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Guest

Fri May 18, 2018 9:45 pm   



Greetings one and all


I am laying plans to start working with SMT for the first time. Would
0805 components be a suitable size for a beginner, or would another
size be appropriate?



I have been a sometimes hobbyist for a long time, since the mid 70's
when I was a teenager, but until now I have never ventured beyond
through hole construction, mostly due to a combination of tooling and
a complete lack of dexterity.

I have recently been convinced by someone that SMT has a much wider
availability of components and the prices are generally much less than
the equivalent THT components. The compactness of SMT construction is
also very attractive.

I plan to start with a small hot air station and then move up to a
more proper reflow setup if I ever get more ambitious.

My primary concern is the handling of components. The 0805 sized
components seem to be very common and I strongly doubt I could ever go
below that due to vision and dexterity issues.

However, is 0805 too small for a klutzy beginner? I'm not
particularly ambitious at this point, but that could change, depending
on my interests and level of success.


Ray

Gareth
Guest

Fri May 18, 2018 11:45 pm   



With the right equipment I would expect 0805 to be manageable, though
obviously that depends on your ability which you are in a better
position to assess than me.

Before you layout a PCB maybe you could buy some 0805 resistors and see
how well you can handle them? Maybe print some actual size footprints on
paper and see if you can place the components? perhaps not very
realistic but should give you an idea of what you are getting into
without the time and expense of laying out an actual PCB.

Personally I have found component density to be more of an issue than
size, e.g replacing an 0402 with plenty of space around it would, for
me, be easier than replacing an 0805 in the middle of tightly packed
area, especially if it is a small component between two tall capacitors.

For low cost components make sure you get some spares - you don't want
your project to be delayed because a resistor pinged out of the tweezers.

On 18/05/2018 21:43, rayRemoveThisotwell_at_gmail.com wrote:
Quote:
Greetings one and all


I am laying plans to start working with SMT for the first time. Would
0805 components be a suitable size for a beginner, or would another
size be appropriate?



I have been a sometimes hobbyist for a long time, since the mid 70's
when I was a teenager, but until now I have never ventured beyond
through hole construction, mostly due to a combination of tooling and
a complete lack of dexterity.

I have recently been convinced by someone that SMT has a much wider
availability of components and the prices are generally much less than
the equivalent THT components. The compactness of SMT construction is
also very attractive.

I plan to start with a small hot air station and then move up to a
more proper reflow setup if I ever get more ambitious.

My primary concern is the handling of components. The 0805 sized
components seem to be very common and I strongly doubt I could ever go
below that due to vision and dexterity issues.

However, is 0805 too small for a klutzy beginner? I'm not
particularly ambitious at this point, but that could change, depending
on my interests and level of success.


Ray


Phil Hobbs
Guest

Fri May 18, 2018 11:45 pm   



On 05/18/18 16:43, rayRemoveThisotwell_at_gmail.com wrote:
Quote:
Greetings one and all


I am laying plans to start working with SMT for the first time. Would
0805 components be a suitable size for a beginner, or would another
size be appropriate?



I have been a sometimes hobbyist for a long time, since the mid 70's
when I was a teenager, but until now I have never ventured beyond
through hole construction, mostly due to a combination of tooling and
a complete lack of dexterity.

I have recently been convinced by someone that SMT has a much wider
availability of components and the prices are generally much less than
the equivalent THT components. The compactness of SMT construction is
also very attractive.

I plan to start with a small hot air station and then move up to a
more proper reflow setup if I ever get more ambitious.


I'd suggest 0805 or 1206 to start with. Hot air isn't a slam dunk for
assembly because it's easy to blow the components away--paste isn't very
sticky. I suggest using an adjustable hotplate from a chem lab (which
are cheap on ebay) with a _thick_ aluminum frying pan on top (also cheap).

For protos we use one of those plus a chunk of 1/2-inch aluminum jig
plate from McMaster-Carr. You really need the aluminum to spread out
the heat, or the board won't reflow uniformly. A thermocouple
thermometer is pretty cheap as well, but you need to really squash the
sensor against the hot plate, e.g. with a screw or a big binder clip.

Quote:

My primary concern is the handling of components. The 0805 sized
components seem to be very common and I strongly doubt I could ever go
below that due to vision and dexterity issues.


