What do you use for masking?

 I'd highly recommend a very light grey primer coat.  Also, use the casting lines in the plastic as a guide so both sides will be the same.  That'll really #### you off if you don't...ask me how I know!?

I use only Tamiya tape for edge masking, and 3M blue tape for area masking. The blue painter's tape is formulated to be easy to remove. Don't use ordinary brown masking tape. I would advise against using any brand of painter's tape other than 3M for the large areas. I've found off-brand tapes to be of uniformly lousy quality. Either they don't stick, or they stick too tight and damage the surface underneath. I've never tried auto pinstriping tape for masking, but I might give it a try next time I have to do a difficult curve.

Something you could consider for some curves is to make a template, then lay out wide Tamiya tape on a sheet of glass and cut it to the template. This works for something like the front of the maroon stripe on a Milwaukee Road F unit, and ensures that both sides are the same. It depends on what the curve is like; sometimes you just have to freehand with the tape. 

I usually clear seal the edges, but it isn't necessary when airbrushing acrylic paints. Acrylics dry very quickly and don't run unless they are laid on way too thick. For solvent based paints, clear sealing is a good safety measure. 

I agree with the others, the cheap brown is lousy.  That stuff is better to labeling boxes and other meaningless tasks lol.  Like my Dad has always said, "buy price...buy twice!"

I've used both Testors tape, made expressly for model painting and automotive pin stripe tape for fine taping.  Pretty much equal quality and ease of use in my experience.  Larger areas get high quality 3M automotive masking tape.

Paint creep under the masking is less likely to occur if you can apply the paint a tad on the dry side.  That's where the flexibility of an airbrush comes in handy.

If you're pulling off underlying paint when removing masking tape it's best you start over anyway and do a proper prep job.

Bruce

I've done several locos with curves and multi-colors included Warbonnet, which I think is pretty difficult as repaints go.  I use green frog tape and a #11 X-acto blade to cut the lines.  One thing I have learned is the let each coat dry and harden for about thee days before moving on to the next coat.

A hobby shop sells special tape for masking models and other "fine" work.

Thanks to all who offered advice on products and methods in this thread.  It's been so long since I've done this I'd forgotten more than I thought I had, and there are materials suggested that I haven't used previously.

On a more frustrating note, the whole issue of masking curves for the GN Empire Builder F units would be avoided if Microscale had replenished the supply of the O scale decal set for this very application.  I'm considering the purchase of the HO version and having it enlarged to O scale.  I'd then use the enlarged version to create templates primarily for the curves at the front of the A units.

Thanks, again, for the help.  And more suggestions and recommendations are welcome and solicited.

I was going to ask a similar question.  I have bought 3M tan masking tape in various widths from HD and Lowes and all of it, in my opinion, is absolute garbage. It will not stay intact as you peel it from the role. It splinters into strips.  what is a good masking tape product?  

I had "bleed-under" when I used the blue 3m striping tape from the auto parts store when i repainted an AM gp-30.

I probably should have used the tamiya tape.

There is more to it other than what you use for masking.Yes get the good masking tape.Also use the proper painting  method.The biggest mistake people make is applying to much paint at the edge.Several LIGHT coats.Nick