How do you guys go about painting inside intake ducts of jets like the F-15?
I fixed the seams in the ducts of my Revell 1/48 F-15E kit the best I could and then painted them inside, which was no easy task being that they are 3-1/4" long and only 1/2" in diameter. It calls for gloss white but I used flat white as it is easier to work with than the gloss, and then I was planning on using Future to make it glossy again. The problem is that the MM Acryl flat white left a pebbly surface which I have now given about 4 coats of Future to try and level out with no success. I guess I am going to have to use Easy Off oven cleaner on the insides and start over. [banghead]
I should have just used MM enamels as they seem to behave better for me, but being that the airbrush must spray down into an opening like this I need the paint to not dry as quickly so that I don’t get the pebbled surface that happened with the Acryl. How do you old pros do it and what methods do you employ so as to have the finish come out the way you would like?
If the ducts (tailpipes,etal) come in halves, I always carefully mask the mating edges and paint the interiors before they are glued together. If seams need to cleaned up try to disturb the painted interior as little as possible. Then you only need to repaint the seam area. Use the airbrush for areas you can reach and finish touch-up with a brush. I use Floquil Reefer White (a model railroad color) for all of my painting with white. It’s flat, sprays even and has the best coverage of any white hobby paint I’ve used. If you need gloss, Future works well over the Floquil. For brush paint touch-up, I use Vallejo acrylic, which also offers excellent coverage. The problem with most white paints is the amount of build-up you get before the color looks good. These two paints will eliminate that problem.
I guess I will strip the paint and try again with either Floquil reefer white or MM flat white enamel.
With all the time I’ve spent on these intakes I could have built two other models by now. [:D]
Hi Mike, Ive also had this problem, here,s a few things I’ve found to help me. I think it’s caused by the paint particles bouncing all around inside the tube because of disturbed air flow, then settling when almost dry. The only way I could stop it was to try for the hardest to reach areas first and leave the easy to get areas till last. Also I found it better to not try to get the job done in one go and be very conscious of how much paint is actually getting sprayed around in there. In my efforts to paint these areas I also found I would use way more paint than usual for the surface area I was trying to cover and the next thing you know you’ve got a problem which just gets worse as you add more paint. Like you I got out the EasyOff and started over. Probably haven’t told you anything you didn’t already know. Good luck with it mate.
This worries me somewhat about the A-7 I’m going to start on when I finish my Spit. It has a long and curved intake that may well be a real pain. Hopefully, it’ll fit nicely and I’ll only have to do some light scraping. I made a tool at work that works nicely for that kind of thing.
If it’s hollow, specifically open at the other end, maybe you could hold it close (not real close, just in the vicinity) of a vacuum cleaner. Sounds crazy and I’ve never tried it, but maybe that would get a little air flow through it so the stray particles got pulled out instead of settling.
It’s certainly feasable MusicCity. I’ll be waiting until there’s no-one else around before I do the trials though. What with the Cutex for excess filler removal, foundation brushes for pastel application, stockings for straining paint, there could be some serious questions asked if I now start sneaking off with the vacuum cleaner!
LOL.[:-^]
Well I took Swanny’s advice and went and bought some Floquil Reefer White paint, thinned it 2:1 with lacquer thinner and sprayed it at 20 psi inside the intake ducts of this F-15E. It came out much better and I am waiting an hour or so and applying a second coat to even it out a bit.
I brushed on a coat of Future to gloss the inside of the air ducts and after drying and inspecting them they still look bad. I’m ready to turn them into liquid sprue. [banghead]
I should have just used gloss white as I am having a heck of a time getting the finish smooth inside these things.
Mike, you’re making me pretty nervous about the intake on my A-7. I’m going to start seriously looking at getting the seamless suckers intake for that.
That’s what I originally did but I didn’t like the looks of the seam showing inside so I went and filled the seam and painted them afterward.
It’s hard to get a good, even coat of paint spraying into a 1/2" diameter tube that is 3" long.
I’m soaking the intakes overnight in Future to remove the three coats of Future that I applied inside these intakes. Tomorrow I am going to try and sand the interiors somehow and try painting them once again.
My son says I should just use the intake covers that come with the kit but I told him I thought it would look funny with the intake covers on with a full load of GBU-10’s and GBU-16’s or whatever mix I load.
No, but they have no seam inside, so you’re already that far ahead. As far as painting goes, I might brush the deep inside, then airbrush the closer parts. The intake on this thing is huge, and any kind of seam or screwup would show like neon. I think that the larger intake would really help eliminate the little paint beads you get when painting into corners. I sure hope so anyway. Also, the intake on this is basically round, so I won’t have those corners like the F-15 does. I’m interested to follow your progress on this and learn from you here Mike. I’ll be struggling with you the whole way.
Sorry to hear you’re having a real struggle Mike. I guess you tried really thinning the paint like 2 parts thinner to 1 part paint and dropping the pressure right back to about 10 PSI, then doing light sprays over about 3 sessions to get coverage? Man, I wish I could be more help, sorry!
Actually, I was spraying the Floquil reefer white thinned at about 75% paint to 25% lacquer thinner at around 18-20 psi. Maybe I should drop down even lower and thin the paint more. It seems to be drying so quickly that it is leaving a sandy texture that you don’t really notice that much until you apply the coat of Future inside.
Maybe the lacquer thinner is causing the paint to dry too fast? I wish I had some regular mineral spirits to try out, maybe that would slow the drying process.
After the Future dries you can see places that are still a rough texture that the Future is not sealing over well and it is noticeable looking down the intakes with some light.
Of course, if you’re not building this for a contest nobody is very likely to look down the intakes with light. Once the whole thing is assembled, it may not be noticeable at all. Is it mostly down inside the tube, or closer to the intake mouths that it’s happening? On a completed model, I’d wager that nobody would ever take a flashlight to it, and once it’s all inside the model, the light probably won’t reach it. I might be tempted to just go with it as is at this point. Of course, you are a better modeler than me also [:)] and things like that may make the difference.
I think you are probably right Josh, but I am just too much of a perfectionist I guess. [:D]
The intakes are soaking in Easy-Off right now and after I have stripped the paint, I am going to give it one more try and call it good enough. [;)]