Get some good lab glasses. If you were a teenager in the 1970s (as I
was) you'll be needing bifocals. My lab glasses are +0.75 (comfortable
for a desktop computer) and +2.25 for close work. Your reading
correction plus 1.25 or 1.5 diopter is the ticket. I pay about $40 for a
pair of those from Zenni Optical. Don't use drugstore ones unless you
happen to have the matching interpupillary distance--even a millimetre
of error makes a difference.

For small stuff, e.g. checking TSSOP packages for solder bridges, I use
an original Mantis microscope ($1400 used) with 4x and 8x lenses. There
are a lot of Chinese scopes on eBay for a few hundred bucks new.

Make sure you get a _stereo_ microscope and not just a _binocular_ one.
Stereo scopes provide normal stereopsis, i.e. your eyes look at the
field from different directions so that you get depth perception. It's
cool and useful to be able to look around stuff, and the Mantis is great
for that.

Also spend the money for decent stainless-steel tweezers, not the
Chinese or (especially) Indian ones. You want pointy ends with not too
skinny a taper, one pair straight and one pair curved. You'll use the
curved ones the most. Get some alcohol to keep the tweezers clean,
because otherwise flux will make them stick to the parts. Another tip
is to make adjustable self-closing tweezers: Use a small binder clip
sliding up and down the jaws of the tweezers to adjust the closing
force. That really helps prevent losing parts when you change your grip
on the tweezers.

You'll also need a jig for applying paste. You can get good solder
stencils for cheap along with your Chinese PCBs, but you need to
surround your board with other bits of board of the same thickness, or
the stencil won't lie flat on the board and the paste will go everywhere.

Quote:

However, is 0805 too small for a klutzy beginner? I'm not
particularly ambitious at this point, but that could change, depending
on my interests and level of success.


The key is to get the paste right and then apply the parts with
tweezers, resting the heel of your hand on the bench so only your small
muscles have to coordinate. An adjustable-height chair and a fairly
tall workbench (36 inches or so) are a huge help there too.

After that, start saving up for decent test equipment. ;)

Have a great time at it!

Cheers

Phil Hobbs


--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

Gone Postal
Guest

Sat May 19, 2018 3:45 am   



On Fri, 18 May 2018 23:00:04 +0100, Gareth <me_at_privacy.net> wrote:

Quote:
With the right equipment I would expect 0805 to be manageable, though
obviously that depends on your ability which you are in a better
position to assess than me.

Before you layout a PCB maybe you could buy some 0805 resistors and see
how well you can handle them? Maybe print some actual size footprints on
paper and see if you can place the components? perhaps not very
realistic but should give you an idea of what you are getting into
without the time and expense of laying out an actual PCB.

Personally I have found component density to be more of an issue than
size, e.g replacing an 0402 with plenty of space around it would, for
me, be easier than replacing an 0805 in the middle of tightly packed
area, especially if it is a small component between two tall capacitors.

For low cost components make sure you get some spares - you don't want
your project to be delayed because a resistor pinged out of the tweezers.

On 18/05/2018 21:43, rayRemoveThisotwell_at_gmail.com wrote:
Greetings one and all


I am laying plans to start working with SMT for the first time. Would
0805 components be a suitable size for a beginner, or would another
size be appropriate?



I have been a sometimes hobbyist for a long time, since the mid 70's
when I was a teenager, but until now I have never ventured beyond
through hole construction, mostly due to a combination of tooling and
a complete lack of dexterity.

I have recently been convinced by someone that SMT has a much wider
availability of components and the prices are generally much less than
the equivalent THT components. The compactness of SMT construction is
also very attractive.

I plan to start with a small hot air station and then move up to a
more proper reflow setup if I ever get more ambitious.

My primary concern is the handling of components. The 0805 sized
components seem to be very common and I strongly doubt I could ever go
below that due to vision and dexterity issues.

However, is 0805 too small for a klutzy beginner? I'm not
particularly ambitious at this point, but that could change, depending
on my interests and level of success.


Ray


Egads!

I just tried some of what you suggested. I whipped up a simple little
0805 layout in KiCAD and then printed the mask to have a look.

Without serious magnification, I couldn't tell the pads from the
traces!

I'll definitely start with the 1206s for now! I'll save the 0805s for
once I get a good feel for SMT and get some sort of reflow plate.

Thanks!

