tapering a saw with electrolyis?

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tapering a saw with electrolyis?

Postby Gavin Longrain » February 4th, 2017, 8:54 am

Electrolysis removes rust. I'd guess it could remove steel from the saw too... ?
So - perhaps by shielding part of the saw with an insulation layer of say grease and possibly by fixing the red battery-charger clip to the saw-plate to make that the sacrificial anode - would it be possible to selectively remove steel and so taper grind a saw via electrolysis?
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Re: tapering a saw with electrolyis?

Postby Jim_Thode » February 4th, 2017, 6:43 pm

Gavin,
You are correct, if the polarity or leads are reversed then the electrolysis process is reversed and it will eat steel. That is how logos can be etched in steel. I've did that to "age" steel items and it works quite fast. The main problem with using the process to taper a saw is that it is not smooth and uniform. Just like rusting steel the surface will be rough and pitted.

Leave it in too long and it will look like this:
IMG_6673a.jpg


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Re: tapering a saw with electrolyis?

Postby PATCsawyer » February 5th, 2017, 6:31 am

I'd call that one a "fixer-upper".
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Re: tapering a saw with electrolyis?

Postby Gavin Longrain » February 7th, 2017, 5:32 am

I have this detailed comment from someone who clearly knows:

What you have described is called Electro-Chemical Milling (ECM). It is widely used in the aerospace industry for parts with complex contours. Characteristics of the process would seem to make it ideal for tapering saws:

* Metal removal rate is independent of metal hardness. You can mill hardened tool steel at the same rate as annealed mild steel.
* Can produce mirror-like finishes with no need for secondary grinding or polishing.
* Is extremely accurate
* It produces no stresses or heat-affected-zones in the machined part
* The same process can be used to profile the part, like water jet cutting


I looked into this process (as well as a similar process, Electo-Chemical Grinding) two years ago. Here is the downside:

* Very high capital investment costs (> 250,000 US$)
* Very high cost of operation (primarily electrical power)


Why:

* The tool (cathode) must be positioned very accurately in relation to the workpiece (anode, in this case saw). The gap between tool and workpiece needs to me maintained at 0.1 to 0.2 mm.

* The current required is typically 1000 Amps at 8-20 VDC (lethal amperage, the equipment must meet very stringent safety requirements)

* The electrolyte used must be forced between the cathode and the workpiece under very high pressure (3 MPa or 435 psi) to prevent the removed metal ions from being deposited onto the cathode
* The electrolyte must be continually filtered to remove contamination
* When depleted, the electrolyte must be disposed of as toxic waste
* The metal removal rate is about 1/30 that of conventional milling


If you use a tank and simply mask off surface areas, the exposed areas will not be dissolved at a uniform rate due to variations in voltage potential over a large volume resulting in a pitted and wavy surface. There is no way to maintain the required accuracy. The process would also be very slow (days, weeks?).


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Re: tapering a saw with electrolyis?

Postby Gavin Longrain » February 7th, 2017, 6:16 am

Jim_Thode wrote:... if the polarity or leads are reversed then the electrolysis process is reversed and it will eat steel. That is how logos can be etched in steel.


    1. Has anyone hints, tips , suggestions or ideas how I can put logo on steel?
    2. From what material do I make my template?
    3. What is electrolyte should I use?

Here is Flinn Garlick's acid-etch method.
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Re: tapering a saw with electrolyis?

Postby Jim_Thode » February 7th, 2017, 7:55 am

Gavin Longrain wrote:
Jim_Thode wrote:... if the polarity or leads are reversed then the electrolysis process is reversed and it will eat steel. That is how logos can be etched in steel.


    1. Has anyone hints, tips , suggestions or ideas how I can put logo on steel?
    2. From what material do I make my template?
    3. What is electrolyte should I use?

Here is Flinn Garlick's acid-etch method.



Here is a simple way to etch a logo:
https://www.youtube.com/watch?v=bV-PItEcLXY

You can get way more sophisticated. Do a Google search for "electrolysis steel logo etch" for a ton of ideas.
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