Dangerous Prototypes

General Category => Tools of the trade => Topic started by: digistump on February 02, 2013, 01:07:44 am

Title: Cheap Solder Paste
Post by: digistump on February 02, 2013, 01:07:44 am
I'm not sure if this should be here or in General Discussion - but this seems like it might be the right place...

What do folks use for cheap solder paste - not $50 Kester syringes -I use Kester a lot but I'm looking for something to use on cheap prototypes and the like with the reflow oven I have on the way.

Like something like this:
http://www.ebay.com/itm/1pcs-50g-MCN-30 ... 4cfebf823b (http://www.ebay.com/itm/1pcs-50g-MCN-300-Soldering-Solder-Paste-63-37-25-45um-B217-/330691478075?pt=LH_DefaultDomain_0&hash=item4cfebf823b)

Any opinions? Favorites? Good sources? etc?
Title: Re: Cheap Solder Paste
Post by: arhi on February 02, 2013, 02:58:09 am
well i think it's the perfect time to order it as when summer starts you can bet those packages will hit 50-60C easily in different transport containers .. so getting solder paste in winter might be the the good idea :D
Title: Re: Cheap Solder Paste
Post by: touch on February 02, 2013, 03:15:15 am
I use that exact Mechanic soldering paste, never had any complaints about it, seems to work fine for me, flows pretty good, but not as good as the Kester stuff.
Title: Re: Cheap Solder Paste
Post by: digistump on February 02, 2013, 04:02:56 am
@arhi - good point, I never would have thought of that!

@touch - awesome, I'll give it a try

Has anyone tried the Lodestar brand?

http://www.ebay.com/itm/50G-Soldering-R ... 2576a67e21 (http://www.ebay.com/itm/50G-Soldering-Repair-Solder-Paste-Cream-Welding-Paste-/160904412705?pt=LH_DefaultDomain_0&hash=item2576a67e21)
Title: Re: Cheap Solder Paste
Post by: arhi on February 02, 2013, 04:11:27 am
that lodestar looks like just a flux without solder balls inside
Title: Re: Cheap Solder Paste
Post by: matseng on February 02, 2013, 05:26:45 am
I got a few of those from Deal Extreme some years ago.  They do have tin balls, but the tubs dries out very quickly and the paste 'pops' a lot during reflow even after a long pre-heat so half my parts usually ends up somewhere else on the pcb :-)

It might work better with a proper reflow temp profile...
Title: Re: Cheap Solder Paste
Post by: arhi on February 02, 2013, 06:42:43 am
i purchased solder paste from ebay twice, both times it was without solder (not that one). now when I don't see then percentages of tin and lead I assume it's flux only
Title: Re: Cheap Solder Paste
Post by: digistump on February 02, 2013, 07:55:00 am
I like the logic of buying the paste that actually gives the metal content - I went ahead and bought some of the Mechanics - thanks guys!

I bought some 63/37 thin solder from ebay awhile ago - it certainly wasn't anything close to 63/37 - it pretty much turned into plastic smelling paste when melted - so its good to hear the Mechanics stuff actually might be solder...
Title: Re: Cheap Solder Paste
Post by: neslekkim on February 02, 2013, 08:39:01 am
[quote author="arhi"]i purchased solder paste from ebay twice, both times it was without solder (not that one). now when I don't see then percentages of tin and lead I assume it's flux only[/quote]

The Amtech?, I bought an 5pack with amtech solder paste, no solder at all, but flux. The flux itself is good to use (I like it atleast), but no tin inside it.
I bought similar to this: http://www.ebay.com/itm/271137159147 (http://www.ebay.com/itm/271137159147)
I complained to the seller that this was no tin, now it seems everyone actually calls it flux.
Title: Re: Cheap Solder Paste
Post by: ian on February 02, 2013, 08:45:10 am
Quote
Mechanic soldering paste

Sjaak got me some of this. I left it out, he keeps it in the fridge. I cracked it open for the reflow oven and hot plate tests and placed with tweezers and  it seemed to work great.