Gone Postal
Guest

Sat May 19, 2018 3:45 am   



On Fri, 18 May 2018 18:11:36 -0400, Phil Hobbs
<pcdhSpamMeSenseless_at_electrooptical.net> wrote:

Quote:
On 05/18/18 16:43, rayRemoveThisotwell_at_gmail.com wrote:
Greetings one and all


I am laying plans to start working with SMT for the first time. Would
0805 components be a suitable size for a beginner, or would another
size be appropriate?



I have been a sometimes hobbyist for a long time, since the mid 70's
when I was a teenager, but until now I have never ventured beyond
through hole construction, mostly due to a combination of tooling and
a complete lack of dexterity.

I have recently been convinced by someone that SMT has a much wider
availability of components and the prices are generally much less than
the equivalent THT components. The compactness of SMT construction is
also very attractive.

I plan to start with a small hot air station and then move up to a
more proper reflow setup if I ever get more ambitious.

I'd suggest 0805 or 1206 to start with. Hot air isn't a slam dunk for
assembly because it's easy to blow the components away--paste isn't very
sticky. I suggest using an adjustable hotplate from a chem lab (which
are cheap on ebay) with a _thick_ aluminum frying pan on top (also cheap).

For protos we use one of those plus a chunk of 1/2-inch aluminum jig
plate from McMaster-Carr. You really need the aluminum to spread out
the heat, or the board won't reflow uniformly. A thermocouple
thermometer is pretty cheap as well, but you need to really squash the
sensor against the hot plate, e.g. with a screw or a big binder clip.


My primary concern is the handling of components. The 0805 sized
components seem to be very common and I strongly doubt I could ever go
below that due to vision and dexterity issues.

Get some good lab glasses. If you were a teenager in the 1970s (as I
was) you'll be needing bifocals. My lab glasses are +0.75 (comfortable
for a desktop computer) and +2.25 for close work. Your reading
correction plus 1.25 or 1.5 diopter is the ticket. I pay about $40 for a
pair of those from Zenni Optical. Don't use drugstore ones unless you
happen to have the matching interpupillary distance--even a millimetre
of error makes a difference.

For small stuff, e.g. checking TSSOP packages for solder bridges, I use
an original Mantis microscope ($1400 used) with 4x and 8x lenses. There
are a lot of Chinese scopes on eBay for a few hundred bucks new.

Make sure you get a _stereo_ microscope and not just a _binocular_ one.
Stereo scopes provide normal stereopsis, i.e. your eyes look at the
field from different directions so that you get depth perception. It's
cool and useful to be able to look around stuff, and the Mantis is great
for that.

Also spend the money for decent stainless-steel tweezers, not the
Chinese or (especially) Indian ones. You want pointy ends with not too
skinny a taper, one pair straight and one pair curved. You'll use the
curved ones the most. Get some alcohol to keep the tweezers clean,
because otherwise flux will make them stick to the parts. Another tip
is to make adjustable self-closing tweezers: Use a small binder clip
sliding up and down the jaws of the tweezers to adjust the closing
force. That really helps prevent losing parts when you change your grip
on the tweezers.

You'll also need a jig for applying paste. You can get good solder
stencils for cheap along with your Chinese PCBs, but you need to
surround your board with other bits of board of the same thickness, or
the stencil won't lie flat on the board and the paste will go everywhere.


However, is 0805 too small for a klutzy beginner? I'm not
particularly ambitious at this point, but that could change, depending
on my interests and level of success.

The key is to get the paste right and then apply the parts with
tweezers, resting the heel of your hand on the bench so only your small
muscles have to coordinate. An adjustable-height chair and a fairly
tall workbench (36 inches or so) are a huge help there too.

After that, start saving up for decent test equipment. ;)

Have a great time at it!

Cheers

Phil Hobbs


Thank you for all the tips and advice! This is exactly what I need to
hear.


Guest

Sat May 19, 2018 3:45 am   



Oops, sorry for using my old handle there.

Ray

DJ Delorie
Guest

Sat May 19, 2018 5:45 am   



Way back when I did a "sampler" board to help answer this question, and
found that I could do 0603, 0402, and maybe 0201, sized resistors by
hand (soldering iron Smile. The 01005 was a bit too small, even with a
microscope.

