Smoothing out airliner windows.....good putty to use?

[DutyCat]

I am building the old Airfix 737-200 in US Air livery. This is a natural metal finish with a red stripe UNDER the cabin windows. I plan on representing the windows with decals. Given the location of the fuselage stripe and the fact that it is a NMF, it is critical that the mold outlines for the cabin windows be completely invisible. I used Squadron green putty to fill them in, and after 'normal' sanding, I used polishing cloths. But I can still distinctly feel where the windows are when I run my finger down the fuselage. My theory is that Squadron green putty is kinda soft so the sandpaper takes more of a bite out of it than the surrounding, harder plastic, leaving a non uniform surface. I have heard that 3M Blue is a very good "glazing" putty, but I have also heard that it comes in large tubes for about $20. I am not so keen on that. Anyone have any experience with this problem and can offer a suggestion? I'll buy a large tube of 'Blue' if I really have to to get the job done right.

[Phil Ciborowski]

i usually apply a piece of .020 styrene behind the windows im going to fill in and then after the glue as cured (CA+ gap filling) i go back and with ole' trusty squadron white putty i carefully fill in the windows (using a piece of scrap .020 plastic as a "putty knife"). When the windows are all filled and before the putty is dry, i roughly shape the area... and once dry i sand smooth everything..

i have been using this for a while and havent noticed any sinkholes in the windows i have filled, or have had any problems....

the reason for the plastic backing to the windows is so that in the course of building, you dont press the putty window plugs through the window opening and have to re do them (experience on that one lol)

[trojansamurai]

Most of the solvent based putties are soft and porous, as you have pointed out. They also tend to shrink, so a week or so of drying is recommended for complete curing prior to sanding. Tamiya's basic putty seems to address these issues the best.

The best thing to do at this point is to dress the puttied areas with Gunze's Mr. Surfacer 1000. It may require a few coats to completely seal the putty. Once cured, lightly sand with 1000 grit to blend.

An alternative is to dress the area with superglue. It serves the same purpose of Surfacer, but is even harder and plastic-like. However, it can be harder to sand and feather, but it will certainly eliminate the problem you're currently experiencing.

[Jay Chladek]

A 2 part epoxy putty such as Milliput or Aves Apoxie Sculpt (my favorite) works well for filling like this since the hardened putty is very robust. Simply mash in the putty on the insides of the fuselage until it produces a raised area on the other side, then sand flush when dry. Plus, it doesn't affect the surrounding plastic like Squadron Green can. But, to fix your current problem, there are some things you can try. Has the putty completely dried and cured or might it still be fresh (i.e. less then a week old)? As such, I would wait until it has fully cured since Squadron can have this annoying tendancy to throw additional curveballs by shrinking more if it is rushed too much (i.e. shrinking after paint is applied). I just don't like it as a filler.

For something like this where you need an even surface, then I highly recommend primering with something like Gunze Mr. Surfacer 500 or 1000, simply because the raw plastic and putty surface probably isn't likely to react to the NMF method you use quite the same (one of the reasons I prefer Alclad to Metalizer, since it can be shot over primer and still achieve a high shine). If you primer first, then you'll have a uniform surface and this will also help highlight any flaws that have to be addressed before painting anyway. One thing you can try is to apply a thicker drop of primer to the surface of each window if it shows up as a recessed area after primering, then sand and polish like you did before. Mr. Surfacer 500 has some filling properties and they also make a product called Mr. Putty which is a thicker yet, but can be applied with a brush. I've found the stuff works well for filling recessed panel lines with a spot application. You could also potentially do it before primering as well.

Best way I've found to check for fine surface flaws before primering is to hold the model up to a light and see how the light reflects off the surface. This way, you can usually spot flaws that are too tiny for your finger to catch when you rub the surface with it.

[DutyCat]

Thanks, everyone, for all of the suggestions. No one here can vouch for the suitability of 3M Blue automotive glazing type putty for this?

[ismaelg]

Hello,

I highly recommend Milliput, the fine grain one (white), and automotive primer/filler like Plastikote T-235. That's my favorite primer in a spray can because it works with lacquers, enamels, acrylics, urethanes, and anything else this side of nuclear fusion. Milliput will NOT shrink, dries rock hard and it is very stable. Plastikote will sand down very smooth and you can even polish it. You can get Milliput at Micromark.com and Plastikote at many automotive paint retailers. I hope this helps.

Thanks,

Ismael Gonzalez

Puerto Rico

[trojansamurai]

Thanks, everyone, for all of the suggestions. No one here can vouch for the suitability of 3M Blue automotive glazing type putty for this?

It's a good putty, but you're still going to get some amount of shrinkage and porosity. You would still need to seal it with Mr.Surfacer 1000 (not 500), a good lacquer primer, or superglue to achieve the surface prep.

Edited November 28, 2006 by trojansamurai

[Phil Ciborowski]

i should also mention that i have used Tamyia's 2 part epoxy putty to fill windows on the curved superstructure of a ship model and that worked without the backing..

[seamaster]

Here, Here, I can vouch for the 3M Putty. All I ever use for filling seams or for that matter filling anykind of seam, window, injector pin depressions etc. 3M Acryl Blue Glazing Putty. I think that stuff is the best thing since sliced bread. It does not harm the plastic in any way, feathers beautufully, shrinks very little, and sands very easily with dry abrasive sheets or wet or dry sandpaper. If you want a really smooth finish dry sand lightly to shape, go over with wet or dry used wet. and polish out with varying grades of Micro Mesh Cloths. Accepts any kind of primer, which you should use to seal it, than paint. You can thin it to any consistency you want, like say Yogurt, and paint it on seams and get a real thin application. Keep repeating the process after the the initial application is dry. Sand until the seam or depression is the way you want it. Thin it with Denatured Alcohol only. When you thin with Alcohol, stir it up real good till it,s nice and creamy. If you added too much Alcohol, just pour the exceess off. Clen your brush by dipping it in Liquid cement like Testors. Cleans the brush right off. Do Not thin the putty with the liquid cement. Use ONLY Alcohol. As they say, Try It. You,ll Like It. A little pricey though. About 15 bucks for a large tube at your local Automotive paint supply outlet. But I gurantee you, it will probably outlast more models than you may have in your collection. It,s all I ever use. Dennis

[Phil Ciborowski]

can you add this putty on as a form of texturing on large scale aircraft weapons as well?

[DutyCat]

Thanks Seamaster. The word on the street here is the 3M Blue stuff is wonderful, as you have described. I just wanted some broader input to confirm, especially since I am trying to pull off a NMF.

[seamaster]

can you add this putty on as a form of texturing on large scale aircraft weapons as well?

Cannot comment on the use of the Acryl Blue for texturing since I have only used it for what I described. seam filling, depressions etc. I would suggest though that if you have any scrap kits that are unbuildable as we all have, try what you want to do and see what happens. If you do it , let us know the results. Would be interesting.

[Phil Ciborowski]

i save all the extra weapons from all kits so i can go and pull one unpainted bomb out and give it a shot... provided i get to the store and pick the stuff up... it sounds like its fantastic to work with on any modeling project tho.