In Shenzhen I bought a big tub of "Sparkle" paste that was stored in a fridge properly. I froze it before bringing it home, and have stored it in the fridge (in a bag or two) since. I googled it and found it is 6x/3x tin lead made in Japan. The Japan part I highly doubt for this particular one at 70 or 90RMD (12-14 bucks), but I will try it to day with teh dispenser when the air compressor arrives.
Title: Re: Cheap Solder Paste
Post by: digistump on February 02, 2013, 10:22:31 am
I looked at the sparkle paste too - of course more expensive on ebay then you paid, but still not bad if it turns out to be any good:

http://www.ebay.com/itm/Japan-Senju-Sol ... 2c64ef7e20 (http://www.ebay.com/itm/Japan-Senju-Soldering-Solder-Repair-Sparkle-Paste-500g-/190671978016?pt=LH_DefaultDomain_0&hash=item2c64ef7e20)
Title: Re: Cheap Solder Paste
Post by: Sleepwalker3 on February 02, 2013, 01:37:31 pm
[quote author="neslekkim"][quote author="arhi"]
The Amtech?, I bought an 5pack with amtech solder paste, no solder at all, but flux. The flux itself is good to use (I like it atleast), but no tin inside it.
I bought similar to this: http://www.ebay.com/itm/271137159147 (http://www.ebay.com/itm/271137159147)
I complained to the seller that this was no tin, now it seems everyone actually calls it flux.[/quote][/quote]

Even if you go for Amtech Flux (as distinct from solder paste) on ebay or Dx, it's all fake, not real Amtech, the real stuff is fairly expensive
Title: Re: Cheap Solder Paste
Post by: arhi on February 02, 2013, 02:27:23 pm
one was amtech in syringe, other was some other brand in a case similar to ones in this thread .. didn't really remember the name
Title: Re: Cheap Solder Paste
Post by: tayken on February 02, 2013, 04:59:07 pm
I use the same Lodestar paste from Deal Extreme. Once opened, you have to keep it in the fridge. Did some boards this week with it, it flowed perfectly even after being opened 6 months ago. But of course I wouldn't use it for manufacturing purposes, but cheap & good enough for prototypes.
Title: Re: Cheap Solder Paste
Post by: ian on February 03, 2013, 07:51:15 am
Any idea if soldering paste for pneumatic dispensers should be thinned out or something? I can't get it to dispense even at 100 PSI.
Title: Re: Cheap Solder Paste
Post by: katjap on February 03, 2013, 08:08:37 am
I don't imagine it could hurt to try!
Title: Re: Cheap Solder Paste
Post by: matseng on February 03, 2013, 08:26:09 am
Have you tried it with a thicker syringe tip like a 18 ga?
Title: Re: Cheap Solder Paste
Post by: ian on February 03, 2013, 10:30:16 am
I guess I over did it. Started a new syringe with only 1CM of paste and it's working ok with the plastic tip. Blue seems to be the smallest of the plastic ones, and it works. Haven't been able to get any of the needles to work.
Title: Re: Cheap Solder Paste
Post by: Sjaak on February 03, 2013, 10:36:37 am
I think those are mend to dispense that tacky flux or glue.
Title: Re: Cheap Solder Paste
Post by: matseng on February 03, 2013, 10:57:03 am
The guy in this video http://youtu.be/rcLAskvaujA?t=18s (http://youtu.be/rcLAskvaujA?t=18s) is using a needle with metallic tip and have the syringe filled to 50 %...
Title: Re: Cheap Solder Paste
Post by: neslekkim on February 03, 2013, 11:20:52 am
http://www.nordson.com/en-us/divisions/ ... spensetips (http://www.nordson.com/en-us/divisions/efd/products/Documents/product-part-numbers/part_numbers.html#dispensetips)
I guess he's using 18gaugue tips?
The typical ebay tips doesnt seem to be using these colors, but since he had its tips in an box like that, I would guess they might follow that guide?

And after watching that video, I really want one of these.. His compressor was very quiet though..
Title: Re: Cheap Solder Paste
Post by: Zuph on February 03, 2013, 05:25:37 pm
I really like ZephPaste for prototypes. http://www.zeph.com/zephpaste.htm (http://www.zeph.com/zephpaste.htm)

$17 per 12 gram tube, but they really mean it when they say 6 month shelf life.

Their tech papers and videos are really good also, though they use them to heavily promote their own products.
Title: Re: Cheap Solder Paste
Post by: neslekkim on February 03, 2013, 07:35:46 pm
Syringes that looks like that, are they ready to be mounted on the solder dispensers?, if so, they would be very nice to use
I have this, syringe looks the same, but I'm not sure if there is an standard for them: http://www.proto-advantage.com/store/pr ... id=1200045 (http://www.proto-advantage.com/store/product_info.php?products_id=1200045)
Title: Re: Cheap Solder Paste
Post by: erdabyz on February 03, 2013, 08:06:26 pm
I use top quality chipquik paste. I stenciled 24 robots like this:
viewtopic.php?f=19&t=2594&p=42524#p42524 (http://dangerousprototypes.com/forum/viewtopic.php?f=19&t=2594&p=42524#p42524) (two-side load boards)
and I didn't  even spend half a 35g syringe, wasting quite a lot of paste in the stencilling process (basically I wasted all leftover paste stuck to the squeegee after each run, and I did runs of 4-6 robots)

I mean, why hoarding solder paste when a quality syringe would last the average (and not so average) user more than the product's shelf life?