Project here in case you want to make one yourself:
http://www.delorie.com/pcb/smd-challenge/

I typically use 0603 size, and 0.5mm pitch ICs, with a soldering iron
(40 mil chisel). You learn how to design PCBs that are easy to solder
parts onto ;-)

I will add the caveat that I'm a bit crazy:
http://www.delorie.com/pcb/inkjet/insanity_II.html

John Larkin
Guest

Sat May 19, 2018 8:45 pm   



On Fri, 18 May 2018 16:43:36 -0400, rayRemoveThisotwell_at_gmail.com
wrote:

Quote:
Greetings one and all


I am laying plans to start working with SMT for the first time. Would
0805 components be a suitable size for a beginner, or would another
size be appropriate?



0805's are a good size. That's my preferred size for production
boards, too.

Quote:

I have been a sometimes hobbyist for a long time, since the mid 70's
when I was a teenager, but until now I have never ventured beyond
through hole construction, mostly due to a combination of tooling and
a complete lack of dexterity.

I have recently been convinced by someone that SMT has a much wider
availability of components and the prices are generally much less than
the equivalent THT components. The compactness of SMT construction is
also very attractive.

I plan to start with a small hot air station and then move up to a
more proper reflow setup if I ever get more ambitious.


Hand soldering isn't bad. People use kitchen convection ovens or hot
plates, too.

Quote:

My primary concern is the handling of components. The 0805 sized
components seem to be very common and I strongly doubt I could ever go
below that due to vision and dexterity issues.


You'll need some magnification, something with some working distance.
I love my Mantis, but that may be too expensive for you just now. A
desktop immuminated magnifier should be enough, 3x or so maybe.



Quote:

However, is 0805 too small for a klutzy beginner? I'm not
particularly ambitious at this point, but that could change, depending
on my interests and level of success.


1206's frightened me once. Now 0603s are fine, but I hate 0402s.

I make prototypes by Demeling copperclad FR4. Works great.

https://www.dropbox.com/s/7bihbjbaojvta0z/Z382_1.JPG?raw=1

https://www.dropbox.com/s/9av93ul8148zdjm/Z356_SN2.JPG?raw=1

https://www.dropbox.com/s/5nlhqy7c8mt2xv3/LDP2.JPG?raw=1


Try surface mount. It's not bad at all.


--

John Larkin Highland Technology, Inc

lunatic fringe electronics

Phil Hobbs
Guest

Sat May 19, 2018 9:45 pm   



On 05/19/18 00:03, DJ Delorie wrote:
Quote:

Way back when I did a "sampler" board to help answer this question, and
found that I could do 0603, 0402, and maybe 0201, sized resistors by
hand (soldering iron Smile. The 01005 was a bit too small, even with a
microscope.

Project here in case you want to make one yourself:
http://www.delorie.com/pcb/smd-challenge/

I typically use 0603 size, and 0.5mm pitch ICs, with a soldering iron
(40 mil chisel). You learn how to design PCBs that are easy to solder
parts onto ;-)

I will add the caveat that I'm a bit crazy:
http://www.delorie.com/pcb/inkjet/insanity_II.html


All that work on gEDA, no doubt. ;)

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

Ecnerwal
Guest

Sat May 19, 2018 9:45 pm   



In article <ojv0gdp9ejfavltql4dlmsmbjchevdgjtc_at_4ax.com>,
Ray Otwell <rayRemoveThisotwell_at_gmail.com> wrote:


Quote:
I've seen the breadboarding via islands before, but I really hadn't
thought much about dremeling a board for SMT, but that looks like it
actually works quite well.

Due to handling issues I'm really starting to think in terms of 1206,
at least until I gain some experience with tweezers and small objects.
I would like to move to 0805 because I like the extra compactness.


You may also find it easier to find parts in 0805, depending on the part.

Quote:
One other thing I've recently discovered by working on some smaller
items is that I need a raised work area, and that goes double if I'm
going to do surface mount work of any sort. With strong glasses my
focal length is just too short otherwise.


There are other methods, as I mentioned in my first reply (right about
as you were writing this, I'd guess, so you wouldn't have seen them) -
the camera-scope and screen is probably the most affordable of them,
unless you find a handy source for cheap used microscopes and find a
suitable one among those, or happen to have one. Trick being you need a
scope that gives you room to work - dissection scopes are often as
suitable (optically) as those sold as "assembly scopes."

