Solder paste

[RickyDean]

Since we were talking about soldering in another thread. Does anyone have any experience with a soldering paste like this? https://www.scarfloft.com/products/lotpaste-2  Seems to be easy to use, but I don't know about durability?

[Shift838]

I have used this exact one before and it works well.  It has a low melting point so that's good for your components.

[+dhe]

I've been doing some research on soldering, and these appear to bet 'best practice' recommendations.... (Open for feedback)

 

600°- 650°F (316°- 343°C) 

   15-20W - Bad, they take to long to heat up. 

   30-40W - Good, but you need to be quick. 

 

   Brass solder tip cleaners are better on the tip, then wet sponge.

 

   Also, size matters, watch the size of your solder.

   .5mm seems good for everything. 

   .8mm maybe?

    Try to get solder with 3% silver.

 

Per-Heat soldering table?

[Shift838]

12 minutes ago, dhe said:

I've been doing some research on soldering, and these appear to bet 'best practice' recommendations.... (Open for feedback)

 

600°- 650°F (316°- 343°C) 

   15-20W - Bad, they take to long to heat up. 

   30-40W - Good, but you need to be quick. 

 

   Brass solder tip cleaners are better on the tip, then wet sponge.

 

   Also, size matters, watch the size of your solder.

   .5mm seems good for everything. 

   .8mm maybe?

    Try to get solder with 3% silver.

 

Per-Heat soldering table?

I never use a wet sponges, rather go with the brass wool type.  works great.

 

I typically use the .5mm solder.  I also try to get solder that has a melting point under 600°F.

[Forrest]

The silver solder is better is a myth from the 80’s.

 

I pay more for name brand solder such as Kester.

 

Use the solder temperature range listed on the solder mfr data sheet

[+FarmerPotato]

23 hours ago, dhe said:

I've been doing some research on soldering, and these appear to bet 'best practice' recommendations.... (Open for feedback)

 

600°- 650°F (316°- 343°C) 

   15-20W - Bad, they take to long to heat up. 

   30-40W - Good, but you need to be quick. 

 

   Brass solder tip cleaners are better on the tip, then wet sponge.

 

   Also, size matters, watch the size of your solder.

   .5mm seems good for everything. 

   .8mm maybe?

    Try to get solder with 3% silver.

 

Per-Heat soldering table?

I think those temperatures would be too high.   

 

The Sn/PB alloys start to melt at 183 °C, 361 °F.   I settled on working temperature 232 °C, 450 °F, or 470 °F when it seems slow.  That happens to be the MAXIMUM on the 63/37 paste temp profile.  

 

In mid-life, I put a little more money into better tools and solder.

 

I'm using:

 

Solder:  Just 0.8mm (0.032").   Radio Shack 60/40, til it runs out.   Also MG Chemicals 63/37.  

Paste:   ChipQuik TS391AX 63/37 has become my favorite!  Room temperature stable (since 2019!)  Hate the metal hypo tip.  Plastic cone works for me. 

Flux:     Syringe, ChipQuik SMD291 63/37. Tack Flux.  Didn't like the clear liquid.

 

From this Kester temp chart:

 

 

Mid-Range        °C          °F
Sn60Pb40         183-190     361-374    wire
Sn63Pb37         183         361        paste, wire
Sn62Pb36Ag2      179         354        paste, wire

Lead-Free
Sn99.3Cu0.7      227         441        wire    
Sn96.5Ag3.5      221         430        paste, wire

 

I tried lead-free and hated it, especially harder to de-solder (add lead to remove it.)

 

Technique

 

Solder: Rich said I need a finer gauge.  With 1.27" spacing, I can't bring the wire to the pad.  I melt the solder on the tip and REMOVE the excess before I can make a mess & that's working great for me.

 

Paste: I had a lot of difficulty with the metal tube tip.  With the plastic cone tip, I extrude a teeny drop, then "stamp" it onto the pad.  After a row of pads, I scrape up any mess, using a very thin plastic ruler (Lockheed swag).

 

Tools

 

$ 95 Quick 957DW+.  (Clones go for $60.) 

$120 Hakko FX-888D for temp control.  

 

Temp Control really wants to be your friend!!!

 

Not sure I believe the readout.  Experimented to get 450-470 °F.  Around 550 °F,  it can gouge the solder mask, lift pads and break traces like Superman!

 

The "K" Knife tip is my favorite--it holds a lot of heat and solder, the sharp corner is great for drag solder. My favorite overall. Sold separately.  However, Amanda prefers a sloped, sorta fine-tip, and I'm happy with that too. We tried the "C" concave type, but didn't see a big advantage.  

 

Heating

 

Toaster oven, good oven thermometer:  I got close to the temp/time curve, by manually toggling the on/off switch. 

Coffee warmer:  I tried this to pre-heat small boards.  Meh.

Griddle: scary.

Air Fryer:  not going to go there.

 

 

(* If I ever upgrade, I will get a Weller.)

(** At that time, I got the PINBALL 33% discount off the bundle with now-$300 Hakko 300 desolder gun)

 

Happy solder day!