Primer Test - Part I

Tools, Techniques, and Reference Materials Painting and airbrushing
1

Well, I finally got around to setting up the primer test. I decided to test out three brands:

  • Vallejo Acrylic Polyurethane
  • Badger Stynylrez
  • AK Interactive Waterborne polymer

No particular order to it. My main reason for this is am wanting a primer that is acrylic that I can sand. I have used the Vallejo in the past and it works very well as a base coat, but I cannot sand it. It comes off in chunks. Now to be fair I can polish it with a very fine grit paper but that is not what I am looking for out of a primer. I want to be able to spray, inspect seams and the like, and then repair. I have used Tamiya’s fine grey rattle can and it is wonderful, but I don’t like the cans and I don’t like the lacquer smell plus the overspray is messy and want to spray indoors.

So before I get to the first part of the test, I am not going to say one is good and one is bad, I just wanted to see what I find. OK, I took a plain piece of card styrene and wiped it down with Testors Polly-S plastic prep:

Obviously this is from my abstract period in painting:) I wanted to make sure I had something for the primer to cover. I then sprayed the three on the divided section of the card:

The AK is on the top (I have the grey), the Badger is in the middle (I have black), and the Vallejo is on the bottom (I have grey but it really comes out almost white). You can see that all covered just fine. I used a good solid coating that I built up with many passes in light coats. I used it straight out of the bottle with a .5mm needle in a Badger Patriot at 25 psi about 6 to 8 inches away.

All of them spray just fine with that configuration and gave the airbrush no trouble. The Vallejo has the most odor which is kind of sweet. The AK has a faint distinct odor that you have to get real close to, and the Badger had hardly any. All cleaned up with plain water and some Testors acrylic airbrush cleaner. The AK seemed to be the thinest out of the bottle and reminded me the most like actual acrylic paint. The Vallejo was a bit “rubbery” and was the most difficult to clean. the Badger was the thickest but cleaned very well.

So for part 1, none seems to be “better” than the other. I amgoing to let the card sit for 72 hours. I am in Arizona and the current humidity is around 20% tops in the afternoons. The house may be a little less. I think 72 hours should be more than enough time to make the surface ready for sanding. I am looking forward to the results.

John

2

ready

3

These are exactly the same three I was going to test side by side.

I will be following your test closely,and will do whatever parts you leave out or bypass.

My own personal list of what a primer has to do are these things:

It has to stick to plastic and putty all on its own. For that I burnish down some tape, then remove the tape to test the primer’s adhesion.

It has to sand, otherwise, as you say, you can’t primer, make repairs, primer, etc. (this would really disrupt the whole fill, sand, primer, sand, fill or primer, sand, etc, etc routine)

then, no matter how well it sticks to plastic, how well it covers over colors, or how well it sands,paint has to stick to it with the same masking and removal test.

In both of our cases, we need something besides smelly, toxic lacquers and enamels,if Polly Scale and Aeromaster and LifeColor won’t adhere to my primer,I might as well be using Enamels,which is not an option anymore here at the Hangar Deck.

Rex

ps, I bought the Stynylrez based on your posts here on FSM, took the opportunity to pick up some Badger parts while I was at it,so far, I love the quick drying time of the Stynylrez.

4

The Vallejo primer is not sandable. It is less durable than AK and Tamiya. The Vallejo primer doesn’t bite the plastic. Instead, it forms a rubbery surface on it.

You’d better clean your AB with lacquer thinner or denatured alcohol after shooting the Vallejo primer.

5

I have never had an issue with cleaning the Vallejo with the Testor’s airbrush cleaner. I have used Vallejo on several models. I also hear good things about the Vallejo airbrush cleaner but I haven’t tried it.

Just an update after 16 hours only the AK seems to have any odor left to it. I think I will do a 24/48/72 hour test and see if there is any difference. Rex; thanks for taking up my slack. With this being a test on just a smooth surface, it might be good to try it on a rough surface or two sections of card glued together where there would be a seam. my hunch is that once there is a “crack” in the primer, it may get pulled up from that point going forward.

John

6

I’ve used and have Vallejo, AK & Tamiya primers. In my experience, the AK & Tamiya are more durable and adhere to the plastic much better than the Vallejo primer, based on my trusty “scratch the surface with a toothpick” method.

BTW, the Testor & AK cleaner both have denatured alcohol as an ingredient according to the folks at other forums.

7

looking forward to what happens

Rick

8

Not at all a scientific method of evaluating, but I’ve noticed that acrylic paint seems to me to dry to a hard and durable surface, even somewhat scratch resistant when compared to enamel. More than once while handling Model Master flat enamel painted models, I’ve left finger nail marks behind. Clear coats of course take care of that. Since MM enamel apparently is softer than acrylics, several times I have used it as a primer. A few light coats a couple of minutes apart, let cure overnight, then a light sanding with WELL USED 600 grit and it sticks well, doesn’t strip away. Seems to me to do a very good job of filling and finding the little flaws that I was looking for, I think it leaves a well prepped surface for the final finish to lay down on. I’ve even experimented with adding a bit of lacquer thinner to the MM flat paint, which seems to me should give it even more bite for adhesion to the plastic. I didn’t notice any reaction between that and the acrylic sprayed over as final finish, but I was just testing a bit to see if it would react. Indeed there was no need for it, as like I said, I’ve never had the MM scrape away with sanding. For what it’s worth, I have found the acrylic primers to be a good bit more touchy and sometimes unpredictable, the old time MM flat enamels just seem to be (for me) a predictably user friendly and forgiving medium, for priming and sanding. There, those are my two pennies. Patrick

9

OK, the results are in on the 48 hour test. I wanted to do a 24 hour one, but the AK still had a faint odor. Neither the Vallejo or the Badger had any after 24. After 48, all was quiet on the sniffing front:) Now to what I found.

