Paint Question

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beriah

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I have seen where people said to prime before paint. Does the paint+primer spray paint work? I have been less then thrilled with the results, and was wondering if that was because of what I bought or operator error.
 
I am not impressed with the new “ColorMaster” Krylon paint; the stuff that combines primer and pigment.

First of all most people shoot their rockets with Filler Primer before applying any color coat so the model already has a primer.

Shooting that “ColorMaster over the filler primer has resulted in a pebbly finish on more than one occasion.

Krylon paints could soon be a bygone product with regards to finishing my rockets.
 
That stuff is terrible, it's no wonder you're less than satisfied :) Just consider it a necessary evil and you will get better at it the more you do. You will learn the magic of wet sanding and feathering an edge and other arcane arts. Really the hardest part of painting is getting all wet at the same time without runs.

I really like the Rustoleum 2X paints and yet there's those here that curse them so YMMV but take special care to have the can warm, 75*ish, and shake the can much longer than the stated 1 minute. I'd say shake ALL cans of paint for a good 3 minutes or better. What can it hurt.. Warming the can raises the pressure and thins it just like warm oil runs better than cold. Stay smooth in your motion. Find some large flat object like a dresser or door and paint it with spray to learn a smooth motion, how to start the motion then the spray and carry through at the end.

If you already know this then ignore me, most do :D
 
I am not impressed with the new “ColorMaster” Krylon paint; the stuff that combines primer and pigment.

First of all most people shoot their rockets with Filler Primer before applying any color coat so the model already has a primer.

Shooting that “ColorMaster over the filler primer has resulted in a pebbly finish on more than one occasion.

Krylon paints could soon be a bygone product with regards to finishing my rockets.

When you say filler primer, are you talking about automotive filler?
 
That stuff is terrible, it's no wonder you're less than satisfied :) Just consider it a necessary evil and you will get better at it the more you do. You will learn the magic of wet sanding and feathering an edge and other arcane arts. Really the hardest part of painting is getting all wet at the same time without runs.

I really like the Rustoleum 2X paints and yet there's those here that curse them so YMMV but take special care to have the can warm, 75*ish, and shake the can much longer than the stated 1 minute. I'd say shake ALL cans of paint for a good 3 minutes or better. What can it hurt.. Warming the can raises the pressure and thins it just like warm oil runs better than cold. Stay smooth in your motion. Find some large flat object like a dresser or door and paint it with spray to learn a smooth motion, how to start the motion then the spray and carry through at the end.

If you already know this then ignore me, most do :D

You wet sand your rockets?
 
When you say filler primer, are you talking about automotive filler?

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You wet sand your rockets?

Yep, between every coat of paint. All you should be doing when you sand between coats is to knock down any high points and take the shine off, this prepares the surface to bond with the next coat of paint, Wet sanding helps the paper from clogging with paint by carrying off the excess. Sandpaper can also heat up when sanding causing problems with that, too. 400 is about as fine as you really need for sanding although a better results can be had on clear coats with the ultra fine papers, 1000-2000 grit or there abouts. I have some 4000 that came in an assortment I got off eBay, I'll never use it :p
 
Primer and paint serve different functions... IMHO the primer/paint combo products are pure crap-- they're for occasional use by people too lazy to actually do a PROPER paint job... for lawnmowers, yard furniture, and other such things where the actual finish appearance doesn't matter, they're probably okay... and if it makes it easier for those type users, appealing to them as a marketing ploy, so much the better as far as the paint companies are concerned.

For the best finish, you need to apply a few coats of primer, let the dry, and then sand, usually with a 220 grit paper to take the surface down and level it out, then a 400 grit to really smooth the surface out. You might have to repeat this step a time or two to get the surface really smooth and blemish free... Personally I even sand the surface with 400 grit paper that's been dipped in water and then lightly daubed off on a towel-- this "damp sanding" really smooths the surface out very, very smooth. Basically, the surface should be as smooth and blemish-free as possible after priming and sanding as you can possibly get it... sand only in small circles to avoid/minimize sanding scratches, and always keep the paper moving, so you don't sand in flat spots... Basically, the surface finish you have when you finish sanding the primer is as good as it's going to get... Hold the rocket up and observe the reflected glint of light off the tube from a bright window or lamp or light across the room-- if you can see any imperfections in the reflection, you want to fix them now, or decide if you want to live with them.

Remember, paint does not cover up imperfections, it MAGNIFIES them... so immaculate surface prep is a MUST for an excellent final finish. While "doing the primer finish right" is essential to a great finish, you can STILL mess the finish up if you don't apply the paint right. Multiple thin, even coats are what you want... Runs, drips, or sags will ruin the finish and set you back to having to sand off the affected areas. The final coat of paint you'll apply a little heavier, so that the paint flows out smoothly and evenly onto the surface, without "orange peel" or dry spray (speckles of paint particles that don't flow out into the paint film on the surface).

Anyway, that's the basics... all this has been covered any number of times on the forum in numerous threads... but as for your original question, NO, I would NOT recommend the combination paint/primer products... Find a paint system (primers/paints/clears/etc) that you like and that works well for you, and stick with it is my best advice... mixing and matching different products is asking for problems as well IMHO... it can be done, but you HAVE to know what you're doing... and do paint tests to make sure that it will work... and then, in some cases, some prayer never hurts...

