Tamiya acrylic adhesion

What are you thinning the Tamiya acrylic with?

Also, I'm not sure a couple hours is a fair test. There is a difference between dry and cured.

How long are you allowing the Tamiya primer to cure before spraying the acrylic over it?

I've found Tamiya primer followed by just about any hobby quality acrylic to be pretty durable.

 

i have that problem with their flat black.

It may be a color by color problem.

Acrylics dry from the outside in, where enamels dry from the inside out.

I always give paint three or four days to really cure.

 

In my experience, Tamiya acrylics are very tough when cured and adhere to plastic better than other acylics.  You need to give them 24-48 hours to completely cure.  I only use Tamiya's acrylic or lacquer thinner to thin them to a ratio of 1:1.  As with any other paints, you need to stir the paint very well before thinning.  I use the Tamiya stirrer, which works better than anything else I've used (including an electric stirrer).

If you want to experience super soft acrylics, try Vallejo .

I'm not an acrylic paint frequent user but the times I have used Tamiya's acrylics, I have found them to be of excellent quality. The rattle can or bottled surface primers are also of excellent quality and I use them frequently. 

I don't know if you have a bad batch or just are turning bad with age? A while back I had a very old MM Acryl paint bottle which looked to be ok and sprayed just fine. The paint simply rubbed off like powder a few hours later. I guess it went bad.

thanks for the replies everyone, I'm thinning with Tamiya X-20A acrylic thinner. The primer coat has definitly cured, on some samples I sprayed the acrylic on bare (dust free) primer which was sprayed years ago. It doesn't seem to have a whole lot of effect. About half of the areas i spray just seem to scratch very easily (leaving bare primer underneath), others not as much. On the plus side with most areas masking tape will not lift the paint, however on some areas with lighter coats, it will take the paint off. Since I have used Tamiya rattle cans for years I'm considering decanting some of them for use in the airbrush, and mixing to make the correct colours. Does anyone have any advice on decanting rattle cans? specifically how to clean the airbrush afterwards (I recall that lacquer it being fast drying and tough stuff). Thanks for the help so far... James

Inconsistent results you are getting are not normal. I've never had a problem like you describe with Tamiya acrylics. I let the paint cure 24 hours myself.

One possible explanation is surface contamination after you apply the primer. Skin oils can interfere with paint adhesion. I find I get much better adhesion when I don't handle a primed model with my bare hands.

Also, I suggest applying the paint in several thin coats rather than one or two thicker ones. I don't know why, but I get better adhesion when I do thin coats.

JamesF

thanks for the replies everyone, I'm thinning with Tamiya X-20A acrylic thinner. The primer coat has definitly cured, on some samples I sprayed the acrylic on bare (dust free) primer which was sprayed years ago. It doesn't seem to have a whole lot of effect. About half of the areas i spray just seem to scratch very easily (leaving bare primer underneath), others not as much. On the plus side with most areas masking tape will not lift the paint, however on some areas with lighter coats, it will take the paint off. Since I have used Tamiya rattle cans for years I'm considering decanting some of them for use in the airbrush, and mixing to make the correct colours. Does anyone have any advice on decanting rattle cans? specifically how to clean the airbrush afterwards (I recall that lacquer it being fast drying and tough stuff). Thanks for the help so far... James

 

I have decanted Tamiya rattle can enamels before and they spray wonderfully through an AB; however, just as with any other brand that you decant, be sure to let the paint off-gas for awhile (several hours if possible) to make sure that you get rid of all the propellant gases that are mixed with it. I've had instances where even after a couple of hours just the body heat from my hands have caused the trapped gasses to rapidly escape causing quite the mess (this was likely due to the fact that I did this in my garage in the middle of the winter). Another thing I found with decanted Tamiya paint is that the paint can be pretty "hot" and if your decanting into a plastic container, it may react with the plastic and melt the container...again, learned the hard way. Just some ideas to consider.

In that case my next guess is maybe you are spraying the Tamiya Acrylic on 'too dry'? (partially drying in the air before it hits the model)

In general, I think you will find that you will airbrush much closer to the target than with rattle cans.

Hope you get this sorted out. I agree with the others here, Tamiya acryls spray and adhere great and you shouldn't be experiencing this.

thanks again for the advice everyone, after 3-4 days the paint has hardened up a little bit, but is still easily scratched in most areas (usually the lighter coated areas). Curiously enough i sprayed some of the acrylic directly onto the inside wing surface of a new kit (where you cant see it when built) less than 24 hours ago and it has adhered perfectly, yet a spray a few days old still hasn't. I am spraying quite close and i'm getting a wet film of paint over the surface. However I'm definitely doing something wrong here, I might try decanting some cans and see how I like using them instead. Is cleaning the airbrush much harder using the decanted paint? Thanks especially to jelliott523 for that advice about the plastic container, that's exactly what i was planning on doing 0_0

To decant from a rattle can look for a large diameter plastic drinking straw. I know Burger King has them. Place the straw over the can button nozzle and spray into it and on to a small containerto collect the decanted paint. I let it sit for a few minutes to let any gasses or bubbles escape then use it in your AB. No need to thin as it is just perfect to use.

And again about the adhesion problem, I will not rule out bad paint. It happens once in a while as with Alclad and their black gloss primer that would not cure.

thanks, I have tried different bottles an different colours, still the same problem. I think i might just work with decanted laquer, even out of the can i have gotten good results with it. Thanks for the help, James

Hi James, I have never had any issues with Tamiya so not sure what's going on there. If you like lacquer, I would just switch to Gunze Mr. Color. Best hobby paint out there and you won't have to deal with decanting.

Jay

thanks for the adivce Tucohoward, but unfortunatly in my area Gunze Mr. Color are in short supply, i'll keep a look out for them but until i find then the tamiya cans are the way to go for me.

 

Thanks,

James