Bad luck with metallic paints

[BDB]

The last two times that I have used metallic paints it has ended badly. The first time was with Rusto metallic blue over Rusto filler primer. Tonight it was with Duplicolor metallic over the same Rusto filler primer.

There are patches that look like this on a few spots around the airframe. Is this a result of primer incompatibilities, grease spots that I didn't wipe up, or something else?

 

[manixFan]

I have had decent luck with Duplicolor metal paints over Dupilcolor primer. I have found that atmospheric conditions are critical to good metal paint application. The humidity has to be in the right range, (medium) along with temps (between about 70 - 85 degrees). But that is for Texas painting. If the temp is too high the paint will 'flash dry', if the humidity is too high it will be splotchy. If the humidity is too low it can also flash dry.

I always wet sand the primer with 400 grit before using a metal paint. And the surface must be squeaky clean. I start with the filler primer and then end with the primer sealer for a smooth surface. I got over the price of Duplicolor after trying many other brands.

I gave up on trying to mix brands long ago. I stick with either all Duplicolor for my nice rockets or Krylon for everything else. But the new Krylon doesn't seem to be nearly as good as the old stuff.

At least it will sand off so you can start over. Good luck,


Tony

 

[rms]

The last two times that I have used metallic paints it has ended badly. The first time was with Rusto metallic blue over Rusto filler primer. Tonight it was with Duplicolor metallic over the same Rusto filler primer.
View attachment 316051
There are patches that look like this on a few spots around the airframe. Is this a result of primer incompatibilities, grease spots that I didn't wipe up, or something else?

Looks like incompatibility with the top coat over the primer to me.
Greg

 

[T-Rex]

Assuming you followed the directions for re-coat times, there is an incompatibility there. If you didn't heed the directions, then that is where the problem lies.

 

[jimzcatz]

I have had great luck with Nason enamels mixed at NAPA. But that is automotive paint. I use 1$ a can Walmart primer with great success.

 

[Trident]

But the new Krylon doesn't seem to be nearly as good as the old stuff.

Tony

The old Interior-Exterior Krylon (lacquer-based) is available under a new name -- Krylon Acryli-Quik. I have cans of the old stuff that I bought over 15 years old ago, and just used one of them yesterday. Worked fine. The secret is to shake them annually (!), alternate storage from right side up to upside down, and clean the nozzles after use with lacquer thinner.

 

[les]

I thought for most of the metallic paints they want a black undercoat and not just sprayed over primer....

 

[BDB]

I suspect that this is an incompatibility issue too, though the first time I saw this I was laying Rusto metallic over Rusto primer. But Tony's comment about temperature may also be worth considering. It's definitely not 70' F up here in New England. The can says apply between 60' and 80' F. It was probably 45'-50' F last night, so I did the run-outside-and-paint-fast method; then I brought it into the heated basement to dry. I think I did the same thing last time with the Rusto metallic blue. I was probably too greedy. I just need spring to finally come so I can finish all of my winter projects.

 

[jimzcatz]

I thought for most of the metallic paints they want a black undercoat and not just sprayed over primer....

I would never do that. Too hard to cover. I prefer a white /gray primer as a base. Covers easily.

 

[ksaves2]

I suspect that this is an incompatibility issue too, though the first time I saw this I was laying Rusto metallic over Rusto primer. But Tony's comment about temperature may also be worth considering. It's definitely not 70' F up here in New England. The can says apply between 60' and 80' F. It was probably 45'-50' F last night, so I did the run-outside-and-paint-fast method; then I brought it into the heated basement to dry. I think I did the same thing last time with the Rusto metallic blue. I was probably too greedy. I just need spring to finally come so I can finish all of my winter projects.

I'd let the primer dry for a minimum of 3 days preferably a week. You can do a test shot to see if it works on some scrap material. Usually primer from the same maker should be good with their paint. Temperature and or failure to allow the
primer to "outgas" (ie. dry long enough) can lead to problems. Kurt

 

[Bat-mite]

Temperature/dew point spread?

 

[AfterBurners]

I agree maybe incompatibility.

