Solder Paste Recommendations.

[wade7575]

I'm going to start doing Hot Air soldering and I have been wanting to for a while and I just couldn't decide on witch cheapy unit to buy like a Baku because I heard something things about them and the other cheapies I didn't and I got a bit gun shy on pulling the trigger and just ordering one.

I was talking to a guy that has a small electronics shop he runs from his home where he also does a lot of repair and I told him I was looking to get into Hot Air for soldering SMD hobby kits because I do a lot of them in spare time and give them away to friends or as projects to do with kids I know.

When I called up the guy I know I told him what I needed to order then told him I was looking to get into Hot Air soldering very soon and he told me he ordered a Quick 861DW for a guy without taking any money down and got stuck with it when the guy did not come back to pick it up and he told me I could have for the 189.00 US funds it cost him so I sent him the money threw PayPal and I'm going to pick it up this later this week.

The guy I'm getting this from does very little Hot Air soldering and so he could not advise me on what kind of solder paste to buy,I'm only doing hobby kits for the most part and will use it for some repair work,I do not want to buy the most expensive solder paste on the market and have go bad before I even use a quarter of the syringe,I don't mind spending a few bucks for something better but I don't want to waste my money either.

Has anyone tried the Mechanic brand found on Banggood and ebay and if so what's it like,for me I would like a solder paste that flows ice and is easy to clean off but is not 30 to 40 bucks a tube,I like to use AIM wire solder and I pick it up when I'm in the city but I don't want to spend that much for a paste that is only good for a year that I may only use half of.

I have gotten some really good solder from China off ebay before that flows and wet's really nice and the joints are not a shiny as a product like AIM's but to me if your on a really tight budget that's a small pay off,I'm not some much on a tight budget it's more of a thing where I hate wasting something that you have to pay a premium for.

[JustMeHere]

I got some of this. 

MG Chemicals 4860P 63/37 No Clean, Leaded Solder

A little will go a long way, but the paste will go bad as the flux breaks down (or whatever it does)

No clean is actually hard to clean up, but you don't have to.  Dirty boards look like crap though.

[wade7575]

What do you use to clean up the MG Chemicals stuff.

[nanofrog]

Be careful, as $189 for a Quick 861DW sounds really fishy to me (there are some clones out there being sold as 861DW's; example). The cheapest I've seen a genuine unit go for lately is $265, and a real one wouldn't be that hard to sell at a fair price.

As per solder paste, leaded or lead-free?

For example, you could could get MG Chemicals 4860P-35G (63/37 tin-lead, 35g, no-clean). Most will be no-clean, but some of these use modified rosin, which is easier to clean than the synthetic resin based variants. So check the datasheets. Kester's EP256 (also 63/37) is one such example. CML Supply breaks it down and sells in hobbyist/small repair shop friendly sizes (syringe & jar). Indium offers 63/37 that uses RMA flux in a 4oz. jar, 10ml or 30ml syringes, as does AIM's RMA258-15R (10ml syringe & 500g jar).

As a general rule, stick with well known brands such as MG Chemicals, AIM, Indium, and Chip Quik (these offer 10ml syringes). Kester and AIM for example only sell in large sizes meant for production (i.e. cartridges).

[wade7575]

There is one thing I forgot to mention about this deal and I can see by me leaving it out it may sound fishy.

I have known this guy for a long time and I only go to his shop 2 to 3 times a year at the most and he mails stuff to me but I never knew he had a access to the Quick line of products.
When I was deciding whether to buy purchase a Hot Air set up and I read so many bad things about the Baku that you either got a good one or you did not I seen a smaller Quick Hot Air station and I was considering I forget the model number but anyway I was planning on buying something and just hadn't gotten it nailed down.

I called Quick USA about the smaller model and asked if they had any dealers in Canada and they said they do not have any official dealers in Canada but they a few people who buy their stuff to resell and they mentioned the guy I know who is more of a repair shop but will sell to people if they can't find what they are looking for.

