4130 tube preparation for primer

The most important thing before priming the surface of 4130 is to remove any oil (commonly with acetone), make it clean, and to run over the surface with some fine grit aluminum oxide if there are any surface contaminants such as rust or other. Bead blasting can be used for thin wall tubing but with the Sonerai fuselage it is not recommended to use sandblasting because it takes too much off the surface of the metal and some consider it to reduce the structural integrity of the 4130 tubing.

Preventing and Managing Corrosion on 4130 Tubing

I have had a few thoughts about how I am going to prevent corrosion on the exterior of my 4130 steel tubing for the fuselage. I know that after a weld the join can more easily become corroded. So I thought I could probably prevent this by adding some etch primer over each weld, but this may cause problems later when the fabric gets laid and etch primer certainly doesnt stick as well as epoxies. I did find an epoxy primer in an aerosol from Septone, but I'm yet to find out if it is suitable, ie. does the epoxy stick well enough and to make sure it isnt affected by the polyfiber coatings. It sure would be alot more convenient if there was an aerosol epoxy primer that was compatible with the polyfiber process.

After emailing Polyfiber, they said that only 2 part epoxy primers are suitable for undercoats under their covering. This is because it doesnt disolve or degrade when it comes into contact with the polyfiber coatings.

Love to hear your comments or suggestions.

Boiled Linseed Oil

After some time researching, I have come to the conclusion that there is one method which is suitable for protecting the inside of 4130 tubing.  Swash/Swish Boiled Linseed Oil around the inside of the tube. In practical terms it is easy, cheap and effective. The literature mentions that it is only necessary on the structural lengths such as longerons. The reason for using boiled linseed oil rather than just linseed oil is that the boiled variety dries quicker rather than staying too wet or runny.

I will use this method where possible and have recently found that it is available in some of my local hardware stores. Locally, I get it from Bunnings or I can also get it from Blackwoods (p/n: 03972708) here in Sydney. I believe that this product is used within the woodworking industry and is fairly common.

Jabiru engine in-hand

I have purchased a Jabiru 2200 engine for the Sonerai. It has the original smaller heads and only 63 hours on it.  I will have it in storage until mounting/fitting time, which should be about 12 months away.

My Sonerai

An article about a very happy Sonerai builder called "My Sonerai". The article comes from the May/June 2006 Edition of Orange Aeroclub Newsletter based in NSW, Australia. A pleasant and informative story indeed with some amazing performace figures.

Metal tubing arrives

Today, I received most of the metal I require to build the steel tube fuselage for the Sonerai. A few short pieces are on backorder. The metal was delivered direct to my house on the "Performance Metals Australia" delivery truck. This certainly made the logistics alot easier for me because I don't think I could have carried the raw long lengths on my box trailer or my car roof. I must say that Matt certainly does do a good job of running the company. Included with my delivery were some complimentary lollipops and a pen, a nice touch. I highly recommend using Performance Metals Australia for all your metal requirements. Their service is second to none.

Colin

Just before I started this Sonerai blog I went to visit Colin in Wollongong. I found Colin in the Sonerai.net roll call.

Here are some pictures of Colin's project. It is also a Sonerai 2 LS and at the time of visiting his fuselage was completely welded and the wings were complete. Covering, canopy, FWF, engine, and fuselage covering were not complete.