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2017-07-03 by Brad
I have been using ferric to etch boards for a while now. Recently I got lucky and came into a cache of 1973 vintage copper clad PCB stock, which will enable me to make some reproduction pieces that are pretty much indistinguishable from originals in terms of look. However, I have noticed that the ferric solution stains these boards, adding a yellowish tint. Is there any way to avoid this? Or clean it after?
2017-07-03 by D. Beans
When I made boards back in the late 70's I used ammonium persulfate most of the time. Works good, no stains. I have no idea if it's still readily available or where to get it. Steve ------------------------------------------------------------ At 06:56 PM 7/2/2017, you wrote:
>I have been using ferric to etch boards for a while now. Recently I >got lucky and came into a cache of 1973 vintage copper clad PCB >stock, which will enable me to make some reproduction pieces that >are pretty much indistinguishable from originals in terms of >look. However, I have noticed that the ferric solution stains these >boards, adding a yellowish tint. Is there any way to avoid >this? Or clean it after?
2017-07-03 by LEON HELLER
Oxalic acid removes ferric chloride stains. I've got a big bottle of it somewhere but have never used it.
Leon
On Monday, 3 July 2017, 2:56, "'Brad' unclefalter@... [Homebrew_PCBs]" <Homebrew_PCBs@yahoogroups.com> wrote:
I have been using ferric to etch boards for a while now. Recently I got lucky and came into a cache of 1973 vintage copper clad PCB stock, which will enable me to make some reproduction pieces that are pretty much indistinguishable from originals in terms of look. However, I have noticed that the ferric solution stains these boards, adding a yellowish tint. Is there any way to avoid this? Or clean it after? #yiv8950091904 #yiv8950091904 -- #yiv8950091904ygrp-mkp {border:1px solid #d8d8d8;font-family:Arial;margin:10px 0;padding:0 10px;}#yiv8950091904 #yiv8950091904ygrp-mkp hr {border:1px solid #d8d8d8;}#yiv8950091904 #yiv8950091904ygrp-mkp #yiv8950091904hd {color:#628c2a;font-size:85%;font-weight:700;line-height:122%;margin:10px 0;}#yiv8950091904 #yiv8950091904ygrp-mkp #yiv8950091904ads {margin-bottom:10px;}#yiv8950091904 #yiv8950091904ygrp-mkp .yiv8950091904ad {padding:0 0;}#yiv8950091904 #yiv8950091904ygrp-mkp .yiv8950091904ad p {margin:0;}#yiv8950091904 #yiv8950091904ygrp-mkp .yiv8950091904ad a {color:#0000ff;text-decoration:none;}#yiv8950091904 #yiv8950091904ygrp-sponsor #yiv8950091904ygrp-lc {font-family:Arial;}#yiv8950091904 #yiv8950091904ygrp-sponsor #yiv8950091904ygrp-lc #yiv8950091904hd {margin:10px 0px;font-weight:700;font-size:78%;line-height:122%;}#yiv8950091904 #yiv8950091904ygrp-sponsor #yiv8950091904ygrp-lc .yiv8950091904ad {margin-bottom:10px;padding:0 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Hi Sorta new here and trying to catch on to some of the procedures described here. Was wondering if anyone knows if theres a chemical or chemicals (s) that will safely dissolve epoxy that some manufacturers use to encapsulate boards to protect them and make them more or less unservicable when a component fails? I have hears there is a chemical that they can be soaked in for many days, and you have to check on it daily before it eats through things that u dont want it to damage. Steve Hearns Technotronic Dimensions [USA] WWW.TECHNOTRONIC-DIMENSIONS.COM 1.518.663.3421 (MAIN) 1-877-817-9885 (Voice / Fax Toll Free - US Only) E-Mail: Steve@... -- Webmaster, Parts-Link: (http://www.parts-link.com) Group Moderator: TV-Repair (http://groups.yahoo.com/group/tv-repair) Monitor-Repair (http://groups.yahoo.com/group/monitor-repair)
----- Original Message -----
From: "LEON HELLER leon355@... [Homebrew_PCBs]"
<Homebrew_PCBs@yahoogroups.com>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Monday, July 03, 2017 12:56 AM
Subject: Re: [Homebrew_PCBs] Ferric chloride staining PCB substrate
Oxalic acid removes ferric chloride stains. I've got a big bottle of it
somewhere but have never used it.
Leon
On Monday, 3 July 2017, 2:56, "'Brad' unclefalter@...
[Homebrew_PCBs]" <Homebrew_PCBs@yahoogroups.com> wrote:2017-07-04 by Dave Sage
Simple: Don't use ferric chloride. Try HCL and Hydrogen peroxide (which becomes Cupric chloride) or the other old school etchant - Ammonium chloride.
