Frequently Asked Questions
Bob Aberle | [email protected]
Lead-free solder
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 "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. 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.
Traditional solder has a melting point of approximately 350°F. RoHS solder has a higher melting point of 440°F.
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 lead-free, 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°F. If you want something sophisticated and expensive, Weller offers the WESD51 Soldering Station. I've listed this 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 lead-based 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 controlline activity, building an airplane to practice on, and designing another after many years of inactivity in that area. It looks like there is more activity in controlline 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 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, foam-type, throw-away brushes. No solvent is necessary and the foam-friendly spray paint can do its job.
Sources:
- RoHS (lead free) solder
www.hardwaresecrets.com/article/RoHS-Explained/232
- Restriction of Hazardous Substances Directive
- Radio Shack
- Weller WESD51 Soldering Station
www.all-spec.com/products/WESD51.html
- AMA
(765) 287-1256 www.modelaircraft.org
- PAMPA
- Stevens AeroModel
(719) 387-4187 www.stevensaero.com
- Krylon Short Cuts
Transcribed from original scans by AI. Minor OCR errors may remain.
