Etching Process Quesrion???

[WLS]

Do you have to use a floresent light in the positive photofabrication process or will any light source due?

I am going to use MG's positive presensitized boards from mousers to etch.

I already have a light fixture that rus off of two forty watt bulds that is compact and would be excellent for this process if I could use it.

Thanks!

[Ice-9]

You need to use a UV (ultra violet ) tube, i use a single tube of 8 watt, and made my own exposure box, but UV will damage your eyesight if you look at it.

[solderman]

Do you have to use a floresent light in the positive photofabrication process or will any light source due?

I am going to use MG's positive presensitized boards from mousers to etch.

I already have a light fixture that rus off of two forty watt bulds that is compact and would be excellent for this process if I could use it.

Thanks!

I made a short and not very good but jet a tutorial om mi site http://www.soldersound.com/ about using this technique to etch PCB:s follow the "tutorial " link

//Solderman

[WLS]

I made a short and not very good but jet a tutorial om mi site http://www.soldersound.com/ about using this technique to etch PCB:s follow the "tutorial " link

//Solderman

So, the light has to be UV. This may sound dumb but does it have to be white or will a black light work?

Finally got the Pt-80 breadboarded. Tough circuit to put on the board. Thanks for the tip on the trace though.

Oh, by the way good talking to you again.

[MarcoMike]

UV lamps are what you call "black light"s... if you have one already u can try and see if it works... sun should work as well...
anyway.. in my opinion PnP or cheap equivalents are the way to go...

[captntasty]

Plain old fluorescent bulbs work just fine.  No need for black light...

[WLS]

UV lamps are what you call "black light"s... if you have one already u can try and see if it works... sun should work as well...
anyway.. in my opinion PnP or cheap equivalents are the way to go...

Plain old fluorescent bulbs work just fine.  No need for black light...

Since it does not matter if it's a black or white I went out to the store and shopped around and got what I think is a good deal at Menard's Hardware. It L Ks like I will have a black light. I picked up a 21" fixture with a 60 watt bulb for only ten dollars.   

Thanks to everyone for clearing this up for me!

[Ice-9]

Any light source will work , but the length of time needed to expose the photoresist will be increased. The longer it is exposed to light the more chance you have of the areas you want left will get slightly developed as well.

I ve an 8 watt UV (not black) that take 2min and 15 secs to fully develop and it only cost £8 UK much better for getting the exposure time right as that is really imoprtant.

good luck with making your pcb's.

[R.G.]

My positive setup uses two 24" UV bulbs.

All fluorescent tubes are producers of UV primarily, usually from the glow of mercury vapor. Since we have found that carbon emissions are more deadly than mercury spread around all over the planet, our political heros are thrashing themselves to be the first to outlaw incandescent bulbs which cause deadly carbon emissions in favor of the more environmentally-friendly mercury-containing compact fluorescent bulbs. But that's neither here nor there.

To get much visible light out of a fluorescent bulb, the glass has to be coated with a phosphor which glows in the visible range when struck by UV. The glass tube soaks up much of the resulting UV that's left over. If you take a standard fluorescent bulb and change the glass a bit, it still glows visibly from the phosphors, but also lets more UV out. This is the variety of bulb I use. It's quicker than normal fluorescent bulbs.

"Black Light" bulbs have a setup to prevent as much visible light from escaping as possible to preserve only the UV coming out. The glass tube prevents the nastier UV wavelengths from escaping and only leaves a fairly benign longwave UV that's not deadly to look at.

There is a third kind of fluorescent bulb. This is the germicidal lamp. The envelope on these is quartz, not ordinary glass, and it lets all of the UV out, including some much shorter-wave stuff than the glass on ordinary tubes blocks. This stuff is ugly, and will fry your retinas, cause cataracts, as well as killing microbes. I use a 24" germicidal lamp to sterilize my drinking water here. But do not even think of using these for PCB exposure.

In case someone missed that, DO NOT USE GERMICIDAL UV LAMPS FOR PCB WORK.

As has been mentioned, ordinary fluorescent works fine for positive process, and that's as far as beginners or other people who value their eyesight should go.