2017-07-04 by roylowenthal@...
2017-07-04 by Russell Shaw
On 04/07/17 04:57, 'Technotronic~Dimensions' infotech@... [Homebrew_PCBs] wrote: > Hi > > Sorta new here and trying to catch on to some of the procedures described > here. > > Was wondering if anyone knows if theres a chemical or chemicals (s) that > will safely dissolve epoxy that some manufacturers > use to encapsulate boards to protect them and make them more or less > unservicable when a component fails? > > I have hears there is a chemical that they can be soaked in for many days, > and you have to check on it daily before it eats through > things that u dont want it to damage. An easy way is to have a stream of hot air directed at the board (hot air gun on a stand), and pick away at the epoxy with a thin sharp screwdriver and thin pliers. Hot epoxy goes soft and rubbery.
2017-07-04 by Harvey Altstadter
Steve, With regard to dissolving epoxy, I have good news, and I have bad news. The good news is that there are chemicals used for depotting encapsulated assemblies. Back in the days before dirt was invented, I ran a failure analysis lab for my employer where my technicians used several chemicals from Dynaloy. They were sold under the Dynasolve product line. We also used another product of theirs called Decap. Here is a website for one of their distributors: http://www.ellsworthadhesives.ca/manufacturer/dynaloy I note that they now have a greater variety of chemicals than were available "way back then." That being said, there are a few issues (the bad news): 1. The chemicals don't dissolve the epoxy. They swell the epoxy and cause it to flake off. Active removal (scraping) is required 2. I think we had to match the chemical to the epoxy cure system, i.e. amine, phenol, etc., to get the best performance. I don't know if this is more or less so now, with the greater number of chemicals available today. 3. Since the circuit boards are usually epoxy impregnated, they will suffer as a result of this treatment. Any other parts that are epoxy encapsulated, or made with certain plastics would likely be adversely affected. 4. To say that the chemicals were pricey, would be a gross understatement. We bought them by the gallon, and each gallon cost an arm, a leg, and someone's first born son. The chemicals did the job for us because our usual need was to retrieve the failed components from the assembly. We had little concern for the assembly itself. The items we were after were in metal or ceramic packages, and therefore were not affected by the chemicals. Although the possibility of removing the epoxy and repairing an assembly exists, it is expensive and labor intensive, with a low probability of success. On the very rare occasion that a module had to be repaired because there was no other choice, a different technique was used. This technique is not generally available outside a lab like ours, but I present it just in case you have access to the necessary machinery/information. This technique requires good information on the construction of the module. We started by performing X-Ray in X, Y and Z axes. The X-Ray results were compared to the original assembly drawings, and the component of interest was located. By using extremely precise drilling and milling tools, combined with progressive X-Rays, a cavity was made around the part to be replaced. Every attempt was made to make the cavity very close to the part. The cavity was then filled with the chemical of choice, and the epoxy slowly scraped away, exposing the component. Just watching this process was painful. I don't even want to discuss how difficult it was to replace a component once the cavity was open and the defective component removed. To underscore: this was only done when there was no possibility of getting a replacement module, or the time it would take to get a replacement would have a devastating impact on delivery schedule. Harvey A On 7/3/2017 11:57 AM, 'Technotronic~Dimensions' infotech@... [Homebrew_PCBs] wrote:
> > Hi > > Sorta new here and trying to catch on to some of the procedures described > here. > > Was wondering if anyone knows if theres a chemical or chemicals (s) that > will safely dissolve epoxy that some manufacturers > use to encapsulate boards to protect them and make them more or less > unservicable when a component fails? > > I have hears there is a chemical that they can be soaked in for many > days, > and you have to check on it daily before it eats through > things that u dont want it to damage. > > Steve Hearns > Technotronic Dimensions [USA] > WWW.TECHNOTRONIC-DIMENSIONS.COM > 1.518.663.3421 (MAIN) > 1-877-817-9885 (Voice / Fax Toll Free - US Only) > E-Mail: Steve@... > -- > Webmaster, Parts-Link: (http://www.parts-link.com) > Group Moderator: > TV-Repair (http://groups.yahoo.com/group/tv-repair) > Monitor-Repair (http://groups.yahoo.com/group/monitor-repair) > > ----- Original Message ----- > From: "LEON HELLER leon355@... [Homebrew_PCBs]" > <Homebrew_PCBs@yahoogroups.com> > To: <Homebrew_PCBs@yahoogroups.com> > Sent: Monday, July 03, 2017 12:56 AM > Subject: Re: [Homebrew_PCBs] Ferric chloride staining PCB substrate > > Oxalic acid removes ferric chloride stains. I've got a big bottle of it > somewhere but have never used it. > Leon > > On Monday, 3 July 2017, 2:56, "'Brad' unclefalter@... > [Homebrew_PCBs]" <Homebrew_PCBs@yahoogroups.com> wrote: > >
