Re: [Homebrew_PCBs] flatbed scanner lamps
2013-02-23 by Leon Heller
... You need UV lamps (long wave for positive resist)! Leon -- Leon Heller G1HSM
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flatbed scanner lamps
2013-02-23 by dave_donlan
Has anyone got any idea of the suitability of the scanner lamp for pcb exposure. If ok I was planning on positioning the lamp further away from the glass and
Re: [Homebrew_PCBs] Re: DIY pcb exposure box UV tl
2013-02-23 by Hari Hendaryanto
So germicidal works on negative photoresist and won t work on positiv 20 nor dry film. need near UV and longwave UV (IIRC). If I m understanding this
Re: [Homebrew_PCBs] Re: DIY pcb exposure box UV tl
2013-02-23 by Harvey White
... You used Germicidal (bare) lamps with the old Kodak KPR chemistry, a negative resist. Current positive films need near UV and longwave UV (IIRC). NEVER
Re: DIY pcb exposure box UV tl
2013-02-23 by tda7000
I don t think so, I think the wavelength is wrong, exposure won t work or won t work properly. Never mind that they are much more dangerous for your eyes etc!!
Re: [Homebrew_PCBs] DIY pcb exposure box UV tl
2013-02-23 by Hari Hendaryanto
harvey s opinions also true, i spent ~ $50 just for hot air rework station, because i m starting dealing using smd part :D ( that was fun) about the exposure,
Re: [Homebrew_PCBs] DIY pcb exposure box UV tl
2013-02-22 by Harvey White
... Ah, then cost trumps cute unless you can make sexy trump cost. No problem Harvey
RE: [Homebrew_PCBs] DIY pcb exposure box UV tl
2013-02-22 by Rick Sparber
Harvey, I failed to mention that this particular project is not just part of my hobby. Someone else is trying to make some money with it. So cost does matter
Re: [Homebrew_PCBs] DIY pcb exposure box UV tl
2013-02-22 by Harvey White
... Exposure timer. Exposure timer (if it has an a/d) with sensitivity to exposure. Do it because it s neat. You re talking about a 50 cent difference (but
Re: [Homebrew_PCBs] DIY pcb exposure box UV tl
2013-02-22 by Missouri Guy
I was afraid of that.... I suspect the Lights of America fixtures use an electronic ballast instead of an inductor/transformer/standard ballast and no
RE: [Homebrew_PCBs] DIY pcb exposure box UV tl
2013-02-22 by Rick Sparber
Hari, I sent a picture and text via private email. It is a bit OT. Rick ... From: Homebrew_PCBs@yahoogroups.com [mailto:Homebrew_PCBs@yahoogroups.com] On
Re: [Homebrew_PCBs] DIY pcb exposure box UV tl
2013-02-22 by Hari Hendaryanto
Sound interesting, may I see your schematic if you don t mind Thanks Hari ... From: Rick Sparber [rgsparber@aol.com] Date: Fri, Feb 22, 2013 To:
RE: [Homebrew_PCBs] DIY pcb exposure box UV tl
2013-02-22 by Rick Sparber
Hari, I am fascinated with the ATTiny85 (computer system on a chip and cost under $1) but refuse to take the leap until I can find a really cool application.