 

[TangoJuliet]

I would never do that. Too hard to cover. I prefer a white /gray primer as a base. Covers easily.

Actually, it's exactly how you're supposed to do it with Alclad II Metal Lacquer's. I recently shot it on an ACME Spitfire and it turned out beautifully. I just sprayed Gloss Black on a Trajector earlier this week in preparation for Alclad II. It may not be necessary to do it that way with all metallic paints, but I suspect it does enhance the overall finish.

 

[TangoJuliet]

... It was probably 45'-50' F last night, so I did the run-outside-and-paint-fast method; then I brought it into the heated basement to dry. I think I did the same thing last time with the Rusto metallic blue. I was probably too greedy. I just need spring to finally come so I can finish all of my winter projects.

I think what may have occurred, besides the possible incompatibility, is that you may have allowed for a film of condensation between the coats by going from one extreme to another and back again with the temperature/humidity. I have to be careful of the same thing happening here in the south, but opposite. I build in the cooler A/C and lower humidity of the house, then go outside in the higher temp and humidity to spray paint. Not as bad during the middle of the day, but mornings or evenings seem to be an issue, making my glasses fog over.

 

[Bat-mite]

Actually, it's exactly how you're supposed to do it with Alclad II Metal Lacquer's. I recently shot it on an ACME Spitfire and it turned out beautifully. I just sprayed Gloss Black on a Trajector earlier this week in preparation for Alclad II. It may not be necessary to do it that way with all metallic paints, but I suspect it does enhance the overall finish.

Putting black underneath is an aesthetic choice but not a requirement for compatibility, no?

 

[TangoJuliet]

Putting black underneath is an aesthetic choice but not a requirement for compatibility, no?

In the case of Alclad, it's the recommended choice to get the Chrome or other Metal finish to really show properly. I recently saw a video of a similar paint product that also uses the black base coat on YouTube, but I'm unable to post a link from work on the company server. You can search YouTube though for other videos of the Alclad II paint system.

 

[jimzcatz]

Maybe I'm just lucky, I prime, sand paint wetsand and paint second coat all in the same day. Never had issues. Waiting 3 days is nuts IMHO.

 

[samb]

I've experienced this same thing when using Rusto metallic over Rusto filler/primer. It looks like a chemical reaction to me, the primer on that portion of the rocket was still outgasing when you hit it with the color. Maybe a heavier bit was laid on in that area. I've taken to waiting a good 5 days between filler/primer and the next coats. FWIW when I've sprayed in too humid conditions I get a lovely smooth fogged up finish but not cracking like you got here.

 

[samb]

Maybe I'm just lucky, I prime, sand paint wetsand and paint second coat all in the same day. Never had issues. Waiting 3 days is nuts IMHO.

No, some guys just have the knack. What paint are you working with when you do that ?

 

[Woody's Workshop]

Primer/Surfacer is just that.
You need a sealer coat.
The only time you can put color coat on top of primer if it's lacquer with chromates.
Good luck finding anything with chromates in it these days. It's been banned for decades.

 

[Oberon]

Rusto filler primer seems touchier than their standard stuff in terms of cracking, compatibility issues, etc. in my experience. And the metallics are very easy to over-spray.

I've had better success spraying the metallics on top of a gloss base coat (white or black) than primer. That could just be me though.

 

[qquake2k]

Ah, the Rusto Wrinkles. I've had this happen with Rusto paint over Rusto filler/primer. It hasn't happened to me with 2X paint over 2X primer.

 

[Nytrunner]

This is an interesting occurrence. I'll have to remember about quickly changing temperature areas (warm to cold to warm again)
Do you recall the humidity when you painted?

So far, I've gotten orange peel problems, but the only time I've gotten wrinkles was when I sprayed 2X clear coat over paint that was only 3 days old. (I now attempt to wait a week before applying clear.

Primer/Surfacer is just that.
You need a sealer coat.
The only time you can put color coat on top of primer if it's lacquer with chromates.
Good luck finding anything with chromates in it these days. It's been banned for decades.

Primer is supposed to promote paint adhesion to the surface in question.
I've never heard of sealer as a requirement, but -after looking it up- I'm now of the opinion that its a subjective method. Some like it, others don't, and different people will get better results with one over the other. And now I've learned a new way of doing something which is always a good thing.