2017-07-04 by Technotronic~Dimensions
Hi Harvey Great info, thanks. With more stuff out there being designed not to be fixed, and thrown away, I had always wanted to know more about the possibilities. I remember when I worked in the Aerospace industry, the painter at our plant carried MEK / Methyl Ethyl Keotene around in ample supply, and some of that on a cloth woould pretty much take the paint right off the surface of an airplane no problem. I remember it was not very pleasant at all to smell and it had a pretty high hazmat rating sticker on it and he did not leave that container open unless he was using it. He was suppose to wear a respirator also if I remember right. I got the impression that stuff would dissolve most anything even maybe tough epoxy but never tried it. Steve Hearns Technotronic Dimensions, VT [USA] WWW.TECHNOTRONIC-DIMENSIONS.COM 1.518.663.3421 (MAIN) 1-877-817-9885 (Voice / Fax Toll Free - US Only) E-Mail: Steve@... -- Webmaster, Parts-Link: (http://www.parts-link.com) Group Moderator: TV-Repair (http://groups.yahoo.com/group/tv-repair) Monitor-Repair (http://groups.yahoo.com/group/monitor-repair) ----- Original Message ----- From: "Harvey Altstadter hrconsult@... [Homebrew_PCBs]" <Homebrew_PCBs@yahoogroups.com>
To: <Homebrew_PCBs@yahoogroups.com> Sent: Tuesday, July 04, 2017 12:40 AM Subject: Re: [Homebrew_PCBs] Ferric chloride staining PCB substrate > Steve, > > With regard to dissolving epoxy, I have good news, and I have bad news. > The good news is that there are chemicals used for depotting > encapsulated assemblies. > > Back in the days before dirt was invented, I ran a failure analysis lab > for my employer where my technicians used several chemicals from > Dynaloy. They were sold under the Dynasolve product line. We also used > another product of theirs called Decap. Here is a website for one of > their distributors: http://www.ellsworthadhesives.ca/manufacturer/dynaloy > > I note that they now have a greater variety of chemicals than were > available "way back then." > > That being said, there are a few issues (the bad news): > > 1. The chemicals don't dissolve the epoxy. They swell the epoxy and > cause it to flake off. Active removal (scraping) is required > > 2. I think we had to match the chemical to the epoxy cure system, i.e. > amine, phenol, etc., to get the best performance. I don't know if this > is more or less so now, with the greater number of chemicals available > today. > > 3. Since the circuit boards are usually epoxy impregnated, they will > suffer as a result of this treatment. Any other parts that are epoxy > encapsulated, or made with certain plastics would likely be adversely > affected. > > 4. To say that the chemicals were pricey, would be a gross > understatement. We bought them by the gallon, and each gallon cost an > arm, a leg, and someone's first born son. > > The chemicals did the job for us because our usual need was to retrieve > the failed components from the assembly. We had little concern for the > assembly itself. The items we were after were in metal or ceramic > packages, and therefore were not affected by the chemicals. Although the > possibility of removing the epoxy and repairing an assembly exists, it > is expensive and labor intensive, with a low probability of success. > > On the very rare occasion that a module had to be repaired because there > was no other choice, a different technique was used. This technique is > not generally available outside a lab like ours, but I present it just > in case you have access to the necessary machinery/information. > > This technique requires good information on the construction of the > module. We started by performing X-Ray in X, Y and Z axes. The X-Ray > results were compared to the original assembly drawings, and the > component of interest was located. By using extremely precise drilling > and milling tools, combined with progressive X-Rays, a cavity was made > around the part to be replaced. Every attempt was made to make the > cavity very close to the part. The cavity was then filled with the > chemical of choice, and the epoxy slowly scraped away, exposing the > component. Just watching this process was painful. I don't even want to > discuss how difficult it was to replace a component once the cavity was > open and the defective component removed. To underscore: this was only > done when there was no possibility of getting a replacement module, or > the time it would take to get a replacement would have a