Frequently Asked Questions-2011/07

July 2011 71
Traditional solder has a melting point of
approximately 350°. RoHS solder has a
higher melting point of 440°.
New equipment that is assembled with
lead-free solder is okay by itself. If you
don’t add or repair anything that requires
soldering, you are home free. If you are
doing your own soldering and start with and
continue to use lead-free solder, again you
will not experience any issues.
The problem arises when you change a
connector or electrical component that has
been soldered with lead-free solder. If you
use traditional solder on top of the leadfree,
you could have
complications. The difference
in the melting points of the
two solders is the real
problem.
An electrical connection
made with both types of solder
can look visually perfect,
but electrically you may
only have a partial
connection. In time that
type of joint will fail
and so will your
electronic equipment.
The heat of the
solder iron’s tip is
critical. I went looking for
irons that can go higher in
temperature—more than 440°.
If you want something
sophisticated and expensive,
Weller offers the WESD51
Soldering Station. I’ve listed this
PLEASE WRITE
in with your
questions, since that
is the only way we
can keep this column
format going. When
referring to already
published questions
and answers (for
follow-ups), provide
the number as a
reference.
Also note that
references to
addresses and
websites are placed
in a group, separate
from the text, at the
end of this column
under “Sources.” A
“Tips” feature is also
provided in addition
to frequently asked
questions; these hints
are numbered in the
same sequence as the questions and answers.
Q506: “I heard recently that we are facing a
situation where our traditional solder is
being replaced by a lead-free variety. I also
understand that failure to use this new form
of solder properly could lead to problems
with our electric-power components as well
as our RC systems. What do I need to know
about this new type of solder and how can I
identify where it is being used?”
A506: Lead-free solder requirements started
in the European Union and in Asia in 2006.
Legislation involving consumer electronic
equipment has been established to reduce
the amount of heavy metals disposed of
annually.
Conventional solder usually consists of
63% tin and 37% lead, which is known as
eutectic solder. The new lead-free solder is
called RoHS (pronounced as ro-hoss), which
stands for Restriction of Hazardous
Substances. It is 95% tin and 5% antimony.
It is typically used (or soon will be) in
electronic equipment to reduce lead content.
Electronic equipment made with RoHS
solder will be marked with small
identification placards or stickers. I’ve
included photos of several of these stickers.
If you use an Internet search engine and
search for RoHS, you will find much
detailed information.
I visited my local Radio Shack and found
electronic items imported from the Far East
that had these RoHS stickers affixed. I also
noted that Radio Shack is already selling
lead-free solder!
Lead-free solder
Bob Aberle | baberle@? Frequently Asked Questions optonline.net
Also included in this column:
• Getting back into CL flying
• Tip for spray painting foam
Far left: This is one of several labels affixed
to electronic equipment indicating that the
connections are made with lead-free solder.
The te rm RoHS st ands fo r Re stric tion of
Hazardous Substances.
Bob Hunt is holding one of his original CL
S tu n t C h a m p i o ns hi p m o de l s , th e
Cap rice. He fli es CL and RC, bu t
prefers CL.
Left: This is another variation of the RoHS
labels that you will be seeing in the future.
Above: The Weller WESD51 is a top-end
soldering iron w ith a digital readout that
lets yo u d i al u p t ip t e mp e r a t u re t o
ap proximately 800°. If you a re a s erious
modeler, this is the way to go.
07sig3.QXD_00MSTRPG.QXD 5/24/11 10:12 AM Page 71
72 MODEL AVIATION
designing another after many years of
inactivity in that area. It looks like there is
more activity in controline flying today
than there has been for many years. You
might want to discuss a few key points and
aim people to the details.”
A507: To get the best answer I asked
Aeromodeling Editor Emeritus Bob Hunt,
who is a former International CL Stunt
Champion, to supply some comments.
Bob’s response would best be handled as a
separate feature article and I encourage him
to do that! In the meantime I’ll paraphrase
some of his thoughts.
Bob indicated that CL activity has
increased in recent years, after a long
period of reduced interest by the modeling
community. Bob speculates that many
modelers began in the hobby flying CL
models, but gravitated toward RC when it
became popular.
Many of these people are returning to
CL flying because it offers them something
that RC cannot: the actual feel of the model
in flight. I hadn’t heard that reasoning
before, but I’m sure it wasn’t meant to
upset our RC enthusiasts.
