2. Solder paste doesn't keep (seems to have about the same time constant
as Horowitz & Hill's wet fish)

Solder paste must be kept refrigerated to maximize its shelf life. (read the
manufacturer's storage and handling instructions CAREFULLY, both for proper
storage for product longevity and for safety reasons)

I sure hope "solder paste" is NOT the same thing as "soldering paste flux",
or else my shoe-polish-size can of "Kester Soldering Paste Flux" (with a
hole in the lid through which I occasionally poke a soldering pencil)
that's been sitting on my workbench for at least the last 25 years hasn't
heard about those storage and handling instructions!

--Myron.
--
Five boxes preserve our freedoms: soap, ballot, witness, jury, and cartridge
PhD EE (retired). "Barbershop" tenor. CDL(PTXS). W0PBV. (785) 539-4448
NRA Life Member and Certified Instructor (Home Firearm Safety, Rifle, Pistol)

2. Solder paste doesn't keep (seems to have about the same time constant
as Horowitz & Hill's wet fish)

Solder paste must be kept refrigerated to maximize its shelf life. (read the
manufacturer's storage and handling instructions CAREFULLY, both for proper
storage for product longevity and for safety reasons)

I sure hope "solder paste" is NOT the same thing as "soldering paste flux",
or else my shoe-polish-size can of "Kester Soldering Paste Flux" (with a
hole in the lid through which I occasionally poke a soldering pencil)
that's been sitting on my workbench for at least the last 25 years hasn't
heard about those storage and handling instructions!

--Myron.
--
Five boxes preserve our freedoms: soap, ballot, witness, jury, and cartridge
PhD EE (retired). "Barbershop" tenor. CDL(PTXS). W0PBV. (785) 539-4448
NRA Life Member and Certified Instructor (Home Firearm Safety, Rifle, Pistol)

"Ian White, G3SEK" wrote in message
...




2. How can we either store it so it stays fresh; or re-constitute it
after it's gorn orf?

It keeps much better if it is kept in a fridge.


Leon
--
Leon Heller, G1HSM
http://www.geocities.com/leon_heller

"Ian White, G3SEK" wrote in message
...

2. Solder paste doesn't keep (seems to have about the same time constant
as Horowitz & Hill's wet fish)

2. How can we either store it so it stays fresh; or re-constitute it
after it's gorn orf?

Solder paste must be kept refrigerated to maximize its shelf life. (read the
manufacturer's storage and handling instructions CAREFULLY, both for proper
storage for product longevity and for safety reasons)

Note: If you don't have a dedicated refrigerator and *must* use one you
keep food in, you *must* take the *utmost* of care to do (at least) the
following
before even *considering* putting solder paste in your (regular, food
storage) refrigerator (and you should probably do this even if you have a
dedicated refrigerator):

1) clean the tube VERY well after use to make sure no paste is on the
outside
2) place the tube in a plastic "zip-lock" bag (which must not be
contaminated with solder paste)
3) place the bag, with the tube inside into a plastic container with a
tightly sealing lid (again, this must be clean and not contaminated with
solder paste)

Doing this *very carefully and meticulously* will at least minimize the
possibility of contaminating your refrigerator with solder paste particles,
which are VERY small ...

Further notes: You should, at after each step above, THOROUGHLY wash your
hands to assure that you don't transfer any solder paste to the outside of
the bag or the plastic container. Use a fresh, brand new bag each time
(they are cheap). Also wash the plastic container THOROUGHLY inside and out
each time you prepare to re-store your solder paste (don't wash it in your
dishwasher - do it manually and clean up afterwards as if you were cleaning
up a hazmat spill). And finally, NEVER use the plastic container for food
after you've stored solder paste in it, NOT MATTER HOW WELL YOU THINK YOU'VE
CLEANED IT.

Ultimate note: If you have children in the home who could get into the
refrigerator and get at the solder paste, you probably shouldn't even
consider putting solder paste in your refrigerator where the children could
get at it ...

DISCLAIMER: While I believe the precautions above to be adequate and use
them myself, I take no responsibility for any consequences of a proper lack
of care on anyone's part in doing what I describe above, or any inadequacy
in my suggestions. Anyone following these suggestions does so solely at
their own risk.

73,
Carl - wk3c

p.s. Additionally, anyone considering the "ez-bake" method of reflow
soldering needs to understand the ABSOLUTE necessity of having a dedicated
toaster oven that is NEVER used for food preparation. It, along with all
soldering supplies should be used and stored in an area that is inaccessable
to children (keeping in mind how inquisitive children are and their ability
to get into things that you *thought* were secure or inaccessable).