Re: [Homebrew_PCBs] DIY pcb exposure box UV tl
2013-02-22 by Hari Hendaryanto
Hi rick, New url is okay. I ll check if it s(or equivalent) available on my local suplier Yes you were right about how people build things. It s just a matter
RE: [Homebrew_PCBs] DIY pcb exposure box UV tl
2013-02-22 by Rick Sparber
I suspect it generates as much RFI as any fluorescent fixture. I use it in my shop which has 1 KW of fluorescent fixtures. They make it near impossible to play
Re: [Homebrew_PCBs] DIY pcb exposure box UV tl
2013-02-22 by Missouri Guy
Just outta curiosity, does that Lights of America fixture produce RFI? (I.e., radio interferrence). Thanks, Charlie On Fri, 22 Feb 2013 07:06:52 -0700 Rick
RE: [Homebrew_PCBs] DIY pcb exposure box UV tl
2013-02-22 by Rick Sparber
Hari, The line broke. Try this We all have different reasons to make
Re: [Homebrew_PCBs] DIY pcb exposure box UV tl
2013-02-22 by Hari Hendaryanto
hi, rick thanks for your quick response ... it s just a wooden box with avr(atmega8535L) module to set the timer, LOL :D ... this link not work for. it s said
RE: [Homebrew_PCBs] DIY pcb exposure box UV tl
2013-02-22 by Rick Sparber
Hari, VERY fancy exposure box. Being a minimalist, I bought two of these http://www.walmart.com/ip/Lights-of-America-24-Fluorescent-Blacklight-Fixtur
DIY pcb exposure box UV tl
2013-02-22 by Hari Hendaryanto
hi guys, just to make sure i m on the right track, while i m waiting for my dry film, i wanna ask some favour. i m deploying compact PCB uv exposure box ( not
RE: [Homebrew_PCBs] Re: Mektronics in Sydney .au: source of 0.8mm copper-clad FR4
2013-02-21 by Tony Smith
... place ... 3 ... Good luck trying to buy from Wiltronics. Last couple of times I ve tried their cart was broken - checkout dumps you into PayPal s test
Re: Track widths, current and maximum temperature rise.
2013-02-21 by Bob Butcher
If you can design the board for a 10 degree C rise, that would be great, but you probably can live with 20 degrees C. I would keep the leads fairly short and
Re: [Homebrew_PCBs] Track widths, current and maximum temperature rise.
2013-02-21 by Mitch Davis
... Some of my customers leave the soldermask off their high-current traces: The HASL solder will carry some more current. Mitch.
Re: [Homebrew_PCBs] Track widths, current and maximum temperature rise.
2013-02-20 by Todd F. Carney
I would think you could allow a temperature rise at least as much as the operating-temp rating of your mosfets. That might be as high as 125 degrees C., but
Track widths, current and maximum temperature rise.
2013-02-20 by scubadogct
Hi I am designing and building a pwm motor controller. I am desigining it to run a DC motor with a maximum current of 8 amps and 12 Volts DC supply. I am using
Re: Mektronics in Sydney .au: source of 0.8mm copper-clad FR4
2013-02-20 by cunningfellow
... Wow - It amazes me every time I see a company with worse prices than radio spaces. When I was younger we used to joke about RS being the dearest place in
Re: [Homebrew_PCBs] Re: Etching woes: Press-n-Peel, Laminator, Etch Tank + Sodium Persulphate
2013-02-20 by Todd F. Carney
... Todd, What are your ratios, particuly the sodium chloride(salt) ? Ollie, I m actually no longer using the salt additive, just the muriatic (hydrochloric)
Re: [Homebrew_PCBs] Re: Etching woes: Press-n-Peel, Laminator, Etch Tank + Sodium Persulphate
2013-02-20 by William Whyte
(excess quoting trimmed by moderator - please trim!) Todd, What are your ratios, particuly the sodium chloride(salt) ?
Re: [Homebrew_PCBs] Re: Etching woes: Press-n-Peel, Laminator, Etch Tank + Sodium Persulphate
2013-02-20 by Todd F. Carney
Phil, I use an muriatic (hydrochloric) acid and peroxide etchant in a tray. I mix the etchant just before use, and since the combination is *exothermic*, it
Re: Etching woes: Press-n-Peel, Laminator, Etch Tank + Sodium Persulphate
2013-02-20 by phil.quinton@ymail.com
Todd, Thank you for the advice. If you use a tray for etching, how do you keep the temperature up for the sodium persulphate? Or is it just a case of getting
Re: [Homebrew_PCBs] Re: Etching woes: Press-n-Peel, Laminator, Etch Tank + Sodium Persulphate
2013-02-20 by Todd F. Carney
Either ammonium persulfate or sodium persulfate is used by commercial pcb manufacturers. They do not use ferric chloride, not for decades. Only hobbyists use
Re: Etching woes: Press-n-Peel, Laminator, Etch Tank + Sodium Persulphate
2013-02-20 by tda7000
I have used the toner transfer method with the laminator described here: http://ultrakeet.com.au/write-ups/superfuser I have not used Press-n-peel blue, just
Re: [Homebrew_PCBs] Etching woes: Press-n-Peel, Laminator, Etch Tank + Sodium Persulphate
2013-02-20 by Todd F. Carney
In the trade what you have what is called undercutting. If the resist in firmly applied, undercutting is usually caused by exhausted etchant and therefore
Mektronics in Sydney .au: source of 0.8mm copper-clad FR4
2013-02-20 by Robin Whittle
There s a source of M. G. Chemicals single and double-sided copper clad FR4 material in Australia, including 0.8mm double-sided material. I recently bought
Etching woes: Press-n-Peel, Laminator, Etch Tank + Sodium Persulphate
2013-02-19 by phil.quinton@ymail.com
Hi, First post, hopefully one of many.. To cut a long story short, I m having problems after etching with Sodium Persulphate in my very
Re: [Homebrew_PCBs] conductive epoxy
2013-02-18 by r.d. terramir
a reprap type application maybe with a modified frostruder might be useful for thinned out conductive epoxy like this and maybe use a pick and place kinda
[Homebrew_PCBs] conductive epoxy
2013-02-18 by Mark Lerman
Here s a link to a conductive epoxy that is one part and can be diluted with acetone. It is heat cured. So, theoretically one could print the circuit, stick
Re: [Homebrew_PCBs] soldering surface mount without solder resist.
