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Kits - When to Paint

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Kits - When to Paint
Posted by Attuvian on Thursday, March 9, 2017 11:11 AM

When a plastic kit will require wholesale painting to some other color, I'd generally be inclined to do it before assembly - if only for the sake of efficiency.  This is especially true where there are lots of exposed parts that come on sprues.  My concern involves the security of bonds when CA is used over paint.  I suppose that one could always scrape away a tiny spot or strip where a surface joint is called for (and retouch later), rebore drill holes in the original size or glue from the backside where that is possible.  And there may be other work-arounds, too.  BUT - is this issue a significant one?

There are likely only three possible answers here: yes, no, sometimes.  I guess the question creates a poll by its very nature.  Please vote and opine based on your experience!

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Posted by Canalligators on Thursday, March 9, 2017 11:23 AM

I can't think of any time when it wouldn't be better to paint before.  That eliminates most cases of overspray or misdirected brush strokes.  Although glue will often bond even with paint on the part, it's certainly better to bare the plastic first.  Cleaning off the paint with a knife or drill takes precious little time, and your bond will be much better.

Genesee Terminal, freelanced HO in Upstate NY
  ...hosting Loon Bay Transit Authority and CSX Intermodal.  Interchange with CSX (CR)(NYC).

CP/D&H, N scale, somewhere on the Canadian Shield

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Posted by Eric White on Thursday, March 9, 2017 11:42 AM

I like to use plastic solvent cement on plastic models instead of cyanoacrylate adhesive (CA or super glue).

If I'm assembling major components, such as gluing two walls together, I scrape paint away for a secure bond. Many solvent cements will also dissolve paint, so if it's a non-critical bond, or one that I can get to after the kit is built, I may not scrape paint away.

Sometimes, a detail part may be too small to scrape paint from in any practical fashion, so I don't bother.

Also, I try to assemble parts that will be painted the same color before painting. This allows me to finish seams as well as get a more secure bond.

Eric

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Posted by BigDaddy on Thursday, March 9, 2017 11:47 AM

I painted a Walthers Vulcan Manufacturers before assembly.   Even though I tired to mask off the window edges, with Tenax I've had constant problems with the window frames falling off. On buildings where I didn't clean the joint well enough before cementing, and I had a gap or a weak joint, CA was more effective than styrene solvent type cements in this situation.  However I think the solvent cements do a better job if paint is not an issue. 

The downside of assembling then painting is that the masking can be very tedious and blue painters tape sometimes doesn't prevent bleed underneath the edge and sometimes removes the underlying paint (assuming you are using muliple colors)

 

Henry

COB Potomac & Northern

Shenandoah Valley

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Posted by JOHN C TARANTO on Thursday, March 9, 2017 1:40 PM

In the 40+ years that I have been assembling plastic kits, I don't think I have EVER used CA.  My adhesive of choice is Tenax.  If necessary I'll use thicker styrene glues.

If the kit has many small parts (like windows) I'll leave them on the sprue and airbrush them.  Once dry, I'll scrape away paint to make a clean surface for the glue.  When painting larger parts like walls, I always assemble them first, using clamps until dry, then paint.

 

 

 

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Posted by dstarr on Thursday, March 9, 2017 2:35 PM

Paint in the glue joint weakens the joint.  If you use CA to bond two painted parts, you get a bond between the CA and the paint.  The true strength of such a joint depends upon how well the paint bonds to the plastic.  And paint to plastic bonds are way way weaker that CA to plastic bonds. 

   I don't use CA on plastic.  The solvent welding plastic cements are way cheaper, and last much longer on the shelf.  CA will harden into a transparent brick in less than a year on the shelf, the plastic welders last forever.  They give a bond (on plastic) that is as strong as the original plastic, which is as good as it gets.  If you paint with lacquer (the late lamented Floquil for example) the plastic welder is the same stuff as lacquer thinner, so it softens the paint and can yield a fairly good joint on painted surfaces.  

   In some cases, rolling stock for example, I assemble the entire model, spray paint the whole thing the base color, and brushpaint the small details that want to be a contrasting color.  For structures with lotsa windows that you want to be a contrasting color (trim color)  I paint the windows on the sprue, the walls as they stand, and scrape paint off the backsides of the windows and the window openings with a Xacto knife. 

 

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Posted by DSchmitt on Thursday, March 9, 2017 2:52 PM

I  assemble major componets that will be one color and attach any details that will be the same color, then paint. Details that are a different color are painted seperatly then attached.

I use solvent cement on plastic, but sometimes tack parts together with CA to hold them before applying solvent. I have found that sometimes CA alone is adequate to hold small details and there is less risk of crazing paint

I tried to sell my two cents worth, but no one would give me a plug nickel for it.

I don't have a leg to stand on.

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Posted by mbinsewi on Thursday, March 9, 2017 3:10 PM

I've painted before and after.  One project that I painted first was 2 sets of Walters 53' spine cars, in the fantasy Santa Fe red scheme, to a TTX yellow.  While assembling, I scrapped off the paint, where needed,  and touched it up after I was done. 

