More painting troubles! Paasche cork gaskets, DUST, Humbrol Maskol.

My paint booth was commerically manufactured. I did not have errant dust problems while spraying in this booth during the winter and late past fall when conditions were damp outside and dust was naturally kept down in the atmosphere. I don't suspect my booth itself is the culprit. 

Hi;

   Hmmm, quite the set of Un-Intended, Boo-Boos. First and foremost You Cannot spray, even in a booth without using a shop Vac (Well sealed on the outlet). The Fans in the Booth do generate static Electricity which draws the errant dust particles in the air.

   The Shop Vac MUST have a good seal in the body to removeable top, as well as the hose to body. Here's a tip. Do this. In my booth I wipe it down with a Tac-Cloth before spraying after which I also wipe it with a static Free Damp cloth. Learned that years ago painting life sized objects!

     No Fans in the room and a filter of sorts in my Air -Conditioning vent! This helps too.

    As far as the other part of the post. I do put parts on a painted surface and carefully draw a sharp X-Acto around them. Then scrape carefully inside that area till bare plastic is visible then, Using a tiny glue applicator glue the piece on. Plastic Glue will Not glue to paint, or Chrome! Now that said, C.A. glues glue Painted surface to Painted surface. It does not penetrate the paint either.

Eaglecash867

As an alternative to scraping paint away, you can also use a Q-tip that is just barely damp with isopropyl alcohol.  I have little, pointed foam Q-tips also for more precision.  That avoids a lot of the mechanical stress caused by scraping with a piece of metal and you don't have to worry about slipping and accidentally gouging something.

 

That is a good tip. I will try to remember that one. It might have helped me on the recent debacle I had.

I usually use an Xacto knife to scrape paint away. For example, the chrome plating on two rim halves that are to be glued together. When I mount my truck engine to my chassis, paint will first be scraped away in those inconspicuous areas. The motor mounts. Where marker lights are to be glued to the top of the truck cab in high cosmetic areas, no scraping there. Yes, these are models, not Tonka toys. That cured Testors enamel is plenty tough enough to Super Glue small trim parts too. Liquid plastic cement, however, will eat right through that paint and it won't have good adhesion. 

As an alternative to scraping paint away, you can also use a Q-tip that is just barely damp with isopropyl alcohol.  I have little, pointed foam Q-tips also for more precision.  That avoids a lot of the mechanical stress caused by scraping with a piece of metal and you don't have to worry about slipping and accidentally gouging something.

JonBailey

Sometimes parts do have to be glued to painted surfaces like trim pieces or mirrors to a body. Scraping paint from a body might cause cosmetic damage. I use a product like Super Glue in those cases. I only use cement where I can feasibly glue bare plastic to bare plastic as in the assembly of a vehicle chassis. 

Very true. The cosmetic aspect is another reason why I CA to paint. If using glue that melts the plastic like Tamiya, I try to scrape. Its a mix mash of different glues.

oldermodelguy

 

 

Bakster

Sounds like a cool project. 

I was wondering if sanding the base coat to prep for a top coat of clear was recommended for good adhesion.

No, not needed. You should not have problems with that and especially since you will be using Testors Glosscote for the clear. That stuff sticks. I have never had a problem with that coming up. If it does, it will pull up the base coat and maybe the primer even. In fact, I just had that happen. A part part broke off and the glue pulled up the paint right down to the primer. The Glosscote didn't fail, the paint did. The base paint and or primer is what I worry about most. If it's gonna fail, it will most likely be the base paint.

Good luck! I hope it goes well. 

 

 

 

 

When you glue something I'd think/hope you're not gluing to paint. The idea is to scrape the paint away so you have plastic to plastic bond. Course I may be reading your message incorrectly.

 

Hi Dave. There are times in my work flow that scraping paint is not a good option. It puts the model in more jeopardy than it's worth trying to scrape. So yes.... sometimes I do glue to paint. Its meant to be displayed and not endure rough handling. The failure I mentioned was in fact brought on trying to scrape paint! Lol. 

No, I meant adhesion of the clear coat to the base paint.  The reason why some bare surfaces are sometimes primed for base coats. I want the clear to level properly and not bead. 

Sometimes parts do have to be glued to painted surfaces like trim pieces or mirrors to a body. Scraping paint from a body might cause cosmetic damage. I use a product like Super Glue in those cases. I only use cement where I can feasibly glue bare plastic to bare plastic as in the assembly of a vehicle chassis. 

Bakster

Sounds like a cool project. 

I was wondering if sanding the base coat to prep for a top coat of clear was recommended for good adhesion.

No, not needed. You should not have problems with that and especially since you will be using Testors Glosscote for the clear. That stuff sticks. I have never had a problem with that coming up. If it does, it will pull up the base coat and maybe the primer even. In fact, I just had that happen. A part part broke off and the glue pulled up the paint right down to the primer. The Glosscote didn't fail, the paint did. The base paint and or primer is what I worry about most. If it's gonna fail, it will most likely be the base paint.

