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Laying out multiple colors with base/clear

Maxrate

Well Known Member
After reading several auto paint threads I wanted to see what others have done laying out multiple colors using base coat/clear coat. Most product sheets (PPG and SW) give a maximum time of 24 to 48 hours before clearing your base. After spraying several fenders as a trial to the plane it became clear to me that I will not be able to spray the whole planes primary color, install the tail and cowling, lay out the stripes and mask the whole plane again, spray the stripes and clear coat the final product within that time window. This process will probably take me a week. BTW wings will be shot at a different time from the fuselage as not to confuse.

I have read of something called intercoat clear, but have no experience with it. Anyone that has laid out several different patterns using base clear care to weigh in would be appreciated. Also I plan on applying PPG Deltron base/and high solids clear.
Thanks all
 
I used SPI base and clear on my 10. I was a simple two tone and able to get it all on in 24 hours. Can't speak to other mfr's but the owner of SPI told me that there are no adhesion issues if you go beyond the 24 hour limit. The real issues around the 24 limit are airborne contamination (you would be amazed at the amount of invisible contamination floating around in our outside air) and UV light (this is a "no no" on base before clear application), as they can impact adhesion between the base and clear. In a controlled shop envionment that can control those factors, he said it would be fine to go several days or longer.

Intercoat clear would work, but is a major hassle if your doing lots of colors and even more changes in depth that will have to be sanded out later. I have never used it so can't really comment.

One thing that is important is base to primer adhesion. Even though the SPI epoxy window is 7 days, it was recommended that I get the base coat on within 24 hours of the epoxy for best adhesion. I believe the chemical bond strength continues to drop over that 7 days.

Activating your base may not help if you get too far outside the window, if you plan to do that.

Larry
 
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Thanks Larry, just the info I was looking for. I plan on applying a main color with two separate tone stripes. Not real busy, but time consuming. 24 hours just won’t be sufficient time to complete. The project will be in a controlled booth the whole time.

The intercoat clear is many more man hours of sanding and prep work to lay out the stripes and apply the final clear coats, not to mention added weight.

Thanks for weighing in!
 
Something I learned watching a much more experienced painter work is to work in reverse of what you think. The smaller the feature on the paint the sooner in the process it is done.

For example a stripe would be painted first, then masked off and the next larger feature painted. Once I saw that technique it made much more sense.
 
Did my fuselage one weekend and wings another weekend. Its a lot of work. Spent 27 hours innone weekend just spraying fuse. You can spray a coat of clear in between coats then just wet sand before you continue spraying. Good luck.
 

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Agree with what Jeff wrote. Spray the small details first. For example a full length stripe being 3/8" wide with a contrasting 3/16" border stripe would be done as follows.
On your primed and prepped service and without masking, spray the base coat colour where your first stripe line is wanted. Don't worry about the overspray. The basecoat flashes off fairly quickly, so once dry to the touch very carefully lay out the painters 3/8" wide masking tape on top of your first layer of basecoat. Some painters will pass the sticky side of the paint over their hand so its not so sticky. You don't want to jam the tape into the fresh basecoat. You want a nice clean edge on your paint with no bleed through under the tape, but don't get carried away pressing the tape hard against the fresh basecoat.
Now that you've taped for your first stripe colour, spray the preferred border colour over top of your freshly masked first stripe layer. Again, don't worry about overspray.
For a 3\16" contrasting stripe either side of the first 3/8" stripe, you will need to very carefully and accurately lay 3/4" tape over top of the first stripe layer.
You will still be able to see the edge of your first layer of masking even though you've just sprayed over it. Measure 3/16" very carefully from the edge of the painted masking, using pieces of tape to temporarily mark reference points to aid in very carefully placing the 3/4" painters tape. You want to be careful here, because if you aren't accurate laying the second layer of tape over the first first layer, your stripes won't be perfectly aligned. I have permanent proof of that... Remove your reference marking tape before you spray again. After accurately placing the 3/4" tape, can now spray the primary colour(s)
Though I haven't sprayed an airplane have done a full sized pick up with four colours and two coats of clear in one day. Its a pile of work and the clock starts ticking once you start, so pays to be organized before you start.
When layering on the basecoat colours and after spraying the clear, there will be ridges between the different the layers. The final wet sanding and buffing out of the clear coat will blend and smooth everything nicely. Painting the smaller details first is definitely the way to go after I've seen my results. Hope this helps someone out.
Cheers
 
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I’ve got a couple of old fenders. I’ll have to try a layout and do what you recommend. Thanks
 
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