Yes, cutting islands in copperclad is a very handy 1-off at-home
technique with SMT. For some applications (not all, particularly high
frequency ones) generic adapter boards to get back to DIP pin spacing
are also handy/useful.

--
Cats, coffee, chocolate...vices to live by
Please don't feed the trolls. Killfile and ignore them so they will go away.

Ecnerwal
Guest

Sat May 19, 2018 9:45 pm   



In article <bneufd9h0p2s19sv8vkvst47m0jm6svues_at_4ax.com>,
rayRemoveThisotwell_at_gmail.com wrote:

Quote:
Greetings one and all


I am laying plans to start working with SMT for the first time. Would
0805 components be a suitable size for a beginner, or would another
size be appropriate?



I have been a sometimes hobbyist for a long time, since the mid 70's
when I was a teenager, but until now I have never ventured beyond
through hole construction, mostly due to a combination of tooling and
a complete lack of dexterity.

I have recently been convinced by someone that SMT has a much wider
availability of components and the prices are generally much less than
the equivalent THT components. The compactness of SMT construction is
also very attractive.

I plan to start with a small hot air station and then move up to a
more proper reflow setup if I ever get more ambitious.

My primary concern is the handling of components. The 0805 sized
components seem to be very common and I strongly doubt I could ever go
below that due to vision and dexterity issues.

However, is 0805 too small for a klutzy beginner? I'm not
particularly ambitious at this point, but that could change, depending
on my interests and level of success.


Ray


I prefer to use (inch) 0805 or larger, but can manage (inch) 0603
without too much invective. The metric coded 0603 parts are much smaller
- 0603 inch is 1608 in metric, and metric 0603 is inch 0201 (don't
sneeze.)

That said I've been known to cruise sleazebay for surplus partial reels
of 2512, 1210 and 1206 parts (while there are some intermediate sizes
between those, they seem to be much less common, though I will search on
them as well - 1008 also seems to be uncommon) looking for parts I might
make use of at low cost in sizes that are easier to see/handle.
Overkill, perhaps, and not as compact as possible, but I'm mostly making
stuff on my own, not for production.

I use a soldering iron - Weller WTCPN/TC201 with a long pointy cone,
(1/64" radius tip) that I mostly use the side of. I have other tips, but
have not changed that one since I first started messing with surface
mount. Many folks do think you need a fat chisel tip, but I find the
versatility of the long point (if you grok using the side as well as the
tip) is better for me.

I (now) have a rework station but only use it for desoldering, usually -
messing about with applying paste has not found much appeal as yet.
While there are supposed to be horrors from assembling SMT with a normal
iron, I have yet to run into them personally, and thus weight the horror
stories kinda low.

I got a set of "my normal prescription with 5 diopters added to it"
glasses - that, and a lot of light, are helpful, though a fancier setup
(microscope or the like) with a longer working distance might be nicer.
+1 puts your "infinity" at a meter, +2 is half a meter, +3 is 1/3 of a
meter, +4 is 1/4 of a meter, and +5 is 1/5 of a meter, or roughly 8
inches from your eyeballs. Some folks use a USB microscope/camera and a
monitor (the larger the better) as a different means of magnifying the
work area with plenty of eye relief.

The parts I hate are the multi-pin packages with insanely small spacing.
SOP seems quite comfortable by comparison with vast 1.27mm pin spacing.
SSOPs and tighter tend to make me feel either grumpy or hopeless. I
probably would hate BGAs if I was inclined to use any, but so far I've
been spared that joy. I'll happily use DIPs when available.

Solder surface tension plays a big role in production assembly and
soldermask is very important as a result, especially for the tight
spacings - if you have the right amount of solder, a chip that's more or
less in the right place will self-center when the solder melts. A hot
tweezer gives you the fancy way to do this on a two-terminal device (or
remove it easily) but you can often heat both ends with a single iron if
you move quickly. Manageable packages are hold in place, tack a pin on
one corner, tack a pin on the other corner, correct if needed, and then
solder the rest of the pins. Unmanageable packages you have to solder
them all at once and try to avoid bridges from too much solder.

--
Cats, coffee, chocolate...vices to live by
Please don't feed the trolls. Killfile and ignore them so they will go away.

