I’m on my fourth model. Each one gets better as I learn from my previous mistakes. I’m currently building an Accurate Miniatures Allison Mustang. Despite an egregiously-bad “step” between the fuselage and the wings, the parts fit together better than the two old Revell/Monogram kits I built before (no surprise), or the Hasegawa F4U-4 (not bad, despite raised panel lines).
I wanted to make this Mustang count, so I spent a lot of time checking seams and filling them in (repeatedly) with Perfect Plastic Putty or Mr. Surfacer 1000. I used silver paint (a silver paint pen, actually) to check the obvious places to make sure the seams were filled. When I thought I was all done, I primed the model with Vallejo surface primer. And…
Seams.
Seams where I thought I had no seams. Seams where I thought I had fixed seams. Seams on trailing edges, seams along top of fuselage…the usual places.
So now I have to sand down the primer, fix the seams, then re-prime. This results in a “gunky” model, and my recessed panel lines are starting to fill in before I’ve even begun to actually paint.
So, my question is: am I doing it wrong, or is this par for the course? Do you all postpone the application of primer until you’re 1000% sure you got all the seams, or do you use the primer as a final check for seams, knowing that you may have to re-apply primer in some places?
Primer is just for that. To help find flaws and to act as a builder/filler. When u sand be sure to protect surrounding detail with tape and sand with progressively finer grits. You will have to rescribe some panel lines after heavy sanding. Do this before the original panel line disappears completely.
If you apply and sand primer thoroughly the model surface should not be gunky. As Adam said, rescribing seams is a normal modeling activity. In my opinion the seam engraving on many models is overdone anyway. Seams are fairly evident on natural metal finishes, but usually not very visible on painted aircraft.
I had the same frustrations when I built my first couple of kits. I used the same putty you use and I was really tired of all the work for the results I got. So, I changed tactics and I am much happier with my results.
Instead of filling all the seams I can find I use my Tamiya extra thin in steps as I work along the seam. Basically, I glue a stretch that I can hold with just my fingers and and then apply gentle pressure to that spot to get the plastic to “ooze” out of the seam just a touch. Then when I sand the seam it will totally disappear. I work my way along the seam step by step controlling the process as I go until I get all the seams done. This way I use very very little putty and the sanding goes much faster and I get a clean seam. Before I would glue the whole thing up at once and then fill and sand. That was just too much work.
I also use an old body man’s trick to finding trouble spots. Using very light pressure from you index finger or that finger nail, close your eyes and “feel” for a seam. You won’t notice it with your eyes open but you will find more with them closed. Then work that spot till your happy. When you prime you won’t see the seam.
Another tip is to dry fit the snot out of everything first before you go to gluing. I will often spend quite a bit of time making sure I have the exact fit I want on the whole area before I comment to glue. Often times i will have to sand out something that is interfering with the fit, or as you mentioned about the “step”, I will insert something to prop an area up to make the fit correct. When I am confident that the fit is right, then I glue. I had to do a inner wing insert on my P-51B at the left wing root as there was a noticeable step there. But with some sprue cut and sanded to the correct size and inserted, the wing now matches the fuselage correctly.
Thanks, BrandonK. I, too, began gluing parts together, just as you described, using the Tamiya thin. That definitely helped. I’ll try the “feel the seams” approach next time. I have been doing lots of dry-fitting as well, but perhaps not enough. The wing-to-fuselage join caught me by surprise after gluing. Don’t know how I missed that before. I could also see that the trailing edge seams should’ve been noticed by more scrutinizing during the dry fitting as well. I suppose the big take-away here is that I’m on the right track, but I just need to spend even more time on prep before primer–working smarter, not harder.
Adam, you mentioned you have Mr. Surfacer 1000. That is the perfect thing to use to check your seams. Just brush a thin coat on the seam and let dry. It will show up any issues. If everything looks good, just remove it with thinner on a Q-tip.
My technique is to use tamiya putty, acetone (nail polish remover) and sandpaper (usually a sanding stick). I apply a light coat of putty, smoothed out with acetone and q-tips. Let dry, then sand. Repeat as necessary. A sharp toothpick, while the putty is still damp, is good to clean out panel lines you didn’t want putty getting into. If you even think there’s gonna be a seam showing, it will be there, clear as day, when primed. I try to get the seam to what can only be described as a glass-like finish.
