I'm looking to buying some solder, but I'm confused between solder and lead-free solder. From a health perspective, is the lead-free one considerably better? Or are they just equally as bad? Also, what do you guys think of AIM solder? The guy at my local hobby store said AIM is comparable to Kester.
Also, looking at the OP, is this lead free?
http://www.parts-express.com/kester-44-rosin-core-solder-63-37-031-1-lb-spool--370-074#lblProductDetails
Kester 44 is not lead free, it is made of 63% tin and 37% lead (thats what the 63/37 stands for). It is recommended as it melts at lower temperatures and is easier to work with.
Both is bad if you breathe it and you should wash your hands after soldering. Open your window while soldering or have a fan near your soldering area and you should be perfectly fine.
kester 44 actually doesn't refer to the alloy. there is kester 44 60/40 as well as 63/37. kester 44 actually refers to the specific RA flux formulation. it is incredibly effective while being very low in halides and other really nasty stuff. rosin is actually a plant derived solvent, and it can be activated with really nasty stuff, or not so nasty stuff. the nastiest fluxes will actually corrode the joint if you leave it on. kester 44 leaded solder was incredibly popular for 40 some odd years because it was no-clean in an industrial sense; that is it was corrosive enough to disrupt oxide layers, but not corrosive enough to corrode joints, boards or components (in the expectation, of course). of the kester 44 variants, the best for hobby soldering is 63/37 because it has no glass transition phase between solid and liquid. it phase changes at exactly 183C, which is very low, for the least chance of component heat damage, and the easiest work and rework during assembly or repair. in small diameter (0.02-0.03"), it is extremely versatile, has excellent wetting characteristics (the flux to solder ratio is extremely copacetic to good flow of solder into a joint), is fairly non-toxic, and has very good performace when flux residue is not cleaned off the board.
geekhackers.org does in fact carry kester 44 RA 63/37 in the 0.02" variant, but unless you order a learn to solder kit or soldering accessories kit, i am ridiculously swamped at the moment, and taking a 10 USD order, packing, fulfilling and shipping it leaves me way negative. i'm guessing you'd prefer that geekhackers' resellers have stock of lubricant anyway with how quickly it keeps selling out on me XD
also: hat tip, i'm working on a GB of premium hand tools right now. i have to do some intensely boring tabulation and cross-checking and demo a few things, but i'm getting pretty excited about it. i have an opportunity to offer extremely premium hand tools for a very reasonable price. sorry, completely off-topic. back to packing lube.