Ray Otwell
Guest

Sat May 19, 2018 9:45 pm   



On Sat, 19 May 2018 11:50:19 -0700, John Larkin
<jjlarkin_at_highlandtechnology.com> wrote:

Quote:
On Fri, 18 May 2018 16:43:36 -0400, rayRemoveThisotwell_at_gmail.com
wrote:

Greetings one and all


I am laying plans to start working with SMT for the first time. Would
0805 components be a suitable size for a beginner, or would another
size be appropriate?



0805's are a good size. That's my preferred size for production
boards, too.


I have been a sometimes hobbyist for a long time, since the mid 70's
when I was a teenager, but until now I have never ventured beyond
through hole construction, mostly due to a combination of tooling and
a complete lack of dexterity.

I have recently been convinced by someone that SMT has a much wider
availability of components and the prices are generally much less than
the equivalent THT components. The compactness of SMT construction is
also very attractive.

I plan to start with a small hot air station and then move up to a
more proper reflow setup if I ever get more ambitious.

Hand soldering isn't bad. People use kitchen convection ovens or hot
plates, too.


My primary concern is the handling of components. The 0805 sized
components seem to be very common and I strongly doubt I could ever go
below that due to vision and dexterity issues.

You'll need some magnification, something with some working distance.
I love my Mantis, but that may be too expensive for you just now. A
desktop immuminated magnifier should be enough, 3x or so maybe.




However, is 0805 too small for a klutzy beginner? I'm not
particularly ambitious at this point, but that could change, depending
on my interests and level of success.

1206's frightened me once. Now 0603s are fine, but I hate 0402s.

I make prototypes by Demeling copperclad FR4. Works great.

https://www.dropbox.com/s/7bihbjbaojvta0z/Z382_1.JPG?raw=1

https://www.dropbox.com/s/9av93ul8148zdjm/Z356_SN2.JPG?raw=1

https://www.dropbox.com/s/5nlhqy7c8mt2xv3/LDP2.JPG?raw=1


Try surface mount. It's not bad at all.


I've seen the breadboarding via islands before, but I really hadn't
thought much about dremeling a board for SMT, but that looks like it
actually works quite well.

Due to handling issues I'm really starting to think in terms of 1206,
at least until I gain some experience with tweezers and small objects.
I would like to move to 0805 because I like the extra compactness.

One other thing I've recently discovered by working on some smaller
items is that I need a raised work area, and that goes double if I'm
going to do surface mount work of any sort. With strong glasses my
focal length is just too short otherwise.

I've seen all sorts of articles on hot plates and different ways to
customize them for SMT use. I've also seen some projects for
converting toaster ovens for reflow use. One of those is probably the
route I'll eventually take, $$$ are a strong concern. Most likely a
hot plate approach as I think it quite unlikely I'll make more than
one or two boards at a time, or week even.

I suppose I'm going to have to start ordering boards, too. I don't
think my homebrew boards are going to survive this transition unless I
move to photo developing boards.

An awful lot of considerations to move into light SMT work. I
underestimated the amount of preparation I'm going to need to start,
but I'm starting to really think I can do it AND enjoy it.

Thank you for the input!

Ray

Ray Otwell
Guest

Sun May 20, 2018 4:45 am   



On Sat, 19 May 2018 16:17:08 -0400, Ecnerwal
<MyNameForward_at_ReplaceWithMyVices.Com.invalid> wrote:

Quote:
In article <bneufd9h0p2s19sv8vkvst47m0jm6svues_at_4ax.com>,
rayRemoveThisotwell_at_gmail.com wrote:

Greetings one and all


I am laying plans to start working with SMT for the first time. Would
0805 components be a suitable size for a beginner, or would another
size be appropriate?



I have been a sometimes hobbyist for a long time, since the mid 70's
when I was a teenager, but until now I have never ventured beyond
through hole construction, mostly due to a combination of tooling and
a complete lack of dexterity.

I have recently been convinced by someone that SMT has a much wider
availability of components and the prices are generally much less than
the equivalent THT components. The compactness of SMT construction is
also very attractive.

I plan to start with a small hot air station and then move up to a
more proper reflow setup if I ever get more ambitious.

My primary concern is the handling of components. The 0805 sized
components seem to be very common and I strongly doubt I could ever go
below that due to vision and dexterity issues.

However, is 0805 too small for a klutzy beginner? I'm not
particularly ambitious at this point, but that could change, depending
on my interests and level of success.


Ray

I prefer to use (inch) 0805 or larger, but can manage (inch) 0603
without too much invective. The metric coded 0603 parts are much smaller
- 0603 inch is 1608 in metric, and metric 0603 is inch 0201 (don't
sneeze.)

