PROBLEM: masking tape, even when I have removed some of the stickiness, pulls up my paint!!!
Tools:
Masters airbrush .5mm
Using ALCLAD 2 primer (not thinned)
Sprayed per bottle instructions (15-20 psi), 2 moisture traps, sprayed in an indoor paint booth.
Prep:
Sanding parts in most places with 600-800 grit
Degreasing all parts with purple power, manual cleaning with a toothbrush, and rinsing all parts well. 48-72 hrs dry time.
Applied primer is allowed 24hrs minimum curing time.
GENERAL:
I have no idea what Iām doing wrong. And I havenāt had a single kit that hasnāt had this issue.
Iām frustrated because I see builders paint on raw plastic and have no issue. I am doing everything I know, and not one kit hasnāt experienced āpull awayā from masking tape. I have some very detailed painting I want done but cannot attempt until I fix this! Please help!
I havenāt used Alclad paints so donāt have any tips regarding that specific paint.
A couple of questions that may give a little more insight to the problem before offering any advice.
Does it lift the paint all the way back to plastic or just the primer?
What type of masking tape is being used?
Whatās the average temp in the room where the parts are left to dry?
That is a real puzzler all right. Tamiya is an excellent low adhesion masking tape. Iāve never had a problem with it pulling up any paint. Unlike various brands of generic painters tape that did it quite easily.
Only two things come to mind after reading your process.
The Purple Power is leaving an unexpected reside thatās affecting adhesion. This seems unlikely as I am pretty sure I have heard of others using it successfully.
Humidity level. Iāve discovered that acrylic paints are sensitive to both temperature and humidity when it comes to curing properly. When not cured properly Iāve definitely had the paint lift easily.
My recommendation is to test these independently.
The easiest and fastest to test is #1.
To eliminate the prep as the cause I highly recommend doing a test by cleaning one of the parts with just isopropyl alcohol. It removes the releasing agents with no problem, evaporates quickly, and leaves no residues behind. You can prime it within moments of wiping it down.
Apply the primer. Give it the usual 24 hours to cure. Apply the masking tape, burnish it down thoroughly and give it rip.
Testing #2 is a bit more involved, but can be done with some common household items.
When I first started using acrylics I had issues with peeling etc no matter how long I let it stand. Turns out the temperature was too low and the humidity too high. Quick solution was creating a dry box.
I built one out of a small cardboard box, an old 60w incandescent lamp, and used an old meat thermometer to check the temp.
Basically you just need an enclosed space where you can hit about 110F. It drives out the moisture and helps the paint harden.
If you donāt have an incandescent light bulb cutting a hole and sticking in a hairdryer at low heat can work too. After priming put it in the drybox for about 15-20 min at a minimum. I started with a very excessive 12 hours and found the paint came out extremely hard and resistant to scratches. Iāve never had a problem with paint lifting after that.
(EDIT: Iāve never run a hair dryer for 12 hours and wouldnāt recommend it for safety reasons. My initial test was with the incandescent bulb. Iād suggest trying 15-20min if using a hair dryer. Then let it stand for a few hours to let it finish any curing.)
I assume youāre using alclad gloss black primer for a natural metal finish? If so, its been know to take some time to dry. Iāve had great success using tamiya gloss black right from the rattle can and shooting alcads over the top.
Hello! Iād suggest doing it all āwrongā - minimum prep, quick and dirty to see how it compares. It might be that somehow youāre āoverdoing itā. And yeah, if you canāt mask right it makes the work really frustrating. Good luck with your project and have a nice day!
PaweÅ
For one reason or another your primer is not sticking to the plastic. Obviously the color coat is sticking to the primer. Part of my painting procedure, when I test new combos and paint products for myself, is a tape pull test. I usually use plastic spoons, but might use a floor pan or other part with some surface to it, as well. I prep, prime, I paint, dehydrate, then use blue painters tape for my pull test. If it passes detacked, I then try full tack.
Anyway, itās either the Purple Power wash job or the primer itself thatās your problem, IMOā¦ But do some testing.
By the way, in another post I mentioned some things I did using Createx products in Vallejo Model Color paints. That was a spoon test and yes, it passes full tack blue painters tape yanked right off the surface. The primer was Mr Surfacer. I have no Alclad primer, if I did Iād do a test for you.
I appreciate your offer. I havenāt been able to test just yet. Work and my wife came down with bronchitis. So my week has been busy.
I will be testing and report back on my findings. Personally, I suspect itās a lack of curing the Alclad primer. Iām building the drying box this weekend. So Iāll be able to do a lot of testing Sunday. Helping a friend move on Saturday.
I had an issue with my primer not adhering and peeling as I took off my masking. With my next model I decided to try this out. I had it left over from a different project.
After cleaning my model, I spray the adhesion promoter.
It is strange that the primer is getting pulled up as well.
If I were you I would consider sanding the plastic to 400 grit instead of 600-800 and then using a surfacer / primer.
Splash paints makes a great surfacer that would fill in 400 grit texture great. It is what I do quite often.
I hate suggesting Rustoleum products, I honestly donāt think they work well for scale models. HOWEVER, if you prep sand with 400, their primer would be a great product for filling in the texture.
IDK, my tape pull tests have passed scuffing with 1000 grit micro pads, and pulling with blue painters tapeā¦ I use Stynylrez primer or one of the Mr Surfacer 1000 varieties. And various top coats to include craft paint or Vallejo acrylic. And this passes the test, as mentioned.
Something is interrupting the OPās primer bond to the plastic. Personally, Iād start by changing the bath he puts his parts into. I use IPA 91 or odorless mineral spirits. If that doesnāt pass a test shoot, then change the primer. I just kind of think his sanding grit should be good.
We also know nothing about the plastic in use here, unless I missed that.
I have a dry box built and will be doing my testing this weekend. Life has been annoying lately. But I should have results next week and will report back on my findings. Thank you to everyone who has commented so far. All are very good and helpful tips to try.
I always try to use Tamiyaās grey primer and Tamiyaās masking tape. Iāve found that when I use those acrylic craft paints, I need to do a clear coat(flat or gloss) first over that paint before I apply the masking tape. Good luck.
Life lifed and I just got around to testing your suggestions.
TL;DR. SUCCESS!! Thank you so much!
So, I wasnāt able to find a source for incandescent light bulbs and had to go the hair dryer route. Would have preferred the bulbs for noise reasons. But whatever.
Used a plastic container for the box and a goodwill blow dryer.
Cleaned off the previous paint job with purple power. Interestingly enough, that didnāt pull all of the paint off. So I washed the half painted parts with dawn just to get them flake free and then started to wipe with alcohol. Which DID take the rest of the Lacquer primer off. Weird, but again whatever.
Got them paint free washed them again with dawn. Dried them, wiped them down with alcohol again, just to be sure. I have oily hands no matter what. Used gloves.
Then primed them and immediately put them in my hotbox for 2 hours running and an overnight rest.
Then, cause why not, I tested with blue painters tape and BAM!!! GREAT RESULTS!!! Thank you again. You have saved my love of this hobby.
As you can see in the last image, I did get a small speck of pull off. But I consider this trivial as I will be sanding and priming again anyway.
Thinking of letting the pieces run longer than 2 hours as well. Just to see if that improves things.
Thatās great, success ! Might have been dust specks under the little flecks that lifted off. Remember too, blue painters tape is a brutal test ! Itās just my standard in test shoots I perform.
Iām currently working on a straight build project for a local Con to be displayed. I have 2 I want completed by the event in May. Just technique demonstrators.
Once I am done with those, Iāll be getting back to this project and will likely do that. Iām so excited now to do the painting!