[WLS]

Any light source will work , but the length of time needed to expose the photoresist will be increased. The longer it is exposed to light the more chance you have of the areas you want left will get slightly developed as well.

I ve an 8 watt UV (not black) that take 2min and 15 secs to fully develop and it only cost £8 UK much better for getting the exposure time right as that is really important.

good luck with making your pcb's.

So, with the 60 watt bulb then my expouser time would be a lot less approx: 1 1/2 to 2 minuets. I purchased three 6x6 boards to start with I was planning on cutting them into smaller pieces and then start to play with expouser time till I get it right. But I see what you mean that if I over expose the board I may loose traces.

Maybe I should put the clear cover back over the light it was cutting down the intensity. That's why I removed it to allow more light. 

My positive setup uses two 24" UV bulbs.

All fluorescent tubes are producers of UV primarily, usually from the glow of mercury vapor. Since we have found that carbon emissions are more deadly than mercury spread around all over the planet, our political heros are thrashing themselves to be the first to outlaw incandescent bulbs which cause deadly carbon emissions in favor of the more environmentally-friendly mercury-containing compact fluorescent bulbs. But that's neither here nor there.

To get much visible light out of a fluorescent bulb, the glass has to be coated with a phosphor which glows in the visible range when struck by UV. The glass tube soaks up much of the resulting UV that's left over. If you take a standard fluorescent bulb and change the glass a bit, it still glows visibly from the phosphors, but also lets more UV out. This is the variety of bulb I use. It's quicker than normal fluorescent bulbs.

"Black Light" bulbs have a setup to prevent as much visible light from escaping as possible to preserve only the UV coming out. The glass tube prevents the nastier UV wavelengths from escaping and only leaves a fairly benign longwave UV that's not deadly to look at.

There is a third kind of fluorescent bulb. This is the germicidal lamp. The envelope on these is quartz, not ordinary glass, and it lets all of the UV out, including some much shorter-wave stuff than the glass on ordinary tubes blocks. This stuff is ugly, and will fry your retinas, cause cataracts, as well as killing microbes. I use a 24" germicidal lamp to sterilize my drinking water here. But do not even think of using these for PCB exposure.

In case someone missed that, DO NOT USE GERMICIDAL UV LAMPS FOR PCB WORK.

As has been mentioned, ordinary fluorescent works fine for positive process, and that's as far as beginners or other people who value their eyesight should go.

I'm glad I purchased a safe one since I did not have a clue about the harmful rays. 

[Ice-9]

I'm not sure  but i think a 60watt standard bulb will take a lot longer than a 8watt uv. correct me if i'm wrong.
The way i would test it is to take a piece of pcb about 4 inches long and about half inch wide , then take a piece of cardboard (thin) and leave only say half inch of the length exposed, treat that to the light for 1 min then move the card another half inch so that 1 inch is exposed 1 minute. That then gives 2 mins exposure to the first bit and 1 min to the next bit. Keep moving the card half inch every minute. Then when you develop the board you will see which time was the best.

bear in mind tho that diff lights require huge time differences, for example the first light i built i used 40 uv leds but this took about 45 mins at least so a few mins either way doesnt make much difference but with my uv light box 15 seconds can make the difference between a good board and a failed board.

Maybe someones can give a clue as to how long you can start with for the light you have.

[solderman]

I'm not sure  but i think a 60watt standard bulb will take a lot longer than a 8watt uv. correct me if i'm wrong.

I have not tested a standard 60W but i guess you are right. I use a Philips TL 8W and I give my fotoresist cuppelamin in averidge 12min at 5cm (2") cupper to tube differs a bit depending on brand. If you underexpose with too short time there is no way you can save fix this since there will be to little fotoresist that will be developed and there is no way you can fix that in the etche bath. If you overexpose it is easier to compensate when etching the cupper. The size of the board is not critical as long as the board ceaps within 45 deg from the centerline on both sides and is not longer that the tube. If broader move tube at halfe time and add 50% time. It is importent to have a pice of clear glass or plexi on top of the mask so that you dont get stray light under the mask. I have tried PnP, Glossy magazine technique and sharpie pen . This beats them all by miles. Its easy to produce pro quality stuff with this method. And do NOT forget to take the redundant fororesist off with aceton or such from the ready board traces or you will not be able to solder.

