Solder choice questions from beginner

I am a hobbyist looking to get started with soldering. My first project will be replacing a defective switch on a mechanical keyboard. I’m in the process of researching equipment for my setup and am trying to choose a solder. Based on my research I think I need to buy solder with the following specs:

  • RMA flux
  • 63/37 Sn/Pb
  • 0.020" diameter

When putting those filters into Digi-Key I obtain the following results:

Are those spools of solder really what I should buy? I did a double-take at the price. Is that how much a spool of solder appropriate for a beginner typically costs, or I did I pick some option that selected a “premium”, “professional grade”, etc. product, or too large of a roll? 1 lb of solder seems like it would last a hobbyist forever but maybe that’s the standard size. I also doubt I would go through a pound of solder before it expires and would hate to have to buy another roll at that price just to complete my next project that only requires a tiny bit.


Thank you for contacting the Technical Forum. Solder has gotten a lot more expansive. I agree. One of those rolls would last a long time. I did another search. I went with a similar 63/37. This is Rosin activated. These are smaller rolls , but quite a bit cheaper. Here is the link I found : . These options would get you started and see if you even like soldering. It would be nice to know before you invest a whole lot of money into your hobby.

A pound of solder is basically a lifetime supply for hobby purposes. While more costly by weight, the ounce-scale packages give opportunity to try different products at a more approachable cost. Note that thicker solders tend to kink, tangle, and break less easily than the fine stuff.

Also, the expiry dates on solder can be more or less ignored for casual use. The flux will lose some of its potency over time, yes, but the roll of Kester 285 that’s been sitting on my desk for the past 12 years seems to work just fine. In the rare circumstance that it doesn’t, the ten-year old jar of paste flux provides a very adequate supplement.

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It looks like my requirement of RMA is excluding some cheaper options, but is that tradeoff worth it? It looks like the main difference between RA and RMA is that the RA must be removed to avoid damaging the PCB, whereas RMA doesn’t need to be removed (but removal is still recommended). Water Soluble solder seems like it doesn’t have any downsides compared to the other options. Is that correct?


There are many options. I agree. I guess it all comes down to what you want to use. I usually do not use the RMA or RA types. I guess if you would like the water soluble it is easier to remove. Though it is still recommended to clean. There are even some no clean water soluble . Here is the link for the size you need. This has the no clean and also the just the water soluble: .
There are some cost effective options on this link also.

Is there any downside to using solder with “No-Clean, Water Soluble” flux vs RMA or RA flux? The description of “Water Soluble” flux in the link I posted above makes it sound like it is better than any of the other types.

It appears they are more moisture sensitive in humid environments. They can extract moisture making them more soupy in very humid environments. In most cases they should work though that would be something to keep in mind.

That would only be an issue when the solder is being melted in a humid environment, correct? Meaning once the connection is formed there is no downside vs any of the other flux types used in solder?

Yes. That was the biggest down side to it that I could find. So once it is formed and hardens this should no longer be an issue.