Vallejo Adhesion Problems

[Immortal]

I've recently re-started the hobby and I am working on one of my first models back, an Airfix 1:72 Spitfire. I'm learning how to Airbrush with a used Aztec I bought from a friend.

I primed the model with Vallejo's Grey Primer. I then sprayed Vallejo paint (I can't remember the colour off the top of my head). I thinned the paint with Testor's Universal Acrylic Thinner and I got decent coverage. The problem is that the paint rubs off with minimal handling. You can kind of see it in the photo below.


I found that this adhesion problem is present with air-brushed or brushed paints. The photo shows wear, even after it's been touched-up a couple times.

I tried an experiment with a variety of thinning agents and a new primer (Krylon Lacquer Rattle Can):

V T = Vallejo thinned with Testor's Universal Acrylic Thinner


V V = Vallejo thinned with Vallejo Thinner


V P = Vallejo thinned with Pledge with Future Shine


Sorry for the crummy photos.

1. I primed the bottle with Krylon Sandable Primer and left it to dry for a few days,
2. I drew the squares with a permanent marker and painted in each area as noted. I left this to dry for about 2 days,
3. I stuck a continuous piece of painter's tape over the swatches and let them sit for about 5 minutes, trying to ensure the pressure applied to each swatch was the same.
4. I removed the tape to see if any paint came up.
5. I rubbed each swatch with my thumb 10 time, trying to keep equal pressure on each one.
6. I scratched the swatches with a metal paint stick.
7. I applied the same piece of tape from above and let sit for about 5 minutes and removed.
8. I tried to treat each swatch equally, so as not to influence the results.

It's hard to tell from the crappy pictures but the paint thinned with the Testors was the least adhesive. A piece came off with the first round of tape and it seemed to scratch the easiest.

The Humbrol was okay, though it didn't cover as well as the others and would have required a second coat.

The paint thinned with the Vallejo thinner and the paint thinned with the Future were about the same. The Future did make the paint a little more glossy though. Both adhered well when removing the tape. Both resisted scratching about the same.

Having conducted this experiment, I think I am going to continue using Vallejo paints. They seem to be quite popular and well-recommended and they seemed to adhere fairly well in today's experiment. While searching for some pointers, I came across the following that may help me:

In the past I had issue with the paint rubbing off down to the primer. Through trial and error I have found that VMC needs a little tooth in the primer for the best adhesion. Mr Surfacer 1000 airbrushed is just too smooth for the paint and I have had much better luck airbrushing Mr Surfacer 500 or an automotive primer from a rattle can. I also had better results with paint adhesion by using their thinner instead of water.

The paint is far too thick for hand painting right out of the bottle. The paints can be thinned with tap water or their thinner. Their Model Color thinner is nearly as thick as the paint, so a tip I learned was to thin their thinner 50/50 with water and then use this to thin the paint. Store the thinned thinner in a similar eyedropper bottle to ease dispensing.

I have since re-primed my Spitfire with the aforementioned Krylon Primer to see if this helps my cause. I guess I'll find out.

Has anyone else had this problem with Vallejo Paints? Any suggestions about how to fix it?

Thanks for reading.

 

[Elm City Hobbies]

If you use a compatible thinner with Vallejo paints, IE: not Humbrol or Testors, but Vallejo's own thinner, you shouldn't have any problems.

I have been using Vallejo for years, and have never had the problems you are having.

Just because Testors says "universal acrylic thinner" doesn't really mean universal. Their thinner is formulated for their paint, which is a far cry from Vallejo Acrylics, IE: not all acrylics are created equally, or with the same base. Vallejo is a polymer resin based paint, most other acrylics are an isopropyl alcohol base....mixing the 2...might as well try and mix water with oil.

Using Future, which is basically just a gloss acrylic medium, will work (although I haven't tried it myself), friends of mine have tried it, and like using it....only thing is, if what you are doing you don't want to be gloss, then you have to hit it all with a matt varnish when you are done.

Still better off using Vallejo's own thinner.

 

[Immortal]

If you use a compatible thinner with Vallejo paints, IE: not Humbrol or Testors, but Vallejo's own thinner, you shouldn't have any problems.

Do you "thin" the thinner like mentioned in the quote I put in the original post?

What do you use as a primer?

 

[Elm City Hobbies]

Think we are missing something here.

"Do I thin the thinner?"

No, I use the Vallejo Thinner, to thin the Vallejo Paint, and airbrush.

Primer I normally use the Vallejo Primers.

Also, make sure you shake the Vallejo Thinner before using, and well shake the Vallejo Paint. The Vallejo thinner has some retarder in it, and if left set awhile the retarder can separate from the thinner and I believe the retarder will sit on top of the thinner, so if not shaken well, you could be thinning your paint with just retarder, which isn't so bad, but might take longer to dry.

 

[Immortal]

Thanks for the tips.

The thing about "thinning the Thinner" came from this quote in my original post:

"The paint is far too thick for hand painting right out of the bottle. The paints can be thinned with tap water or their thinner. Their Model Color thinner is nearly as thick as the paint, so a tip I learned was to thin their thinner 50/50 with water and then use this to thin the paint. Store the thinned thinner in a similar eyedropper bottle to ease dispensing."

I didn't realize I needed to shake the Thinner as well so that could help. I'll have to try using the thinner once I shake it up. Maybe I'll be able to find a larger bottle of it too. So far I've only found the 17ml bottles here in town.

 

[Elm City Hobbies]

I agree, the Model Color even to brush paint needs to be thinned out a bit to brush well.

I usually go 2 drops of paint to a drop of water, mix up with your brush, and good to go, the water just helps the paint flow better when brush painting.

