Surface preperation for 6061 T6

[Vorticity]

G'day,

 

I am trying to get my head around corrosion protection options for aircraft built with 6061 T6. There has to be plenty of savannah/701 builders around SEQLD in particular that can help me out.

 

There are a range of options being provided. Some people will not budge on the etch/alodine/zinc chromate or zinc oxide process. I contacted sonex and they said not to do anything, 6061 T6 is corrosion resistant. They back this up with the fact that none of their aircraft are treated and they have had no issues. I dont know if ohio is a good judge for the conditions of heat and humidity found along the QLD coast.

 

My preference at the moment would be to prep with precote and then treat mating surfaces with zinc oxide. I noticed on the canzac video on building a 701 rudder they used a product called cortec 373, which sounds great but I cant find any local info on it.

 

So I guess my questions are:

 

- What are people using on their 6061 built kits and why?

 

- Where have you sources the supplies, if possible in SEQLD?

 

All responses would be greatly appreciated!

 

 

[facthunter]

general comment.

 

Corrosion "resistant" is not corrosion proof. Moisture and salt would be significant, more than heat, in causing corrosion.. Good aircraft are corrosion proofed at assembly. (The ones that are used for floats particularly). Absolutely, if in contact with sea water. Fresh water you might get away with not doing it. The C-180,185's that were put together for salt conditions, do not suffer the deterioration and corrosion damage that the ordinary Cessna's did. The Piper Commanche was treated extremely well for corrosion at assembly and survives very well especially when compared with some of the Cherokee models made subsequently which can have serious problems. You have this opportunity to do this at assembly which will add value to your aircraft and piece of mind as time goes on. It would also add a little weight and cost, but I feel that it is worth it.

 

The only skin material that used to be considered to have some resistance to surface corrosion was a product called "Alclad" which had a thin film of pure aluminium on it. When you drill holes in it or get it impacted by stones you negate that. It is only mechanical protection, not chemical or galvanic. Nev.

 

 

[Thruster87]

G'day,I am trying to get my head around corrosion protection options for aircraft built with 6061 T6. There has to be plenty of savannah/701 builders around SEQLD in particular that can help me out.

 

There are a range of options being provided. Some people will not budge on the etch/alodine/zinc chromate or zinc oxide process. I contacted sonex and they said not to do anything, 6061 T6 is corrosion resistant. They back this up with the fact that none of their aircraft are treated and they have had no issues. I dont know if ohio is a good judge for the conditions of heat and humidity found along the QLD coast.

 

My preference at the moment would be to prep with precote and then treat mating surfaces with zinc oxide. I noticed on the canzac video on building a 701 rudder they used a product called cortec 373, which sounds great but I cant find any local info on it.

 

So I guess my questions are:

 

- What are people using on their 6061 built kits and why?

 

- Where have you sources the supplies, if possible in SEQLD?

 

All responses would be greatly appreciated!

6061-T6 will corrode, I've been building a 601xl from 6061-T6 for the past yr and a couple of sheets left untreated started to corrode within 6 months ,even thro they where wrapped in clean dry paper and indoors so protection is a good idea.Anywhere along the coast lines it will corrode within a few months if left unprotected, inland another story [longer times]. Cheers

 

 

[Vorticity]

I was interested in the practicalities of the process; I'm interested in what people are actually using, I know that 6061 will corode. There has to be plenty of Savannah builders out there who had to face this decision?

 

 

[RetiredRacer]

Vorticity, I'm building a RV9a and I went through what you are going through.

 

I checked out all the RV web sites and asked questions.

 

This is what I came up with. I've been told it is a bit of an overkill but we plan on doing some overnight stays at Island and beach strips.

 

I finished up getting Turco 1 which is a acid cleaner and deoxidizer. and Alodine 1200s used for producing paint bonding, corrision resisting coatings on alloys.

 

I got these from "Avanti Aviation" on the south side of Brisbane, here is their web address AVANTI Chemicals

 

I got the Alodine in powdered form.

 

Just some food for thought.

 

Bob Dennis

 

 

[Thruster87]

Prekote is a product that can be used instead of the alodine process.It is a water based product and is a lot easier to use then alodine.I used it on the outside surfaces of the wings.Time will tell how good it is.You may get what you need from the following mob:

 

Aviall Australia Pty Ltd

 

• Aircraft Equipment & Maintenance
   
   
  

 

 

 

 

Address:Aviall Australia Pty Ltd, Archerfield Airport, Qantas Avenue, Archerfieldshow map & street view

 

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Contact: Phone (07) 3277 8322

 

 

[Vorticity]

Thanks very much guys, the precote sounds great. I'll chase up those susuppliers.

 

 

[Vorticity]

I need some feedback from all those 100s of very happy savannah builders out there!

 

After checking out the savannah site in the US I noticed that the kit is supplied with a non toxic paint for application to the joining surfaces within the structure. On the website they say the same thing as sonex; 6061 doesnt need the protection but they apply this grey paint anyway. The same is said in the rudder assembly video for the CH-701 and they also apply a non-toxic compound to the joining surfaces.

 

Ive been in contact with the Oz savannah agent and there is 1kg on its way to me.

 

As final piece if mind, how are all your savannahs going out there? They would have to be a great fleet of aircraft to collect info from as there are so many flying from all types of locations. If there is anyone from up north I would be particularly interested.

 

At this stage I am very happy to go the ICP method on fuse and wings as I can get access to apply ACR50 or corrosionX type compounds....just wondering about the small bits like rudder, flaps etc.

 

I'd love to hear from some of you savannah owners out there:wave:

 

My beloved fisher mk1 sold yesterday and will be heading home to casino again very soon. It seems that 'dudly'was only taking a 1 year sabatical in QLD before heading home. My sonex kit arrives in Brisbane this week. Im like a 4 year old waiting for christmas day!!!

 

 

[Guest Walter Buschor]

Hi Vorticity,

 

I do have a Savannah Vg and I did undercoat it with the "grey"stuff. None of the people I know who built savannah's have used the Supplied black goo.

 

It does work really well. There are some very small "blisters" on the finish but this is not due to corrosion but rather less than perfect surface preparation. We do fly to sandy beach strips but so far have not had any issues regarding corrosion.

 

I do however wash the plane after returning from a beach - trip.

 

I did use approx. 20 ltrs of the undercoat on the plane and sprayed all parts before assembly. This should make it last for "ever".

 

I do now of other owners who used the same stuff and are very happy with it.

 

If you're interested I' more than happy to find out the product name.

 

pls. don't hesitate to contact me

 

the grey nomad