I tried the LodeStar paste and the only compliants I have is that it smells bad and its flux is quite hard to clean off. The behaviour was much like chipquik paste and it didn't pop off or boil or spill or anything. My PICqueƱo (which has a TQFP28 and a TQFP64) was soldered with lodestar paste and a crappy etched copper stencil and it turned out with very few shorts.

Anyways I still prefer the pro stuff. It smells so good and it's so easy to clean....
Title: Re: Cheap Solder Paste
Post by: Sjaak on February 03, 2013, 08:14:40 pm
I think those can be mounted on the solderdispenser like the one Ian got. I saw various endcaps for syringes.

that zephpte looks quite neat. What are the shippingcost apprx?
Title: Re: Cheap Solder Paste
Post by: Zuph on February 03, 2013, 08:40:44 pm
Shipping in the US is on the expensive side of reasonable, about $15 (I've never bought enough stuff at one time to bump the shipping above that).  Shipping internationally is pretty pricey.
Title: Re: Cheap Solder Paste
Post by: touch on February 03, 2013, 10:11:59 pm
A bit off topic, but whats the best way to apply paste without a stencil? I was trying apply some to make a video on how the paste looks, but without a stencil it just doesn't work out very well.

and like I read someone else saying, it does seem like its tiny balls of solder in flux and it does pop around a bit if you get too much on there, I've had it move 0805 stuff, but for the price I really cant complain.
Title: Re: Cheap Solder Paste
Post by: Sjaak on February 03, 2013, 10:29:21 pm
[quote author="touch"]A bit off topic, but whats the best way to apply paste without a stencil? I was trying apply some to make a video on how the paste looks, but without a stencil it just doesn't work out very well.

and like I read someone else saying, it does seem like its tiny balls of solder in flux and it does pop around a bit if you get too much on there, I've had it move 0805 stuff, but for the price I really cant complain.[/quote]

You can use a dispenser like ian bought or you can use a toothpick to apply the paste. there was a post on hackaday about this a couple day ago: http://hackaday.com/2013/02/01/populate ... -tweezers/ (http://hackaday.com/2013/02/01/populate-smd-boads-using-a-toothpick-and-tweezers/)
Title: Re: Cheap Solder Paste
Post by: ian on February 04, 2013, 09:49:25 am
I find the toothpick unreasonably difficult :)
Title: Re: Cheap Solder Paste
Post by: erdabyz on February 04, 2013, 11:11:21 am
[quote author="ian"]I find the toothpick unreasonably difficult :)[/quote]

Toothpick fails because wood is porous and it absorbs your fluxes so the paste thickens and doesn't properly stick to the board. Paste has two fluxes, one liquid that helps wetting and cleaning and one solid (which melts with the solder itself) that helps solder flow. You must use something that isn't porous. I use the tip of my tweezers but any plastic toothpick would do I guess. My method is to apply a reservoir drop 2mm away from the tip of the tweezers and let it drip to the tip. Then you just dab the tip agains the pads and most times the right amount is dispensed. Big reservoir drop for big pads, small reservoir drop for 0402's and such. Gravity does the rest.

I found that I could only do this with the chipquick stuff and I have to wait till it gets to room temperature (always store paste in the refrigerator). Lodestar paste is just too thick for that.
Title: Re: Cheap Solder Paste
Post by: ian on February 04, 2013, 02:04:17 pm
Great info. I've never actually done it with a toothpick, I use my tweezers in the same way I'd use a toothpick though and find it difficult with the fluxes I have available.
Title: Re: Cheap Solder Paste
Post by: Sjaak on February 04, 2013, 07:10:20 pm
[quote author="ian"]I find the toothpick unreasonably difficult :)[/quote]

You got a machine, I only got my hands.. :)
Title: Re: Cheap Solder Paste
Post by: arhi on February 04, 2013, 07:35:14 pm
I was few time close to purchasing a dispenser but a proper air compressor was always a problem. It's not that they are expensive as you can get a great one for 200eur, problem is that darn thing is big and loud...
Title: Cheap Solder Paste
Post by: TomKeddie on February 04, 2013, 08:43:46 pm
[quote author="arhi"]I was few time close to purchasing a dispenser but a proper air compressor was always a problem. It's not that they are expensive as you can get a great one for 200eur, problem is that darn thing is big and loud...[/quote]

As I mentioned in Ian's dispenser forum, take a look at ex dental units, they run quiet.


