Anyone had this happen to them? I tried painting AK Interactive Acrylic (gunmetal color) on top of both Tamiya fine gray primer on plastic as well as Tamiya metal primer/undercoat, and beaded up like oil on top of water. I tried MIG and Valleyo acrylics on the same Tamiya-primered surfaces and they stuck just fine. What's the deal?

I forgot to type "and on top of Tamiya metal primer sprayed on PE parts-the AK doesn't stick to that either

Yeah I had this happen as well. But not with Vallejo acrylics- just with Mig Ammo acrylics. Some other people had a similar issue and the advice from someone who worked for the company was that it is caused by surface tension- that first coat should, supposedly, be put on very light and sparing and it should break that surface tension, allowing subsequent coats to bed down nicely. Can't say I tried that myself as I just switched over to a Tamiya paint to avoid any more mess but it may be worth a shot. Alternatively you could try using the AK or Mig Ammo primer instead of Tamiya.

Yeah, had it too a few months back.
Would be interesting to know if the same happens on Mr Surfacer primer.

Well, I guess I won't use their paints anymore. Luckily I only have that one color.

the official response from AK is that the paint won't work on a non-acrylic primer base. You have to use an acrylic primer. I guess the Tamiya is not acrylic but the can doesn't say.

You could try an acrylic flow release , same thing as breaking up surface tension .

too many products from different brands..unnecessary...I'll just use what works for now..

Tamiya is not a true acrylic - has some lacquer-like properties.

I'd love to see pictures of these. First time I heard of this problem in painting.

A lot of people use tamiya spray can primers and if the statement of AK holds (and it being roughly similar to vallejo and mig ammo), then this should have been a rampant problem since tamiya spray can primers and mr. surfacer are lacquer based.

Typically I use lacquer or PU for primers, acrylic for base coats, and enamel for washes and detailing. This really piqued my curiosity.

I have the same problem on Tamiya fine primer in can but i don't remember if was Vallejo,lifecolor or Italeri acrilycs,i try with Tamiya normal primer (not the "fine" one) and the problem was desapeard!!...some people use a little bit of glass cleaner to thin the acrilycs paint, to break the surface tension ,in Italy is called "Vetril".

Here are the 2 email replies from Fernando at AK, copied and pasted here. From what I read on the interwebs, acrylic primers are not that great and hard to find, but I am not sure if this is true..?:
1.the color works better over an acrylic primer, if is a glossy surface not this, but all acrylics metallic colors don’t work fine, you can test other bottle from another brand but will be same, if you varnish before in acrylic you can use without problem



2.Tamiya label their products like aqueous or acrylic but in really are laquers that need their solvent to use and not are exactly acrylics,

I don’t have used their primer but I suppose is the same, anyway if you have other gun metal there and want to test we both solve doubt

This has me worried as my M4A3 build is nearing the stage where I want to put primer over the engine bay. Never worked with AK Interactive, Ammo Mig Jimenez or Vallejo colors before and never used primer before either just Revell colors.