"Ian White, G3SEK" wrote in message
...

For many irons, you can also buy fork-ended solder tips that bridge over
the parts. I made one by cutting and filing an old tip, and it worked OK
for parts removal. However, it would need some co-ordination to make the
tip contact the two pads without also knocking the part out of place.

Yes, a number of SMT tips for Pace and Weller soldering irons/stations.

Weller TCP series
http://www.wassco.com/csmsurmounsm.html

Pace irons (3/16" tip)
http://store1.yimg.com/I/was_1789_9025999


The toaster oven looks like a much better method for a whole-board
assembly project, except for two key problems:

1. Solder paste is expensive

Depends on the size you are looking at. Yes, the large sizes can be
expensive.

The syringe sizes (35 g) are about what I pay for a 1 lb roll of solder
and are the only sizes that I purchase for small projects (less waste)
http://www.wassco.com/kessolsn.html

R276 No-Clean, 35g WAS-01-021403$12.95
R500 Water Soluble, 35g WAS-01-021603$12.95

2. Solder paste doesn't keep (seems to have about the same time constant
as Horowitz & Hill's wet fish)

Ian, my brother is the buyer/shipping coordinator for a major fresh water
fish distributor in SE USA.
Missed plane connection in Anchorage, Alaska (polar route from Hong Kong to
Atlanta) ..
leads to frozen fish .. when you wanted live !

Wassco notifies all buyers of their shipment policies:
Solder Paste must ship overnight in a refrigerated condition.
We will contact you to discuss the extra freight charges that will apply.

Those are big problems for occasional, low-volume users such as
ourselves. So the questions a

1. Where's a low-cost source of solder paste? (in various parts of the
world)

Wassco is the recomemnded source for solder and tools Elecraft builders.
Of course this is California based. Maybe a talk to some of the UK
distibutors?

2. How can we either store it so it stays fresh; or re-constitute it
after it's gorn orf?


Refrigerator - that's how I bought it at the Acitve Electronics stores in
US, before they closed.
I was also told they did not keep solder paste more than 2 to 3 months at
each store.

Store in a refrigerator away from your normal late night consumables .....
or that pasty taste in your mouth might be the last tube for your project.

Surface Mount Technology Assn.
http://smta.org/

Greg
w9gb

well i have just made 12 boards holding 100 or so 0805, 223, 20sm dil.etc..
it took a day..
in the end i got out very small twezzers placed the components on board held
in place by small drop of super glue dispensed by end of tooth pick, and
held down by other end of pick till dry....
then soldered using small iron...
all worked first go...

BUT.. my eyes didn't half hurt by the end...

there must be a better way..ez-bake i dont think is it..any other ideas??

how is it done professionally..???

g0zen
"G.Beat" wrote in message
news:48Tkc.9109$0H1.998600@attbi_s54...
"Ian White, G3SEK" wrote in message
...

For many irons, you can also buy fork-ended solder tips that bridge over
the parts. I made one by cutting and filing an old tip, and it worked OK
for parts removal. However, it would need some co-ordination to make the
tip contact the two pads without also knocking the part out of place.

Yes, a number of SMT tips for Pace and Weller soldering irons/stations.

Weller TCP series
http://www.wassco.com/csmsurmounsm.html

Pace irons (3/16" tip)
http://store1.yimg.com/I/was_1789_9025999


The toaster oven looks like a much better method for a whole-board
assembly project, except for two key problems:

1. Solder paste is expensive

Depends on the size you are looking at. Yes, the large sizes can be
expensive.

The syringe sizes (35 g) are about what I pay for a 1 lb roll of solder
and are the only sizes that I purchase for small projects (less waste)
http://www.wassco.com/kessolsn.html

R276 No-Clean, 35g WAS-01-021403$12.95
R500 Water Soluble, 35g WAS-01-021603$12.95

2. Solder paste doesn't keep (seems to have about the same time constant
as Horowitz & Hill's wet fish)

Ian, my brother is the buyer/shipping coordinator for a major fresh water
fish distributor in SE USA.
Missed plane connection in Anchorage, Alaska (polar route from Hong Kong
to
Atlanta) ..
leads to frozen fish .. when you wanted live !

Wassco notifies all buyers of their shipment policies:
Solder Paste must ship overnight in a refrigerated condition.
We will contact you to discuss the extra freight charges that will apply.