That said I've been known to cruise sleazebay for surplus partial reels
of 2512, 1210 and 1206 parts (while there are some intermediate sizes
between those, they seem to be much less common, though I will search on
them as well - 1008 also seems to be uncommon) looking for parts I might
make use of at low cost in sizes that are easier to see/handle.
Overkill, perhaps, and not as compact as possible, but I'm mostly making
stuff on my own, not for production.

I use a soldering iron - Weller WTCPN/TC201 with a long pointy cone,
(1/64" radius tip) that I mostly use the side of. I have other tips, but
have not changed that one since I first started messing with surface
mount. Many folks do think you need a fat chisel tip, but I find the
versatility of the long point (if you grok using the side as well as the
tip) is better for me.

I (now) have a rework station but only use it for desoldering, usually -
messing about with applying paste has not found much appeal as yet.
While there are supposed to be horrors from assembling SMT with a normal
iron, I have yet to run into them personally, and thus weight the horror
stories kinda low.

I got a set of "my normal prescription with 5 diopters added to it"
glasses - that, and a lot of light, are helpful, though a fancier setup
(microscope or the like) with a longer working distance might be nicer.
+1 puts your "infinity" at a meter, +2 is half a meter, +3 is 1/3 of a
meter, +4 is 1/4 of a meter, and +5 is 1/5 of a meter, or roughly 8
inches from your eyeballs. Some folks use a USB microscope/camera and a
monitor (the larger the better) as a different means of magnifying the
work area with plenty of eye relief.

The parts I hate are the multi-pin packages with insanely small spacing.
SOP seems quite comfortable by comparison with vast 1.27mm pin spacing.
SSOPs and tighter tend to make me feel either grumpy or hopeless. I
probably would hate BGAs if I was inclined to use any, but so far I've
been spared that joy. I'll happily use DIPs when available.

Solder surface tension plays a big role in production assembly and
soldermask is very important as a result, especially for the tight
spacings - if you have the right amount of solder, a chip that's more or
less in the right place will self-center when the solder melts. A hot
tweezer gives you the fancy way to do this on a two-terminal device (or
remove it easily) but you can often heat both ends with a single iron if
you move quickly. Manageable packages are hold in place, tack a pin on
one corner, tack a pin on the other corner, correct if needed, and then
solder the rest of the pins. Unmanageable packages you have to solder
them all at once and try to avoid bridges from too much solder.


Thank you for the ideas!

From time to time I have wondered if a very narrow tip could be used
for the larger SMT items. I've seen tutorials on how to do the SOP
and SSOP packages with larger tips.. It doesn't look easy at all, but
doable. I can't even wrap my head around trying one of the small
packages, though. I have a decent Hakko 888D that seems to do
everything I need. I already have a similar time to the one you
described, maybe I should get it out of the package and use it! The
only reason I hadn't is because I'm still doing THT work, but as you
said, using the side as well may let me use it for normal work too.

I'm continually improving my technique with soldering, but I have an
essential tremor that makes fine work difficult without having to
brace the iron against something. I may be able to manage the 1206
packages with some work, but anything smaller I just don't think is
within my abilities.

I've just ordered a set of bifocals with a higher diopter, I hope that
will let me ditch the magnifier headband I have been using. It works
well, but it throws shade over my work area if I'm not careful and
lean in too close.

Thank you

John Larkin
Guest

Mon May 21, 2018 1:45 am   



On Sat, 19 May 2018 23:06:17 -0400, Ray Otwell
<rayRemoveThisotwell_at_gmail.com> wrote:


Quote:
From time to time I have wondered if a very narrow tip could be used
for the larger SMT items. I've seen tutorials on how to do the SOP
and SSOP packages with larger tips.. It doesn't look easy at all, but
doable. I can't even wrap my head around trying one of the small
packages, though.


I use a pretty big wedge tip on my old Metcal, for just about
everything. Really small stuff, I glop solder on all the leads then
wick most of it off.





I have a decent Hakko 888D that seems to do
Quote:
everything I need. I already have a similar time to the one you
described, maybe I should get it out of the package and use it! The
only reason I hadn't is because I'm still doing THT work, but as you
said, using the side as well may let me use it for normal work too.

