Building Soon

[jw wright]

Gentlemen,

I expect to be getting my Sparrowhawk package very soon, and I was wondering what the consensus is about anodizing or powder coating, and what parts should be doon.

Thanks
JW Wright

[StanFoster]

Jeff:

I am looking forward to seeing you progress on your SparrowHawk. Please call, e-mail me for any questions you have while building it. I want to provide plenty of service after my sale of the kit to you. You should find it a very rewarding experience building....and just you wait till flying it. I have never been so satisfied with a machine in all my life. You will find that you are basically going along for the ride most of the time.

Best to you on your building progress.

Stan

[automan1223]

I got the "factory" powder coating that was supplied with the kit. All the steel parts are coated great, the aluminum has a lot to be desired. I called them about doing an anodizing job and they did not want to do it saying it makes the aluminum brittle. I have never never seen a failure or cracking,

Air command and other builders have gone the anodizing route with great results, so I dont know. I might find a high quality powder coating firm to do your airframe but, to keep things simple I might do paint, can be repaired and touched up without major work....just chose a proven system and dont cheap out on quality materials.

Jonathan

[jw wright]

Thanks Jonathan,
I have seen a couple of builders websites where the builders complain about chipping. One claimed that he could repair it but never showed the results. Has anyone had any experience with what I will refer as a rubberized paint?
JW

[Racer]

To make paint "Rubberized paint the painter adds a flexing agent into the mixture, This is used often when they paint Polly urethane bumpers on cars.
I am going to try something different on my Gyro in the next few weeks you may be interested in, I am going to spray on a clear adhesion promoter on the bare aluminum, spray on a transparent paint (Candy Blue) then I am going to seal it with "Clear Bra" material. I think this will give me a very nice looking finish that will be very damage resistant. Another benefit is I will still be able to see the aluminum through the paint so if a crack does form for some reason I will be able to visually see it. I have not done this yet but I will let you know how it works out.

[jw wright]

Racer,
I would be very interested in seeing or hearing how you come out with this proccess. Is clear bra a technique or brand name?

JW

[Racer]

This is a very tuff clear adhesive film made by 3M. You see this on many cars along the leading edge of the hood and front tips of the fenders, Also applies over headlights to protect from rock chips and oxidation. Once applied it is nearly invisible but provides excellent protection. One disadvantage is you will have either a seam or overlap because it is applied in sheet form and not sprayed on, But I am going to put my seam on the bottom side so it will be out of sight.

[scottessex]

Johnathan, look up a good automotive speed shop that does powdercoating stay away from the industrial shops. Here in Atlanta I have had Conyers Speed World do some jobs and they did John Stevens first Screwdriver, they do very nice work and actually take pride in doing a good job.

Paint will work but you must make sure you use the proper primers etc. or chipping will be an issue.
Cost will be about the same.

[Racer]

Just a quick note, Powder coating is essentially coating the part in plastic. They attract the plastic beads to the part by giving the part a positive charge and the plastic beads stick to it like a magnet, Then very carefully they move the part into an oven and bake it to the point that the plastic beads melt together. When the part cools you have a plastic coating that is very strong and is resistant to almost everything. It is a bit more technical than this but I hope you get the basic Idea.

[giro5]

I personally do not have any particular knowledge of the subject but I read somewhere on the forum that powder coating of heat treated aluminum can susbject the part to heat very near to that of the origional heat treating which probably would not be good. Anodizing is an acid etch on the surface of the aluminum but it is so thin that I do not think it would affect the aluminum part but again I am no expert. I do know it does not come out shiny like paint but could probably have clear put over it and it would be a good surface to paint. I have my mast, keel, and landing tube anodized. I plan to have all of the steel parts powdercoated eventually.

[Robert G. Stark]

Power coating of aluminum structural parts will change the temper and weaken the part because of the soaking temperature. Stay away from the power coat on aluminum. Anodizing will not change the strength, Anodizing
in a process of oxidizing the surface of the aluminum, then possible dying it a color, then sealing the surface. I do small parts in my shop using gold dye.
You have to have the part CLEAN before you start this process. Handle parts that have been cleaned with gloves CLEAN gloves on. Skin oil will make stains that show.

[dynacure]

Many of the problems with coatings have to do with an unclean surface.
Preparing with ScotchBrite soaked in aceton or MEK would be a good thing.

A electrolytic form of powdercoating is called cataphoresis, what results in a well sealed thin layer in- and outside; sounds perfect to me.

I 've found a lot of information concerning DIY powdercoating. Anybody on the forum who has first-hand experiences with it?

Kind regards,
Willem