Composites Central


Reply
Old 10-21-2013, 12:40 PM   #1
berridos

Composites Expert
 
Join Date: Feb 2011
Location: madrid
Posts: 202
Thanks: 2
Thanked 3 Times in 3 Posts



Default Plug Finish

Hi everybody
I finally finished my horisontal stabiliser plug to take molds off. I sprayed the plug with 2k poliurethane paint. Layer after layer my spraying technique improved but is far from perfect. The colour is black brilliiant. How should I proceed? Can i sand the paint with ever finer sanding grades and finally polish until it gets briliant? Or should the paint be perfect right after painting without aftertreatment. Some special tool or product you can recommend to polish?
berridos is offline   Reply With Quote
Old 10-21-2013, 01:36 PM   #2
Michiel

Composites Expert
 
Join Date: Jul 2012
Location: Netherlands
Posts: 452
Thanks: 7
Thanked 42 Times in 35 Posts



Default

The best painters in the world never get a perfect finish, they also polish to get a perfect result. Your starting grid depends on the finish off your paint. Start around 600, if the finish is flat fast (no orange peel) move up and if not move down in sanding grid. You've to get the feeling for it.
Michiel is offline   Reply With Quote
Old 10-21-2013, 01:49 PM   #3
berridos

Composites Expert
 
Join Date: Feb 2011
Location: madrid
Posts: 202
Thanks: 2
Thanked 3 Times in 3 Posts



Default

Ok got it. Thanks. I have very little orange peel but still some. Are there special polishing compounds for 2k poliurethane paint? Should i equip my mirka sander with a special polishing disc?
berridos is offline   Reply With Quote
Old 10-23-2013, 01:25 AM   #4
Michiel

Composites Expert
 
Join Date: Jul 2012
Location: Netherlands
Posts: 452
Thanks: 7
Thanked 42 Times in 35 Posts



Default

The best way is to use soft sanding pads. M3 (there are other brands) has them specialy for 2k polishing, but they cost around €70 for 15 pieces. There are to many polishing compounds and a lot of them are fitted for 2k paint. It totaly depends off your budget and the expensivest is not always the best.
Michiel is offline   Reply With Quote
Old 10-23-2013, 12:34 PM   #5
harrisonaero

Moderator
Member
 
Join Date: Feb 2012
Location: CDA, ID
Posts: 121
Thanks: 12
Thanked 19 Times in 15 Posts



Default

IMO for an airplane you're not after a perfect tooled finish. Most likely you'll end up knocking the final product down with 120 grit before you prime and paint anyway.

So my gut says you're overthinking it and to move forward with rapid and steady speed and get on the next mold.

Don't forget it's a *huge* project to even build an airplane, let alone build one from scratch, let alone design one and then build it from scratch.
harrisonaero is offline   Reply With Quote
Old 10-24-2013, 01:11 AM   #6
nash

Member
 
Join Date: Apr 2011
Location: Italy, close to Cremona
Posts: 80
Thanks: 18
Thanked 10 Times in 9 Posts



Default

Berridos,

Don't use mirka sanding disks, make yourself a flexible sanding block like say 30cm long, 6cm wide, and have a velcro on one side. On that you can stick flat and long strips of wet/dry sand paper. Then the proper technique will be to keep the longer length of this block (the 30cm side) parallel to the spar and while keeping the block in that that position move it at 45deg angle to the spar, first one side then the other. This will enable you to move along the contours properly.

Hope this helps,
N
__________________
www.nashero.com
NASHERO -- Highest quality, safe, sleek, efficient, comfortable, spacious, intuitively easy and fun to fly aircraft
nash is offline   Reply With Quote
Old 10-24-2013, 02:20 AM   #7
berridos

Composites Expert
 
Join Date: Feb 2011
Location: madrid
Posts: 202
Thanks: 2
Thanked 3 Times in 3 Posts



Default

Hi have a hand sanding block but its a nightmare for sanding 2k poliurethane paint. Can i polish with a mirka ceros sander or a re the rpms not appropiate for polishing?
berridos is offline   Reply With Quote
Old 10-24-2013, 08:05 AM   #8
nash

Member
 
Join Date: Apr 2011
Location: Italy, close to Cremona
Posts: 80
Thanks: 18
Thanked 10 Times in 9 Posts



Default

Use wet and dry paper, wet it some, and keep at the sanding, eventually it'll work out. Ask your local auto paint Shop what they use and how they do block sanding for fine finishing. Knock down all the orange peel and of necessary, re spray, then do the same stuff again. To get a high quality finish, you need to take your time.
All the best,
N


Sent from my GT-N5100 using Tapatalk 4
__________________
www.nashero.com
NASHERO -- Highest quality, safe, sleek, efficient, comfortable, spacious, intuitively easy and fun to fly aircraft
nash is offline   Reply With Quote
Reply

Bookmarks

Tags
finish, plug

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -8. The time now is 02:42 AM.
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2017, vBulletin Solutions, Inc.

Inactive Reminders By Icora Web Design