devastating > impact on delivery schedule. > > Harvey A > > On 7/3/2017 11:57 AM, 'Technotronic~Dimensions' > infotech@... [Homebrew_PCBs] wrote: >> >> Hi >> >> Sorta new here and trying to catch on to some of the procedures described >> here. >> >> Was wondering if anyone knows if theres a chemical or chemicals (s) that >> will safely dissolve epoxy that some manufacturers >> use to encapsulate boards to protect them and make them more or less >> unservicable when a component fails? >> >> I have hears there is a chemical that they can be soaked in for many >> days, >> and you have to check on it daily before it eats through >> things that u dont want it to damage. >> >> Steve Hearns >> Technotronic Dimensions [USA] >> WWW.TECHNOTRONIC-DIMENSIONS.COM >> 1.518.663.3421 (MAIN) >> 1-877-817-9885 (Voice / Fax Toll Free - US Only) >> E-Mail: Steve@... >> -- >> Webmaster, Parts-Link: (http://www.parts-link.com) >> Group Moderator: >> TV-Repair (http://groups.yahoo.com/group/tv-repair) >> Monitor-Repair (http://groups.yahoo.com/group/monitor-repair) >> >> ----- Original Message ----- >> From: "LEON HELLER leon355@... [Homebrew_PCBs]" >> <Homebrew_PCBs@yahoogroups.com> >> To: <Homebrew_PCBs@yahoogroups.com> >> Sent: Monday, July 03, 2017 12:56 AM >> Subject: Re: [Homebrew_PCBs] Ferric chloride staining PCB substrate >> >> Oxalic acid removes ferric chloride stains. I've got a big bottle of it >> somewhere but have never used it. >> Leon >> >> On Monday, 3 July 2017, 2:56, "'Brad' unclefalter@... >> [Homebrew_PCBs]" <Homebrew_PCBs@yahoogroups.com> wrote: >> >> > >
2017-07-04 by Harvey Altstadter
Steve, I didn't want to mention MEK. This is bad stuff. Our company used it in the shop to clean up epoxy spills and the like. A respirator or aggressive ventilation system is a must. It is highly flammable, and is directly absorbed through the skin. Apparently, it is a neurotoxin. Definitely something to stay away from. On 7/3/2017 10:32 PM, 'Technotronic~Dimensions' infotech@... [Homebrew_PCBs] wrote:
> > Hi Harvey > > Great info, thanks. With more stuff out there being designed not to be > fixed, and thrown away, I had always wanted to > know more about the possibilities. > > I remember when I worked in the Aerospace industry, the painter at our > plant > carried MEK / Methyl Ethyl Keotene > around in ample supply, and some of that on a cloth woould pretty much > take > the paint right off the surface of an > airplane no problem. > > I remember it was not very pleasant at all to smell and it had a > pretty high > hazmat rating sticker on it and he did not > leave that container open unless he was using it. He was suppose to > wear a > respirator also if I remember right. > > I got the impression that stuff would dissolve most anything even maybe > tough epoxy but never tried it. > > Steve Hearns > Technotronic Dimensions, VT [USA] > WWW.TECHNOTRONIC-DIMENSIONS.COM > 1.518.663.3421 (MAIN) > 1-877-817-9885 (Voice / Fax Toll Free - US Only) > E-Mail: Steve@... > -- > Webmaster, Parts-Link: (http://www.parts-link.com) > Group Moderator: > TV-Repair (http://groups.yahoo.com/group/tv-repair) > Monitor-Repair (http://groups.yahoo.com/group/monitor-repair) > > ----- Original Message ----- > From: "Harvey Altstadter hrconsult@... [Homebrew_PCBs]" > <Homebrew_PCBs@yahoogroups.com> > To: <Homebrew_PCBs@yahoogroups.com> > Sent: Tuesday, July 04, 2017 12:40 AM > Subject: Re: [Homebrew_PCBs] Ferric chloride staining PCB substrate > > > Steve, > > > > With regard to dissolving epoxy, I have good news, and I have bad news. > > The good news is that there are chemicals used for depotting > > encapsulated assemblies. > > > > Back in the days before dirt was invented, I ran a failure analysis lab > > for my employer where my technicians used several chemicals from > > Dynaloy. They were sold under the Dynasolve product line. We also used > > another product of theirs called Decap. Here is a website for one of > > their distributors: > http://www.ellsworthadhesives.ca/manufacturer/dynaloy > > > > I note that they now have a greater variety of chemicals than were > > available "way back then." > > > > That being said, there are a few issues (the bad news): > > > > 1. The chemicals don't dissolve the epoxy. They swell the epoxy and > > cause it to flake off. Active removal (scraping) is required > > > > 2. I think we had to match the chemical to the epoxy cure system, i.e. > > amine, phenol, etc., to get the best performance. I don't know if this > > is more or less so now, with the greater number of chemicals available > > today. > > > > 3. Since the circuit boards are usually epoxy impregnated, they will > > suffer as a result of this treatment. Any other parts that are epoxy > > encapsulated, or made with certain plastics would likely be adversely > > affected. > > > > 4. To say that the chemicals were pricey, would be a gross > > understatement. We bought them by the gallon, and each gallon cost