yellow

Yellow is the hardest color to get coverage from, IMO. If you're using enamel yellow, you're in a tough boat to row. Did you use primer? A "must" for yellow schemes! Also, with yellow you do have to use more coats than normal, esp. if you're using enamels.

I'm currently working on a SuperBee in enamel yellow, and it's a patience-tryer! One of the things you can try is to paint it over a flat yellow base; this prevents "bleed through" somewhat.

I would recommend Tamiya acrylic, painted over a base of Tamiya flat yellow. Sand the flat a bit though, to make it smoother. I have found the Tamiya yellow to be pretty good for coverage, and it dries fast too. 

Their "Clear" gloss coat from the rattlecan is simply amazing!

With a white primer undercoat I've had pretty good luck with Duplicolor and Krylon yellows. It also helps if you lightly sand any sharp edges before priming. It doesn't take much sanding, just a couple of light passes with a fine sand paper but it does help a lot with getting good coverage on those corners.

I like to use a white primer and then a flat insignia yellow for the first coat or two. Then hit it with your gloss yellow. Like others have said it takes more coats. I usually use Mm enamels.

Heres an example:

Good luck on getting it worked out.

Mckay

I've noticed Tamiya rattle cans tend to have great coverage, with the exception of the silver.

Also yellow seems to run alot easier then other paints so in addition to the more coats for coverage you have to go a bit thinner in the coats.

All other suggestions given are definately right on the mark.  Yellow is such a pain I'm considering not using it to paint my AMT international Payhauler and instead paint it up in a chartruese green, with purple decepticon decals in order to replicate the transformer "Long Haul."

When i spray yellow i use tamiya white primer and then tamiya gloss yellow with a bit of flat base mixed in it and then finish of with tamiya clear coat.

 Mike

I really suggest using a white primer first.  I also tend to not thin my yellow as much as other colors.