Acid etching to make crossover boards?

[lunchmoney]

A buddy at work recommended that I could copper acid etch the boards instead of hand soldering.

Anyone done this?

[curt_c]

Re: Acid etching to make crossover boards?

There is no reason you cannot, and it will make for a nice clean look. I don't see any sonic benefits over point to point wiring.

C

[john trials]

Re: Acid etching to make crossover boards?

As part of my job, I design printed circuit boards for military and commercial applications. When I started looking at people's build threads on the DIY speaker forums, I was appalled at the crossovers (built on peg board, etc.)...how crude! But when it came time for me to build crossovers, that's exactly how I made mine.

I've etched my own boards way back when. I'm not sure about the chemicals these days, but there may be environmental issues (disposal) involved.

If the chemicals and related equipment are costly (and you don't want to deal with the mess), you could also check out www.expresspcb.com. I've used them many times, and had great results, especially with solder mask and silk screen layers added. They've basically eliminated the need to etch your own boards.

Unless you are going to display your crossover, it's probably best just to wire it together like you've been doing. There is no electrical advantage to going with a circuit board.

[Squidbait]

Re: Acid etching to make crossover boards?

I etched my first crossovers and they looked great!!!

But I haven't seen them since I closed them up. Probably not worth the cost/time/effort.....

[benchtester]

Re: Acid etching to make crossover boards?

I have done a fair amount of PCB (printed circuit board) etching at home

The most common etching fluid is ferric chloride. It is fairly safe and easy to use, but it does stain everything yellow. So you want to plan you work and wear gloves.

You need to make the image on the copper. If you don't care about looks you can draw the crossover circuit on the copper with a "Sharpie" marker. Do a couple of coats. It resists the ferric chloride fine. If you want a better image, you can laser print (I doubt ink jet will work) on a special sheet then iron-transfer the toner on to the copper board. I often touch-up any porosity with the sharpie marker.

If you have choice, you probably want thicker traces. Commonly boards are "1 oz."; this refers to 1 oz. of copper per an area (square foot?). But you can get 2 oz. boards.

You will want to drill holes for the component leads. I like solid boards, and holes in the predrilled boards will be too small for crossover component leads.

Having said all this, I think etching boards is more work than soldering crossovers with wire, so I haven't done a crossover board yet. Someday I will: when I want a good looking board or to make multiples of the same circuit.

BTW-1: An easy alternative is to buy a PCB like these:

http://www.parts-express.com/wizards/searchResults.cfm?srchExt=CAT&srchCat=197&CFID=5218202&CFTOKEN=84510698

and madisound has some very generic ones with many square pads.

BTW-2: If there is interest, I can write up the step by step directions I use for the iron-on transfer method.

[JRT]

Re: Acid etching to make crossover boards?

A buddy at work recommended that I could copper acid etch the boards instead of hand soldering.

Anyone done this?

I think point wiring is at least as good at the low frequencies involved in this.

And wouldn't you be hand soldering the components regardless which you chose?

[rogoll]

Re: Acid etching to make crossover boards?

If the chemicals and related equipment are costly (and you don't want to deal with the mess), you could also check out www.expresspcb.com. I've used them many times, and had great results, especially with solder mask and silk screen layers added. They've basically eliminated the need to etch your own boards.

Unless you are going to display your crossover, it's probably best just to wire it together like you've been doing. There is no electrical advantage to going with a circuit board.

Wow, this company has some great pricing. Two things that have held me back from designing a board were the cost (I thought) and the drafting/CAD. This place has both bases covered. I'm going to try them out on a little LED speaker power meter I've been working on. It it turns out well, I'll post some pics and comments.

[dthomas]

Re: Acid etching to make crossover boards?

A buddy at work recommended that I could copper acid etch the boards instead of hand soldering.

