Primer for Float Painting

[MT12]

Hey all,

I acquired a set of Edo 2000's for my newly flying PA-12 project, they are in good shape so I decided to clean them up and prep them for install early next spring. I had them media blasted with crushed walnut shells and they turned out great, the blasters were able to blast down and leave much of the original zinc chromate looking primer. Some elbow grease and a few hours later they are mostly silver, I figure where the chromate looking stuff wants to stick it won't easily peal in the future either.

From reading a bunch of other threads my next step seems to be etching and alumadyning them, shooting some primer and float lacquer. I've been using the PPG DX 303 and DX 330 with good luck for cleaning and etching. In the past I have used OMNI, 2 part epoxy primer on the main plane metal parts with good luck. I'm hoping for one last blast of warm air here next week for the painting.

So my questions:

Do floats take any special kind of primer under the float lacquer? I've ordered lacquer and thinner from Spruce.

And while I'm at it,

Is one type of pump out plug better than any other, I'm thinking of the $3 kind.
What length of float pump is recommended: 15, 24 or 36".

 

[Bearhawk Builder]

Southern Polyuerethanes Inc. Very nice epoxy, used in marine applications too

 

[stewartb]

Use aluminum pump-outs. The plastic ones get brittle and crack allowing water in, and the cracks are usually hard to see. As for pumps? Bigger will push more water but is harder to stow. I like medium size and always kept mine in the float lockers, which is something you really ought to consider adding before you paint.

 

[skywagon8a]

Check for leaks before you paint. Also check the inboard row of rivets which hold the hydro boosters to the flat skins on the bottoms. That joint doesn't have any structural support so tends to loosen and leak with the flexing of the bottoms. Riveting a piece of angle stock to the inside along the rivet line will stiffen the joint.

 

[Alex Clark]

Iron Inge and I used fuel tank sealant from NAPA. It is supposed to go inside a fuel tank. We first did the rivets ( as seen here ) and a year later painted the entire bottom of the floats with the stuff after it was etched and alu-dyned. Since it has lead in it, it seems to work..

 

[MT12]

Thanks all, will 3m 5200 hold primer and final lacquer coat, or will 'paint'peal off of it

 

[stewartb]

Paint will stick but any time the paint is harder than the substrate the paint can crack. Minimize the 5200.

 

[MT12]

Thanks all for the coaching. I got the floats all cleaned up with walnut shell media blasting and some sanding with green scrunge pads. As recommended on another post i checked for leaks by pressurizing them with a shop vac exhaust and soapy water.

I then used 3m-5200 thinned on one float and sucked it into cracks with vacuum pressure to seal the few seam leaks i found. At that point i realized the 7 day cure time of 5200 and used pro-seal on the second float with equally good results.

I etched with 303 amd 330 alodine stuff; epoxy primed with Omni 2 part epoxy thinned with acetone as directed and sprayed them
outside on the last 65 degree day of the year and the last day before our first real snow of the year. They now sit in the corner of the hangar til its warm enough to spray on the randolf float lacquer i have for them. Thanks again

Doug

 

[skywagon8a]

MT12, If possible try to spray on the float lacquer soon so that it can cure for a few months before going in the water. Some water will lift fresh lacquer.

 

[stewartb]

Do you expect to scuff the epoxy primer before painting? I’ve never painted over fully cured primer.

 

[MT12]

I got a surprize today, our forecast is for 64 today, so even as i type i am scuffing it with scotch bright, hope to spray this p.m.

 

[MT12]

Yee Haw, the wx was as forecast, and got them all laquered up. Thanks again for the tips and advise.