Aircraft Spruce and Specialty Co

[aviator25]

I have the 4130 fuselage on my home build ready for priming. Do I need to prepare the 4130 tube serface for priming? and what is the best primer to use?
Also is Zinc Chromate an acceptable primer to use on 4130?

[Craig]

Aviator, by all means prep the surface! If you have a good autobody shop around, they will bead blast it for a nominal sum - usually $100-200 or so.
After the tubing is all cleaned by bead blasting, do not hesitate in priming it. Wipe the tubes down with alcohol or another suitable solvent, then prime with a good epoxy primer. I use Polyfiber zinc chromate epoxy - a bit pricy at $63/qt, but it lasts about forever, protects the metal well, and is unaffected by the glues and solvent used in covering.

Be sure that ALL welding of attachments, etc. is done before priming - put in plenty of ground attaching points around where your instruments and stuff goes. After it is primed, the only way to attach new stuff is with cushion clamps or similar - you would have to scrape all the epoxy and top coat paint off a large area to weld anything else on!

Any sub-assemblys can be coated when they are finished - your tail feathers, controls, etc.
_________________
Craig
NX96CW