Primer and assembly

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Sylk

New Member
Hi everybody,

I'm totally newbie to model painting, and to know how to begin, a question comes to me.

When done before the model assembly, aren't primer and paint a problem for precise fit and interlocking of parts?

Thanks

(Please forgive my english)
 

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Analyzer

Sr Member
Hi everybody,

I'm totally newbie to model painting, and to know how to begin, a question comes to me.

When done before the model assembly, aren't primer and paint a problem for precise fit and interlocking of parts?

Thanks

(Please forgive my english)

yes, with snap kits you can absolutely run into issues painting the parts first if you paint the connectors.

In terms of Bandai's snap fit kits this can be a big problem as some of the tolerances leave very little room and trying to snap two pieces together may cause fit/alignment issues from the paint layers

What I do is either mask them off (something as quick as some blue tac or playdough etc...) or you can also scrap off the paint of the connectors

For some traditional glue kits where you use styrene cement or plastic glue you want the bond to be against unpainted plastic. I use the same method above, but tend to lean towards scraping off the paint/primer on the bond areas first
 

starks

Active Member
Everyone has different ways of putting models together.
If there is a part that needs the primer/paint before hand, you could always try and tape off the area that locks/glues to another part.

Agreed. Something like aircraft cockpits are big here as need paint before gluing inside the fuse.

Personally I scrape paint off with a razor blade where I need to glue. Your other option is glue as much together first as necessary then train yourself to pick out those details in paint. Either way works.

Cheers,
Josh
 

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Sylk

New Member
Thanks so much to everyone for your quick answers.

The technique of scraping the surfaces in contact with a blade seems the most relevant, but does that not weaken the hold of the paint on the edge? And about varnish?
Also as I will include lights in each model, I would like to keep the possibility of disassembling certain elements (to repair them, improve them, etc.), so I would not want the paint to come off when extracting the part.

Indeed my models are very precise Bandai models.
Regarding the hidden fixing points, no problem, I will do some masking.
But I am particularly worried about this kind of connections / contacts between ultra-tight elements (see attached files).

Thanks
 

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Sluis Van Shipyards

Legendary Member
It may send me to model hell, but with regular plastic model kits, in the past I almost never used primer. I've never had a problem with paint adhering to it. I usually do primer now because I don't want the modeling gods to strike me down or something, I don't know.
 

Analyzer

Sr Member
For the BB-8, I did paint the metals and the white body before assembling. I don't remember any real fit issues but I was also careful not to paint the the inside

For the X-Wings I did in sub-assemblies. The main thing with the X-Wings is not getting paint layers on the connector pins for the upper and lower body shells and the wing hinge mechanism in the middle of the wings. Those parts are really tight even before paint. You fine with the engines and stuff
 

starks

Active Member
If you plan on disassembling the models once painted I would strongly suggest painting everything separately. Otherwise you are susceptible to paint bridging the joins and tearing on disassembly.

No scraping the paint off the edge on a model kit wont weaken its hold onto the surface.

Cheers,
Josh
 

starks

Active Member
It may send me to model hell, but with regular plastic model kits, in the past I almost never used primer. I've never had a problem with paint adhering to it. I usually do primer now because I don't want the modeling gods to strike me down or something, I don't know.

Styrene is a pretty soft plastic so it doesn't take much for the paint to bite. Even most modern waterbased paints dont have the luxury of a solvent bond so are designed to have good adhesion.

The primer, apart from filling imperfections, will bite into the plastic, then the paint you put on top will bond to the primer.

Unless your models are going through heavy hot/ cold heat cycles there's little chance the paint would fail.
Cheers,
Josh
 

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ID10T

Well-Known Member
If you clean the plastic with alcohol and dry before painting, I have not needed primer (for bond). I have used it for color change to avoid seventeen million color coats to cover. Or to blend repairs or modifications.

Now I have not used water based paints so maybe primer is more important. But in general I like to keep paint as thin as possible so I don’t wash out the details.
 

Sylk

New Member
Thanks for answers.

I plan to use Vallejo Air paints (therefore water based) which seem to be good products. Knowing that I'm new to airbrushing, I think it's safer and less expensive than starting with more prestigious and expensive brands. Perhaps you have already experienced Vallejo products and have some advice for me about their use. You may also know if its adhesion is sufficient to reasonably allow an application without a coat of Primer.

Regarding the choice of the most suitable Primer, here again your advice will be very useful. I am considering buying Tamiya (Fine Surface Primer), knowing that I also have the Perfect Grade 1/72 Millennium Falcon, for which I am really scared of spoiling its paint and losing the finesse of its details. The irreversible aspect of the painting scares me so much. :oops:

For the X-Wings I did in sub-assemblies. The main thing with the X-Wings is not getting paint layers on the connector pins for the upper and lower body shells and the wing hinge mechanism in the middle of the wings. Those parts are really tight even before paint. You fine with the engines and stuff

Funny, taking the photo of the wing of the X-wing, I was wondering precisely what would be the behavior of the paint / primer subjected to friction on the moving parts, such as the axis of the wings, or joints like the "neck" of BB-8 or "neck ring" of R2.

If you plan on disassembling the models once painted I would strongly suggest painting everything separately. Otherwise you are susceptible to paint bridging the joins and tearing on disassembly.
Indeed, this requires anticipating above all which parts will need to be disassembled and which can be painted together. I have to calculate my stroke really well before attacking the painting!!
 
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JNordgren42

Active Member
I use that tamiya fine surface primer from an aerosol on everything and have had no problems.... remember to apply in lighy coats.
Cheers,
Josh
I've used the Tamiya Fine Surface Primer on most of my builds since I got back into modeling at the beginning of the year and I've been extremely happy with it. On my current builds (1/72 TIE Advanced x1, 1/144 U-Wing set) I moved to an airbrush primer. I planned on going with Mr. Surfacer 1500 but my local shop was out. They recommended a relatively new product, Modo* MK-11 Surfacer and after a little experimentation, it goes on flawlessly. It is lacquer based, so there are fumes to worry about, but my paint station is in the garage and I'm in Southern California where we get good air movement most of the time, so it's not an issue for me.

20210410_195458.jpg
 

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JNordgren42

Active Member
On assembly, there are a ton of different answers depending on personal preference, experience, and even the individual model. I try to build up things into logical subassemblies wherever possible so that I can deal with seams and filling, even on Bandai snap fit I try and glue where possible. But different models require different strategies. On the TIE Advanced x1, I primed the interior parts, painted, applied decals and assembled, then built up the main body and wings separately. Those assemblies were then primed as nearly complete units. On the 1/144 U-Wing by contrast, I'm painting almost every single piece individually because of the assembly sequence with the swing wings. I was able to glue a few minor assemblies together (rear halves of the engine cans and exhaust cones, laser canons and nose grill) but that's it. Compare this shot of the U-Wing in primer to the TIE Adv. above. Also, I haven't had any issues with fitting painted parts on my Bandai kits so far (1/144 Falcon, 1/144 & 1/72 X-Wing). I even painted the wing scissor supports in the 1/72 X-Wing, but I try to put on paint as thinly as possible.

20210411_211247.jpg
 

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