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Let'sgoflying!

Let'sgoflying!

Touchdown! Greaser!
Joined
Feb 23, 2005
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west Texas
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Display name:
Dave Taylor
I have been pondering the things that go into a good paint job lately, just for interest's sake. It's widely established that good paint is a mix of black magic and sorcery, with some alchemy thrown in the mix. If you've ever messed with even a small pot of paint, and a paint gun, you'll know what I'm talking about. (Basically impossible to do a great job if you are new at it) Yes, there is lots of science involved but there is a heavy dose of artistic experience required.

One topic that struck me tonight was regarding two-component polyurethane. The old Imron (is it Axalta now?) has instructions on their cans, for example, of how much activator to mix with the paint.
If you ever had a can of PU paint you'd see how the paint, sans activator, dries to a nice gloss on the rim of the can, or any drips you caused on the outside of the can. Makes me wonder what you would be sacrificing if you were to apply the unactivated paint? Paint only, and no activator. Would you lose flex? Would it fail to adhere and peel later?
 
Let'sgoflying! said:
If you ever had a can of PU paint you'd see how the paint, sans activator, dries to a nice gloss on the rim of the can, or any drips you caused on the outside of the can. Makes me wonder what you would be sacrificing if you were to apply the unactivated paint? Paint only, and no activator. Would you lose flex? Would it fail to adhere and peel later?
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Normal solvents would remove the paint. The paint shop I'm familiar with matches paint for repairs by using dabs of un-activated paint. They literally stick a fingertip in the un-activated paint and dab it onto a painted section of the airplane to see if they correctly matched the tint. When the paint dries, they can see if they need to further adjust the paint color. Once they are satisfied with the match, they just use MEK or another solvent to wipe off the un-catalyzed dabs of paint.
 
Let'sgoflying! said:
dries to a nice gloss on the rim of the can,
Click to expand...
Let'sgoflying! said:
Paint only, and no activator.
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You're intermixing drying with curing. While it may dry to the touch it will never cure 100% (harden, bond) especially with a 2-part paint like urethane. Where it gets real fun is with the latest water-borne paints vs the solvent based paints.
Let'sgoflying! said:
Makes me wonder what you would be sacrificing if you were to apply the unactivated paint?
Click to expand...
The entire paint job. Have seen the results of no activator several times to include my own work.:rolleyes:
Let'sgoflying! said:
It's widely established that good paint is a mix of black magic and sorcery, with some alchemy thrown in the mix
Click to expand...
Let'sgoflying! said:
Yes, there is lots of science involved but there is a heavy dose of artistic experience required.
Click to expand...
As with any skill its all about learning the basics. And now with youtube and the like all the secrets are out. So use good equipment, know your paint, manage your air supply, and practice x10. A good practice medium is paint the wax side of freezer paper. I still use it to set my gun up.
 
Let'sgoflying! said:
I have been pondering the things that go into a good paint job lately, just for interest's sake. It's widely established that good paint is a mix of black magic and sorcery, with some alchemy thrown in the mix. If you've ever messed with even a small pot of paint, and a paint gun, you'll know what I'm talking about. (Basically impossible to do a great job if you are new at it) Yes, there is lots of science involved but there is a heavy dose of artistic experience required.

One topic that struck me tonight was regarding two-component polyurethane. The old Imron (is it Axalta now?) has instructions on their cans, for example, of how much activator to mix with the paint.
If you ever had a can of PU paint you'd see how the paint, sans activator, dries to a nice gloss on the rim of the can, or any drips you caused on the outside of the can. Makes me wonder what you would be sacrificing if you were to apply the unactivated paint? Paint only, and no activator. Would you lose flex? Would it fail to adhere and peel later?
Click to expand...

The paint will take forever to dry, might never cure all the way without activator. It will under preform and would waste all the time that was spent on preparation which is 90% of the work involved in painting.


Good paint is achieved by hard work, nothing magic about it.
 
Read, read, read… it’s not that much dark magic. I’ve repainted my interior as well as a couple panels of the exterior and gear legs on my c140. I’d never touched a paint gun before, the jobs turned out just fine. I maybe had $60 into the set-up - just from harbor freigh, their purple gun is very popular in the experimental world. I made a few errors, none that weren’t correctable with some wet sanding. If you want to just do touch ups try even just a Testors airbrush… a hit of a mist of the reducer after painting really brings a gloss out and erases minor rookie errors.

the stuff I got my local maps mixed for me and it was just three parts, the cocktail wasn’t difficult… there were $1 cups with marks to help.
 
I did all of this as my first experience with a paint gun…

5231F65B-3A7B-4900-8ED7-FD12A8D2AA31.jpeg 4CAB58FD-A6ED-4F13-BBF2-79398ACEC440.jpeg 0F6C8786-6E1E-41EC-BF7E-B13AE4E076B9.jpeg 544B847E-B1DF-4A50-88D9-574EB3970179.jpeg 76DE2FBC-9E72-4A87-83AC-DB2CBE7107D5.jpeg 4234229D-8675-44E3-81F1-7EF75F7729BC.jpeg
 
Hey Huckster, you painting or COVID adverse?

BWAHAHAHA BWAHAHAHA

I crack myself up.... and DANG, that looks good!
 
On a serious note - modern two part paints are remarkably forgiving (if you avoid metallics) - when I did a sailboat I ended up using a brush for the boot stripe - you couldn't tell that it wasn't sprayed it flowed out so nicely.
 
Thanks guys. The photos of the protective gear reminded me to ask if cyano-paints are still in use or are they mostly gone for safety reasons? I know that water based paint is so much less intoxicating, it's a joy to be around compared to other solvent-based paint.
(how is that 140 front end suspended?!)
 
Some airlines use rollers to apply to avoid overspray issues and allow folks to work

on the aircraft while small area paint projects are going on.

I’ve seen a couple of light aircraft done the same way that looked good.

My belief is the flow-out characteristics of the paint is key.
 
Let'sgoflying! said:
Thanks guys. The photos of the protective gear reminded me to ask if cyano-paints are still in use or are they mostly gone for safety reasons? I know that water based paint is so much less intoxicating, it's a joy to be around compared to other solvent-based paint.
(how is that 140 front end suspended?!)
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Its rednecked…. She’s sitting on cement blocks :). Had to put wheels on my rusted out Camaro to get the blocks tho :)
 
Let'sgoflying! said:
The photos of the protective gear reminded me to ask if cyano-paints are still in use or are they mostly gone for safety reasons?
Click to expand...
Isocyanate-based polyurethanes still account for half of the higher-end coatings used today. In my opinion they are the best at what they do even today. Unfortunately, I got sensitive to isocyanates and certain fabric dopes and had to give up that work years ago. That is until I found Stewart's Systems for the fabric and some of the newer water-borne poly-urethanes. But painting water-borne is a whole new experience and am having to relearn years of solvent-based paint application techniques.
 
Magman said:
I’ve seen a couple of light aircraft done the same way that looked good.
Click to expand...

You're talking my language as mine was painted using marine paint:

photo-3.png
 
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