Anyone done this?

http://www.erseaudio.com/Products/PCBoards;jsessionid=0a010b441f43e914f0762e504e7a90d9ff5528493f18.e3iKaNePch4Re34Pa38Ta38PbNb0

These work great and they are inexpensive. i use them all the time. Makes for a neater job. Sometimes you have to get creative in attaching notch filters etc... but at the end of the day they are great.

Madisound used to sell them not sure if they still do.

[rogoll]

Re: Acid etching to make crossover boards?

http://www.erseaudio.com/Products/PC...4Pa38Ta38PbNb0

These work great and they are inexpensive. i use them all the time. Makes for a neater job. Sometimes you have to get creative in attaching notch filters etc... but at the end of the day they are great.

Madisound used to sell them not sure if they still do.

Erse has some great products and prices. They manufacture the "Dayton" crossovers with the dual 4/8 ohm low pass sections (I'm pretty sure).

I keep an eye out for sales and close outs of prebuilt XO's like this and this, then once I've desoldered the components, I have a blank board to use, as well as spare parts for much less than I could have purchased just the boards for. In the same way, I stocked up on the terminal cups that had the filter soldered to the back of it. Just use a solder sucker and disassemble the parts until they're needed.

[jonpike]

Re: Acid etching to make crossover boards?

I have done a fair amount of PCB (printed circuit board) etching at home...

BTW-2: If there is interest, I can write up the step by step directions I use for the iron-on transfer method.

I'd be interested in hearing/getting something about your methods and experiences, Bench.

I've researched the laser printed transfer method off and on for years... keep meaning to give it a try. Always ends up (for work) I do point to point, solder up some kind of protoboard, or just go with a commercial layout/boardhouse for larger scale things.

Now I'm starting to play with customised active filter boards, I'm a bit more motivated..

On the general topic, search around for DIY PCB construction methods. Many prototyping styles... for smaller (IC and discrete parts) and larger (our big honking caps and coils of crossovers) component boards. Ham Radio sites can be good jumping off points. Still some homebrew DIY efforts out there...

[neildavis]

Re: Acid etching to make crossover boards?

I'd be interested in hearing/getting something about your methods and experiences, Bench.
...

I still think the best "quick and dirty" technique for making home boards is using a paint pen. I never had much luck with the Sharpie, but the paint resists water fairly well, and the traces usually come out OK. By drilling first you can make budget double-sided boards. There is an old thread (Jan 2007) on this topic at this location:

http://techtalk.parts-express.com/showthread.php?p=1423001&highlight=wallin#post1423001

[benchtester]

Re: Acid etching to make crossover boards?

I'd be interested in hearing/getting something about your methods and experiences, Bench.

If a couple of days is okay, I will blog the laser printer procedure and post a notice here. (i.e. tell me if you need it quicker)

That link is pretty good and I found envisionelec's comment very amusing (voice of experience):

"Almost anything will "block the acid", Blair. Tape, Sharpie, a finger print, copper oxide."

I did a photo method once (before laser printers!) on a simple board; but I like the laser printer method for "normal" circuits. I think the laser method is good down to 0.050" spacing. I recently bought a photo kit, but haven't played with it yet. I expect that it will do a better job with a little bit more work. Although, the photo method certainly would save time on complex circuits since I now retrace the toner with the sharpie.

[john trials]

Re: Acid etching to make crossover boards?

If you guys are doing the laser print method and etching your own boards, you should still check out expresspcb. Their software download is free, and you can use it to lay out your traces (and print it 1:1). It's pretty nice software. They even have a schamatic layout software that can be linked to the PCB layout.

[neildavis]

Re: Acid etching to make crossover boards?

If you guys are doing the laser print method and etching your own boards, you should still check out expresspcb....

I use expresspcb alot--just made the amplifier board in the picture. But the entry price is $60 for the express service and even with their overnight shipping it takes a few days to get the board done. So it's nice to have a quick, cheap alternative for simple designs like crossover boards.

[john trials]

Re: Acid etching to make crossover boards?

I was suggesting that you could just use the expresspcb software for the layout, then laser print the traces 1:1 and use that to etch your own board.