Favourite parts with off-label uses?

of PWBs made? I recall several outfits that panelize multiple designs into one batch so you can order a small number of boards at not a high price.

etc.

g might

size range and I was concerned the board cost might be getting up there so I checked with these guys. Not bad at all. But while exploring options I noticed some oddities.

', but they add another $9 to the 'board' cost. So it's really $25 extra. Same with 2 oz copper weight. Odd.

the 'board' price just a bit less than $4, then add $4 to the 'engineering fee' so the total is a actually a little bit more!

fee, but the "engineering fee" goes up a LOT. I guess that's the labor and the board fee is the material.

on't see a way to specify the stackup as in layer thickness. They talk abo ut fiducials being made as holes in the PWB either half way through or all the way through. Wouldn't this just be another drill hole? Or is this mad e with a higher accuracy?

at that price you don't get a choice of stackup, every one gets the same because they nest everyones design on large panels, that's also why anythin g "special" like enig and 2oz copper adds up I think fiducials half or all way through is for when you order a solder paste stencil

tty expensive by the time I add in the smaller hole size and ENIG it's push ing toward $200. Still not bad really.

with jlcpcb you can also get vscored panel for not much more so you can fit many smaller boards on the 100x100mm

s of PWBs made? I recall several outfits that panelize multiple designs in to one batch so you can order a small number of boards at not a high price.

sk etc.

ing might

al size range and I was concerned the board cost might be getting up there so I checked with these guys. Not bad at all. But while exploring options I noticed some oddities.

sh', but they add another $9 to the 'board' cost. So it's really $25 extra . Same with 2 oz copper weight. Odd.

r the 'board' price just a bit less than $4, then add $4 to the 'engineerin g fee' so the total is a actually a little bit more!

" fee, but the "engineering fee" goes up a LOT. I guess that's the labor a nd the board fee is the material.

don't see a way to specify the stackup as in layer thickness. They talk a bout fiducials being made as holes in the PWB either half way through or al l the way through. Wouldn't this just be another drill hole? Or is this m ade with a higher accuracy?

retty expensive by the time I add in the smaller hole size and ENIG it's pu shing toward $200. Still not bad really.

ly (but not RF, which we prefer to order domestically)

ith this Coronavirus thing.

Yes, jlcpb.com was the site. I bookmarked it.

--

  Rick C. 

  --+ Get 1,000 miles of free Supercharging 
  --+ Tesla referral code - https://ts.la/richard11209

ies of PWBs made? I recall several outfits that panelize multiple designs into one batch so you can order a small number of boards at not a high pric e.

mask etc.

pping might

sual size range and I was concerned the board cost might be getting up ther e so I checked with these guys. Not bad at all. But while exploring optio ns I noticed some oddities.

nish', but they add another $9 to the 'board' cost. So it's really $25 ext ra. Same with 2 oz copper weight. Odd.

wer the 'board' price just a bit less than $4, then add $4 to the 'engineer ing fee' so the total is a actually a little bit more!

rd" fee, but the "engineering fee" goes up a LOT. I guess that's the labor and the board fee is the material.

I don't see a way to specify the stackup as in layer thickness. They talk about fiducials being made as holes in the PWB either half way through or all the way through. Wouldn't this just be another drill hole? Or is this made with a higher accuracy?

pretty expensive by the time I add in the smaller hole size and ENIG it's pushing toward $200. Still not bad really.

ally (but not RF, which we prefer to order domestically)

with this Coronavirus thing.

is the same company so you can combine PCB and component order

They also have cheap assembly, though it is limited to a selection of LCSC parts and only smd

I think you missed a note in there -- they've changed the product. The original (that worked) was shellac(?), but it has been changed to a new formula that allegedly does not work as well.

Ammonia strips acrylic floor wax, so maybe it would strip an acrylic undercoating, if acrylic is all we can get.

I don't know which Rust-Oleum formula I got. Whatever's in my two-or-three-years-old can of the stuff works wonderfully. It wipes off the open surfaces readily with 90% alcohol(*), but stays in the toner's pores, sealing them.

(*) 50% IPA was unsatisfactory.

Yes, exactly. I've designed a class-C HF QRP PA using CMOS gates that might see first power this way. LTSpice says it's about 80% efficient, ideally, from d.c. input power to 50-ohm load.

Yep. The dry photo resist film method looks easier than spincoating, but I'd really like to _reduce_ the wet steps and process variables.

There sure is something magical about it and that's exactly why I do it. It's liberating.

Frankly I'd still be using unmodified toner transfer if it hadn't quit on me. Previously I was making 0.012" traces and spaces with ease. I had no problems at all, worked every time without trouble, and I wondered what everyone else was griping about. But once it quit, no amount of fiddling has gotten it working again. Same papers, same printer, same clothes iron, etc., but no joy.

My problem is getting the toner to adhere to the copper. I had the same difficulty transferring thermally, and with the cold transfer (solvent) methods that rely on making the toner sticky--the darn toner just won't stick to the board. But I must say toner sticks very aggressively to a sticky lacquered board, whether I use heat or solvents to soften the lacquer and make it sticky.

