

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Done!

Finished my contraption a few weeks ago and have since used it to do some long case hands.
Worked really well as I was able to dial in the temperature a bit at a time and experiment.

Interestingly the steel wouldn't blue absolutely consistently despite my being absolutely sure it was being evenly heated.
No wonder it was so difficult at times even without a machine such as this.

Photo shows the bluing underway.

Ralph B. DSCN1772.jpg
 

Max Phillips

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Done!

Finished my contraption a few weeks ago and have since used it to do some long case hands.
Worked really well as I was able to dial in the temperature a bit at a time and experiment.

Interestingly the steel wouldn't blue absolutely consistently despite my being absolutely sure it was being evenly heated.
No wonder it was so difficult at times even without a machine such as this.

Photo shows the bluing underway.

Ralph B.
Nice work! I need to put together something like this, it's only a matter of time until I need to blue pieces that are really too large to easily do over a propane torch or alcohol burner. Regarding the even bluing, I can see your hands aren't making good contact with the heated surface, in your picture. I think you'll have much better results if you place your hands on a bed of something that will make uniform contact on the underside of the parts being blued. Clean brass shavings work really well but for stuff that size I'd be tempted to try some good clean, dry sand... I've even heard of using salt. You probably know this already, but cleanliness plays a huge role in the bluing process as well. Any trace of oil or moisture will ruin your color (it often manifests as spots or blotches where the contaminant was present), and also be aware that moisture/oil in your bed of material (sand, brass, whatever) or on the underside of the part being treated, will tend to migrate up onto the top surface of the part and, again, give you blotchy/spotty color. I haven't been doing this a long time, but that's my 2 cents.
 

Ralph B

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You're right about the contact Max but to get those old hands dead flat would be a mission on its own.
I have a tin of clean, dry brass filings I used to put in an old frypan to blue hands so I'll use those next time to see if it does a better job.

There was one part of the seconds hand that refused to blue well even though the entire hand was flat and making good contact.
I have suspicions that the way the steel was treated/tempered made for inconsistencies in its structure that influenced the bluing.

This thought is reinforced by another job I did recently.
As a bit of light relief from clocks I made a "preacher", ( for a friend, as I already have one ).
The three small steel stakes required were made out of silver steel, ( drill rod is your nearest equivalent), and just the tips hardened. They were then cleaned up and blued on my new toy.
The hardened ends were all a slightly different shade of blue from their unhardened ends.
So I was thinking that with 200 year old, poor quality, probably hand forged steel, there will be some hands that won't blue perfectly.

All the metallurgists can kick in here...:D

Cheers
Ralph B.
 

69BBNova

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I'm not actually quite sure if the blueing is done openair by just controlling the temps, but thats what it looks like...

As for the stands that raise the brass block above the plate transfer too much heat in your opinion I think I have a solution...

Consider air cooled engines, think older VWs, motorcycles, I dont know about nowadays but they use to have a cast jug with fins to dissapate the heat and the cylinders were pressed into them...

Solid round aluminum bars of the diameter of your choice, thread for fasteners both ends and try to keep the fins fairly thin dont go nuts and keep the spacing between the fins 4-5x the thickness, it does seem about that on heatsinks...

If the fins are large enough (depth) it will be enough (within reason giving overall size), otherwise you can always add a small computer fan, (and it dosent have to be large at all), just pick one thats quiet...

Look at newegg.com to get an actual idea of spacing, although most are nickle plated copper.

Anyhow I will read the entire thread later on...I love this kind of stuff.

No insult to your skills are intended, I may consider one for myself if I ever had the need.


Edit... I've decided a fan would be a bad idea making stable temps more difficult to attain.
 
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skippp66

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Harold,
I am very interested in your blueing contraption. Could I impose on you to furnish a shopping list of exactly what i need to buy on Amazon.com, giving complete names of each part so I can order the exact same parts as you did. In other words I need a very specific list of what to buy on Amazon. I am an idiot when it comes to electrical stuff and know nothing about any of the parts you describe but if I can accurately order all the parts, a friend will help me assemble it. I work strictly on watches and do have a solid piece of brass 2 inches round and 4 inches long which I can cut to a shorter length. Thank you.
Skip, that Hamilton Nut.
 

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