I haven’t tried the Tamiya putty (yet, I have some on the bench to test on my next project) but I found that beyond the smallest of seams, Squadron and Testor’s putty would leave me with a gritty surface that I wasn’t fond of. Great for tiny seams, not so much for bigger gaps. I have found that gap-filling CA works great for me. I do all the prefitting before committing glue, but I have found that using the thick super glue works best for me. The added benefit is that I can put down some tape to protect the surrounding areas, hit it with some accelerator, and start sanding about 5 minutes later without having to wait for anything to dry. I’ve also found that for bigger gaps I can build it up pretty quickly.
Funny, I started out on this return-to-modeling journey using zap-a-gap for seam filling. I think that because the first couple of practice models had such large gaps/seams to fill that the CA glue wasn’t quite working for me. Maybe I’ll try it again with the next model. That’ll be a Tamiya P-51B.
The same thing still happens to me, so don’t feel bad.
Make sure you have plenty of light at your workbench. I had this problem when I first returned to the hobby. My AM P51B looked great at my workbench. I took the unpainted model to a club meeting, which had better lighting than my workbench. The improved lighting revealed that my seems needed more work. I was bummed, so I bought a swivel lamp for my bench.
A good primer can help fill minor defects. I use Alclad II primer and microfiller. When the primer reveals a seam, I sand it smooth and apply more primer to the seam in thin coats. A final sanding and the seam disappears.
Hypertext-- Very good point about lighting. My lighting is not great for detail work. It’s a fluorescent fixture, which works for general lighting but it doesn’t reveal details. I will have to get something better. It’s also interesting to read here what people use for primer and how they use it. I’m using Vallejo, which forms a sort of skin. If I sand it off to rework an area, it leaves a slight edge due to the thickness of the primer. It’s also a little rubbery, so I don’t like to mess with it once it’s on the model. I think I’m going to try something else. I have Tamiya’s liquid surface primer that I haven’t used yet. I may give that a go on a test-bed model I should receive in the next couple of days. Maybe I’ll order some Alclad primer as well. If anyone else has suggestions for a tough primer that takes well to sanding and re-spraying, I’m listening.
Good lights may well be the most important tools at your modeling bench. You need directional lighting and some general overall light. One thing a high light level at your bench does is stop down the pupil of the eye (create a higher f/#). This increases the depth of field. Many of us have accomodation problems as we age, and we cannot see close up very well. Dim light makes this problem worse. I have a positionable light on my bench, and it is amazing how much better I can see close up when I move the light down closer to the model!
A lot of people have had problems with Vallejo’s primer doing exactly what you described. I don’t think it was designed to be sanded, just as a sealer prior to paint. My personal favorite primer is Tamiya’s fine primer. You can even use Krylon, Rustoleum or other larger rattle can primers.
There are a few members that use a silver Sharpie over seams to highlight seams and swear by it.
I have one of those illuminated swing arm lamps with the magnifying lens on it. Couldn’t work without it.
“Do you all postpone the application of primer until you’re 1000% sure you got all the seams, or do you use the primer as a final check for seams, knowing that you may have to re-apply primer in some places?”
Yes to both.
I hope you are letting the putty dry for a week or more, because many of the model putties on the market shrink slowly. (The Squadron Green is very similar to automotive glazing putty, which is not fully cured in 48 hours at room temperature.) Did you say what putty you use, Adam148?
There are some putties that don’t shrink, but even if they don’t, you must consider which material is softer when you go to sand it, the plastic of the kit, or the putty. If the putty is softer, then you need a light touch and a sanding block or something similar, so that you won’t remove too much putty and create the need to apply more of the stuff.
If the plastic is softer than the putty, you run the risk of damaging the surface of the model when you sand or file, as NathanT says. This was your problem with the CA glue; it’s much harder than the surrounding plastic.
For very fine crevices, you can use the primer or paint itself as the filler, but that would just be for prep, not a finish coat. You can also use liquid cement alone, or a slurry of liquid cement and plastic shavings dissolved in it as a filler, but that also needs drying time. This is sort of what BrandonK is doing: using the plastic of the model itself as your filler. It works well, but you have to let it cure thoroughly before you sand.