Krylon used to be the 'go to' brand for rocket finishing, now IMHO their products are pretty much absolute crap... I've used the stuff, but it's ALWAYS my paint of last resort-- only for colors that I can't get in any other brand... it's finicky and even when applied following the can instructions and wait times TO THE LETTER can STILL go wonky and ruin a paint job halfway through the process... or worse yet, at the VERY END... IMHO there's MUCH better product brands out there that work extremely well without all the hassle, some of them are cheaper and everything else is about on par for cost... Personally I've had EXCELLENT luck with the WalMart Colorplace primers and paints... the only bad thing about them is an EXTREMELY limited color palette... but for plain black/white paint jobs like a lot of scale NASA type rockets, they work very very well. Rustoleum has some good paints, and Duplicolor is top of the line... Testors works very well but its expensive due to the small can sizes.

The main thing is, practice, practice, practice, and know what you're using... the different formulations don't always play nicely with each other... for instance, you can apply enamels over lacquers, but not the other way around (99% of the time-- some folks DO, but it is NOT a beginner technique...) Most paints on the market are alkyd enamels, but the different manufacturer's tweak their formulations enough now that you have to be careful mixing brands on the same paint job... for instance, applying Rustoleum over Krylon might not be a problem-- OR, it might "alligator up" and wrinkle all to h3ll on you within minutes of spraying it on, ruining both the paint job and the primer work you've already done. That's where paint tests come in.

Best of luck! OL JR :)
 
When you say filler primer, are you talking about automotive filler?

Probably not-- some folks use filler products, be it Bondo Glazing and Spot Putty (essentially, red oxide primer about the consistency of toothpaste, using just enough LACQUER THINNER in it to make it like toothpaste... remember NOT to apply it over surfaces already sprayed with ENAMEL primer, as it will attack it and take it off) which is usually used for filling tube spirals and stuff like that, or Elmer's Carpenter's Wood Filler (CWF) thinned out by putting a dollop in a little container and adding a few drops of water and working it in with a brush until it's about the consistency of hot dog mustard, and then brushing it onto the surface, allowing to dry, and sanding it down smooth. Some folks use model airplane dope or balsa sanding sealer or such things to fill surface imperfections, especially in balsa fins, nosecones, and transitions, but they really stink to high heaven due to the solvents and really do no better job than thinned CWF, which is cheap and cleans up with water (and uses water as a solvent). Some folks swear by just applying several coats of "high build primer" (high-solids primer), that is, a primer with a larger amount of the actual filler material (red oxide or gray solids or whatever is in it) in the primer, applying that several times to fill in all the surface imperfections and sanding that down smooth before painting. Personally I don't think it's enough for balsa surfaces-- unless you want to spray a couple cans on it and sand a half dozen times between all those applications... so for balsa nosecones and transitions, I first harden them with ultra-thin CA (cyanoacrylate "super glue", the pink bottle stuff from Hobby Lobby is what I use) wicked out into/onto the surface and allowed to "drink it in" until it will hold no more. Then I sand the cones with 220 and 400 grit to get them smooth, then brush on an application of thinned CWF, let that dry a couple hours, and sand it again with 220/400 to get it nice and smooth. Give it a couple coats of primer and let that tack up 20 minutes, give it another couple coats, let that tack up, and then a couple more if it looks like it needs it, let it dry several hours to overnight (more if conditions warrant) then sand that with 220 followed by 400, and the surface will be indistinguishable from a plastic nosecone... maybe even smoother...

For fins, 99% of the time nowdays I just paper them and be done with it. Stack sand your fins after you pop them out or cut them out, sand in any desired airfoil, grab some regular printer paper, and apply a VERY VERY THIN layer of white glue to the fin, press it down on the paper, apply another VERY VERY THIN layer of white glue to the fin, then roll the fin over the LEADING EDGE onto the rest of the paper, sealing the balsa fin inside the paper... burnish it all down tight using a sharpie marker to squeeze ALL the excess glue from between the two. Allow to dry overnight, then trim the paper back flush to the edges with a SHARP hobby knife and lightly sand the edges. This method seriously increases the strength of the fin, while adding only a very small amount of weight, and it totally covers the coarse grain of the balsa and all those pores in the wood that require repeated sealing and sanding and priming steps to eliminate all that wood grain. Glue the fins on the rocket and primer the rocket, then sand them down, and the fins will look virtually like plastic... easy peasy...

Anyway, that's my recommendations. I've posted pics of all this several times, but you can see them in my "Dr. Zooch Vanguard Eagle Beta Build" thread and "Dr. Zooch SLS Beta Build" thread with a quick search, along with a more detailed step by step explanation and pics... Later! OL JR :)
 
My favorite primers are the Duplicolor Automotive filling sanding primers found at most Auto Parts stores, they are ready to sand in no time (about 30 mins at room temp) and dont seem to run easily. As for Krylon the good stuff is gone from most stores but it lives on in the Krylon Industrial brand which is available where I live at Lowes Home Improvement.
 
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