Salvaging project with Vallejo primer

I would strip it all off and start again, especially since it's only the primer coat.

I'm with Tojo on this.  Strip it and start over.  Pick up some Tamiya Grey or Fine White Surface Primer and the Vallejo stuff will just be a bad memory.

Tango Balboa

Does Vallejo Surface Primer ever dry to the point where it can be feather sanded? Is there anything I can do to harden the stair-stepped edges so I can feather the VSP into the repair areas and complete the model?

No, it will not be sandable, ever. (answer to both questions)

For remedial action, I agree with Tojo and Eaglecash.

Welcome to the club, many of us have learned this the hard way. I did.

I have attempted to use the Vallejo line of paints and honestly i can tell you that they are not good.  The model air colors are too thick, the surface primer is (as your seeing) not good at all.  I have had great luck with the Tamiya line of paints whether it be airbrushing or brush painting.  I even use the Tamiya line of paints for my D&D Miniatures.  My advice ?  Get rid of the Vallejo pints and go with the Tamiya Line

lowfly

I have attempted to use the Vallejo line of paints and honestly i can tell you that they are not good.  The model air colors are too thick, the surface primer is (as your seeing) not good at all.  I have had great luck with the Tamiya line of paints whether it be airbrushing or brush painting.  I even use the Tamiya line of paints for my D&D Miniatures.  My advice ?  Get rid of the Vallejo pints and go with the Tamiya Line 

Conversely, I like the Vallejo line of products.  Model Color/Game Color are optimized for hand brushing, but the spray well when thinned to 2% milk consistency.  Model Air/Game Air are pre-thinned for airbrushing.  I add a couple drops of the Vallejo Flow Improver

Reaper MSP Core Colors are similar to model color and spray similarly when prepared like the Vallejo.  Just don't pay attention to the fantasy names. 

I will admit that Vallejo primers sprayed onto raw plastic do have a tendency to pull away when unmasking  I often use Stynlyres, but often as not I will use Vallejo colors over Tamiya spray primer  

Scale Colors & AK acrylic paints are also good.   Thin as necessary. 

It takes a bit of practice.  Don't just jump back in without doing a bit

I also have no problems with the Model Color and the Panzer Aces Line,I have learned to spray them pretty easily over Tamiya primer,its just the Primer that presents problems

I can't condemn the whole line of paint based on their primer being lousy. I personally have had a good experience with the Model Air line and wouldn't hesitate to use ModelColor for brush painting. Even though truth be told I use more craft paint and get along with it very well...

My acrylic primer of choice, in fact primer of choice in general except maybe for hot lacquer top coat which I'm not a fan of anyway, is Stynylrez primer. Been with that primer for over 4 years now.

#4 in support of Vallejo paints here.

I don't use their primer because of what the OP asked about, you can't sand it. but I use the Model Air and Model Color line extensively.

With respect, it might not be fair to condemn Model Color because it is too thick. It is designed for brush painting and thus to be thinned to taste on your pallete. With proper thinning, it is airbrush friendly. It brush-paints like a we......uh, like a dream.

Vallejo has a learning curve. I find thier product line confusing and it takes time to get used to whicht product does what. I've been using Vallejo for 8 years and I still don't understand half of their product line!

Folks who are used to Tamiya acrylics tend to create multiple problems by using alchohol as a thinner, same to clean the airbrush, and end up with a mess and hating the stuff.

Perfectly understandable, I've been there too.

Thank you for the suggestions to just wipe it off! It never occurred to me that I could wipe down the entire model. I used the Vallejo airbrush thinner, and voila, the VSP rubbed off rather quickly. It took less than 30 minutes and a bunch of cotton balls. I may have dissolved a little bit of putty in the repair areas, but I had to touch those spots up anyway.

It's a shame as the VSP went on beautifully, quickly, and easily, but it defeats one of my purposes for primer: check for imperfections, fix, repeat as many times as necessary until it's all good to go to color. I don't want finickiness.

I've used the Tamiya grey and like how it goes down, I'm just not a fan of spray cans - they don't give me the same sense of control as the airbrush and I always worry about errant nozzle spittle. But that said, I'd rather wet sand a few errant drops of spittle down than mess around with VSP.

Thanks again.

Cheers.

You can decant the Tamiya and run it through the airbrush.  Was a thread on that in the past couple weeks

Tango Balboa

I've used the Tamiya grey and like how it goes down, I'm just not a fan of spray cans - they don't give me the same sense of control as the airbrush and I always worry about errant nozzle spittle. But that said, I'd rather wet sand a few errant drops of spittle down than mess around with VSP.

Here is a thread on Tamiya primer.  I have my mess-free method of decanting Tamiya primer in it, along with pictures.  Makes it so you can decant an entire can at a time which makes the time spent worthwhile.  Airbrushes beautifully.  I thin mine with MEK to help it grab onto the plastic even better.

http://cs.finescale.com/fsm/tools_techniques_and_reference_materials/f/18/t/189063.aspx

I have a bottle of acrylic sandable primer on order from Scale Colors.  Will report on its usefulness once it arrives.  

I agree that Vallejo primer is relatively useless unless on a small part that will never be taped or touched.  

I like the way decanted Tamiya works, but am always looking for a way to save steps.  I just got a bottle of the MRP fine surface primer.  It sprays well and lays down very much like T-FSP.  A little bit of a bluish tint to the gray, but nothing obnoxious.  Of course, it is lacquer and brings the negatives that you'd expect in terms of smell, flammability, etc.  

Mission acrylic primer seems more solid than Vallejo, but still weak adhesion compared to T-FSP. Also, no option for spraying a lacquer over the top of it without gumming things up.  If you are strictly using acrylic colors, it's not a bad option at all.