noob soldering Luxeon III questions

[tankhog]

This will be my first time using a soldering iron and I have some questions about what would be the best kind to use, from the actual iron to the solder, as well as confirmation on the theory of technique.

I watched the soldering basics video from Erv posted in a thread, which says to use a low temperature one, but found a conflicting thread (firebird's stickied how to solder) where someone says they use an 800f iron.

So what's better? a cheap 400f or a dual temp 850f-950f?

And in regards to the solder, I understand that I need to be using a lead free rosin. I am able to get electrical solder (that says its for speaker wires, motors/ appliances) as well as a 'specialty solder kit' that says it is silver solder and water soluble flux (that says the kit is for circuit boards and jewelry repair).
Which would be better to use?

As for technique, I think I get the gist of soldering wires together, but for soldering the wire to the luxeon star is where I start to get worried...

I don't want to wreck the LED

and I think my correct course of action is to pre-tin the wire, then heat up the point on the star where I want the connection to be and then place pre-tinned wire to that spot and that's it? It sounds almost to simple to be easy. How heat sensitive is the LED star - can using that 850f soldering iron damage it ? (aside from touching the LED obviously)

At the moment I am just wiring in a LuxeonIII but plan to use soundboards in the (near)future, that's why I think it best to use the specialty kit. even though I dont know what the flux is for!

[Jedi-Loreen]

I don't think 400 degrees is hot enough. Most irons are usually categorized by their wattage. Many of the casual hobbyists use 25W irons.

Just get a roll of rosin core, lead free solder. Silver solder takes more heat to melt, which means you also will be heating up your pad longer than you want to do. You also don't want to use flux, because you need to wash that off. Flux is slightly acidic, meant to clean and slightly etch metal, and if you leave it on your parts, it will corrode your wires after a while.

As for soldering the wires onto the LED, you've got it half right. Tinning the stripped wire is correct.

You also want to add a little extra solder to the pad on the LED star and allow it to cool.

Then take hold of your wire, heat up the solder in the pad till it's liquid again, and slide the tinned end of the wire into the liquid solder and remove the soldering iron tip. Hold onto the wire until the solder cools and solidifies again.

It's also important that you don't strip the ends of the wires too far back. It doesn't need to be stripped any farther than the length of the pad you are soldering it to. If there is too much bare wire exposed and it hangs over the edge of the LED star, it can contact the metal of the star, or even the heat sink and cause a short.

[Silver Serpent]

I believe Erv's low temperature comment was actually describing his solder, not his iron. In my personal experience as a soldering newbie, I found that using 60/40 solder (60% tin, 40% lead) was much easier than using the unleaded variety. It melts almost 100 degrees faster than the lead-free I was attempting to use, and flows very smoothly.

Using a thin gauge of solder helps a lot as well, so you won't have nearly as much to heat and melt. It also reduces your chances of having large globs of solder on your components.

And just in case you haven't done so already, mount the star on the heat sink before you start soldering. It'll help keep you from cooking your new LED.

Good luck on your build!

[RevengeoftheSeth]

Personally, I don't like to solder with temperatures any higher than I need to (only what is required to liquify the solder itself). Make sure you use flux on both the wire and the pad on the LED Star base to clean the surface and allow the solder to have a better grab on the metal it is connecting to.

Overheating your solder iron can cause you to accidently damage circuitry and can cost you big time (hello, Crystal Focus!)

As J-Lo said, never overstrip your wires and never use more wire than you have to. extra wire takes up volume in your hilt and when it starts twisting around, you can snap off valuable parts inside the hilt.

[jin starkiller]

also don't forget to clean the flux off after done soldering so you don't get corrosion

[tankhog]

Is using the flux that big of a deal? If avoidable I would rather do with out it as it's one or two! less steps.

I purchased some lead-free 1.2mm rosin core solder today, but had been thinking that a smaller gauge might be easier to work with. I went with the higher gauge as it was the only one listed as being "lead-free".

So pretty much:

lead free solder is not as harmful for you to breathe the fumes, but requires a higher temp to melt,

where as
the 60/40 mix solder is easier to work with (smaller gauge) and a lower melting point.

So it boils down to personal preference really?
__________________________
thanks for all the tips everyone I really do appreciate all the input!

[Shadar Al'Niende]

Pretty much, a lot of us use 60/40. As long as you aren't soldering every day, and not directly breathing the fumes you will be fine. Also i never use flux, and have wired up 5+ sabers (if you count re-wires on electronics) i have a 15 watt iron (wish it was 25 watt) that gets to about 400 degrees and use the 60/40 rosin core solder. Hope it helps


PS J-LO soldered for a living.. listen to her ;)

[Gin Malinko]

i have a 40watt fine tip iron, and use small coil rosin core lead free solder. works great for me.

and what is flux used for in soldering? ive been soldering since middle school and never heard of anyone using flux. far as i knew that was a blacksmithing thing.

[KuroChou]

The rosin is your flux. Flux compound is from an older era of soldering (and welding), and is used for two things. Cleaning off dirt, debris, and oxides from the surface you're soldering to, and keeping air out of the joint, making it stronger and more effective. You used to have to smear the flux goo on whatever you were soldering to and heat it up to clean it, then smear it on the solder while heating it into the joint.
It's easy enough to say it was more complicated this way. I personally suck at it, but there are those who still prefer it that way.
Rosin cored solder, means that the solder has a thin bead of rosin flux running through the center of the wire, exactly the opposite of the way flux coats the outside of the rod in arc welding. In TIG and MIG welding, your flux comes in the form of an inert gas (almost always co2) blowing through a nozzle surrounding the wire(MIG) or the electrode(TIG).

[Jedi-Loreen]

KuroChou is correct.

One other thing that flux does it improve the "wetting" qualities of liquid solder, enabling it to flow more easily and to adhere to the pcb pads, and components, ect., that you are soldering.

[Gin Malinko]

tha nks for the info. out of all my time soldering, i never knew that.

[Skottsaber]

Also, it is used when soldering SMD components for those reasons, and also it draws some heat away from the PCB, preventing damage. This is most important for people who drag solder Integrated Circuits.

[cardcollector]

Look, if you can't help or don't know, don't bother answering.

That Was a rather trollish thing to do. Maybe you need some starbucks...

[Skottsaber]

FYI to everyone: Do not reply to the posts of PETER.PHIL, he is most likely a bot or at the very least a troll. You may notice all the posts are off topic. Ignore him, the mods will get here soon enough.