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Title: Re: Cheap Solder Paste
Post by: arhi on February 04, 2013, 08:46:22 pm
not sure they can produce enough pressure
Title: Re: Cheap Solder Paste
Post by: ian on February 06, 2013, 02:58:56 pm
I plan to seek a dental unit. My little 6L compressor (109Eur) takes up less room than my tower PC case or (smallish) laser printer. It is, however, deafening. I'm sure the downstairs neighbors love it too :) For that reason I only get to use it noon to 5, so I know I'm never annoying anyone.

Agree that a 24L compressor is a beast. I was not allowed to have it in the office by the powers that be :D
Title: Re: Cheap Solder Paste
Post by: neslekkim on February 06, 2013, 03:03:48 pm
I would try this:
viewtopic.php?f=68&t=5121#p49630 (http://dangerousprototypes.com/forum/viewtopic.php?f=68&t=5121#p49630)

Atleast, very quiet ;)
Title: Re: Cheap Solder Paste
Post by: arhi on February 06, 2013, 03:14:09 pm
[quote author="ian"] For that reason I only get to use it noon to 5, so I know I'm never annoying anyone.[/quote]

:D :D :D

Here the "quiet time" is 13-17 so in those 4 hours you can't make noise (and between 22 and 07)
Title: Re: Cheap Solder Paste
Post by: katjap on February 06, 2013, 05:03:25 pm
Could you get a large air tank like this: http://www.sears.com/craftsman-5-gal-ho ... 915200000P (http://www.sears.com/craftsman-5-gal-horizontal-air-tank-135-psi/p-00915200000P)  (or maybe bigger) and fill that durring the daytime and use it to dispense paste at night?? It would be quiet, and at least extend your working hours a bit.
Title: Re: Cheap Solder Paste
Post by: arhi on February 06, 2013, 05:15:38 pm
you can always get a bigger tank, but a huge metal can full of air takes a lot of expensive office space :(
Title: Re: Cheap Solder Paste
Post by: Sjaak on February 06, 2013, 06:15:40 pm
[quote author="ian"]I plan to seek a dental unit. My little 6L compressor (109Eur) takes up less room than my tower PC case or (smallish) laser printer. It is, however, deafening. I'm sure the downstairs neighbors love it too :) For that reason I only get to use it noon to 5, so I know I'm never annoying anyone.

Agree that a 24L compressor is a beast. I was not allowed to have it in the office by the powers that be :D[/quote]

You can buy rubbermats at the local diy to place under washingmachines to dampen the vibrations. Also planning to drive to baco friday afternoon
Title: Re: Cheap Solder Paste
Post by: arhi on February 06, 2013, 06:41:54 pm
What is the minimum psi dispenser works at ?

I was planning to try to use a small, very quiet compressor and hand made air tank but the max pressure I can have is 30psi and that sounds kinda low :(
Title: Re: Cheap Solder Paste
Post by: touch on February 07, 2013, 04:56:39 am
If you need a quiet compressor, you can use an old Freon compressor from a refrigerator, a/c unit or water cooler. I have one made out of an old refrigerator compressor that I salvaged. They're super quiet.

Here's a youtube video showing what I'm talking about: http://www.youtube.com/watch?v=9jOcLdZXRRs (http://www.youtube.com/watch?v=9jOcLdZXRRs)

I used the exact same air tank that he has that I got at Lowes for $49 on sale.
Title: Re: Cheap Solder Paste
Post by: ian on February 07, 2013, 11:00:51 am
I am using about 40-50psi, but if your paste is fluxie enough I think it works down to 20psi or so. The cheap Mechanic paste (back on topic!) certainly works at 20PSI.
Title: Re: Cheap Solder Paste
Post by: neslekkim on February 07, 2013, 11:05:42 am
The Mechanic, does it exists only in tubs?, not in syringes ?
Title: Re: Cheap Solder Paste
Post by: dpropicweb on February 12, 2013, 05:39:53 am
I've only ever seen it in tubs on eBay and at DealExtreme.
Title: Re: Cheap Solder Paste
Post by: t0mpr1c3 on February 05, 2014, 02:54:31 am
I am going for a pot of Mechanic. Let's see what it is like for $4.