Solder paste for First time smd reflow soldering - Page 1
Forum section: electronics / beginners

author: kolbep
author_rank: Frequent Contributor
timestamp: September 24, 2014, 06:36:16 pm
content: Hi All.While I am waiting for my boards to come from Itead, I am trying to get all the things together for assembly when they arrive.I will be using a small oven (that I am converting as a reflow oven),and I was wondering what solder paste would be best.The most complicated component on the board is a 44 pin tqfp Pic uC. The rest of the board is all SMD components, except for some pin headers, and 2 x Through Hole capacitors, which I can always hand solder later.I was thinking I could just apply some solder paste using a syringe. I am in South Africa, in case there is some local Solder paste supplier you can recommend.I was looking at Ebay, and foundhttp://www.ebay.com/itm/1-MECHANIC-XG-50-REPAIR-SOLDER-PASTE-42g-Sn63-Pb37-25-45um-/181042448195?pt=LH_DefaultDomain_0&hash=item2a26f88743Do you think that is suitable.Much appreciated.P

author: Falcon69
author_rank: Super Contributor
timestamp: September 24, 2014, 06:43:09 pm
content: I ordered mine from Manncorp. Works pretty well. They shipped it to me express delivery and when it arrived, it had 2 cold packs wrapped around it.I dont remember, but a big can of it i think was like $80.That can go along way.

author: kolbep
author_rank: Frequent Contributor
timestamp: September 24, 2014, 07:36:17 pm
content: I think 80USD will be a bit overkill for me. I am only starting off with SMD, and will probably only do a few 5cmx5cm boards to start off (just a hobby). I think I will only really need a syringe size for now.P

author: Falcon69
author_rank: Super Contributor
timestamp: September 24, 2014, 07:44:43 pm
content: they offer 10cc size syringe as well. but you have to order in 5's.The paste I got was this.http://www.smtsolderpaste.com/product-info.php?tin-lead-no-clean-type4-500g-jar-product-page-pid35.htmlIf you only need alittle (10cc) Digikey has it here.http://www.digikey.com/product-detail/en/SMD291AX10/SMD291AX10-ND/2057271

author: sacherjj
author_rank: Frequent Contributor
timestamp: September 24, 2014, 07:50:27 pm
content: I think Falcon's suggestion is good. Go Pd and go no clean. It is much easier to learn the ins and outs of reflow without the extra effort needed for lead free. It also gives you a higher buffer between reflow temperatures and max temp of RoHS parts that need to handle lead-free.In addition to reflow, I find solder paste useful for iron soldering of small pitch leads, like a 0.5mm FPC connector. I lay a thin line of paste down 10mm from the end of the leads. Then I drag my iron tip through to get a little solder and touch then pad and tip of the lead. (Both are pre-fluxed.) Usually much more successful than even the tiniest wire solder.

author: Falcon69
author_rank: Super Contributor
timestamp: September 24, 2014, 07:55:38 pm
content: that mechanics solder off eBay is junk. I bought some, didn't perform well. and they say 50g jar? lies, I think i got about 34g inside. Maybe they count the weight of the jar too?!Don't buy cheap crap if you want your circuit board to operate well.

author: Falcon69
author_rank: Super Contributor
timestamp: September 24, 2014, 07:56:46 pm
content: For a beginner, I wouldn't advise lead free, it's harder to work with and requires higher temps. Plus, it's a pain to get off if you need to.