Good luck! I hope it goes well. 

 

When you glue something I'd think/hope you're not gluing to paint. The idea is to scrape the paint away so you have plastic to plastic bond. Course I may be reading your message incorrectly.

Sounds like a cool project. 

I was wondering if sanding the base coat to prep for a top coat of clear was recommended for good adhesion.

No, not needed. You should not have problems with that and especially since you will be using Testors Glosscote for the clear. That stuff sticks. I have never had a problem with that coming up. If it does, it will pull up the base coat and maybe the primer even. In fact, I just had that happen. A part part broke off and the glue pulled up the paint right down to the primer. The Glosscote didn't fail, the paint did. The base paint and or primer is what I worry about most. If it's gonna fail, it will most likely be the base paint.

Good luck! I hope it goes well. 

I want sealed-in protection for applied decals. I'm doing a Kenworth tractor in custom paint with company livery. I was wondering if sanding the base coat to prep for a top coat of clear was recommended for good adhesion. Obviously, I can't sand over bare decals on top of base paint as that would ruin the decals. I might have to sand/polish over cured clear (with or without decals sealed underneath) for possible dust repair.

JonBailey

hould cured base gloss enamels be finely-grit wet sanded before applying decals

If you lay a glossy color coat, I do not see a need to sand for the purpose of decaling. It just depends on what your goal is. For me-- if let's say I was doing a car body, yes-- I would sand, but mostly for the reasons I outlined earlier. I would sand the enamel to knock down any high points and I would go the gamut up to 12,000 grit. By then-- the paint is gloss enough on its own to apply decals. And let me tell you-- the decals will stick. There should not be any issues of silvering. Then I'd seal the whole thing with gloss and do another sanding/polishing. The order of when I'd lay the decals depends on if I want them under the gloss or over. If you want that sealed in look, or if you want the look of emblems applied on top. Up to the builder, I guess.

JonBailey

Is prepping a base coat for clear topcoats with a toothbrush, water and Comet sufficent? 

I have not tried using comet as an abrasive on paint, so I can't speak to that. I'd be concerned with Comet interacting and/or embedding in the paint, maybe even altering the color. Maybe someone else here can speak to that because I have not tried it.

Bakster:

I have now perfected my airbrushing technique using Testors enamels and lacquer thinner at least for base coats. I never prime: I just light sand them or rough them up with Comet powder and a toothbrush to prep surfaces. Sanding with sandpaper may remove details in "sheet-metal" body parts like molden-in rivets. I use Dawn dish soap and water to cleanse bare surfaces. Later on, I will have to develop my skills to apply decals and then seal them in with clear.

Should cured base gloss enamels be finely-grit wet sanded before applying decals and/or Testors Glossecote or Dullcote with an airbrush? Is prepping a base coat for clear topcoats with a toothbrush, water and Comet sufficent? 

I use the modified Don Yost/Andy-X method for base painting with enamels. When done properly on properly-prepped bare surfaces, I've noticed no appreaciable levels of orange peel. This is a pretty smooth and glassy easy method provided the suface to be painted is smooth. 

Ordering those neoprene washers to fit my 1-oz Paasche jar lids should eliminate the possibilty of paint contanimation those flaky cork gaskets. Neoprene is supposed to have fair-to-middling solvent resistence. A bag of 100 of those little devils set me back $32 with shipping from amazon.  

JonBailey

I would still like to learn in detail more about sanding and polishing painted parts to salvage them from that one or two nasty specs of dust that attacks them without mercy. I can't feasibly just keep repainting and repainting repeadtly to deal with a couple pieces of dust. Learning how to rescue a painted body from a random particle of foreign debris or two is an invaluiable skill in this hobby. Good videos on this would be very helpful and appreciated. 

In my opinion-- you are on the right track here. Not only are we dealing with errant dust and paint particles-- we are are also dealing with orange peel, maybe even drips or sags. Getting a glass smooth finish is near impossible without sanding, and even some of the best luck can produce wavy finishes. It may look smooth-- but do a polish to it and you'll see the difference. But that is just me-- I like taking it to that level.

A few things I will note: 

1. If you spray a primer coat-- make sure to sand it before moving on to the next paint layer. In fact-- each layer should be sanded smooth taking it from primer to color coat, to clear coat. I have seen models (YouTube) where builders skip these steps. They'll bank on smoothing out the finish by polishing the clear coat, or by applying a deep clear such as 2K. Though, on surface it looks good-- when light catches it just right-- you can see through the clear and all those subsequent grainy layers pop to light. For me-- that just ruins it. It screams, I didn't feel like sanding. But hey-- it's their model and if they are happy-- that is all that counts.

2. I did a quick search and found this. By no means is it the best video on the subject but it has the basics. And you don't have to use the stuff he is using. Just Google the subject, there is a lot out there on this subject. 

https://www.youtube.com/watch?v=iZ2sFQX7eOg

OR start at point 3.