When I talked to the guy I know who had the Quick 861DW he told me he was selling it to me at cost because he told me that he would never sell and does not get anyone asking for a bigger machine like the 861DW he also took a screen shot for of his PayPal screen showing me what he paid because I had asked him if it came from Quick because I did not want to buy a fake,plus I confirmed it with Quick that they sold him a 861DW and they said he normally orders the smaller unit if someone wants Hot Air and this was the first one he ordered.

The only reason why I asked him if he got it from Quick or not was not because I don't trust him I don't trust the people that may have sold to him and saying they are a Quick dealer when they are not.,the guy I deal with is a pretty stand up guy and deals with people when certain things are not always fair and try to a middle ground rather then saying tuff crap that's the way it is.

[nanofrog]

You're getting a really good deal then. 

As per cleaning, I use Klean Strip denatured alcohol (50/50 mix of ethanol & methanol, so evaporates cleanly). It's cheap and can be found in paint departments.

Stay away from the cans with the green label, as the denaturing agent will leave a film.

I also keep isopropyl alcohol, xylene, MEK (Methyl Ethyl Ketone), and toluene on hand to help clean the really stubborn gunk.


Another option would be to get an ultrasonic cleaner (heated) and use Branson EC (little goes a long way as you dilute it with distilled water). I'm lazy, so may go with this option myself at the suggestion of another member.

[mrpackethead]

Are you hoping to place parts on paste and then reflow with hot air to solder them?

thats fraught with lots and lots of challenges.   Hot Air is not a good tool for putting parts on boards.  Its a good tool for getting them off.

[wade7575]

I live in Canada and some years back when I was into RC cars the pull starters used a one way bearing and it always fouled and the guys from the USA told me to try denatured alcohol because they said it worked but don't ask me why but you can not find it in Canada,I don't know if it goes by another name like Varsol but that's stuff is just a lower less unrefined version of paint thinner for cleaning paint brush's. 

You're getting a really good deal then. 

As per cleaning, I use Klean Strip denatured alcohol (50/50 mix of ethanol & methanol, so evaporates cleanly). It's cheap and can be found in paint departments.

Stay away from the cans with the green label, as the denaturing agent will leave a film.

I also keep isopropyl alcohol, xylene, MEK (Methyl Ethyl Ketone), and toluene on hand to help clean the really stubborn gunk.


Another option would be to get an ultrasonic cleaner (heated) and use Branson EC (little goes a long way as you dilute it with distilled water). I'm lazy, so may go with this option myself at the suggestion of another member.

[wade7575]

From what I have been told by a few guys that have used Hot Air for placing really small SMD stuff they love hot air so I don't know I guess it could just be a matter of personal preference.

Are you hoping to place parts on paste and then reflow with hot air to solder them?

thats fraught with lots and lots of challenges.   Hot Air is not a good tool for putting parts on boards.  Its a good tool for getting them off.

[JustMeHere]

I have great success with using hot air to solder small things.   I got hot air so I could solder 0603s. 

Regarding clean up, I use a tooth brush and 98% rubbing alcohol.    I also use a clean paper towel.  The paper towel is for cleaning the bristles on your brush.    If you don't, you will end up just spreading things around.

Long wooden cotton swaps help.

[wade7575]

The big question I really want to know is what kind of Solder Paste do you use and is the flux really easy to clean off,I just got some Amtech flux for the first time to see how it cleans off instead of using rosin flux for soldering threw hole stuff and heard the Amtech stuff cleans off really easily if they don't make a solder paste that use's their flux they should,mind you I still have to try my Amtech flux I just got it a few days ago.

I'm trying to find a solder paste that is cheap but also cleans off easily,I was thinking I could get some Aim RMA solder paste as I know where to get for 28 bucks a tube but I'd rather find something cheaper if I can,that what I'm really looking to get out of this thread is what solder paste you guys use that is cheaper and good stuff.

I don't see the point of buying top brand stuff and not using it all before it goes bad that's my main gripe because you never really know how much your going to use.

I have great success with using hot air to solder small things.   I got hot air so I could solder 0603s. 