Bob went on to mention that modelers
in general tend to select one of the three
major disciplines—RC, CL, or FF—and do
that exclusively. He feels that’s a shame
because each has much to offer and many
lessons to teach.
Bob noted that many RC clubs are
adding CL circles to their flying fields.
Numerous older modelers who started
flying CL are now enjoying dabbling in all
of the model disciplines and are having
much fun in the process.
The AMA has a list of CL-oriented
clubs and can provide you with the
necessary contact information. Call the
AMA and ask for Membership Services or
go to the AMA website and click on the
“Clubs” link.
Another suggestion is to look up one of
the AMA SIGs that concentrates on CL
flying. Bob mentioned the popular
Precision Aerobatics Model Pilots
Association (PAMPA). Despite its name,
this group is dedicated to all types of CL
flying. PAMPA offers its Stunt News
“newsletter” that looks and reads like a full
magazine.
I’ve listed PAMPA’s website in the
“Sources” section. If you want more
information, I suggest that you contact Bob
Hunt and recommend that he write a CL
feature article.
As a closing comment on this subject, I
reviewed a small electric-powered CL
trainer aircraft in the January 2011 issue of
MA. The airplane is called the RingRat and
is manufactured by Stevens AeroModel.
This type and size of model was
designed with two purposes in mind: to
allow older modelers to get back into CL
flying easily and to provide a simple
in “Sources.” I used to look for soldering
irons by wattage ratings; now I should start
being more concerned with iron-tip
temperatures.
One suggestion has been to remove any
connector or connector pins. Cut them off
completely then solder in new connectors
with either solder. Doing this should avoid
connection problems later.
You could buy a supply of regular leadbased
solder and use it for many years to
come, but that eliminates the intent of the
lead-free legislation. Do you really want to
do that?
I’m sure more will be discussed about
lead-free solder. I’m reporting it so you are
aware in the future.
Q507: AMA member Harold Craig asked,
“I am reentering controline activity,
building an airplane to practice on, and
Left: Stunt News covers aspects of CL from beginners to expert fliers
and builders.
Below: This is the Stevens AeroModel R in gRat electric-powered CL
tra iner that Bob Aberle r eviewed in the Ja nua ry 2 011 M A . This 6-
ounce air craft is f lown on 3 5-foot lines and c an e asily be f lown in a
large school gymnasium.
K r yl on Sh o r t Cuts s p r a y c o me s in
inexpensive 3-ounce cans. This paint will not
attack foam when sprayed. If you brush it on,
always use a disposable brush. Never clean a
brush with solvents then use it on foam.
07sig3.QXD_00MSTRPG.QXD 5/24/11 10:14 AM Page 72
aircraft to attract newcomers—and
especially young people—to our hobby.
Now would anyone on the FF side care
to add their thoughts and comments?
Tip 508: I have been spray painting new
aircraft that have been constructed from
foam sheeting such as Depron. When
buying spray paint for this purpose, you
must get the type stipulated as “foam
friendly.” It is a good idea to test any paint
on a scrap piece of foam before painting
your aircraft. If the paint is going to eat
foam, let it destroy the scrap piece.
I was using one of my favorite spray
paints made by Krylon, called Short Cuts.
It comes in 3-ounce cans, is inexpensive,
readily available at most craft stores, and it
does not melt Depron foam. But, it is an
alkyd or oil-based paint.
If you are just spraying the paint from
the can, you will not have any problem.
However, I needed to brush on some paint
in areas that were hard to get to before
spraying. I sprayed some paint into a paper
cup then used a brush to get to the desired
area.
Because I was using two colors, I
cleaned my brush with acetone when
switching colors. A short while later I
realized that in the areas where I did the
brushing, the paint had melted the foam.
My stabilizer and fuselage were ruined,
forcing me to practically construct a new
aircraft.
I realized that some residual acetone
was left on my brush, and that was what
melted the foam. The solution to this
problem is simply to use the cheap, foamtype,
throw-away brushes. No solvent is
necessary and the foam-friendly spray
paint can do its job. MA
Sources:
RoHS (lead free) solder
www.hardwaresecrets.com/article/RoHSExplained/
232
Restriction of Hazardous Substances
Directive
http://bit.ly/sNNK
Radio Shack
www.radioshack.com
Weller WESD51 Soldering Station
www.all-spec.com/products/WESD51.html
AMA
(765) 287-1256
www.modelaircraft.org
PAMPA
www.control-line.org
Stevens AeroModel
(719) 387-4187
www.stevensaero.com
Krylon Short Cuts
www.krylon.com/products