Cheers, James Arthur

term

r

a.

just

e .

er,

y

lying-It-t/

a

tried a quick dip in etchant before the transfer?

a few seconds and the copper turns a more dull rough surface

Yep. Have an air compressor with a "blow gun" hose handy to clean out the accumulated toner. About 30 psi seems right. The toner gets into everything. I don't recall if the P2055 uses a laser or an LED array. Probably laser. Sometimes, toner dust gets into the laser and rotating mirror resulting in odd looking shadows. If you bypass the shutter that protects the laser assembly, and blow some low pressure Thanks,

--
Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
Santa Cruz CA 95060 http://802.11junk.com 
Skype: JeffLiebermann     AE6KS    831-336-2558

I didn't mention it earlier but we buy our RF boards (which are nearly alwa ys 6-layers and up) domestically because we often find that we need special stack-ups for impedance control (which JLC doesn't offer), AND lately on a few boards, the parts are getting so small and so densely packed that we n eed to tightly couple our Gerbers (silkscreen, pad tweaks, etc..) to the ve ndor's SMT line so the parts solder correctly during reflow, etc... We've had a couple cases lately where some tiny SAW filters (etc..) float off the (otherwise adequate) paste-up inspection. Resulting in re-work on our end to get the boards to meet spec.

All of which is a big wasted breath on the bean-counters in our company who simply can't understand why you can't shop the design around to just anybo dy who claims to stuff PCB's. They think they can just send the Gerbers an d get perfect first article boards, no matter how complex (or high-frequenc y) the design is.

alcohol is soluble in acrylic, and tends to soften acrylic paints.

"Zinsser B-I-N" is shellac based and has an alcohol solvent, I have purchased it in spray cans in the past. it contains a white pigment.

--
  Jasen.

[snip]

A traditional alternative is a long thin tube whose volume is sufficient to ensure that no inside air gets out or outside air gets in, despite the +/- 7% variation in ambient air pressure. Invented by Louis Pasteur in 1859.

.

Joe Gwinn

The "Export" brand paints available in Supercheap Auto are really crappy, they claim to be enamel paint but seem to never actually cure and always dissolves in mineral turpentine.

Supercheap also have 3M, Septone, and "SCA" brand "Acrylic" lacquer sprays. As these paints are intended for automotive use they are probably alcohol resistant due to the introduction of alcohol in fuel.

They also have SCA brand "multi purpose" Acrylic paint, this stuff will possibly be softened by alcohol. Plasti-Kote and Dulux brand acrylic spray paints from a hardware shop are probably worth a try too.

"Zinsser B-I-N" is a commercialy produced shellac based primer. Spray cans are available (but can be hard to find). Alternatively some places can put paint into a spray can for you.

--
  Jasen.

Actually, the silkworms don't survive harvest. Anyway it's a secretion from a parasite, so its probably mostly resin... you could try pre-coating with liquid flux or OSP.

--
  Jasen.

y

Thanks, that's an interesting idea.(*) Riding on a big-ass harvester in E T exas ot Australia or some such place, it's fairly hard to ensure that rain or wash water never gets in, though.

Cheers

Phil Hobbs

(*) I have a lot of respect for the giants of the past--long ago, after I'd submitted my first and (so far) only theoretical paper, I withdrew it afte r finding that its main result had been published by Lord Rayleigh. One of my less merciful friends asked me, "How does it feel to be on the forefront of 19th century science?"

by

Texas ot Australia or some such place, it's fairly hard to ensure that rai n or wash water never gets in, though.

'd submitted my first and (so far) only theoretical paper, I withdrew it af ter finding that its main result had been published by Lord Rayleigh. One o f my less merciful friends asked me, "How does it feel to be on the forefro nt of 19th century science?"

I seem to reading that probably around the same time period, there was a sa ying: "If you think you have invented some new you need to learn to read German"

What a great subject !!

Kind of like off use of drugs for treating other diseases !

boB

com:

e:

d

a term

.

ner

lia.

re

er just

er

;

y

the

es.

er

aper,

ng

nd

F.

any

s,

a

pplying-It-t/

n a

. e

Yes, thanks, I've tried a quick dip to roughen the copper surface, but it didn't make any difference. It's mysterious.

When TT was working, I prepared the copper with fine steel wool, then sometimes Comet (an abrasive kitchen cleaner with soap and bleach) for de-greasing. I've the original method, rough sandpaper, fine sandpaper, cross-hatching, and etching.

Cheers, James Arthur

Thanks Jasen, very helpful. That should set Clifford on the right track.

Cheers, James Arthur

(and others)

so much about problems and possible solutions that my mailer would reject the post for excessive quoting..

The more I read here, the more I'm convinced to stay with the photochemical priciple. The boards are cleaner than one could ever hope to clean them oneself, surfaces lapped and covered with photo resist and then protection foil.

All one needs is a UV source (face tanner in my case), NaOH as developper and stripper, the etchant, Na- or Ammonium- persulfate and two sheets of glass to enforce direct contact between the film and the board during exposure.

I can easily produce anything my laser printer can print, easily down to 4 mil / 4 mil feature size with offset film. The process takes less than an hour from the time I've printed the film and is absolutely reproducible.

I use their board material: <

> but not their machines. There must be similar offers on other continents.

And yes, I also use PCBway and others when there is time and willingness to deal with DHL and our customs office who question the price of the boards on a regular base. That cheap, absolutely impossible! Fraud!

cheers, Gerhard

Thanks Jeff and Phil.

It works best for me to avoid Deutsche Post, DHL, and Customs whenever possible because it takes an inordinate amount of time for my orders to arrive in America. And shipping costs from Germany to America are typically sky high.

Anyhow, this website shows how to print PCBs on glossy laser paper and then transfer the pattern to plain old copper boards with an electric clothing iron:

Although the website uses ferric chloride, it ought be relatively easy to substitute in persulfate. The hard part is preparing the copper board beforehand.

Thank you,

--
Don Kuenz KB7RPU 
There was a young lady named Bright Whose speed was far faster than light; 
She set out one day In a relative way And returned on the previous night.