Those are big problems for occasional, low-volume users such as
ourselves. So the questions a

1. Where's a low-cost source of solder paste? (in various parts of the
world)

Wassco is the recomemnded source for solder and tools Elecraft builders.
Of course this is California based. Maybe a talk to some of the UK
distibutors?

2. How can we either store it so it stays fresh; or re-constitute it
after it's gorn orf?


Refrigerator - that's how I bought it at the Acitve Electronics stores in
US, before they closed.
I was also told they did not keep solder paste more than 2 to 3 months at
each store.

Store in a refrigerator away from your normal late night consumables .....
or that pasty taste in your mouth might be the last tube for your project.

Surface Mount Technology Assn.
http://smta.org/

Greg
w9gb

well i have just made 12 boards holding 100 or so 0805, 223, 20sm dil.etc..
it took a day..
in the end i got out very small twezzers placed the components on board held
in place by small drop of super glue dispensed by end of tooth pick, and
held down by other end of pick till dry....
then soldered using small iron...
all worked first go...

BUT.. my eyes didn't half hurt by the end...

there must be a better way..ez-bake i dont think is it..any other ideas??

how is it done professionally..???

g0zen
"G.Beat" wrote in message
news:48Tkc.9109$0H1.998600@attbi_s54...
"Ian White, G3SEK" wrote in message
...

For many irons, you can also buy fork-ended solder tips that bridge over
the parts. I made one by cutting and filing an old tip, and it worked OK
for parts removal. However, it would need some co-ordination to make the
tip contact the two pads without also knocking the part out of place.

Yes, a number of SMT tips for Pace and Weller soldering irons/stations.

Weller TCP series
http://www.wassco.com/csmsurmounsm.html

Pace irons (3/16" tip)
http://store1.yimg.com/I/was_1789_9025999


The toaster oven looks like a much better method for a whole-board
assembly project, except for two key problems:

1. Solder paste is expensive

Depends on the size you are looking at. Yes, the large sizes can be
expensive.

The syringe sizes (35 g) are about what I pay for a 1 lb roll of solder
and are the only sizes that I purchase for small projects (less waste)
http://www.wassco.com/kessolsn.html

R276 No-Clean, 35g WAS-01-021403$12.95
R500 Water Soluble, 35g WAS-01-021603$12.95

2. Solder paste doesn't keep (seems to have about the same time constant
as Horowitz & Hill's wet fish)

Ian, my brother is the buyer/shipping coordinator for a major fresh water
fish distributor in SE USA.
Missed plane connection in Anchorage, Alaska (polar route from Hong Kong
to
Atlanta) ..
leads to frozen fish .. when you wanted live !

Wassco notifies all buyers of their shipment policies:
Solder Paste must ship overnight in a refrigerated condition.
We will contact you to discuss the extra freight charges that will apply.

Those are big problems for occasional, low-volume users such as
ourselves. So the questions a

1. Where's a low-cost source of solder paste? (in various parts of the
world)

Wassco is the recomemnded source for solder and tools Elecraft builders.
Of course this is California based. Maybe a talk to some of the UK
distibutors?

2. How can we either store it so it stays fresh; or re-constitute it
after it's gorn orf?


Refrigerator - that's how I bought it at the Acitve Electronics stores in
US, before they closed.
I was also told they did not keep solder paste more than 2 to 3 months at
each store.

Store in a refrigerator away from your normal late night consumables .....
or that pasty taste in your mouth might be the last tube for your project.

Surface Mount Technology Assn.
http://smta.org/

Greg
w9gb

"Ian White, G3SEK" wrote in message
...

For many irons, you can also buy fork-ended solder tips that bridge over
the parts. I made one by cutting and filing an old tip, and it worked OK
for parts removal. However, it would need some co-ordination to make the
tip contact the two pads without also knocking the part out of place.

Yes, a number of SMT tips for Pace and Weller soldering irons/stations.

Weller TCP series
http://www.wassco.com/csmsurmounsm.html

Pace irons (3/16" tip)
http://store1.yimg.com/I/was_1789_9025999


The toaster oven looks like a much better method for a whole-board
assembly project, except for two key problems:

1. Solder paste is expensive

Depends on the size you are looking at. Yes, the large sizes can be
expensive.