Black paint sometimes works well to reveal flaws. Just be sure it is a kind that will not be upset when you put coats of paint on top of it.
I’ve had good luck with both Testor’s enamel primer and Tamiya Acrylic. They are both out of rattle can and the Testor’s can be kinda thick (which is not always bad). Just be careful to use the right kind for the paint you are going to use.
Spruesome: “I hope you are letting the putty dry for a week or more, because many of the model putties on the market shrink slowly.” A week??! Ha. No, I’m afraid I’m too “result-oriented”; I want to see how the model is going to turn out before I’m done with it. Kidding aside (sort of), I typically wait a few days by default before I get around to priming. I’ve used Perfect Plastic Putty (PPP) for the last two models. I haven’t seen any shrinkage, but I have looked at the last two models since I’ve finished them (the “practice” models get hung from the ceiling). The PPP has been used for small gaps, and I do little sanding of that putty since I can wipe the excess away with a damp rag. I used Mr Surfacer sparingly, since I wasn’t that comfortable with it yet and wasn’t sure how I was going to remove the excess once it dried. I can see your point, though, about hardness of the primer versus the plastic itself. The Mr Surfacer seems hard. The CA glue even harder. I’ve been hesitant to sand too much because my initial forays into re-scribing panel lines haven’t been too successful. As a result, I haven’t been making my filled seams truly invisible. They may appear flush and filled, but the primer coat tells-all. I’ve just ordered both Tamiya primer and Alclad II primer/microfiller to try out. I’m going to have to take a step back with my modeling process and try these products. From what I’ve learned on this thread, my approach is a little off. The Vallejo primer, it appears, is not the best representative of the medium. I think I was drawn to it because it’s easy to work with (not a lacquer base). My knowledge of paints is skin-deep, so acrylics seemed most friendly. I read a very informative article about acrylics vs. enamels vs. lacquers that helped me understand how the layers are to be built up, and what should go down first. Lacquer is the way to go.
I use auto body filler, which is very similar to many of the solvent based fillers. I work them as soon as an hour or two unless they are really thick. And I try to avoid too thick a layer, anyways. Much better to build up filler in several thinner coats. However, with the coat thickness I use, I have never had any trouble with uncured filler I work the same day.
I use lacquer type primers- auto body or Krylon primers. Again, I work with it within hours, and never had a problem.
Sorry, I don’t know Perfect Plastic Putty. If it’s for plastic models, I wouldn’t be afraid of sanding or filing it down once it’s dry, and if you’re waiting three days between application and sanding, that should be enough to prevent shrinkage where you have a shallow fill. Sanding it four hours after you’ve applied it wouldn’t be a good idea if it’s the sort of filler that shrinks.
Am not sure what scale you’re working in, but I guess the panel lines are maybe about the same width and depth in 1/72 and 1/48. As a beginner, maybe you should not worry too much about preserving them, Or, if they are very important to you, try laying a guide for your scribing tool by putting some cellophane tape right up to the edge of the line. That will give the tool a little bit of a guide. Maybe you’ve found that scribing a line through certain putties can make them chip. That is one reason I fill with thick paint or a slurry made from sprue and liquid model cement. It doesn’t usually chip if I have to scribe through it.
You mention Alclad primer. Does that mean you’re thinking of applying Alclad on top of it to simulate a bare metal finish? If so, you’re sort of jumping into an intermediate or advanced skill level. If you are not attempting Alclad metal finishes yet, then how about priming just the spot where you put your filler using a brush? If preserving panel lines is important to you, the goal is to minimize the number of coats you put on all parts of the model. Personally, I do not generally use the model primers as such, unless it’s a special situation. Where I use putty, I seal it with model paint of the same sort that will be at the surface.
If you are contemplating the layering of different paint systems on one model, you are maybe rushing your advancement a little.
You can use lacquer as both your filler and your primer, using a brush and a screwdriver blade as your putty knife. It is highly aggressive; its solvent easily crazes the surface of the styrene plastic of the kit. Therefore, it bonds very well to the kit plastic. Respect its toxicity and flammability but do not be afraid to experiment with it.