Soldering paste

For users of Matrix Multimedia Electronics software to discuss projects, circuits and any other electronics concepts.

Moderators: Benj, Mods

Creative25
Posts: 323
Joined: Tue Sep 06, 2011 2:54 am
Has thanked: 166 times
Been thanked: 26 times
Contact:

Soldering paste

Postby Creative25 » Thu Mar 28, 2013 9:22 am

Hi
I experimented a bit with surface mount parts and I got to like it.
But with normal solder wire it is quite a Job to solder all the parts.
Now I am thinking of using soldering paste.
It seems solder paste is usually shipped with a cold pack.
Till it reaches me it will take about 3 week. About two weeks it will be exposed to temperatures of about 38° celsius.
What will the heat do to the solder paste? Will it become unusable or do I just have to mix it nicely?
What are your experiences?
To you keep it always in the fridge?

Best Regards:
Uli

dazz
Posts: 1314
Joined: Sun Jan 15, 2012 3:15 pm
Has thanked: 514 times
Been thanked: 467 times
Contact:

Re: Soldering paste

Postby dazz » Thu Mar 28, 2013 11:25 am

Hi Uli
I keep mine in the fridge, even just getting it out the fridge to use after 1/2 hour or so it does get noticeably runnier im in the uk but where you are I don't know how the heat will affect it, have you any electronics repairers or manufacturers localish,if so try ringing them and asking how they handle paste, they may even be able to supply you some, you can get very fine solder wire online (try ali express or rapid online) which is good for smd parts I tend to add a bit of solder to each pad then add the component touch each end with your iron(you may need just a smidge of flux on the component, then keep the iron on the last side for just a second longer this should heat the solder at both ends and allow the component to centeralise on the pad, the best thing about paste is you can add a bit to each pad place each component then bake for a few minutes or even touch with a soldering iron

Regards
Dazz
These users thanked the author dazz for the post:
Creative25 (Thu Mar 28, 2013 11:34 am)
Rating: 5%
 
To sign up to the V5 forum follow this link http://www.matrixmultimedia.com/forum_upgrades.php

Creative25
Posts: 323
Joined: Tue Sep 06, 2011 2:54 am
Has thanked: 166 times
Been thanked: 26 times
Contact:

Re: Soldering paste

Postby Creative25 » Thu Mar 28, 2013 11:33 am

Hi Dazz
Thanks for the info.
If it is just a issue of getting runny, and can be used again after being in a fridge then I could take the risk of ordering online.
But if it is an issue of the paste getting permanently changed then I would have to look into that.

Best Regards:
Uli

User avatar
JohnCrow
Valued Contributor
Valued Contributor
Posts: 1367
Joined: Wed Sep 19, 2007 1:21 pm
Location: Lincolnshire
Has thanked: 381 times
Been thanked: 716 times
Contact:

Re: Soldering paste

Postby JohnCrow » Thu Mar 28, 2013 11:43 am

These users thanked the author JohnCrow for the post (total 2):
dazz (Thu Mar 28, 2013 12:05 pm) • Creative25 (Thu Mar 28, 2013 12:51 pm)
Rating: 10%
 
1 in 10 people understand binary, the other one doesn't !

dazz
Posts: 1314
Joined: Sun Jan 15, 2012 3:15 pm
Has thanked: 514 times
Been thanked: 467 times
Contact:

Re: Soldering paste

Postby dazz » Thu Mar 28, 2013 12:08 pm

Forgot to say always wear gloves when using paste it gets everywhere, there are some fairly cheap smd rework stations online, which combine an iron and a hotair blower, theres also lots of stuff on using tabletop ovens
Regards
Dazz
These users thanked the author dazz for the post:
Creative25 (Thu Mar 28, 2013 12:51 pm)
Rating: 5%
 
To sign up to the V5 forum follow this link http://www.matrixmultimedia.com/forum_upgrades.php

Creative25
Posts: 323
Joined: Tue Sep 06, 2011 2:54 am
Has thanked: 166 times
Been thanked: 26 times
Contact:

Re: Soldering paste

Postby Creative25 » Thu Mar 28, 2013 12:55 pm

Hi
Thanks for all the replies.
Unfortunately I could not watch the video, my internet connection is too slow.
But I got some useful Information on the forum link.
Apparently it is a issue of the solder particles starting to separate and float on the top.
So I guess for me the best would be if I get some paste that is in a tin.
Best Regards:
Uli

User avatar
Benj
Matrix Staff
Posts: 14676
Joined: Mon Oct 16, 2006 10:48 am
Location: Matrix TS Ltd
Has thanked: 4660 times
Been thanked: 4286 times
Contact:

Re: Soldering paste

Postby Benj » Fri Mar 29, 2013 7:37 am

Hi Uli,

This is quite a good guide on how to use a SMD oven and solder paste.

http://www.001tech.co.uk/index.php?p=proj&f=18&topic=60

The paste I buy does not come with a cool bag and I always generally just keep my paste at room temperature but the stuff I use has lead in it so it melts easier but not ideal for commercial applications. Longest I have had an open syringe is about 6 months.

http://uk.farnell.com/edsyn/cr44/solder ... /dp/876768
These users thanked the author Benj for the post:
Creative25 (Mon Apr 01, 2013 5:18 pm)
Rating: 5%
 

Creative25
Posts: 323
Joined: Tue Sep 06, 2011 2:54 am
Has thanked: 166 times
Been thanked: 26 times
Contact:

Re: Soldering paste

Postby Creative25 » Mon Jul 08, 2013 2:04 pm

Hi I am just about to order some solder paste.
This will be my first time trying solder paste.
I can get a 35ml syringe, or a 250g Tin.
What can be kept longer a syringe or in a tin?
How much can I do with a 35ml syringe?

Just wonder if the solder tin will become unusable before I can ever finish it.

The other question is water soluble vs no clean what are your experiences?

Best Regards:
Uli

arin
Posts: 1
Joined: Thu Aug 15, 2013 4:18 pm
Contact:

Re: Soldering paste

Postby arin » Thu Aug 15, 2013 4:20 pm

There are many types of solder pastes so it really depends upon whether or not it'll get damaged if exposed to higher temperatures. Mostly they work fine; in my lab they are not kept in any fridge or anything and they can be used for weeks. The lab is air conditioned when we are working but we leave them on the table after work without any worries. SMD soldering is easy if we're not talking about soldering DSPs or FPGAs or such. Also, the solder pastes are kept in tins here, I don't know about your working environment though.
Last edited by arin on Tue Jul 28, 2015 10:03 pm, edited 1 time in total.

Brendan
Posts: 223
Joined: Tue Nov 27, 2012 12:53 pm
Location: Cambridge, UK
Has thanked: 136 times
Been thanked: 115 times
Contact:

Re: Soldering paste

Postby Brendan » Fri Nov 01, 2013 2:34 am

For future reference...

We use a variety of solder pastes at work, though all internal boards and prototypes are commonly soldered with leaded (i.e. NOT Lead-Free) paste.

For all prototyping applications I would strongly recommend avoiding lead-free paste, both for optimal reflow wetting and possible rework/modifications.


All the best,

Brendan
These users thanked the author Brendan for the post (total 2):
Creative25 (Fri Nov 01, 2013 8:44 am) • dazz (Fri Nov 01, 2013 11:31 am)
Rating: 10%