[hpsdr] Penny Solder stencils

[Gerd Loch]

Neal,

that will also work with your hotplate even if the solder on the bottom side
gets liquid during the second soldering process. The small components
0805-size are low weight and keep adherent by the surface tension of the
solder pads. The board should be fixed in horizontal position.

Additionally if you do not heat the top of the board in excess the solder on
the bottom side will not get liquid. You should monitor the temperature with
a thermocouple if available. Then you can try to apply the correct soldering
profile by changing the distance between hotplate and board surface by time.
The recommended soldering profile can be taken from the datasheet for the
solderpaste.

Additionally I would recommend to solder the crystal oscillators manually
and not apply solderpaste on their pads. (You can tape these pads if you
have openings in your stencil): This is because the the solderprofile for
the oscillators should be kept close to the datasheet in order not to
overstress them which results in a frequency shift and can damage it.

73, Gerd
DJ8AY



-----Original Message-----
From: Neal Campbell [mailto:nealk3nc at gmail.com] 
Sent: Friday, March 06, 2009 4:09 PM
To: g.loch at nt-electronics.de
Cc: hpsdr at lists.hpsdr.org
Subject: Re: Penny Solder stencils

I was going to use a hotplate and assumed that the parts already
soldered that are now on the bottom would either move or fall off or
prevent enough surface contact for the board to heat up for the top
components. Will this work if I am using a hot plate instead of a hot
air solderer or a reflow oven?

73
Neal Campbell
Abroham Neal Software
Programming Services for Windows, OS X and Linux
www.abrohamnealsoftware.com
(540) 242 0911




On Fri, Mar 6, 2009 at 4:35 AM, Gerd Loch <g.loch at nt-electronics.de> wrote:
> Hi Neal,
>
> where are your problems?
>
> Normally you solder first the solderside (where only capacitors and
> resistors are placed) with this side up.
> You can use hotair or a IR reflow oven. Then you assemble the component
side
> and solder it in the same way. The components on the solder side are then
> upside down. Even if the solderpaste on the bottom side becomes liquid
again
> the components keep adherent through the solderpaste.
>
> Manual assembly is normally done by me with a fine soldertip part after
> part.
>
> Gerd, DJ8AY
>
>
>
>
> Message: 1
> Date: Wed, 4 Mar 2009 18:41:27 -0500
> From: Neal Campbell <nealk3nc at gmail.com>
> Subject: [hpsdr] Penny Solder stencils are on the way
> To: High Performance Software Defined Radio Discussion List
>        <hpsdr at hpsdr.org>
> Message-ID:
>        <325413300903041541h6efbb9ddpebad6cece1b91fbb at mail.gmail.com>
> Content-Type: text/plain; charset=ISO-8859-1
>
> So, I have my Penny partial kit, the parts kit from John on the way, a
good
> supply of kester solder paste and Polulu mylar templates shipped today. I
> kinda figured out that I will not be able to do both sides of the board
with
> a hotplate after I ordered the front and the back stencils but...
>
> Does anyone have a recommendation on a good hot plate for this venture?
>
> 73
> Neal k3nc
>
>
> ************************************
>
>


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