I wouldn't say that the thinner is almost as thick as the paint, but it definitely doesn't look like other paint brand's thinners. I would advise against cutting it with water. It does look like it is too thick to thin the paint, but it works, no need to cut it with water, as you will just lessen the effect that the thinner has on the paint (maybe this is part of your problem).

I sell the thinner in 17ml, 32ml, and 200ml, and can be purchased from my website. 200ml will last you awhile.

 

[ScaleModelMadman]

I thin my Vallejo thinner, it may sound silly but they recommend thinning their paint with either water or their thinner, so I have an old eyedropper bottle of theirs I fill half way with thinner and half way with distilled water.

I go through their thinner so fast as I use it anytime I use their paint, so I do it to save money. I love the way their thinner works but I have also just used water with no issues, so now I just use a mixture of both and it works fine.

Maybe the average person doesn't need to do this but I build and paint about four models a month on average, so I go through a lot of it and it isn't cheap.

 

[Elm City Hobbies]

Not really any more expensive than Tamiya thinner, although likely use more of the Vallejo thinner to thin out the Model color properly.

 

[Immortal]

. . . no need to cut it with water, as you will just lessen the effect that the thinner has on the paint (maybe this is part of your problem)

No, that's not it. I hadn't tried it yet. I have tried the Testors and I have tried straight distilled water though. Maybe it's the Testors.

It looks like more time with the Vallejo thinner is in order. 8)

 

[NecronautDrummer]

Do you use tap water to thin your acrylics? That might be a related issue. Treated public water and plain well water may have dissolved metal ions in it (calcium, iron, sodium) and non-metal ions (sulfates, carbonates, chlorides, fluorides), and may interfere with your paint adhesion, among other issues. Try using distilled water (cases of bottled water or 4L jugs).

BTW, anybody tried Brita filtered water? Is that any good for thinning acrylics?

 

[Immortal]

Try using distilled water

That's what I use when using water.

 

[Elm City Hobbies]

Yeah, like I said, the Testors thinner is just that...Testors thinner. Testors acrylic paints aren't the same (nor even come close to) base as Vallejo, so if that is what you were using to thin Vallejo, then I would say that is your problem.

 

[f2k]

When I build my Jagdpanzer E 100 for this year’s contest I had massive problems with this.

Having experimented a bit with it since then I’ve come up with a somewhat useful plan to combat this.

1) Airbrush a 1:1 mix of distilled water and Vallejo White Primer onto the model, operating with a fair bit of pressure on the airbrush. You could, of course, use a spraycan but I prefer using an airbrush as it gives me better control and doesn’t stink...

2) Airbrush a 1:1 mix of distilled water and the primer colour onto the model, operating with a fairly low pressure on the airbrush.

3) Seal the paint. This can be done in two different ways. Either airbrush several layers of a 1:1 mix of distilled water and Vallejo Satin Varnish onto the model or hand paint it, being VERY careful not to apply any pressure whatsoever to the underlying paint, with a mix of Vallejo Satin Varnish and a wash of your own choice.

4) Apply extra sealing by airbrushing the model with some decantered hairspray using very low pressure on the airbrush. Not only does this provide a nice surface for some scratching and chipping, it also makes your model smell like a cheap hairdressing saloon...

5) Airbrush a 1:1 mix of distilled water and the primary colour onto the model, operating with a fairly low pressure on the airbrush.

6) Lay down any camo-paint you might want as well as any other major surface detail that might need paint using either an airbrush on low pressure or hand paint it on.

7) Do any chipping or damage you might want using the hairspray to loosen the paint.

8) Repeat step 3. Hand painting a mix of varnish and a wash might be useful here, helping to darken the overall colour of the model and pull all the details together. Regardless of how you do it, the important thing is to get all the major paint jobs sealed.

9) Apply decals, do all the small tedious details, and touch-up on all the mistakes.

10) Apply weathering.

11) Seal the model with a 1:1 mix of distilled water and Vallejo Satin Varnish. If you want a shiny model, give a an extra coat, just to be sure. Otherwise, finish with several coats of a 1:1 mix of distilled water and Vallejo Matt Varnish.

The downside is that this technique use an awful lot of varnish and takes a long time to get done since, as I’ve found to my pain, it’s very important to let each layer dry completely before continuing. I’ll often give it 24 hours after a layer of paint or varnish – sometimes even 48 hours if I feel insecure about the adhesion of the layers.

All of that being said, I must admit that I’m still wondering whether or not the Jagdpanzer might have had some mould release residues on it. Or perhaps it was all my greasy fingerprints that caused the trouble. I’ve always heard that you must clean resin parts with hot water and soap before trying to paint them but I don’t know if that goes for plastic parts as well?

Oh well, that’s how I do it. If anyone have any better ideas I’d love to hear them. It seems to be working for me but if anyone have a better way of doing it...

 

[Elm City Hobbies]

Yes, parts should be washed before you put paint to plastic, as they use a petroleum based mold release to get the plastic trees out of the molds.

If your paint is flaking off down to the bare plastic or resin, this is likely the trouble.

You don't necessarily need hot water, even something like Simple Green, or a similar cleaner, something with a grease cutter in it. Spray it on, let it sit for a minute, use an old tooth brush to get into nooks and crannies, and then rinse.

As far as finger prints, as long as your hands are clean everytime you start a modeling session, you should be OK. No KFC and modeling or you will be in trouble when it comes time to paint! ;D

 

[f2k]

Yes, parts should be washed before you put paint to plastic, as they use a petroleum based mold release to get the plastic trees out of the molds.

If your paint is flaking off down to the bare plastic or resin, this is likely the trouble.

That might have been the source of my troubles then, ‘cause that was exactly what happened. As soon as I touched the model the paint would come right off, down to the bare plastic. I'll make sure to wash my Corsair before painting - hopefully that will make it easier to paint...