Regarding clean up, I use a tooth brush and 98% rubbing alcohol.    I also use a clean paper towel.  The paper towel is for cleaning the bristles on your brush.    If you don't, you will end up just spreading things around.

Long wooden cotton swaps help.

[nanofrog]

I live in Canada and some years back when I was into RC cars the pull starters used a one way bearing and it always fouled and the guys from the USA told me to try denatured alcohol because they said it worked but don't ask me why but you can not find it in Canada...[snip]...

Seems you can get it as Marine Alcohol or similar labeling (for alcohol fueled stoves used on boats). Possibly even as glass cleaner. But to know if it's even usable, you'd need to read the datasheets if available.

Regardless, I'm not sure it would be cheaper than isopropyl based on the above link. 

From what I have been told by a few guys that have used Hot Air for placing really small SMD stuff they love hot air so I don't know I guess it could just be a matter of personal preference.

Using hot air to solder can have its challenges, namely getting the heat and airflow settings correct to get good joints (i.e. don't blow the parts off, scorch the PCB, or lift pads). And for one-offs, you can do BGA with a hot air rework station (reliability and joint inspection not withstanding).

But you can use an iron to solder almost any SMD package, IC's included using the drag method (see John Gammell's YouTube videos if you're unfamiliar with this). I do almost all of mine with an iron. Even the really small passives in conjunction with a stereo microscope can be done.

For doing a lot of joints, and BGA's in particular, you'll find it both easier and more reliable to use a stencil and reflow oven.

[wade7575]

This is just it I mainly do hobby kits and other stuff a stencil is not needed for and for me as far as using a normal iron goes I don't mind doing some SMD stuff with an iron it's when you get into the smallest SMD resistors on the market I can solder with an iron no matter how hard I try and I have gotten a few kit's like that and was not able to build them.

The problem I have came into with the smallest SMD resistors on the market is that they did not leave any room for you to touch the iron to the pad no matter what size tip you use,I'm going to get some practice boards and just get good at setting the air flow and writing down what I find works good for not blowing the part's away,I have also watched a lot of SMD video's and understand not to just hold the heat on the device you want soldered you need to move the hand peace around and also preheat the that section of the board a bit as well.

As far as cleaning the flux from the board I will use a rosin based flux paste if I have to and use original Krud Kutter mixed 25 to 30% with water,that's what I use now to remove rosin flux that's really thick and the alcohol won't touch,I apply liquid rosin flux with a small paint brush or Q-Tip and if it's a really crowded spot on the board I do so many and then cut the leads and do some more and that means multi layers of rosin on the board witch IPA won't touch by just rubbing it off. 

I live in Canada and some years back when I was into RC cars the pull starters used a one way bearing and it always fouled and the guys from the USA told me to try denatured alcohol because they said it worked but don't ask me why but you can not find it in Canada...[snip]...

Seems you can get it as Marine Alcohol or similar labeling (for alcohol fueled stoves used on boats). Possibly even as glass cleaner. But to know if it's even usable, you'd need to read the datasheets if available.

Regardless, I'm not sure it would be cheaper than isopropyl based on the above link. 

From what I have been told by a few guys that have used Hot Air for placing really small SMD stuff they love hot air so I don't know I guess it could just be a matter of personal preference.

Using hot air to solder can have its challenges, namely getting the heat and airflow settings correct to get good joints (i.e. don't blow the parts off, scorch the PCB, or lift pads). And for one-offs, you can do BGA with a hot air rework station (reliability and joint inspection not withstanding).

But you can use an iron to solder almost any SMD package, IC's included using the drag method (see John Gammell's YouTube videos if you're unfamiliar with this). I do almost all of mine with an iron. Even the really small passives in conjunction with a stereo microscope can be done.

For doing a lot of joints, and BGA's in particular, you'll find it both easier and more reliable to use a stencil and reflow oven.

[FlyingHacker]

I’ve been having good luck with the MG leaded no clean paste. I just wish I had a finer syringe to apply it. Some very small components, like micro USB port pins (some are smaller than others), required applying the paste with a sewing needle because I did not have a small enough hollow needle. This actually worked quite well, and then hot air at the right temperature (I think 405F, IIRC, but don’t quote me on that) soldered it right down. First time I tried with too little heat. That won’t work.... just watch the airflow doesn’t blow parts away, and keep the nozzle moving. Heat tape on anything else nearby.