I'm continually improving my technique with soldering, but I have an
essential tremor that makes fine work difficult without having to
brace the iron against something. I may be able to manage the 1206
packages with some work, but anything smaller I just don't think is
within my abilities.


Try it. You'll improve with a bit of practice. There's not much
difference between 1206 and 0805. Rest your wrist on something solid
as you solder.

Get some good tweezers!


--

John Larkin Highland Technology, Inc

lunatic fringe electronics

George Herold
Guest

Mon May 21, 2018 2:45 pm   



On Friday, May 18, 2018 at 6:11:45 PM UTC-4, Phil Hobbs wrote:
Quote:
On 05/18/18 16:43, rayRemoveThisotwell_at_gmail.com wrote:
Greetings one and all


I am laying plans to start working with SMT for the first time. Would
0805 components be a suitable size for a beginner, or would another
size be appropriate?



I have been a sometimes hobbyist for a long time, since the mid 70's
when I was a teenager, but until now I have never ventured beyond
through hole construction, mostly due to a combination of tooling and
a complete lack of dexterity.

I have recently been convinced by someone that SMT has a much wider
availability of components and the prices are generally much less than
the equivalent THT components. The compactness of SMT construction is
also very attractive.

I plan to start with a small hot air station and then move up to a
more proper reflow setup if I ever get more ambitious.

I'd suggest 0805 or 1206 to start with. Hot air isn't a slam dunk for
assembly because it's easy to blow the components away--paste isn't very
sticky. I suggest using an adjustable hotplate from a chem lab (which
are cheap on ebay) with a _thick_ aluminum frying pan on top (also cheap).

For protos we use one of those plus a chunk of 1/2-inch aluminum jig
plate from McMaster-Carr. You really need the aluminum to spread out
the heat, or the board won't reflow uniformly. A thermocouple
thermometer is pretty cheap as well, but you need to really squash the
sensor against the hot plate, e.g. with a screw or a big binder clip.


My primary concern is the handling of components. The 0805 sized
components seem to be very common and I strongly doubt I could ever go
below that due to vision and dexterity issues.

Get some good lab glasses. If you were a teenager in the 1970s (as I
was) you'll be needing bifocals. My lab glasses are +0.75 (comfortable
for a desktop computer) and +2.25 for close work. Your reading
correction plus 1.25 or 1.5 diopter is the ticket. I pay about $40 for a
pair of those from Zenni Optical. Don't use drugstore ones unless you
happen to have the matching interpupillary distance--even a millimetre
of error makes a difference.

For small stuff, e.g. checking TSSOP packages for solder bridges, I use
an original Mantis microscope ($1400 used) with 4x and 8x lenses. There
are a lot of Chinese scopes on eBay for a few hundred bucks new.

Make sure you get a _stereo_ microscope and not just a _binocular_ one.
Stereo scopes provide normal stereopsis, i.e. your eyes look at the
field from different directions so that you get depth perception. It's
cool and useful to be able to look around stuff, and the Mantis is great
for that.

Also spend the money for decent stainless-steel tweezers, not the
Chinese or (especially) Indian ones. You want pointy ends with not too
skinny a taper, one pair straight and one pair curved. You'll use the
curved ones the most.

Phil, what's wrong with the cheap tweezers from India? I think that
is what I mostly use. Is there something I'm missing?

George H.

(oh 0805 as others have said.)


Get some alcohol to keep the tweezers clean,
Quote:
because otherwise flux will make them stick to the parts. Another tip
is to make adjustable self-closing tweezers: Use a small binder clip
sliding up and down the jaws of the tweezers to adjust the closing
force. That really helps prevent losing parts when you change your grip
on the tweezers.

You'll also need a jig for applying paste. You can get good solder
stencils for cheap along with your Chinese PCBs, but you need to
surround your board with other bits of board of the same thickness, or
the stencil won't lie flat on the board and the paste will go everywhere.


However, is 0805 too small for a klutzy beginner? I'm not
particularly ambitious at this point, but that could change, depending
on my interests and level of success.

The key is to get the paste right and then apply the parts with
tweezers, resting the heel of your hand on the bench so only your small
muscles have to coordinate. An adjustable-height chair and a fairly
tall workbench (36 inches or so) are a huge help there too.

After that, start saving up for decent test equipment. ;)

Have a great time at it!

Cheers

Phil Hobbs


--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com


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