The syringe sizes (35 g) are about what I pay for a 1 lb roll of solder
and are the only sizes that I purchase for small projects (less waste)
http://www.wassco.com/kessolsn.html

R276 No-Clean, 35g WAS-01-021403$12.95
R500 Water Soluble, 35g WAS-01-021603$12.95

2. Solder paste doesn't keep (seems to have about the same time constant
as Horowitz & Hill's wet fish)

Ian, my brother is the buyer/shipping coordinator for a major fresh water
fish distributor in SE USA.
Missed plane connection in Anchorage, Alaska (polar route from Hong Kong to
Atlanta) ..
leads to frozen fish .. when you wanted live !

Wassco notifies all buyers of their shipment policies:
Solder Paste must ship overnight in a refrigerated condition.
We will contact you to discuss the extra freight charges that will apply.

Those are big problems for occasional, low-volume users such as
ourselves. So the questions a

1. Where's a low-cost source of solder paste? (in various parts of the
world)

Wassco is the recomemnded source for solder and tools Elecraft builders.
Of course this is California based. Maybe a talk to some of the UK
distibutors?

2. How can we either store it so it stays fresh; or re-constitute it
after it's gorn orf?


Refrigerator - that's how I bought it at the Acitve Electronics stores in
US, before they closed.
I was also told they did not keep solder paste more than 2 to 3 months at
each store.

Store in a refrigerator away from your normal late night consumables .....
or that pasty taste in your mouth might be the last tube for your project.

Surface Mount Technology Assn.
http://smta.org/

Greg
w9gb

"zindazenda" wrote in message
...
"Allan Butler" wrote in message
news:ALRjc.5600$Rd4.566539@attbi_s51...
What I have done in the past is to tin the pads where the parts are
going
to be mounted and then I use two soldering irons. One on each pad and
it
pulls the part right down into a good position.

Ok ok I hear the question now. What about parts with more than two
leads?

That is a valid and good question. Only tin two pads for that part and
use
the soldering iron on each one of the pads to get the part mounted and
in
position to finish soldering the rest of the leads one at a time.

no..on investugation this looks well abit crap..i cant see how it is going
to work with 100 sm 0805 components..
so anyother ideas..
can one buy flow soldering equipment s/h???
g0zen..

Actually, for the occasional prototype, the two-iron method, while a bit
tedious, works. (and while 0402 parts are a bit of a bear, even with my
aging vision I can handle 0805's and 0603's with this method ... but it
takes time and patience and I don't like to do a *lot* of parts that way)

You can also, with a bit of practice and care, use a "heat gun" to reflow
boards if you don't envision doing enough of it to justify the cost of
"real" reflow equipment.

I purchased a very nice and effective hot-air system for about $350 new on
e-bay (search on "reflow" - the brand I bought is "ATTEN" and it's
distributed by a company called "smtpros" if I recall correctly) ... and
I've also purchased a toaster oven for the "ez-bake" method ... do a search
on Google or Yahoo and you will find a Yahoo group on "ez-bake" with a long
thread of useful and informative discussion and hints.

Remember, for reflow you need solder *paste* ... available from a number of
sources on the web. I prefer the "no clean flux" kind, though I usually
clean the boards afterwards anyway ...

73,
Carl - wk3c

zindazenda wrote:

no..on investugation this looks well abit crap..i cant see how it is going
to work with 100 sm 0805 components..
so anyother ideas..
can one buy flow soldering equipment s/h???
g0zen..


Sir:

From necessity I did this with well over 500 parts on two assemblies for
radios that were prototypes. The people that had tried to do the assembly
with the approved methods had set the solder paste on the pads, placed the
parts in postion, both steps done by hand and then washed the boards
before they vapor phased the boards. This department then went ahead and
cleaned the filters out of the washing equipment, repasted the boards and
just put the parts where they fit.

I got two blank boards and all the parts sorted out into envelopes in tote
pans with clean prints of the parts list and a component layout with the
task set to get it done in a certain amount of time.

Monday through Saturday I worked 16 hour days and then on Sunday I took it
easy and worked 12 hours.

In addition to the surface mount parts I also had about the same number of
leaded parts on each board.

When I was done I was told that there were a total of 5 errors between the
two boards. It took about 2 to 3 weeks to accomplish this and several sets
of batteries for headset radio.

There were times I would place parts on the bench in front of me, put the
envelope back into the tote pan and could not see the parts. I would find
them after blinking several times, place them and then get up to take a
walk through the area to get things loosened up and relaxed a little bit.

This method I described is indeed a possible method. It has been done by
others than myself and sometimes it is the most expedient method to
accomplish the task.

The smallest parts available would make this method a challenge but it would
still be something that could be done with some time and paitence.

Good luck on your project and I wish you the best Sir.