I’m making my first alclad2 attempt and I have a question.
I airbrushed alclad gloss black lacquer as my base coat on a p-47 with the intention of using alclad2 aluminum. I initially started with something closer to 20psi rather than 10. In the area on the wing where I started with that pressure, the paint is somewhat bubbling. It looks like many tiny little bubbles.
After turning the pressure down, this did not happen again. Will these bubbles go away as the coat dries? If not, can these bubbles be sanded and/or polished down or off after the paint dries? I assume a 2nd coat wouldn’t help and would just make the bubbles bigger.
Ted - I use Future as my primer, I’ve had bad experiences with the Alclad black primer myself… 2 months after putting it on it was still sticky!!!
Alclad’s site listed Future or enamel primer sanded with 1200 grit as primer for non-shiny metallizers… I found future to be a dream!! if ya want spray some acrylic or enamel black first… I didnt and it worked fine but I am going to try it with the black on my current build. I would lightly sand the primer with a fine grit to get rid of any bubbles… then maybe future would be your best bet!
In taking a closer look at the finish as it has dried, it isn’t so much bubbles as it is sort of a mottled appearance. The surface definitely is not as glossy as the rest of the plane, but it is not really rough or uneven. Maybe the surface wasn’t as clean as it should have been, I don’t know what went wrong.
So I could sand the offending area and then go straight to the future? Or should I shoot a 2nd coat of the alclad black and then the future (after waiting for cure time)? I definitely won’t be using the alclad black next time.
By any chance did you use lacquer thinner with your black undercoat? If so, it’s time to strip it and start over. In the fine print on the bottle is says the Alclad black contains MEK. If you mix MEK and lacquer thinner you get a clear sludge, and the paint won’t dry. Thin the undercoat with MEK (using the proper precautions while handling) and I think you’ll like the results a lot better.
No I shot straight from the bottle… it was wierd, I played it off the the humidity down here but I’ve heard the same story from a few other people, it went on smooth with no problems it just never dried might less cured…
Ted - If you plan on shooting more of the black primer on don’t worry about Future, I probably would lightly sand that spot with a high grit paper until smooth then reshoot black primer over it… I use future from the start as the primer itself… good luck to ya!
Really weird. I shot alclad black base first coat straight from bottle. That sucked, same bubbly almost fisheyed appearance. So I stripped with denatured alcohol (didnt bother plastic which was nice). Second coat I actually thinned with laquer thinner about 50/50. Went on really nice, however it took 4 days to dry. Still have to do top half of model I think Im going to strip it again and use tamiya gloss black but need to be sure that is works with polished aluminum as it is shinier finish. Definately wont be using the alclad primer again, Ive heard nothing but bad about it. Just my two cents worth.
What your photographs show appears to be “crawling,” as the paint industry calls it. This can have a number of root causes, but it results from either poor bond to the substrate, excessive coating shrinkage, or both.
From your description, the primer appears to be a water-solvent or similar system, as an organic solvent material would probably not be affected by alcohol (although there are some really strange formulations out there.) Lacquer thinner will patially dissolve the styrene—you get great bond, but all the solvent that migrated into the styrene will take days, if not weeks, to migrate out past the coating. That’s why it’s taking so long to dry.
The “fish-eye” problem you report is caused by localized contaminations—usually oil, but potentially anything—that repel the resin or solvent in the paint. What the contaminant is, in your case, I have no way of telling. It could even be something in the primer, itself. Figuring out what would take a paint lab.
Thanks for the reply, Triarius… So do you think its an acrylic based primer or laquer? Some say one, some the other, I dont know which. Sounds like acrylic. I went ahead and sprayed the top of my b25 tonite with the same 50/50 mix of laquer thinner/primer and it went on great. The thinnner doesnt seem to mind mixing with the primer. I know my first coat sucked because apparently I didnt clean with soap and water after using a plastic polish to get a better surface. I think I got it too slick. I did use rubbing alcohol to clean model before spraying but maybe it didnt get all the polish/wax? Next time, no polish. Let me know what you think.
AHA! Some plastic polishes have materials in the carrier that will interfere with some paint systems. Not cleaning thoroughly after using them may well have caused the crawling and fisheye problems. The actual smoothness of the surface should not be a factor.
I don’t know what the formulation of the primer is. A true “lacquer” cannot be an acrylic. A lacquer forms a film through evaporation of the carrying solvent, not through true polymer formation. Basically, they are a resin dissolved in a compatible solvent. Lacquers form a continuous film that can be dissolved by reapplication of the original solvent. Some lacquers use alcohols as solvents, some more modern formulations use other organic solvents. None of this precludes the primer being some odd polymer forming coating that behaves in some ways as a lacquer. When you took it off with alcohol, did it dissolve, or did it come off in sheets and clumps? If it dissolved, it’s an alcohol lacquer. I suspect this is the case, because a lacquer-like paint using water as a co-solvent would not tolerate lacquer thinner.
Well, there certainly is a lot of scientific “speak” in this thread. I would just boil it down to simplicity. Use Future as a primer for Alclad II and you can’t go wrong. Allow it to cure for at least 24 hrs. The results are great:
I use Tamiya polishing compound on the bare plastic, washing it off with isopropyl alchohol, then apply Future to the bare plastic…then shoot the Alclad II …? works for me.
Steve - that’s what I’ve settled on as the best finish for shooting Alclad onto. Did you use a black base coat before shooting the future on with either one of the pictures you posted? I’ve pondered trying it to see if it brings out a little more brilliancy on the metal sheen…
Paints are technical, and astonishingly complex—and what I posted was significantly “detechnified,” if I may coin a phrase. I once worked with a paint chemist who had great trouble doing that. I barely understood him sometimes, and I had to translate for him! [%-)]
I have a strong tendency to answer the question asked, which in this case was, “What went wrong?”
Your answer was to the question, “How do I avoid this mess entirely and save a few bucks in the process?” This is a good cap for the discussion! [tup]
Nice paint jobs, by the way. I just bought some Alclad II at my “local” hobby shop. Thanks to everything I’ve read at these forums, I did not buy the Alclad primer, and I will be using essentially your method.
It seemed to come off in little specks no bigger than say /16th of an inch. I use cotton swabs soaked in the denatured alcohol. It seems to dissolve it as I was going along. So I agree with you on that one.
Glad you like the booth. It worked awesome last night.
Thanks for the help everyone. I just sprayed my first coat of alclad2 aluminum and it looks great. It went on a lot easier than I thought it would after struggling with the black primer. Very easy and no more fear of doing a bare metal finish.
I ended up sanding down the trouble spot and then spraying future over the entire model. That produced a nice glossy black base coat. I’ll probably spray a 2nd or 3rd coat of the aluminum later today, let it dry, and maybe take a shot at masking off some panels for duraluminum. I’ll post pics of it later.
No black primer, or primer of any kind. The brilliance satisfies me. The key is to polish the finish of the bare plastic so as not a speck of anything is on the surface. Alclad will make a microscopic piece of lint look like a banana peel on the finished surface!
I know Matt Swan advocates decanting Krylon gloss black, and I certainly can’t argue with the Swanny! but for me, a coat of good solidly cured Future does the trick.
I just used polished aluminum and chrome on my P47N, just plain old Future on bare plastic. Keep an eye on the aircraft forum in the next couple of days for finished pycs…
Cool, cant wait. I wonder could a person spray flat black and then future. I guess it depends of how much work one wants to put in. Do you thin the future with anything to airbrush?
