Harvey,
Brilliant suggestions! Gotta try them all in the next day or two.
Thanks,
Rick
On Mar 30, 2013, at 9:01 AM, Harvey White <madyn@...> wrote:
> On Sat, 30 Mar 2013 08:48:37 -0700, you wrote:
>
>> How did you protect the back of the aluminum. I tried applying wax but I
>> think it melted off. Also tried electrical tape and it fell off. Maybe the
>> common factor here is the heat generated by the too strong lye/water
>> mixture. I was thinking about using a Q tip and just dip it in the lye/water
>> mixture and dab it on the masked off area.
>
> It's the heat. You can use the transparent (I like transparent here)
> shelf covering. The one thing of the "Martha Stewart" brand that I'll
> every buy. Cut to size and the adhesive lasts through an etch.
>
> You'd not want to etch too much here, you left it in way too long. I'd
> definitely dilute the lye to get it to act more slowly.
>
> Ferric chloride does react with aluminum, if not the ferric chloride
> itself, then the excess chloride ions. That's why they tell you never
> to etch in an aluminum pan.
>
> A Q tip of diluted mixture would work well, you can rinse it off and
> see how deep it is.
>
>>
>> I've had very poor luck with toner transfer. The closest I came to success
>> was with copper.
>
> I use it on PC boards, works well once you get the parameters right.
>
>>
>> I will be using my new spray on photo resist and a contact print. But first
>> I want to perfect the etching process with just masking using tape, wax, or
>> ??.
>
> You may also want to try making a small dam with clay or plumber's
> putty and etching only a small area (if needed).
>
> Harvey
>
>
>>
>> Rick
>>
>> -----Original Message-----
>> From: Homebrew_PCBs@yahoogroups.com [mailto:Homebrew_PCBs@yahoogroups.com]
>> On Behalf Of Harvey White
>> Sent: Saturday, March 30, 2013 8:36 AM
>> To: Homebrew_PCBs@yahoogroups.com
>> Subject: Re: [Homebrew_PCBs] lye
>>
>> On Sat, 30 Mar 2013 07:31:42 -0700, you wrote:
>>
>>> Has anyone used lye to etch aluminum through photo resist?
>>>
>>>
>>>
>>> As a test, I put a strip of aluminum in lye plus water and after 15
>>> minutes the strip was half of its original thickness. So there is no
>>> doubt that lye can etch VERY deep. But the chemical reaction generated
>>> a lot of heat and the tape I had on there quickly floated off. Next
>>> time I will use more water.
>>
>> I did so a long time ago with photoresist, the back of the aluminum was
>> protected, and it was potassium hydroxide not sodium hydroxide. It did work,
>> though. I filled the etch with ink then lightly sanded the surface. Worked
>> well.
>>
>> I'd do it with toner transfer were it not for the problems with getting the
>> entire piece of aluminum to temperature (as well as potential thickness
>> problems. Possibly a T shirt press would work.
>>
>> also need a negative mask.
>>
>> Harvey
>>
>>>
>>>
>>>
>>> I did have the lye and aluminum outside while I watched from inside.
>>> Nasty fumes!
>>>
>>>
>>>
>>> Thanks,
>>>
>>>
>>>
>>> Rick
>>>
>>>
>>>
>>> [Non-text portions of this message have been removed]
>>
>>
>>
>> ------------------------------------
>>
>> Be sure to visit the group home and check for new Links, Files, and Photos:
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>
>
>
> ------------------------------------
>
> Be sure to visit the group home and check for new Links, Files, and Photos:
> http://groups.yahoo.com/group/Homebrew_PCBsYahoo! Groups Links
>
>
>