an > > arm, a leg, and someone's first born son. > > > > The chemicals did the job for us because our usual need was to retrieve > > the failed components from the assembly. We had little concern for the > > assembly itself. The items we were after were in metal or ceramic > > packages, and therefore were not affected by the chemicals. Although the > > possibility of removing the epoxy and repairing an assembly exists, it > > is expensive and labor intensive, with a low probability of success. > > > > On the very rare occasion that a module had to be repaired because there > > was no other choice, a different technique was used. This technique is > > not generally available outside a lab like ours, but I present it just > > in case you have access to the necessary machinery/information. > > > > This technique requires good information on the construction of the > > module. We started by performing X-Ray in X, Y and Z axes. The X-Ray > > results were compared to the original assembly drawings, and the > > component of interest was located. By using extremely precise drilling > > and milling tools, combined with progressive X-Rays, a cavity was made > > around the part to be replaced. Every attempt was made to make the > > cavity very close to the part. The cavity was then filled with the > > chemical of choice, and the epoxy slowly scraped away, exposing the > > component. Just watching this process was painful. I don't even want to > > discuss how difficult it was to replace a component once the cavity was > > open and the defective component removed. To underscore: this was only > > done when there was no possibility of getting a replacement module, or > > the time it would take to get a replacement would have a devastating > > impact on delivery schedule. > > > > Harvey A > > > > On 7/3/2017 11:57 AM, 'Technotronic~Dimensions' > > infotech@... [Homebrew_PCBs] wrote: > >> > >> Hi > >> > >> Sorta new here and trying to catch on to some of the procedures > described > >> here. > >> > >> Was wondering if anyone knows if theres a chemical or chemicals (s) > that > >> will safely dissolve epoxy that some manufacturers > >> use to encapsulate boards to protect them and make them more or less > >> unservicable when a component fails? > >> > >> I have hears there is a chemical that they can be soaked in for many > >> days, > >> and you have to check on it daily before it eats through > >> things that u dont want it to damage. > >> > >> Steve Hearns > >> Technotronic Dimensions [USA] > >> WWW.TECHNOTRONIC-DIMENSIONS.COM > >> 1.518.663.3421 (MAIN) > >> 1-877-817-9885 (Voice / Fax Toll Free - US Only) > >> E-Mail: Steve@... > >> -- > >> Webmaster, Parts-Link: (http://www.parts-link.com) > >> Group Moderator: > >> TV-Repair (http://groups.yahoo.com/group/tv-repair) > >> Monitor-Repair (http://groups.yahoo.com/group/monitor-repair) > >> > >> ----- Original Message ----- > >> From: "LEON HELLER leon355@... [Homebrew_PCBs]" > >> <Homebrew_PCBs@yahoogroups.com> > >> To: <Homebrew_PCBs@yahoogroups.com> > >> Sent: Monday, July 03, 2017 12:56 AM > >> Subject: Re: [Homebrew_PCBs] Ferric chloride staining PCB substrate > >> > >> Oxalic acid removes ferric chloride stains. I've got a big bottle of it > >> somewhere but have never used it. > >> Leon > >> > >> On Monday, 3 July 2017, 2:56, "'Brad' unclefalter@... > >> [Homebrew_PCBs]" <Homebrew_PCBs@yahoogroups.com> wrote: > >> > >> > > > > > >
2017-07-04 by Malcolm Parker-Lisberg
Or just gho into the garden and pick some Rhubarb leaves, lots of Oxalic acid in them. Just don't eat any or drink what you make from boiling them or the grass will be growing green over your prostrate form. Malcolm I don't suffer from insanity I enjoy it! Mene, mene, tekel, upharsin The writing is on the wall. Ha-ktovet al ha-kir -------------------------------------------- On Tue, 7/4/17, roylowenthal@... [Homebrew_PCBs] <Homebrew_PCBs@yahoogroups.com> wrote:
Subject: [Homebrew_PCBs] Re: Ferric chloride staining PCB substrate
To: Homebrew_PCBs@yahoogroups.com
Date: Tuesday, July 4, 2017, 3:20 AM
Oxalic acid is also sold as, "wood
bleach" usually findable in hardware or paint
stores.
Roy
#yiv3226884296 #yiv3226884296 --2017-07-04 by Brad
I'm considering HCL and peroxide. I just got intimidated when I saw a video and the guy showed all the steps required to handle it all safely. Ferric is a lot less troublesome. I kind of liked the vinegar peroxide solution I was using. The only problem I had was that it was slow, and would often eat under the resist. And it seemed as though it had very limited staying power. However to test my theory that the ferric was discoloring the boards, I put a couple of scrap pieces in and long after I thought the solution had worn itself out, the next day I discovered it had etched all the copper. So it's very slow but still active. tempted to try a sample etching to see how badly it goes after the resist if just left for the day.
