Temporary solder mask for tiny area?

[Hogwild]

Hi friends:

Newbie here. I have some soldering experience, but I'm new to SMD circuit boards.

I need to connect two pads on a commercially made finished PCB circuit where a small resistor normally sits. I don't know the proper term for this.

It's a very narrow area, and to make a long story short, I don't have desoldering wick that will work with my current (unleaded) solder. Anyway, I want to prevent solder from going onto neighbouring components in the area. Is there something I can put down beside the area I'm soldering that will prevent solder from jumping to adacent components? Please, spell it out for this newbie and thanks in advance for any suggestions.


Thanks in advance

 

[cliffforrest]

My experience is old, but we used to stick a small piece of tape over the required area to prevent it getting tinned / soldered.

Obviously this must be robust enough to survive the soldering, and may need an IPA clean afterwards.

 

[Hogwild]

Thanks for that. I was thinking about tape, but then I thought it would too kooky an idea.

Would aluminum foil melt, or would it be feasible? Any other suggestions? I'm guessing you're right that the tape would be a b*(tch to clean up.


Thanks

 

[JMFahey]

The aluminum foil won't work because there's free space between it and the actual copper and capillarity will force solder inside.
1) use leaded solder.
2) use a fine tipped 15W soldering iron , a loupe and good light.
Steady hands are needed, of course.

 

[cliffforrest]

we used to have boards come back with little orange/clear mylar(?) tape squares.

I have used masking tape (painter's crepe tape) for domestic pcbs.

A long time ago. Experiment ....

 

[Hogwild]

CliffForest:

Mylar does make sense to me. The question is, where would you find it locally? Any ideas?


JMFahey:

Thanks for that. I should have indicated earlier that I'm firm on not wanting to use leaded solder, as the entire board is unleaded, and I don't know the two will mix (I've read not well.) If it were of my own making, I'd seriously consider it.

I also should've mentioned that due to health problems, my hands are shaky. That's why this is so challenging for me. A 15W iron won't even come close to melting the solder I'm working with. I'm having trouble with it at 400 C. using a Hakko FX-888 station and semi-decent soldering skills. Until I can find another solder, I need to mask this, somehow.

The aluminum foil won't work because there's free space between it and the actual copper and capillarity will force solder inside.
1) use leaded solder.
2) use a fine tipped 15W soldering iron , a loupe and good light.
Steady hands are needed, of course.

The aluminum foil won't work because there's free space between it and the actual copper and capillarity will force solder inside.
1) use leaded solder.
2) use a fine tipped 15W soldering iron , a loupe and good light.
Steady hands are needed, of course.

 

[cliffforrest]

Google is your friend!

Metalized Mylar - The Tape Depot - TheTapeDepot.com - The One and Only Tape Superstore. We carry Adhesive Tape, ATG Tape, Conspicuity Tape, Copper Tape, Duct Tape, Camo Tape, Carton Sealing Tape, Double Coated Tape, DOT Tape, Electrical Tape, Floor T

 

[Hogwild]

Cliff:

Thanks for that info. IN your earlier post, you put a question mark beside mylar. Does that mean you're guessing it was mylar or you know for sure but you didn't know how to spell mylar or ?? If someone is sure it can work, then I'll be happy to try it. I just don't want to risk expensive gear based on a guess.

Thanks

Google is your friend!

Metalized Mylar*-*The Tape Depot - TheTapeDepot.com - The One and Only Tape Superstore. We carry Adhesive Tape, ATG Tape, Conspicuity Tape, Copper Tape, Duct Tape, Camo Tape, Carton Sealing Tape, Double Coated Tape, DOT Tape, Electrical Tape, Floor T

 

[geraldfryjr]

Mylar will melt!!
Kapton has a much higher melting temp and won't shrink up into a little ball like mylar will.

I Doped the area on my board with a lot of Nonspill Past flux from Radio shack Cat# 64-022.
Flux in general is the only thing to use that I have found that will that allow the solder to flow cleanly with out sticking to everything!

Got a bridged traces?....Just hit with a heavy dose of flux and re-heat it and the solder will pull away.
The stuff is washable and you just rinse it with some denature alcohol dabbing it up with some cotten Q-tips.
This works great for cleaning regular flux off of boards as well.

Here is some pictures of my very First board and I didn't use any mask's with just a standard iron and .020" solder.

http://www.diyaudio.com/forums/construction-tips/221683-smd-soldering.html#post3685868

Have you seen this thread and post?

Here is a post of a link I posted of a little video of how to make solder mask's out of a pop can!!

http://www.diyaudio.com/forums/construction-tips/221683-smd-soldering.html#post3706421

FWIW

jer 🙂