[joeyjoejoe]

Is there a no-clean flux that cleans easily with Isopropyl?

I have ChipQuik SMD tacky flux, and IPA doesn't seem to clean it after even with a nylon brush. Board stays tacky.

I'd prefer to get a flux that cleans easily with IPA as IPA is something that I keep around the house easily enough and use for many other things.

[nanofrog]

...[snip]...it's when you get into the smallest SMD resistors on the market I can't solder with an iron no matter how hard I try and I have gotten a few kit's like that and was not able to build them.

I'm not sure how you're trying to do this, but the basic methodology will work with any size passive.

• Tin one of the pads.
• Flux the newly tinned pad as well as the un-tinned pad (one tinned, one not is based on new PCB).
• Place the part with tweezers with one hand, and hold the part in place. Now touch the tinned pad & part with the iron to tack that end to the pad.
• Solder the other side, then come back, add some additional flux to the tacked side, and finish soldering it.

Sounds more complicated than it is, as it's actually quite quick and easy. Tip selection is important as well, which I'll address below.

Do note that with SMD, additional flux is a necessity as you'll find that contained within the solder wire's core just isn't enough. And this issue becomes more pronounced the smaller you go.

The problem I have came into with the smallest SMD resistors on the market is that they did not leave any room for you to touch the iron to the pad no matter what size tip you use,I'm going to get some practice boards and just get good at setting the air flow and writing down what I find works good for not blowing the part's away,I have also watched a lot of SMD video's and understand not to just hold the heat on the device you want soldered you need to move the hand peace around and also preheat the that section of the board a bit as well.

As mentioned, tip selection is very important, so what are you using?

Generally speaking, chisels or hoof/bevel shapes will do best (size the tip to the pad). Conicals tend to suck for most anything. The one exception would be a fine bent conical (these are good for the very smallest of passives IME).

I'd recommend taking the time to go over Hakko's Tip Selection page as it covers what types of jobs/situations the various tip shapes are meant for. 

...[snip]...IPA won't touch by just rubbing it off.

All the alcohol does is get it to a liquefied state so you can absorb/blot it off using consumables such as Kimwipes, Q-tips (preferably something non-shedding), foam swabs, ... For really heavy deposits, use a brush and rinse as much off as you can with alcohol first. But you'll still have to mop the rest off.

[wade7575]

I have been using a product called Krud Kutter that you can get a Home Depot Canadian Tire and Walmart,you can get it in a 1 gallon jug at Home Depot.

I have been using it for removing rosin flux and Amtech flux from my boards,it's not nasty in anyway shape or form and it works really good.

I just mix it at about 25 to 30% with water and soak the board in the mixture and let it sit for an hour or so,I have only started using the Amtech stuff and it went white and soft and I was able to brush it off easily with a Medium or Hard tooth brush.

I have never had Krud Kutter damage anything and your solder joint's will look as shiny as the day they were soldered after being soaked in Krud Kutter and water and even if you use just Krud Kutter not mixed with anything and put it on pure your solder joints years later will still be shiny,it's not one of those deals where it works great but you signs of stuff you don't want to see much later on.

The only thing I wouldn't do is soak a board with any moving parts on it and solder those parts on last after the board has been soaked and then clean those joints with pure Krud Kutter and let it sit for 10 or 15 minutes then brush it and rinse it.The reason I say not to soak a board with moving parts is because I did a Velleman shake dice kit that has a switch with a ball that rattles back and forth to turn the dice on and a bit of the rosin that was in the water and Krud Kutter got into the switch and it stuck and would not work.

If you let the board soak long enough for an hour or a bit more the rosin just dissolve's and when you lift it out you tell there is nothing there,the Krud Kutter will not hurt caps resistors leds or triodes whether they are threw hole or smd.