From: Homebrew_PCBs@yahoogroups.com [mailto:Homebrew_PCBs@yahoogroups.com] Sent: Monday, July 3, 2017 6:24 PM To: Homebrew_PCBs@yahoogroups.com Subject: [Homebrew_PCBs] Re: Ferric chloride staining PCB substrate Simple: Don't use ferric chloride. Try HCL and Hydrogen peroxide (which becomes Cupric chloride) or the other old school etchant - Ammonium chloride. <http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_cam paign=sig-email&utm_content=emailclient> Virus-free. <http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_cam paign=sig-email&utm_content=emailclient> www.avg.com
2017-07-04 by Brad
Thanks!! Question – will Oxalic eat at the copper traces if I’ve removed the resist already? I haven’t on one board but the other I have.
From: Homebrew_PCBs@yahoogroups.com [mailto:Homebrew_PCBs@yahoogroups.com] Sent: Tuesday, July 4, 2017 6:03 AM To: Homebrew_PCBs@yahoogroups.com Subject: Re: [Homebrew_PCBs] Re: Ferric chloride staining PCB substrate Or just gho into the garden and pick some Rhubarb leaves, lots of Oxalic acid in them. Just don't eat any or drink what you make from boiling them or the grass will be growing green over your prostrate form. Malcolm I don't suffer from insanity I enjoy it! Mene, mene, tekel, upharsin The writing is on the wall. Ha-ktovet al ha-kir -------------------------------------------- On Tue, 7/4/17, roylowenthal@... <mailto:roylowenthal@...> [Homebrew_PCBs] <Homebrew_PCBs@...m <mailto:Homebrew_PCBs@yahoogroups.com> > wrote: Subject: [Homebrew_PCBs] Re: Ferric chloride staining PCB substrate To: Homebrew_PCBs@yahoogroups.com <mailto:Homebrew_PCBs@yahoogroups.com> Date: Tuesday, July 4, 2017, 3:20 AM Oxalic acid is also sold as, "wood bleach" usually findable in hardware or paint stores. Roy #yiv3226884296 #yiv3226884296 --
2017-07-04 by keith printy
Try it on a sample of copper first. Don’t know for sure,but when you get heavy duty radiator cleaner for your car it is oxalic acid .they also put neutralizer in afterwards . thing is most radiators when you used it were made of brass , which is basically a copper alloy.
From: Homebrew_PCBs@yahoogroups.com [mailto:Homebrew_PCBs@yahoogroups.com] Sent: Tuesday, July 04, 2017 12:37 PM To: Homebrew_PCBs@yahoogroups.com Subject: RE: [Homebrew_PCBs] Re: Ferric chloride staining PCB substrate Thanks!! Question – will Oxalic eat at the copper traces if I’ve removed the resist already? I haven’t on one board but the other I have. From: Homebrew_PCBs@yahoogroups.com [mailto:Homebrew_PCBs@yahoogroups.com] Sent: Tuesday, July 4, 2017 6:03 AM To: Homebrew_PCBs@yahoogroups.com Subject: Re: [Homebrew_PCBs] Re: Ferric chloride staining PCB substrate Or just gho into the garden and pick some Rhubarb leaves, lots of Oxalic acid in them. Just don't eat any or drink what you make from boiling them or the grass will be growing green over your prostrate form. Malcolm I don't suffer from insanity I enjoy it! Mene, mene, tekel, upharsin The writing is on the wall. Ha-ktovet al ha-kir -------------------------------------------- On Tue, 7/4/17, roylowenthal@... [Homebrew_PCBs] <Homebrew_PCBs@yahoogroups.com> wrote: Subject: [Homebrew_PCBs] Re: Ferric chloride staining PCB substrate To: Homebrew_PCBs@yahoogroups.com Date: Tuesday, July 4, 2017, 3:20 AM Oxalic acid is also sold as, "wood bleach" usually findable in hardware or paint stores. Roy #yiv3226884296 #yiv3226884296 --
2017-07-04 by keith printy
I got some depotting liquid once from where I used to work when they got rid of it. it basically would turn the epoxy into mush that was easily removed. The downside was it was corrosive to some metals . think it was made by plastronics or something like that. I know it wasn’t MEK as it had no real odor to it. it was a clear liquid though. From: Homebrew_PCBs@yahoogroups.com [mailto:Homebrew_PCBs@yahoogroups.com] Sent: Tuesday, July 04, 2017 1:32 AM To: Homebrew_PCBs@yahoogroups.com Subject: Re: [Homebrew_PCBs] Ferric chloride staining PCB substrate Hi Harvey Great info, thanks. With more stuff out there being designed not to be fixed, and thrown away, I had always wanted to know more about the possibilities. I remember when I worked in the Aerospace industry, the painter at our plant carried MEK / Methyl Ethyl Keotene around in ample supply, and some of that on a cloth woould pretty much take the paint right off the surface of an airplane no problem. I remember