It should result in much better, smoother surface after the final coat is applied, otherwise after so many coats the finish could end up looking too coarse.
After experimenting with flexible sanding film and sanding sticks I decided the best sanding tool to get such a job done should be the flexible sanding pads offered by Micro-mark (“soft touch pad set” keyword at their website). Unfortunately I don’t have any of those in stock so I won’t try them until the next model.
If you sand after priming please share your experience, tools and techniques.
P.S. The Soviets invested a lot of man hours into sanding, by hand, of some of their WWII combat aircraft. The La-7 was hand-sanded to high luster finish before the final coat of clear varnish and this is one of the reason why the thing was so fast.
I use regular wet-dry sandpaper. Anything from 600 to 1000 grit is fine by me. I always use a sandable primer too. That is important as not all primers are sandable. It helps get rid of any imperfections also. I don’t always re-prime either. If it’s not a major flaw, I won’t re-prime. ie: some light sanding scratches. I prefer Alclad gray primer, but have used others, mainly the automotive type.
I don’t know that it’s better prime or not. I just did it to help minimize the flaws on the end product. I know several who do not prime, they either are that good or just don’t care. I used to be like that, but, felt that for me to go further, I had to. Using a sandable primer was a logical step. It would help identify any problems then after sanding, would know if any depressions are present.
I make my sanding pad, blocks or what I need for the project from balsa, foam board, or a sutable material. There should be an assortment of sanding mediums on every bench. You don’t sand a fuel tank with a flat file do you? Or a flat surface with a ribbon type flex-i-file?
I always sand the primer coat, with 800 wet/dry or finer. If the model has raised detail I tape it off and sand around it then use the soft toothbrush with a fine abrasive cleanser… (side note is that I use an automotive lacquer primer and don’t recomend it to beginners, It’s very tempramental to use). The “stick” of lacquer primer is awesome and takes any kind of overcoat. The Tamiya rattle can stuff is very simular and have used it with good results. (The white is great if your painting a red, yellow or any light color hue.)…[8D]
For this model I primed with regular white paint from Testors (it has the additonal benefit of being the foundation for pre-shading as well). I think a professional primer from Tamiya would be a great idea but if that product comes in a spray can I won’t use it. Does Tamiya make bottled primer so I can airbrush it myself? If not, what brand of sandable primer do you recommend?
Also, do you feel the primer should be nitro-based or oil based?
I’ve recently switched to Tamiya acrylics for all my painting needs, and routinely prime with Floquil Gray primer. After the first coat has cured in my home-made drying oven, I lightly sand with Testors sanding films. I start with the 300 grit down to 600. I then wripe the surface with a Tack-cloth to remove sanding dust, lint, etc. leaving a very smooth surface. In most cases, this is sufficient. However, if I have done some fabrication or major gap-filling- I’ll airbrush another light coat and sand this layer with the 600 to prepare for the final color coats. For natural-metal finishes, I’ll sometimes prime the bare plastic with (believe it or not), Testors/ Model Master Semi-Gloss clear laquer. This has just enough “tooth” for the acrylic to grab on to, and a sufficiciently smooth surface to not make the final coats looks rough or flat in appearance. I then airbrush the appropriate Tamiya colors or metalics. Works great with consistant results. I got the idea of using Testors semi-gloss from their first “Model Building Guide” manual, circa 1980.
Gulfstream, what kind of fine abrasive cleanser are you referring to because I know there are polishing compounds and paste out there but I never had a chance to try them out.
When I airbrush my airplane I have a problem with coarse paint appearing in hard to reach spots like wing roots. If I could polish that away with abrasive paste on a toothbrush it would work.
First off, Greg your method sounds like a winner to me, tried and true.(old school is not always dumb school) Monster I’m trying a few out, old school used to be toothpaste, I tried cleanser with bleach and the chorline did wierd stuff to the Tenax glue joints(they fell apart) I’m now trying a polishing type cleanser called Bar keepers friend, I think it’s just a powdered type cleaner/polisher maybe a pumice like agent would work too. Also remember I use a automotive lacquer sandable primmer thinned with acetone and I have had some failures learning this type of system. hth…[8D] good luck and the toothbrush method does work in those problem areas…dosen’t mess up the details.
I usually buff my primer coat before painting, but I don’t try to get a super smooth finish. I actually like the primer to have some “teeth” to help the MM Acryl paint I apply as a top coat to stick. [:)]
