Tips or tricks for making decals?

print black over clear decal paper. You can get them from different sources, Micromark.com has some that I've used.  But if all you need are numbers for tail codes, there are a few companies that make a whole sheet of # in different sizes - mostly US, in black and white. Do a search at greatmodels or squadron. That's much easier than printing your own and you'll have a whole bunch of spares for future projects.

A while back I bought the Testor decal kit just to see if it was worth it. The results were just ok using only what was included in the kit.

On another test run I sprayed it with Krylon's acrylic crystal clear (high gloss).  Results were a little better.

NOTE: I used a high quality color lazer printer.  I have not tested this with ink jets.

I plan on making my own decals for my next project.  By the way I don't recommend the Testor kit.  You get better bang for your buck if you just buy the paper (around $10 for 6 half-sheets)  and the Krylon Clear.

Since I use enamel paints and clearcoat with either Dullcoat or Glosscoat, I am afraid to use acrylic clearcoats on the decals, so I use either the dullcoat or the glosscoat, depending on whether final finish is flat or gloss. I have also clearcoated with polyurethane clear- I find that curls the decal sheet a bit less than the Testors lacquer clearcoats. When I coat the decals, I mist on the first coat very lightly, otherwise the ink has a tenancy to run.  So I put two coats on- very light first coat and heavy second coat.

I use the paper from Micro Mark.

Mike Grant Decals out of Calgary Alberta, Canada will make them for you. Decal sheets can be purchased in clear or white. They should have instructions included which will help a lot. A recent issue of FSM had a informative article on this as well. Search the site`s archives.