The drilling sucks thoug. this is the only upside with vero/perf board

   

[WLS]

Solderman,


I'm still in the collection process. The other day I buoght a jacobs chuck for the dremel. And I am in the process of trying to obtain a dremel 212 press. I have put a lot of thought into this already and have got the bits. I bought them from Dan's special deals.

So I am almost at the point that I can start doing my own boards instead of lining someone's pockets.

Your not the only that has warned me about the drilling process being such a pain in the a#%.

Thank for all your help and useful tips. If you think of anything else well...

[solderman]

Solderman,


I'm still in the collection process. The other day I buoght a jacobs chuck for the dremel. And I am in the process of trying to obtain a dremel 212 press. I have put a lot of thought into this already and have got the bits. I bought them from Dan's special deals.

So I am almost at the point that I can start doing my own boards instead of lining someone's pockets.

Your not the only that has warned me about the drilling process being such a pain in the a#%.

Thank for all your help and useful tips. If you think of anything else well...

About drilling
Three important things to have in mind for a good result and and avoid frustration when drilling.

1. The Drill bit is VERY important. Use a special, made for the task, diamond tipped  Hard metal spiral drills with 3,15mm shafts  0.7 mm for most hole and 1-1.2 mm for what ever bigger.
why? The Cupper lamin you drill trough will ware down a ordinary HSS bit with in a few holes and you will be annoyed. The carbide drillbit will last you for ever. But watch out the carbide drillbit snaps off really easy that's why you need as drill press and something to keep the cupper piece steady.   

http://www.banzaieffects.com/banzaisearch.php?entqr=0&access=p&getfields=productimage&entsp=0&sort=date%3AD%3AL%3Ad1&output=xml_no_dtd&ie=UTF-8&btnG=Search&client=Banzai&q=drill&filter=0&ud=1&site=default_collection&oe=UTF-8&proxystylesheet=Banzai&ip=88.198.55.226&proxyreload=1&start=20



2. A fast rotating electrical drill with a press. Dremmel and press is OK as long as you can fit the carbide drillbit.

3. A firm hand or table vice or some thing to hold the piece. Othervise the drill will snap easily. Put the piece on a piece of wood  and drill only 1 mm trough the cupper in to the wood.

Work in a structuered way  from one end to the other, Use ear plugs and protective goggles, have patients do not drill drunk 

Good luck, its worth the freedom to make the PCB of you're choice or your own  design

//Solderman 

   

[WLS]

About drilling
Three important things to have in mind for a good result and and avoid frustration when drilling.

1. The Drill bit is VERY important. Use a special, made for the task, diamond tipped  Hard metal spiral drills with 3,15mm shafts  0.7 mm for most hole and 1-1.2 mm for what ever bigger.
why? The Cupper lamin you drill trough will ware down a ordinary HSS bit with in a few holes and you will be annoyed. The carbide drillbit will last you for ever. But watch out the carbide drillbit snaps off really easy that's why you need as drill press and something to keep the cupper piece steady...  

3. A firm hand or table vice or some thing to hold the piece. Othervise the drill will snap easily. Put the piece on a piece of wood  and drill only 1 mm trough the cupper in to the wood.

//Solderman 

I do believe that the bits I bought are carbide, the feel very brittel. Check them out and tell me what you think.

http://www.danscloseoutsandspecialdeals.com/dansspecialdeals.html

The next time out I was going to pick up a vice to hold the piece.

As far as staying sober. It comes quite easy these days with health problems you seem to give up on the important things  in life like alcohol and work. That's probably why I enjoy doing this so much.

Again Thank You!

[solderman]

As far as staying sober. It comes quite easy these days with health problems you seem to give up on the important things  in life like alcohol and work. That's probably why I enjoy doing this so much.

Sorry to hear, hope you get better. I think those drillbit will work

//Solderman