3. Years ago when I first tried polishing, I purchased the kit below. It gives you everything you need, from sanding cloths to polishing compound and wax. It's a great way to start. You can modify as you progress but, in my opinion, all that you need is there. The process is simple, just follow the instructions. There is no magic to it. And let me tell you-- it takes the stress out of getting a good finish. Unless the dust is imbedded deep into a layer--it can be taken out. And even if it is deep- just sand it until its gone and then spray another coat. For these issues-- you should never have to strip paint again. Even drips and sags can be sanded. It was a godsend when I learned this because soaking the model in brake fluid became a common occurrence for me. Getting that perfect finish is easy if you take the time and do the process.

https://www.amazon.com/Enterprises-2200-Micro-Mesh-Polishing/dp/B00BN0Z862

Lastly-- as they say--there are many ways to skin a cat-- this is just mine. Others will have their own.

Maybe just vaccum off the front of my shirt before a paint shoot? I wear 100% cotton puillovers. I have a Whirlpool air purifier with HEPA and charcoal filters. Maybe just keep running that in my living room where my paint station is? 

I mount parts to be painted on sticks often for manipulation while shooting. 

I would still like to learn in detail more about sanding and polishing painted parts to salvage them from that one or two nasty specs of dust that attacks them without mercy. I can't feasibly just keep repainting and repainting repeadtly to deal with a couple pieces of dust. Learning how to rescue a painted body from a random particle of foreign debris or two is an invaluiable skill in this hobby. Good videos on this would be very helpful and appreciated. 

One can try their damnedest to prevent a dust attack on painted work in progress but there is never any guarantees. I want to seriously learn proper errant dust-damage repairs for a cured painted model. This is a more important skill than airbrushing technique itself. 

I run 2 electronic air cleaners in my apartment and dust every single thing with microfiber towels every couple of weeks.  Before painting anything, I give the item being painted a quick blast with an air duster, just in case.  Having done this regularly for several years now, I find that there is very little dust floating in the air to settle on anything.  The parts of my F-4B fuselage that aren't currently being detailed have several weeks of dust accumulation on them, but even that is a barely noticeable, miniscule amount of tiny fibers...probably just from my clothing.  My method of airbrushing is very unconventional, so I don't use any kind of paint booth or hood...I paint close-in with low pressure and low paint volume for extremely thin, fine paint layers, so the paint is all going on the model and not into the air.  On the extremely rare occasions I do get a dust particle in the paint, the paint is so thin that the dust particle can usually be removed with #4000 micromesh and the paint usually doesn't get damaged.  In any case, a lot of effort needs to go into paint prep and keeping your finishing area clean if you expect good results.

I mostly shoot into the kitchen trash bag that's in the waste basket there. I just move it out into the room. I get more dust with the booth, probably off my clothing but anything getting stirred up near the booth gets drawn in by the extraction fan. I made my booth up draft and I don't rule out something falling from the filter above that's too heavy to be drawn out. Anyway, all my 60+ years of painting car bodies I've gotten little dust outside a booth so I'm back to that again. Or someties I just mount my body on a holding stick and shoot it just outside the booth, the over spray enters the booth anyway and is drawn out, works well. My problem is with using a stand in the booth. Not to mention I always like shooting down on a model, so on a stick I continually position the model so the surface being sprayed is facing up. Better flow out of paint that way.

Modern professional 1/1 auto refinishing booths have big filters for in coming air, many today are down draft booths with venting in the floor but not all.

A final note: don't rule out the dust coming from or off your closhing. When I shot 1/1 I wore those diposable white suits and blew it off with an air gun. loThings like flannel shirts have a lot of fuzzy stuff to let go of, lint or even mini pill like objects can land in you paint job from your shirt. Here is the big one, blow off your model parts even if you washed them etc. I think 90% of dust comes out of hidden spots , like off cowl vents etc. I just use my airbrush to blow the body down before opening up the paint flow and most of my dust went away. I learned that from shooting 1/1. Most of the dust was there already, in a door seam, under molding clips etc. I always took an air gun and blew the vehicle off before shooting paint, and my white suit as well. Very little dust ever came from the room even if it wasn't spotless.

Is there a video tutorial on how to do this? I have sandpapers from 1,000 through 5,000 grit. I also do have Novus plastic polish. I should also give my living room a thorough top to bottom dusting with the Hoover before continuing painting.

I live in Oklahoma. Dust City. During the winter/cold/damp months dust was not a problem. Cold weather, snow and rain keeps the dust in the air down. How do automobile paint shops and automakers mitigate dust inside the paint booths? How do those die-cast model manufacturers mitigate airborne dust on those commercially-made car models? 

My experience is you can do things to avoid it but you seldom eliminate errant dust. Best solution that I know of is let the paint cure, then sand the dust out and polish. Polish kits are available and some just use Novis to polish.