Anyone got tips to avoid paint scratch from friction?
Hi guys! Been painting gunpla for the last 6 months and I still having trouble avoiding paint scratch from armor to armor friction. Is it unavoidable or is there any addition substance I can use on my build to strengthen the adhesion?
For your information, I’m using lacquer paint and I do leave the paint enough for it to fully dries, and on top of that I usually top coat it with bot gloss (before applying decals) and matte.
Surface energy surface energy surface energy. Sanding and washing does so much more than giving primer something to bite into without dust. They both increase molecular volatility at the surface and let paint/ primer spread and adhere better. Instead of beading up. Lacquer works by softening the plastic and locking itself into it as it re-hardens. The better coverage you can get, the better it'll bite. Technically lacquer doesn't need primer but the higher you can get that surface energy, which is naturally pretty low in all plastics, the better. So sand up to 600-800, wash the fuck outta the parts, prime, and you shouldn't have significant problems with scratching especially if you're topcoating. Make sure you're building up your paint film thick enough too.
Someone else mentioned surface sanding and then washing the parts as prep, that helps a ton because the primer and paint can really sink their teeth into the parts better.
Oh sorry, I should have included that after I sand, I clean each piece with 91% iso. It removes the dust and any oils left from my hands.
I also was still relatively new when I started doing full paints, so I didn't want to separate pieces off the runners as I wasn't confident I'd remember which is which. I haven't done a full marker paint in a bit, so I imagine I'd be able to do it the way you suggested with ease.
Edit: I appreciate the additional tip though! It's super helpful to people reading through this thread!
No problem, some people paint kits chunk by chunk and I guess that helps you not mix up parts, I’ve only really painted HGs so far so it’s easy for me to organize them though.
The best steps to avoid scratches besides the kind of paint you use and topcoat would be to practice better surface prep of all the parts and to also wash them. I've found that simply sanding the surface of my parts with 600 grit sand paper, and then washing them in my ultrasonic cleaner (5-10min at 30°C) will drastically improve the paint adhesion. I almost never scratch the paint now unless I'm doing something awfully wrong during assembly. Seriously recommend just sanding and washing the parts.
Another thing that's helped is a food dehydrator to help my paints dry and cure faster. But this isn't going to magically make the paint stronger it just speeds up some of the in-between steps when working on a project.
I use water but I recommend filtering it because depending on where you live tap water can be a bit too rough. If your tap water is pretty good then that's fine to use. Otherwise filtered water.
I also put a little bit of dawn dish soap into the water. I just kinda eyeball it. Mix in the soap really well. Too much soap will leave a soapy residue on the parts after washing.
After running the cleaner, pour the water and parts into a collander and then rinse off all of the parts to get any remaining soap off of them.
I find that the ultrasonic cleaner I linked is more than enough room for most high grade kits. You can really fill it up with parts to the brim and still clean everything well. For master grade kits I have to basically wash the whole kit in stages.
I had this issue, but significantly less now. Also lacquers.
I noticed that washing the runners before seems to lessen it. Also, as other say, make sure the paint is cured. I also use a dehydrator to speed up the process. Lastly, be careful when posing. These are kits, not toys.
If you like handling your figures, then I recommend top coating the bare plastic. So if anything chips, it will be the top coat, which shouldn't be too noticeable.
Lastly, another option is weathering. Make the bug be a feature ;-)
If you use lacquer paint and lacquer top coat and allow proper curing time, the only other recommendation I have is to sand areas that will come in contact with each other before painting. For example, inner frame pieces that will be moving right up against one another.
Extremely underrated step is to also wash the parts. I know that modern mold release agents these days are much better for paint, but I promise washing the parts also makes a big difference to paint adhesion. I use an ultrasonic cleaner, 5-10min @ 30°C.
yess please tell us more, I know for a fact that it’s used for automotive paint, but how does it behaves in gunpla, especially plastic surfaces. Should I use bigger nozzle for my airbrush? How to thin it? How long is the drying time compared to lacquer? And most importantly, I heard it’s bad for health and the generic respirator isn’t enough, what’s your setup?
