Soldering to homemade pcb...

[elenore19]

Hello.
So I had some homemade boards made for me. I don't have the materials or the time to learn how to do it yet...
So that being said. What's the key to soldering to these beasts?
The solder stuck with my iron the whole time and it's real tough for me to get the solder to get around the pin in the hole. My terminology I'm sure is wrong, but hopefully you'll understand.

Any pointers?

Thanks
-Elliot

All the previous pedals I've done have had professional boards and the solder stuck right down around the pin and in the hole and it worked real swell.

[jkokura]

You really need to make sure that you get the iron to heat up the copper on the board, not just the part. There's a bit of a learning curve, I will admit, but once you do few joints successfully, you'll be doing them like crazy.

Really, concentrate on getting the copper heated properly, make sure the part gets some heat too, and you'll literally see the solder flow to into a nice joint.

Good luck.

jacob

[elenore19]

You really need to make sure that you get the iron to heat up the copper on the board, not just the part. There's a bit of a learning curve, I will admit, but once you do few joints successfully, you'll be doing them like crazy.

Really, concentrate on getting the copper heated properly, make sure the part gets some heat too, and you'll literally see the solder flow to into a nice joint.

Good luck.

jacob

So what about with transistors? aren't they sensitive to too much heat?
Or should I just put the part through, stick the iron on there for a good long while, then give it a shot?

[MikeH]

It helps to give the board a good buffering with steel wool.  When copper sits in open air it begins to oxidize, and that oxidation keeps solder from flowing properly.  I always buff it for a minute os so before I begin to solder, and I only star soldering when I have the time to mount all of the components.  If you can't populate the whole board in one sitting you can tin the remaining pads by soldering them as if there were components in place, and then desolder them.  This will prevent oxidation and make it possible to solder them in the future.

Oh, and you should use sockets for transistors until you've got your technique down.

[Ronsonic]

Like Mike said, clean the board thoroughly. Have a hot-enough iron with a bit of fresh solder on it. You shouldn't be on that joint for two seconds. On, add solder, off.

[elenore19]

It helps to give the board a good buffering with steel wool.  When copper sits in open air it begins to oxidize, and that oxidation keeps solder from flowing properly.  I always buff it for a minute os so before I begin to solder, and I only star soldering when I have the time to mount all of the components.  If you can't populate the whole board in one sitting you can tin the remaining pads by soldering them as if there were components in place, and then desolder them.  This will prevent oxidation and make it possible to solder them in the future.

Oh, and you should use sockets for transistors until you've got your technique down.

Alright, good to know. I'm sort of getting it down. I don't have any sockets...Do the sockets prevent me from damaging the transistors? or are they there for me to try out different ones?

I already soldered in 5 transistors...hopefully I didn't hurt them

So the boards I have seem to have some sort of blue on top of the copper. Should I use steel wool to get that off of the whole board before I start?

[MikeH]

[quote author=elenore19 link=topic=83365.msg692631#msg692631 date=1269302289

Alright, good to know. I'm sort of getting it down. I don't have any sockets...Do the sockets prevent me from damaging the transistors? or are they there for me to try out different ones?

I already soldered in 5 transistors...hopefully I didn't hurt them

So the boards I have seem to have some sort of blue on top of the copper. Should I use steel wool to get that off of the whole board before I start?
[/quote]

The sockets do both.  You can swap them, but you also don't have to solder them, potentially damaging them.  And I don't know what "blue stuff' you might be talking about.  Could it be leftover toner transfer?  Whatever it is, yeah, you probably want to get rid of it.  Try cleaning the board with acetone, and buffing with steel wool.  You should see a nice shiny copper side to solder on.

[perfectsoundforever]

Is 40w too much for a soldering iron?

[jkokura]

No, but it may be high. I've used a 25w primarily. Most guys have temperature adjustable irons, so the wattage doesn't matter as much.

