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| Opinions sought on new way to gap PCB ties. https://fast-tracks.net/forums/viewtopic.php?f=4&t=1192 |
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| Author: | jdm_com_au [ Mon Dec 05, 2011 8:55 pm ] |
| Post subject: | Opinions sought on new way to gap PCB ties. |
What I was thinking was to first build the trackwork (except for installing wood ties) and then giving the assembly a dip in some ferric chloride to disolve the exposed copper on the ties. I used to build my own circuit boards for various electronic projects back in the 80's, so I'm familiar with the process. My only concern is that the ferric chloride may react with the nickel silver or solder. As it would only need to be soaked for a few minutes, I really don't see a problem. But I thought I would ask the opinion of others first. |
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| Author: | emccamey [ Tue Dec 06, 2011 12:12 pm ] |
| Post subject: | Re: Opinions sought on new way to gap PCB ties. |
You could certainly experiment with some cut off bits and examine the effects. I'd be worried that the bonding of the remaining bits of copper and solder to the tie substrate would not provide sufficient strength and integrity. Only by testing with a full assembly can you assess the results. You could simply place drops of the ferric chloride in the center of the ties where cuts are called for and establish the electrical isolation (and not have visible cuts). In any case, neutralize and rise well. -ed- |
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| Author: | jdm_com_au [ Tue Dec 06, 2011 9:38 pm ] |
| Post subject: | Re: Opinions sought on new way to gap PCB ties. |
My thoughts are that the copper would not de-laminate from the fibreglass section of the tie. The only way that normally happens is due to excessive heat being applied during soldering, or through physical damage. I have done both of those in the past whilst building electronic projects, once was with a waaay too big soldering iron for the job. I then purchased a pencil soldering iron that worked off my model railway 12V transformer and never had another problem. So unless the trackwork would come under some sort of excessive torsional load (too heavy train, too fast and a too sharp radii), I see no reason for the trackwork to fail. I had thought of just using a few drops in the middle of the tie to break the electrical contact. The reason for considering dipping the entire fixture was that I was unsure how the PCB ties would look after painting if I took that approach. But yeah, minimum time soaking, maximum time rinsing and air drying is my line of thought at the moment. |
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| Author: | Bernd [ Wed Dec 07, 2011 1:44 pm ] |
| Post subject: | Re: Opinions sought on new way to gap PCB ties. |
I think you would be better off using an abrasvie cut off wheel. I'm sure the acid would attack both the track and solder. I've also done my own boards and used ferric chloride. Why don't you want to use an abrisve tool just to grind off a bit in the middle of the track? Regards, Bernd |
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| Author: | jdm_com_au [ Wed Dec 07, 2011 10:03 pm ] |
| Post subject: | Re: Opinions sought on new way to gap PCB ties. |
Me and grinding tools are not a good mix. Besides, any grinding tool will probably result in a finish on the tie that I'm NOT after. I think I'll assemble a short straight section and leave it soak in a nice strong mix for a while. It will be the sacrificial anode.  But since I'm going on interstae holidays soon, it will probably be mid January before I get around to this.
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