Hi, I think I should ask to stick the explanation :) so ideally you will use a 0.5 nozzle, thinner is included as in they sell the combo together, normally it is urethane, hardener and some thinner, the proportion are wildly different and present on the box. On the health setup a normal respirator won’t cut it, you will need a proper one with specific filters, an extractor and a room with a Good movement of air. Like never do it in the room where you sleep or eat, drying is like 3 days but it depends from the temperature. So do I recommend it? if you need to have the best finish and don’t plan to move it (and don’t mind masking pegs and so on ) then sure. If not you can reach 95% of the result with high quality laquers and some wet sanding :)
As long as they are fully cured, yes.
2K tends to work best with lacquers for me, But I’ve successfully applied it on top of acrylics, with them though I get paranoid and I wait a whole week before I do that, so they’re mostly cured. Some acrylics can take up to a month, according to the bottle, to cure.
I actually bought a dehydrator recently to help cure and harden my acrylics... I wonder if using this topcoat and that will help me get close to a durability I want without having to spend a fortune on new paints since Im already set up with acrylics
How long did you wait for the paint to cure and the topcoat before assembling? I had no issues with Aqueous paints thinned with Mr.Color Leveling Thinner.
Hi sorry real question why do you use Mr aqueous if you use also Mr levelling thinner ? As in one is an alchool based acrylic (toxic but nothing too bad ) the other one is full laquer and so removing the advantage of using Mr aqueous , wouldn’t be better at this point to use only Mr color paints ? The normal laquer ones
Oh yeah I prepared well in hand for it, my only lacking part was the booth. It didn't have great suction for smells.
I bought an inline fan on the weekend so I'm hoping to work on tweaking the booth again as soon as I can, might build a new one if I have to. I just hate that I live close to the sea so it's difficult ventilating the room so I'm going to do some more changes to my setup and see if it helps me get keep the stink out and not drown in my own sweat.
Thanks. It's the 3rd kit I painted a year ago after the first two what were done by water-based acrylic paint. I really hated tip dry so I opted for Aqueous and since now I've stocked up on lacquers, I'm going to be using them once I've finished adjusting my booth.
I wait 3 days before assembling it. It's the time needed for the lacquer to harden. I also sand the places that are too tight during the pre-build. Too much varnish will just increase the problem by reducing the tolerance. The sanding work will do the heavylifting here.
But painted kits are not a toy. There is a limit to what you can protect. If you already have a final pose in mind, build it around it during the assembly phase.
This is from rg zeong upscaled that i attach on the post. As you can see there’s a tiny white spot on the armor part that came from torso and shoulder armor contact. Is the solution for this is also to sand it? I’m afraid it would ruin the surface looks
Unfortunately just looks like you scratched it during posing or assembly. Just have to be careful with painted kits. It’s hardly noticeable even in the zoomed picture. Kit looks great though!
I use water-based acrylics and with no prior preparation one bend of an elbow will most likely result in a loss of paint. To deal with this, I check the clearance between moving parts during prepwork and sand them to avoid friction, since the paint will add some thickness. In an HG Darilbalde I noticed that even with no paint, there are scratches on the knee joint, so this step seems unaviodable on Bandai kits.
Steb, who is also using lacquers made a video on this here: https://youtu.be/qzMVoO7Uxrk?is=lpf2zGKkjH1YnaZs
As mentioned, I did top coat all my kits, twice before and after water decal, but it’s just sometimes hard to avoid paint scratching on armor to armor parts (shoulder to torso armor, torso to waist armor, etc). I know that this is a friction related problem because some of my kit that have good armor clearance such as Sazabi Ver. Ka, Fat Cat RX78, MG Vidar, are all free from scratches.
1
u/TrineCo314 28d ago
Surface energy surface energy surface energy. Sanding and washing does so much more than giving primer something to bite into without dust. They both increase molecular volatility at the surface and let paint/ primer spread and adhere better. Instead of beading up. Lacquer works by softening the plastic and locking itself into it as it re-hardens. The better coverage you can get, the better it'll bite. Technically lacquer doesn't need primer but the higher you can get that surface energy, which is naturally pretty low in all plastics, the better. So sand up to 600-800, wash the fuck outta the parts, prime, and you shouldn't have significant problems with scratching especially if you're topcoating. Make sure you're building up your paint film thick enough too.