sanding primer before paint?

Daywalker

Member since
September 2003
From: South Central Wisconsin

sanding primer before paint?

Posted by Daywalker on Thursday, July 19, 2007 9:31 AM

I have never really primed my aircraft before painting until recently, and was wondering what you guys did to your primer before painting commences. I sprayed on my Mr. Surfacer 1200, and was wondering if I should give the plane a final sanding before I start to paint. The finish of the primer looks fairly smooth as it sits, as I am afraid of sanding it off the edges of protrusions and having to do it over again. Do you sand yours before paint, or do you just start painting over the primer? TIA!

Frank

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ruddratt

Member since
February 2006
From: Smithers, BC, Canada

Posted by ruddratt on Thursday, July 19, 2007 11:05 AM

Frank, the only time I'll prime anything is if the top/finish coats are acrylics, and I'll use any MM light grey flat enamel I have handy at the time (I've yet to try Mr. Surfacer for priming). With the right thinning ratio & pressure they usually dry quite smooth and I can then proceed right to my top coats, but on occasion I've felt the need to lightly go over some areas with a Scotchbrite pad until I see a dull sheen. If I happen to sand down to the bare plastic (which can happen in the areas you mentioned), then I'll re-prime that area only if I intend on masking it and there is a risk of lifting the subsequent acrylic coats.

Mike

"We have our own ammunition. It's filled with paint. When we fire it, it makes pretty pictures....scares the hell outta people."

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Daywalker

Member since
September 2003
From: South Central Wisconsin

Posted by Daywalker on Thursday, July 19, 2007 11:25 AM

Thanks Mike! I like that idea on the scotchbrite pad, should work a treat to "knock back" the primer a lil'. I'll let you know how it goes, but may be a few days before I get to it.

Frank

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ruddratt

Member since
February 2006
From: Smithers, BC, Canada

Posted by ruddratt on Thursday, July 19, 2007 11:31 AM

Happy to help, buddy! I got the idea for using Scotchbrite from Marc (wing nut). They work like a charm. Light pressure is the key. Thumbs Up [tup]

Mike

"We have our own ammunition. It's filled with paint. When we fire it, it makes pretty pictures....scares the hell outta people."

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Anonymous

Member since
November 2005

Posted by Anonymous on Friday, July 20, 2007 10:06 PM

I always wet sand my primer with 600-1000 grit if I'm spraying a gloss paint, i.e. auto models. It really seems to make a big difference when I apply the topcoats. Smoother finish, and rubbing out the finish is easier. Are you applying a gloss or flat paint, or something in between?

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Daywalker

Member since
September 2003
From: South Central Wisconsin

Posted by Daywalker on Saturday, July 21, 2007 12:19 PM

Richard-

I am spraying a semi-gloss (Gunze-Sangyo) aqueous paint. I knocked it down a lil' with a worn out scotchbrite pad (thanks Mike!) and am hoping to start painting it next week. I'll post how it goes!

Frank

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wing_nut

Member since
April 2005
From: Piscataway, NJ!

Posted by wing_nut on Monday, July 23, 2007 7:45 AM

Daywalker wrote:

I knocked it down a lil' with a worn out scotchbrite pad

Since you have already done it the point may be moot, but make sure the paint is really cured or the Scotch-Brite can really get in there and take it off or leave some nice scratches. That's how I do my winter camo.... a light wipe with the pad before the paint is fully cured.