Do all the aluminum kit parts come bare? Is it optional to order them alodined or some equivalent coating. What do you guys recommend for corrosion control.
Do all the aluminum kit parts come bare? Is it optional to order them alodined or some equivalent coating. What do you guys recommend for corrosion control.
Aircraft grade 2024,2075, (T-3,T-6) etc. aluminum is cadnium plated and retards corrosion. When you attach 2 pieces of metal with fasteners there is friction and if moisture gets in there it will eventually corrode. Dissimilar metals; even titanium hi-loks with aluminum, will cause corrosion on the aluminum.
Alodine etches the surface so that a primer can be applied. If you use alodine you also must prime!
I know that when the metal isn't exposed to weather there is less likely hood of corrosin but anywhere there's moisture oxidation occurs and when the metal is aluminum its called corrosion if it's iron it's called rust and if it's composit it'll blow out.
I elect to prep and prime the metal.
Dave
Sorry for the delay in replying Drag;
Yes, as a general rule all of the aluminum parts in the kit will ship bare. That certainly does not mean that you cannot prime them after you get them though. As far as ordering them primed, I don't think that there is an option for that, let me see if I can get Mitch to give his input on that, he manages the kit program and would be able to say for sure.
Pete D.
Drag
At CubCrafters we use 4 different types of aluminum and as you probably already know, the reason the Carbon Cub is so successful is the major weight reduction we have been doing. The aluminum types are 6061-T6 sheet or 6061-T651 in plate and bar, this aluminum is widely used in aviation and other applications when you hear aircraft grade aluminum, 6061 is known for its strength and corrosion resistance. 5052-H32/H34 which we use primarily for non structural applications and is found in many places such as electrical boxes, boat hulls, and where maximum corrosion resistance is required. 2024-T3 which in the bare condition does not have good corrosion resistance, but when you use alclad which adds a few mills of pure aluminum to each side of the bare aluminum, it becomes very corrosion resistant. 7075-T651 which has poor corrosion resistance, but is extremely strong and is widely used as a direct replacement for mild steel. The parts that are made of 7075 and sold in the kit are double primed and wet assembled for maximum corrosion resistance. At Cub Crafters we are working hard to provide a balance between maximum corrosion resistance and minimum weight. We will prime the aluminum parts in a kit, but it will add a significant amount of weight and cost.
Mitch
I'd like to get my kit in a "full metal jacket" configuration. Maybe we can coat the whole thing in stainless steel?
Hey Mitch, thanks for the info below on the corrosion discussion. Having read through all that and hearing your comments on the phone the other day, is there any merit (or benefit) to considering applying some corrosion protection to parts of the wings after assembly?
As mentioned, my concern is over the 2 to 3 months my Cub may be sitting on floats on a northern lake. The rest of the year it will be tucked away in a hanger in Arizona where the humidity is single digits most of the year.
Mitch or Pete;
If a builder desires is there any merit to applying Alodine for better resistance to the elements and primer adhesion?
At the factory when a customer wants to have their wings corrosion proofed, we use a PPG self etching primer that would eliminate the need for alodine. We also prime all of the parts individually and when the wing is assembled we go back and spray all of the fasteners and rivets. It is very time consuming and adds a fair amount of weight. As the manufacturer, the builder could apply either method of corrosion proofing.
I have never seen 2024 or any other alloy, commercial or aircraft grade, that comes cadmium plated. Many of the alloys that are more susceptible to corrosion can be purchased with a thin pure aluminum layer on both sides for corrosion protection. "Alclad" is the trade name for this process that I believe is held by Alcoa.
Paul K.
The Alclad 2024 that Paul is referring to can be found in AMS-QQ-A-250. The cladding alloy appears to be 99.3% minimum pure aluminum and makes no mention of cadmium among the other elements.