Cold Solder Cosistant on Evolv Boards

[iambyrdman]

I know how to Solder!  But I have built 2 other devices and now I'm on a third I plan on selling am am having the same problem I did on the first two.  The Evolv board just does not want to except solder properly.  I get a little on the iron tip and drag it across and it looks like it's bonding.  However just a touch of pressure a it pops right off.  Nothing attached to the board.

When I search for, "Cold Solder" I'm not the first person to bring it up, except the results are usually after the build is finished and they're having technical problems.

What gives?  Anyone else see this?  It's frustrating.  Fire button takes just fine and so does the balance.  It's just the 4 primary flat connections.

I just bought a spot welder, too bad that wouldn't work because I love how good it works on batteries!  Actually, maybe tack a piece of nickle to the board.  Those nickle strips Drink Solder!   I wonder....

[iambyrdman]

I do it like "Analog Box Mods" on YouTube does but they don't stick.

 

My iron is plenty hot.  Maybe too hot at times.

[Ak89]

I personally haven't had this issue.

I do know that the larger pads dissipate heat more and may be contributing to your problems, however, I assume that your main problem is an absence of flux.

Don't rely on the flux within the core of the solder to be sufficient, unless you melt tons of it directly onto a hot pad. (Which could cause board delamination and pads that peel off from the excessive temps---NOT recommended) Instead source standalone flux (Rosin, not the acid stuff for plumbing), preferably no-clean or alcohol cleanable. (Avoid "water" clean, for obvious reasons)

To make things simple, source a "flux pen", a nifty little dispensing pen with a felt tip. However, a bottle of liquid or jar of paste can be used rather simply too....

As a side note, a soldering iron that is "too hot" can cause problems too. Dull joints are a sign of too much heat, or not enough flux. The solder oxidizes, forming a crystaline structure that cracks easily and adds excessive resistance. "Good" joints are round and shiny.

 

Not sure if these are your issues, but something to look at.

 

(Edit):

Also, take note that DNA boards, like most all circuit boards these days, are made with lead-free solder, which has a MUCH higher melting point than standard 60/40 leaded stuff. (Something like 100-200°F more) And mixing lead-free with lead is tricky because of the temp differential between them.

If your iron isn't "Lead-free" capable, meaning adjustable, and able to achieve the higher temps, then this, too, can result in your difficulties.

Edited November 21, 2018 by Ak89
More thoughts

[iambyrdman]

On 11/20/2018 at 5:02 PM, iambyrdman said:

I just bought a spot welder, too bad that wouldn't work because I love how good it works on batteries!  Actually, maybe tack a piece of nickle to the board.  Those nickle strips Drink Solder!   I wonder....

I got it to work out... My iron does get even Too hot and I am using lead free.

I didn't try spot welding this time but the idea makes me want to try it next time.  So wish me luck on a quick sale.  I'll list it on eBay for $300.

[JTree]

I've had no issues. On the 4 large pads, I bend the braided carrier I am using to give me a nice flat piece the same length of the solder pad, flux and tin the wire (no longer as malleable. Then press wire to pad and put the iron on top of the carrier. It melts right into it making a good joint.

 

If it helps, I'm running my iron pretty hot and using a chisel tip for the large pad joints.

[lazunado1974.]

To be honest, I've never used cold solder. Once I wanted to try it in action, but I could not find a really high-quality solder, since absolutely everything in local stores is a cheap Chinese fake that is sold at an inflated price. I much prefer to use a cool soldering iron and solder. In addition, recently on the site https://toolschief.com/best-soldering-iron/ I found a great soldering iron that I really liked and I immediately bought it. I am really happy with this purchase, as it is now much more convenient to solder. I think if you want to solder two parts together, then you should use a similar soldering iron!