I first put down a section of the Staples version of Blu-Tac. It is grey but I am sure works the same way as I have used it just like Blu-Tac. I also then put down a section of Tamiya tape, and then one of Scotch Blue Painter’s Tape. I have no need to try a heavier tack tape. I did NOT de-tack any of the tapes, just from the roll to the card. I let them sit 30 minutes and then peeled them off.

All passed with flying colors. There are two little scratches on the Badger (black) section and those were due to me picking at the corner of the tape. More to come there.

Next was the sanding. I used some 180 grit and some 320 grit paper straight from Home Depot. not sure how this may equate to various hobby grits. Below is the result of sanding both grits. things degrade a bit here, so let me sum it up. Again, this is MY unscientific test.

  1. Both the Badger and the AK sanded off very easily and when I ran my fingers along the sanding area, it was very smooth. I could not detect and edge. the Vallejo came off in smaller “chunks” and the edge was palpable to my fingers. I could feel the edge. The Badger and AK came off as a fine sandy dust.

  2. All did much better with the smoother 320 grit. I am going to say that the finer the grit and the “softer” the sanding action the better. However the end result was the same as number 1 above.

  3. I was able to use my fingernail and scrape off all three. Consistent however with the above results, the AK and Badger was smooth to the touch and the Vallejo was detectable to my fingers.

So what are MY conclusions:

  1. None of them will give you a primer coat that cannot be scrapped off.

  2. All will adhere to the plastic without lifting after drying.

  3. the Badger and AK are so close as to be a tie for the “best” for sanding and keeping a smooth surface.

  4. All are easy to clean with no unpleasant odors and gave my airbrush no problems with water and airbrush cleaner for cleanup.

  5. All come in a variety of colors.

In the end, I will be using the Badger and the AK as my first choices and continue to see how they perform. If I know I have a large area where I know I won’t need to sand, I my use whatever I find is within reach.

I am going to forgo the 72 hour test and do a spraying over them and see how the paint adheres to the primer. that will come over the next couple of days. Thanks for reading and anything you all have would be appreciated I am sure by all of us who are trying to find that perfect primer.

10

I told you that Vallejo was not sandable. The Vallejo primer is the worst I’ve ever used, and there are several horror stories of using it at other forums. When I bough 6 bottles of the Vallejo primer last year, I wasn’t aware of its weaknesses. I mostly use Tamiya and AK primers nowadays and couldn’t be happier.

11

I am not disputing your findings. The purpose of this was to try to show those who might be on the fence what I found. There was a gentleman on another thread awhile back who claims that you can sand Vallejo, so I thought I would try them all out side-by-side. I just thought it might be of interest to present my unscientific test and let folks see and draw their own conclusions.

John

12

Nice job

13

John, your post will help many people!

If someone had posted this kind of experiment last year, I wouldn’t have bought Vallejo primers. I wasted a lot of time (and my sanity) figuring out why I couldn’t sand Vallejo primers.

14

same here, Chrisk-k, I bought the 200 mil gray, the 200 ml white and the 60 olive drab when that thread ran on here.

The good news is that I can use the white as my first white paint coat over primer, and use the Olive drab to do bomb body color. Over AK or Badger primer, of course.

I bought 6 bottles of Acrylic primer since the discussions started on FSM,and can actually use the last three, lol. And because I started to get leery toward the end, those three are all the smallest bottles.

I will be getting the larger bottles of Badger’s primer next time I get supplies, though.

Rex

15

I too bought a 200ml grey and 60ml black and 60ml dark grey. I was thinking the same thing as using the grey (almost white) over the Badger since the light under side RLM colors do better with a light primer. I looked last night and Stynylrez was out of stock on Amazon. Where do you all purchase it?

On a follow up, I sprayed some RLM light blue over the primers and will let them dry until tonight and see what happens on the tape test.

John

16

I’m stuck with five 60 ml Vallejo primers in various colors. One nice thing about Vallejo primers is, once cured, they are impervious to alcohol. If I want winter camo or heavy chipping, I spray a Vallejo primer as a base coat, let it cure, and spray Tamiya over it. Then, I soak a brush in IPA and scrap away. Super easy. No hairspray is needed.

17

you can get Stynlrez at Webairbrushes.com

I used the postage to get a few airbrush spare parts while I was at it,and I tried a Badger Military paint color (not a close enough match for anything)

the primer is halfway (or more) down the paints page

Rex

18

Rex; thanks. Chrisk; good tip. I now have a reason to try that technique:)

John

19

I was certain they didn’t have any last time I looked at webairbrushes. Thx.

20

So I masked all three again with the three different masking options as below:

I am happy to report after 30 minutes when I lifted them off, there was no lifting:

So if you don’t need to sand, they all work great. If you want to sand, stick with Badger or AK. There shouldn’t be any worry about masking any of them. Now I am sure someone will not have the same results I did, but I didn’t do anything out of the ordinary. I prepped the plastic, sprayed, cured 48 hours for the primer and 24 for the acrylic paint. I am off to try the Badger and AK on a real model kit next.

John