it was not very pleasant at all to smell and it had a pretty high hazmat rating sticker on it and he did not leave that container open unless he was using it. He was suppose to wear a respirator also if I remember right. I got the impression that stuff would dissolve most anything even maybe tough epoxy but never tried it. Steve Hearns Technotronic Dimensions, VT [USA] WWW.TECHNOTRONIC-DIMENSIONS.COM 1.518.663.3421 (MAIN) 1-877-817-9885 (Voice / Fax Toll Free - US Only) E-Mail: Steve@Technotronic-Dimensions.com -- Webmaster, Parts-Link: (http://www.parts-link.com) Group Moderator: TV-Repair (http://groups.yahoo.com/group/tv-repair) Monitor-Repair (http://groups.yahoo.com/group/monitor-repair) ----- Original Message ----- From: "Harvey Altstadter hrconsult@... [Homebrew_PCBs]" <Homebrew_PCBs@yahoogroups.com>
To: <Homebrew_PCBs@yahoogroups.com> Sent: Tuesday, July 04, 2017 12:40 AM Subject: Re: [Homebrew_PCBs] Ferric chloride staining PCB substrate > Steve, > > With regard to dissolving epoxy, I have good news, and I have bad news. > The good news is that there are chemicals used for depotting > encapsulated assemblies. > > Back in the days before dirt was invented, I ran a failure analysis lab > for my employer where my technicians used several chemicals from > Dynaloy. They were sold under the Dynasolve product line. We also used > another product of theirs called Decap. Here is a website for one of > their distributors: http://www.ellsworthadhesives.ca/manufacturer/dynaloy > > I note that they now have a greater variety of chemicals than were > available "way back then." > > That being said, there are a few issues (the bad news): > > 1. The chemicals don't dissolve the epoxy. They swell the epoxy and > cause it to flake off. Active removal (scraping) is required > > 2. I think we had to match the chemical to the epoxy cure system, i.e. > amine, phenol, etc., to get the best performance. I don't know if this > is more or less so now, with the greater number of chemicals available > today. > > 3. Since the circuit boards are usually epoxy impregnated, they will > suffer as a result of this treatment. Any other parts that are epoxy > encapsulated, or made with certain plastics would likely be adversely > affected. > > 4. To say that the chemicals were pricey, would be a gross > understatement. We bought them by the gallon, and each gallon cost an > arm, a leg, and someone's first born son. > > The chemicals did the job for us because our usual need was to retrieve > the failed components from the assembly. We had little concern for the > assembly itself. The items we were after were in metal or ceramic > packages, and therefore were not affected by the chemicals. Although the > possibility of removing the epoxy and repairing an assembly exists, it > is expensive and labor intensive, with a low probability of success. > > On the very rare occasion that a module had to be repaired because there > was no other choice, a different technique was used. This technique is > not generally available outside a lab like ours, but I present it just > in case you have access to the necessary machinery/information. > > This technique requires good information on the construction of the > module. We started by performing X-Ray in X, Y and Z axes. The X-Ray > results were compared to the original assembly drawings, and the > component of interest was located. By using extremely precise drilling > and milling tools, combined with progressive X-Rays, a cavity was made > around the part to be replaced. Every attempt was made to make the > cavity very close to the part. The cavity was then filled with the > chemical of choice, and the epoxy slowly scraped away, exposing the > component. Just watching this process was painful. I don't even want to > discuss how difficult it was to replace a component once the cavity was > open and the defective component removed. To underscore: this was only > done when there was no possibility of getting a replacement module, or > the time it would take to get a replacement would have a devastating > impact on delivery schedule. > > Harvey A > > On 7/3/2017 11:57 AM, 'Technotronic~Dimensions' > infotech@... [Homebrew_PCBs] wrote: >> >> Hi >> >> Sorta new here and trying to catch on to some of the procedures described >> here. >> >> Was wondering if anyone knows if theres a chemical or chemicals (s) that >> will safely dissolve epoxy that some manufacturers >> use to encapsulate boards to protect them and make them more or less >> unservicable when a component fails? >> >> I have hears there is a chemical that they can be soaked in for many >> days, >> and you have to check on it daily before it eats through >> things that u dont want it to damage. >> >> Steve Hearns >> Technotronic Dimensions [USA] >> WWW.TECHNOTRONIC-DIMENSIONS.COM >> 1.518.663.3421 (MAIN) >> 1-877-817-9885 (Voice / Fax Toll Free - US Only) >> E-Mail: Steve@... >> -- >> Webmaster, Parts-Link: (http://www.parts-link.com) >> Group Moderator: >> TV-Repair (http://groups.yahoo.com/group/tv-repair) >> Monitor-Repair (http://groups.yahoo.com/group/monitor-repair) >> >> ----- Original Message ----- >> From: "LEON HELLER leon355@... [Homebrew_PCBs]" >> <Homebrew_PCBs@yahoogroups.com> >> To: <Homebrew_PCBs@yahoogroups.com> >> Sent: Monday, July 03, 2017 12:56 AM >> Subject: Re: [Homebrew_PCBs] Ferric chloride staining PCB substrate >> >> Oxalic acid removes ferric chloride stains. I've got a big bottle of it >> somewhere but have never used it. >> Leon >> >> On Monday, 3 July 2017, 2:56, "'Brad' unclefalter@... >> [Homebrew_PCBs]" <Homebrew_PCBs@yahoogroups.com> wrote: >> >> > >
2017-07-04 by keith printy
In the 90’s when I worked in an electronics plant they used ammonium persulfate , I think towards the end though they had to save the used stuff and treat it as hazardous waste. I know if you mix sugar with it and heat ,it will explode. Ferric chloride on the other hand is easier to find as it is used in sewage treatment plants. From: Homebrew_PCBs@yahoogroups.com [mailto:Homebrew_PCBs@yahoogroups.com] Sent: Sunday, July 02, 2017 10:57 PM To: Homebrew_PCBs@yahoogroups.com Subject: Re: [Homebrew_PCBs] Ferric chloride staining PCB substrate When I made boards back in the late 70's I used ammonium persulfate most of the time. Works good, no stains. I have no idea if it's still readily available or where to get it. Steve ---------------------------------------------------------- At 06:56 PM 7/2/2017, you wrote:
>I have been using ferric to etch boards for a while now. Recently I >got lucky and came into a cache of 1973 vintage copper clad PCB >stock, which will enable me to make some reproduction pieces that >are pretty much indistinguishable from originals in terms of >look. However, I have noticed that the ferric solution stains these >boards, adding a yellowish tint. Is there any way to avoid >this? Or clean it after?
2017-07-04 by Malcolm Parker-Lisberg
See: <http://copperplumbing.org.uk/sites/default/files/content_attachments/guide-to-suitability-with-chemicals.pdf> Oxalic acid is slow to attack copper, so rinse well after using it. It is very poisnous, use Nitrile gloves and eye protection. Look up the MSDS on using it. You are unlikely to want a strong solotution, but take precautions. Malcolm I don't suffer from insanity I enjoy it! Mene, mene, tekel, upharsin The writing is on the wall. Ha-ktovet al ha-kir -------------------------------------------- On Tue, 7/4/17, 'Brad' unclefalter@... [Homebrew_PCBs] <Homebrew_PCBs@yahoogroups.com> wrote:
Subject: RE: [Homebrew_PCBs] Re: Ferric chloride staining PCB substrate
To: Homebrew_PCBs@yahoogroups.com
Date: Tuesday, July 4, 2017, 5:36 PM
Thanks!! Question – will Oxalic eat at
the copper traces if I’ve removed the resist already? I
haven’t on one board but the other I have. From: Homebrew_PCBs@yahoogroups.com
[mailto:Homebrew_PCBs@yahoogroups.com]
Sent: Tuesday, July 4, 2017 6:03 AM
To: Homebrew_PCBs@yahoogroups.com
Subject: Re: [Homebrew_PCBs] Re: Ferric
chloride staining PCB substrate Or just gho into the garden
and pick some Rhubarb leaves, lots of Oxalic acid in them.
Just don't eat any or drink what you make from boiling
them or the grass will be growing green over your prostrate
form.
Malcolm
I don't suffer from
insanity I enjoy it!
Mene, mene, tekel,
upharsin
The writing is on the wall.
Ha-ktovet al ha-kir
--------------------------------------------
On Tue, 7/4/17, roylowenthal@...
[Homebrew_PCBs] <Homebrew_PCBs@yahoogroups.com>
wrote:
Subject:
[Homebrew_PCBs] Re: Ferric chloride staining PCB
substrate
To: Homebrew_PCBs@yahoogroups.com
Date: Tuesday, July 4, 2017, 3:20 AM
Oxalic acid is also sold as, "wood
bleach" usually findable in hardware or
paint
stores.
Roy
#yiv3226884296 #yiv3226884296 --