OT: ANOTHER SOLDER QUESTION: can't get solder off the solder gun? The wire is very very thin. I am soldering a circuit board with solder points very close together on an rc helicopter.
I put a little solder on the point of the hot solder tip, then touch the board and wire at the same time. But the solder rolls around or doesn't come off the tip. Would flux help? Never did this before.
Than you in advance! Bob
Don't be afraid to flux. If your working on a PCB you'll be better off with a pencil style soldering iron. Paste flux (just a dab) and thin solid core solder. Hit the contact point with the soldering iron a very short split second before the solder. Don't apply the heat too long. Just long enough to touch the surface mount
Pad without creating any damage. The most important part of soldering is the flux. Without it nothing will Schlick.
Flux and/ or rosin core solder will work. Do not use acid core solder. The circuit board must be hot enough to melt the solder. Ok to put a little solder on the tip of the soldering iron but if the solder pad on the circuit board is not hot enough to melt the solder, you will not have a good connection. Also tin the end of the wire (melt solder onto end of wire). Cleanliness is absolutely essential. Denatured alcohol, available at a pharmacy, is a very good cleaner. Use before soldering and for cleaning the flux or rosin off after cleaning. I repair commercial two way radios where the contacts are sometimes just thousands of an inch apart and have to use magnifying head sets to see.
Awesome! Thank you so much! I will take it from here. Bob
Good points Harry. Especially the magnifying headset. Heating the pad is essential but it happens fast with surface mount components and the flux not only cleans the pad it also transfers the heat very quickly. Through hole soldering is a piece of cake. A good soldering iron that's tinned properly and of an effective heat (wattage) and per tinned components are nice to have. If your doing through hole components tin the soldering iron and the wires ahead of time. It's been 20 years since I did PCB work and I hope things have improved during those years. Great suggestions Harry.
Soldering paste available about any place that sells copper water lines such as Lowes or Home Depot, will work well as flux. It is not expensive. Copper fittings are coated after cleaning before soldering with it. A little dab will do you. You will loose the can before you use it all. I have some professional expensive flux and it will help make it look like it was done at the factory. Don't know if a real high alcohol content drink like vodka would clean flux off or not. Denatured alcohol can run $10+ for a pint. Or get the highest alcohol content rubbing alcohol you can get. Might take extra rubbing or brushing with a tooth brush or small artist paint brush. Many of the parts I work with are only 2 or 3mm long unless it is an integrated chip and has multiple pins.
Way back when I taught Hi-Rel soldering for the Minute Man missile computer system. To get excess solder off the soldering iron tip we wiped the tip on a damp cellulose sponge. To clean the soldering flux off a soldered connection we used a 50/50 mix of alcohol/naptha.
You HAVE to have flux. On a pcb board the ONLY thing to use is thin diameter 60/40 tin/lead with a rosin core. Anything else and your doing amateur work AND making your life a LOT harder !
Bud, the EPA says you Cannot use lead based solder any more. New electronic items are made with lead free solder. If we attempt a repair on a commercial radio (we are Kenwood dealers) and we then have to send the two way radio in for factory repair, they will refuse it. Most if not all lead mines have been shut down by the EPA so ongoing lead based solder will have to be recycled lead.
Go on eBay and find some lead based solder. The EPA got involved since I last soldered any electronics (Heath Kit). I bought some "todays" solder at Radio Shack and made a real mess out of a circuit board I was working on. Wouldn't melt right, balled up and produced cold joints. Also burned up several PC pads. Thought it was just me being old. Didn't know the government had saved me from lead poisoning. I got a small tip iron, some thin lead based 60/40 rosin core solder, a cheap lighted magnifier and a small tin of stuff that cleans and tins my soldering tip. Just push the hot tip in the goop. Comes out clean and shinny. You can find what you need on eBay.
Pray for the folks/pinheads in Washington.
You need to tin the solder gun. take an empty can and heat up your solder gun. Then put some solder on the end of the can and roll you solder Iron in it. You won't believe how much that will help you.
Flux is your answer as told above. The reason it won't flow is dirt/oils from handling on the parts you want to join. Solder hates that stuff and will not adhere to dirty wiring or what ever.
Anyone looking for real lead/tin solder, here's the easy way.
Its a Chinese site that sells lots of stuff - fun to look around on. Lead based rosin core solder cheap, etc.
Guess the Chinese haven't closed their lead mines ;o)
Thinking about my instructor days brought back a memory. There was a propensity for some students to try and flick excess solder off their irons onto the floor instead of using the sponge to wipe the tip. Had one gal who was hard to get the point across until she flicked her iron and the solder hit her in the chest just above the neckline. Didn't need to say anything more.
Did some looking for lead based solder. A company in Dayton, Ohio that I buy items from has both the lead as well as non lead solder. It is MCM Electronics. Their Webb site is MCM.com. I have no financial arrangement with them.
To use non lead solder, I run my equipment at 650 degrees. Probably a non regulated soldering iron would have to be a 30 watt iron. A dual temp soldering gun works well on heavy gauge wire. I think mine is a 150/300 watt gun I picked up at a flee market.
Stained glass guys use 60/40 &50/50 solders that would be 50% lead 50% solder. A good size roll is about $10.00.
Not 50%solder I meant to say tin.