 

[Marc_G]

@BDB, the wrinkling you observed shows the topcoat paint didn't stick to the primer.

Was the Rusto filler primer sanded prior to spraying the topcoat? If not, that probably would have helped. I've seen this sort of wrinkling, usually when I don't sand the filler primer. I believe filler primer is meant to be sanded prior to topcoating. Also, I've usually covered grey filler primer with a thin coat of white primer, back in my lacquer paint days. Then topcoat on top of that. The white primer is designed to adhere to the surface, and be sticky to topcoats that are sprayed onto it in turn.

It's also possible that this is a humidity effect as mentioned above. Evaporating solvents cool the surface, causing condensation. A little film of water could explain what you see.

Marc

 

[Micromeister]

As a few others have mentioned ALL metallic paints should be applied over a Gloss Black base coat to get the maximum punch from the Metallic Flakes suspended in Clear.
Applying directly over primer is NOT recommended though it can be done as long as the primer is "Sniff Test" Dry and been sanded with 320 to 360 grit dry sandpaper.

What you are seeing is a result of the color metallic coat wrinkling and crazing due to outgasing of the Thinner and vehicle from the primer. My guess is the Metallic was applied before the underlaying primer had enough time to outgas. Sniff Testing Works....it's the best way NOT to ruin a paint job.
I believe if you well read the can insturctions most Rustoleum Metallic state for best results apply over High Gloss Black or Blue base coat. depending on the particular metallic chosen. Silver and Gold metallics really "POP" when applied over Gloss Black Base, Copper gets a very interesting hue over Dark Blue Base coats.

 

[BDB]

The primer was definitely dry. It had been applied weeks before and had been sanded, though not completely off. I didn't know about the gloss black underlayment. I'll try that this week, if it ever stops raining.

Can I do gloss black and then apply the topcoat within an hour like the can says (I know there is another thread about this right now), or is there a special curing that needs to occur before I apply the metallic topcoat?

 

[redleder]

The primer was definitely dry. It had been applied weeks before and had been sanded, though not completely off. I didn't know about the gloss black underlayment. I'll try that this week, if it ever stops raining.

Can I do gloss black and then apply the topcoat within an hour like the can says (I know there is another thread about this right now), or is there a special curing that needs to occur before I apply the metallic topcoat?

An hour might be a bit much. I would read the can fully, some say within 20 minutes, while others might be a bit longer. The challenge you run into running longer times is the top layer gets sealed to the touch but the gases are still escaping during the cure time. If it is sealed and you put more paint on top it can orange peel easily. On really hot / dry days, I have literally painted primer, sealer, top coat and clear coat all within an hour and have a had good luck. just super light layers.

It is a bit more art than a science... IMO.

Jarod

 

[Woody's Workshop]

BDB, if your primer was cured for weeks, then sanded, than it was the top coat melting and swelling your primer under your top coat.
Instead of your top coat flashing off, your primer was drawing out the evaporating thinner in your top coat.
Indicator that you need a sealer coat when using that top coat.
Metallic is suspended in a mixing clear, which by nature is a very cold base. Meaning it doesn't flash very fast.
Primers are typically very hot, meaning they flash quickly.
In simple terms, you sprayed water onto a dry sponge and expected the water to evaporate off the sponge.
You needed to coat that sponge with scotch guard first. Make sense?

 

[tomsteve]

I thought for most of the metallic paints they want a black undercoat and not just sprayed over primer....

not necessarily. most metallic are in a solid color paint, so should be sprayed to full coverage.ive shot a few vehicles with metallic right over the primer, which I try to make the primer color an opposite shade of the paint. if I have a dark paint, I use a light colored primer and if a light colored paint I use a dark primer. that way I can tell when I have full coverage. but that doesn't always work out as some paints have less solids thatn others- I can achieve full coverage easily with Sherwin Williams ultra 7000 in 2 coats yet duponts nason requires at least 4.
same goes for spray bombs- some brands have more solids than others.
base color comes into play with candies and pearls.