Jacob

[KazooMan]

I agree, you probably still have the toner transfer residue on the board.  Gotta get that off.

You can help protect transistors with a heat sink.  It's basically just a spring clip that you attach to the transistor lead on the component side of the board.  When you heat the lead and pad to solder, the clip provides a thermal sink so that less of the heat can reach the transistor.  You can use just about anything for this such as an alligator clip from a test meter lead.  Or, you can buy a heat sink made for the job (Radio Shack - yes, the dreaded Radio Shack) sells them for $1.99

[chi_boy]

Is 40w too much for a soldering iron?

My primary is a simple Rat Shack 15 watt with the pointy tip. 

IMHO, the secret is a clean board, a clean tip, .032 diam rosin core solder, and a lightly tinned soldering tip.  The little bit of solder on the tip touches the board and the part, effecting a better heat transfer to both at the same time.  Add a little solder for the joint and the job is done in 2-3 seconds.

You milage may vary, batteries not included, no warranty expressed or implied, yada yada yada.

[Brymus]

Yeah good advice already.
To add,you can use the cheap IC sockets and cut them up to make transistor sockets.
In a pinch an alligator clip will make a heat sink,as will a small vise grip or any small clamp.
I socket all my ICs and Qs just to be safe and to be able to swap as well.
Also you can get tinnit >tin-it in dry form from most places that sell PCB stuff,just mix per directions and tin the whole board at once.
I bought my Tinnit at All Electronics and some Tarnex at Smart and Final,I also picked up some powder cleaner(Bar Keeper Friend) that has the same acid as the Tarnex at the Dollar Store.
I have read that spot not> tarnex> anything with acid based cleaner is good for prepping the copper just rinse well after wards.

[Quackzed]

flux.

[Electric Warrior]

http://www.youtube.com/watch?v=I_NU2ruzyc4

[Brymus]

Wow thats a great video.
Makes me think about cleaning some of the leads on my older components.

[jkokura]

But that's what the flux is for... Watch the video again.

jacob

[Brymus]

Yeah but I have some REALLy oxidized older stuff I picked up super cheap from a wholesaler/resaler

[jkokura]

Sorry, didn't mean to seem argumentative or sharp there. If it's really bad, clean it. Apparently hot flux does a good job - I have a container of it for small electrical work like we do, so I imagine you should be able to find some.

Jacob

[Mark Hammer]

Most of us hobbyists tend to buy a bunch of stuff when it comes up cheap, and then use it up as we need it...slowly.  That means there is a strong likelihood that the leads will become tarnished/corroded and not take to solder particularly well.

These days, I make a point of:

a) Buffing the board after etching with superfine steel wool until it's shiny, and immediately going over it with a thin layer of liquid rosin flux applied via a Q-tip (cotton tipped applicator).  I can either leave that to dry out, or tin the board immediately.  The flux lets a tiny bit of solder (like a sesame seed's worth) spread a long way.  Once tinned, the board will eventually tarnish, but not nearly as quickly as it does if left bare.

b) Scraping the tarnish off component leads with a utility knife blade or X-acto knife before inserting them into the holes in the PCB.  This includes not only resistors and caps,and transistors, but also check IC legs on the outside and inside for tarnish

Something else that I think bears noting is the size of the hole one drills for components.  When the component lead fits snugly through the hole such that there is little gap between the lead and the copper around it, a solder joint is easy to form quickly.  It's not super-critical to have the "right" size of drill bit, because you can always bend the lead over to be in closer contact with the pad.  But if you have the choice of bit to use and can use a size appropriate to the given component, so much the better.  Component leads inserted and soldered in perpendicular to the board lend themselves less to accidental solder bridges when the pads and traces are cramped.

[oldrocker]

If you click on my website below my avatar.  There's a list on the right hand side.  There's one labelled "Assessories".  Scroll down and I posted an informative video on soldering that I think explains it pretty well.  It's by Curious Inventor and it's one of the better videos on basic and understanding how to solder.