The only thing Krud Kutter will attack is polystyrene witch is just white Styrofoam,I also find you can get many use's from a mixed up batch,I have also found it works very very very fast if I'm mixing up a batch for the first time and I use warm water with the Krud Kutter,I have thought about using a Crock Pot or slow cooker to heat the mixture the same way a Sonic cleaner works but need to find out the temps a sonic cleaner works at and also if a Crock Pot or Slow Cooker can be turned down to a low enough temperature.

Here is a link to the product and just as a side not the original stuff has worked great on all house hold cleaning task's and just plain and simply works great on just about any task you throw at it.

https://www.homedepot.ca/en/home/p.krud-kutter-original-cleaner-degreaser-spray-946ml.1000831021.html

Is there a no-clean flux that cleans easily with Isopropyl?

I have ChipQuik SMD tacky flux, and IPA doesn't seem to clean it after even with a nylon brush. Board stays tacky.

I'd prefer to get a flux that cleans easily with IPA as IPA is something that I keep around the house easily enough and use for many other things.

[Raj]

Start with a cheapest one while soldering practice boards with components as small as 0402 or even 0201

[wade7575]

@nanofrog I was just wondering if you can tell me if there is anything you need to watch for when using Toluene and MEK as far as it harming anything on the board,do you mix them together or do you use them separately.

[HB9EVI]

So far I just tried cheap solder paste 63/37 from aliexpress. It dries out quite fast but when fresh, it behaves well, residue removes with IPA

Otherwise, since I have a rework station, I completely stopped bothering to solder smd chips with the solder iron; they pretty much solder by themselves with hot air, the biggest issue when you get newly into it is finding the right amount of paste; wick is in every case a good thing.

[bson]

No problems with MG Chemicals leaded, and as noted I don't really think it needs cleaning.  This is what it looks like; populated this board a few days ago.  (Chip is a 0.65mm SSOP, an NXP 74LVC827APW.)  With enough solder to form fillets and clean surface bonds, but nowhere near huge bloated blobs there won't be enough flux to get all over, and no real reason to clean unless you do controlled impedance stuff.  At least not for one-off prototypes.  The cap is 0402, and the traces 8mil. 

[wade7575]

bson I picked up some MG Chemicals stuff off of ebay 2 days ago so I can start using my Quick 861DW and try out some practice boards that I have as well,I also ordered so Mechanic brand stuff as well because from what I have heard it supposed to be the king of the cheap stuff but I did not feel like waiting anywhere between 3 weeks to 3 months for it to show up.

I find it odd that no where on MG Chemicals stuff do they list the micron size or even the heat at witch it melt's at but I already from what others have said it's 183C,the MG stuff is not the cheapest but it's not the most money either and I like the fact they have a pretty good name and it can be easier then many other brands.

[nanofrog]

Just look up the alloy.

63/37 melts at 183C for example.

[jmelson]

Is there a no-clean flux that cleans easily with Isopropyl?

If you INTEND to clean the board, use WS (Water Soluble) paste.  It works better than NC, in my opinion, and washes off easily with either water or solvent.

Jon

[jmelson]

...[snip]...it's when you get into the smallest SMD resistors on the market I can't solder with an iron no matter how hard I try and I have gotten a few kit's like that and was not able to build them.

I'm not sure how you're trying to do this, but the basic methodology will work with any size passive.

• Tin one of the pads.
• Flux the newly tinned pad as well as the un-tinned pad (one tinned, one not is based on new PCB).
• Place the part with tweezers with one hand, and hold the part in place. Now touch the tinned pad & part with the iron to tack that end to the pad.
• Solder the other side, then come back, add some additional flux to the tacked side, and finish soldering it.

Actually, I tin the first pad quickly, it leaves plenty of flux for later.  Then, hold the part as you say and touch the iron to the pre-tinned pad, the part drops to the PCB surface.  Remove iron, a second later remove tweezers.  Then solder 2nd pad.  No need to go back and touch up first side.  You can do this with solder paste, but I do it with small diameter wire solder.  I have probably done about  100,000 components this way.  Much less, now that I have a P&P machine.

Jon