2013-02-17 by DJ Delorie
... Me too, but under fine pitch parts or between closely spaced pins, you might not have a choice.
Re: [Homebrew_PCBs] soldering surface mount without solder resist.
2013-02-16 by Todd F. Carney
... time this doesn t work is if you have signals that are very high impedance, where the excess flux might cause too much current to flow between pins. . . .
Re: [Homebrew_PCBs] soldering surface mount without solder resist.
2013-02-16 by DJ Delorie
Soldering fine-pitch ICs is a bit easier if you plan ahead and make the copper pads on your PCB stick out a bit more than usual. This gives you a way to wick
Re: [Homebrew_PCBs] Surface mount heat sinks
2013-02-16 by Harvey White
... There are several ways. One involves using an extended plane of copper, I m not sure of the design rules for size, but you might see them in the design
Surface mount heat sinks
2013-02-16 by scubadogct
Hello I am building a DC PWM board. I am designing my own board on diptrace that I intend to etch myself. and would like to use surface mount components. I
Re: soldering surface mount without solder resist.
2013-02-15 by scubadogct
Well I used solder paste and a frying pan as a make shift reflow plate. All worked easily. Only 1 bridge on an IC pin. I am a convert to sufrace mount and
RE: [Homebrew_PCBs] Re: ferric chloride question
2013-02-15 by Rick Sparber
Todd, The precipitate made it harder to see the board while it was etching. I use a translucent tub with a 200W bulb under it. This arrangement lets me
Re: relatively good prices
2013-02-15 by tda7000
I use the Na2CO3 Sodium carbonate (washing soda) for both developer and stripper. For developing, I use a weak solution with warm water. For stripping, a
Re: [Homebrew_PCBs] soldering surface mount without solder resist.
2013-02-15 by Mitch Davis
... Seconded. For fine pitch, flux helps a lot. ... If you get a board made commercially with a 0.4mm pitch footprint, often the soldermask will not survive
Re: [Homebrew_PCBs] relatively good prices
2013-02-15 by Mitch Davis
... Curious. This seems to suggest that the developer is Na2CO3: http://www.ebay.com.au/itm/130690362878 Mitch.
RE: [Homebrew_PCBs] soldering surface mount without solder resist.
2013-02-15 by Jeff Heiss
Maybe an aluminum pie pan would work also for the stencil. Jeff _____ From: Homebrew_PCBs@yahoogroups.com [mailto:Homebrew_PCBs@yahoogroups.com] On Behalf Of
Re: [Homebrew_PCBs] soldering surface mount without solder resist.
2013-02-15 by Dylan Smith
... It s not really a problem. I ve hand soldered 0.4mm pitch LQFPs on a home made board without solder resist. (Making the board with that fine pitch was a
Re: [Homebrew_PCBs] relatively good prices
2013-02-15 by Russell Shaw
... I use 10g/Lt NaOH as *stripper*. What do you strip with? I use Na2CO3 sodium carbonate as developer.