Buildings I usually paint after, but before the windows and doors are put in.

Mike.

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Posted by hornblower on Thursday, March 9, 2017 3:27 PM

For me, it depends on the way the structure model is made.  For structure models with separate window and door castings, I prefer to first assemble and then paint the walls and roof as a complete unit.  I then paint the window and door castings and install them in the assembled walls.  At this point, I weather the building and add the glazing only after the weathering is complete.

For structure models with molded-in windows and doors, I prefer to paint first, then assemble as it is definitely easier to hand paint the details of a single flat wall rather than try to paint the details on a completed structure.  Gluing up the walls after painting typically forces you to go back and touch up the paint along the joints so make sure to hold back a little paint for this purpose, especially when you custom mix colors.  I next weather the building and finally add the glazing (always last).

Hornblower

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Posted by wabashbanks on Thursday, March 9, 2017 3:42 PM

Honestly it depends on the kit. I don't put paint on surfaces to be glued where structural integrity is an issue (so no painted building corners). For windows that are separate and glued on...if I am going to just glue them on then I paint them first. If I am going to put them on and then putty around them then I may or may not paint them since the hard part is painting a straight edge down the putty. Most often what I do is paint the section, at least most of it, before glueing things togehter and then do finish painting after the glue is done. Since I putty a lot of things up after gluing it means there is almost always something that needs touched back up at bare minimum.

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Posted by chutton01 on Thursday, March 9, 2017 4:02 PM

Put me in the normal assemble first then paint, at least for larger items
...but...
Having viewed many modeler videos (car and plane as well as railroads), one thing often done is to mask the approximate areas on the bare plastic which eventually will cemented, then spray paint the model. Pulling the masking tape off leaves a decent sized area for cementing. You can scrap the edges of the paint to enlarge the area for cementing, but still this works fairly well.
Consider window frames with plastic flanges sticking out for attachment to the wall. Line the windows on some cardboard, and tape up the flanges near but not quite to the actual frame (can be done in a row if the windows are the same size) spray paint the frames and peel off the tape - seems to be faster and neater than scraping off the paint (which I do as well).

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Posted by doctorwayne on Thursday, March 9, 2017 11:55 PM

When assembling plastic models, I use solvent-type cement for all plastic-to-plastic joints, contact cement for dissimilar materials, and ca only for metal components which can also be mechanically connected:  for example, metal grabirons or other details installed into pre-drilled holes.

For structures, I like to assemble the major components (foundations, walls, roofs) first, then paint, masking where necessary.  For muti-coloured buildings, I'll decide which colour should be applied first in order to make masking easiest for subsequent colours.  In this case, the brick colour (Floquil Reefer Orange) came first...

...after masking off all of the brick areas, the concrete areas were painted...

And with the tape removed, mortar (pre-mixed drywall mud) was added...

Then rubbed off the surface of the bricks...

The structure is then weathered, followed by the installation of the pre-painted and assembled windows...

If the doors and windows are separate pieces from the wall castings, I mask them on the sprues.  This is easier and faster than later scraping paint off unmasked surfaces.  I place strips of masking tape face down on a sheet of glass, then cut them into narrower strips, which, in most cases, can be applied continuously on the sprues, covering what will be the gluing surfaces.  Primer, if necessary, is then applied, followed by the finished colour...

...when the tape is removed, the gluing surfaces are paint-free...

 The "glass" is cemented to the window, then the window is installed in the structure.
For structures with doors and windows cast as integral parts of the walls, I usually airbrush the walls, then brush paint trim, doors, and windows.  For this one, the porch and steps were done with both brush and airbrush...

For rolling stock, the kit or scratchbuilt car is usually completely assembled before painting, then broken down into sub-assemblies for painting.
On this scratchbuild, the basic carbody and the detailed underframe were completed, but the rivet decals needed to be applied before grabirons, ladders, and end brake gear could be applied...

The brake gear is in place, and holes have been drilled for mounting the ladders...

The entire car (body, underbody, and truck sideframes) was to be painted the same colour, but it was easier to handle the body and underbody separately during painting, and likewise for the trucks, which had the wheelsets removed before the sideframes were sandblasted and painted.  The wheelsets, front, back and axles, were brush painted...

 
The car wasn't re-assembled until it was completely lettered, then it was lightly weathered...

 

Multi-colour paint jobs are usually assembled only to a point where it doesn't interfere with masking, so details such as grabirons may be added after the major painting has been completed.  In that case, those added details are brush painted after installation...

My steam locomotives are usually painted with at least four shades of black.  Other than painting some cab roofs red and masking them off for the balance of the paint application, I apply the various blacks masking only where needed by holding a piece of cardstock to protect adjacent areas.  The locomotive is usually separated into the boiler/cab assembly, the running gear and frame (motor usually installed), and the tender separate from it's underbody.  Any free-standing piping or other detail that is meant to be a shade contrasting to that on which it is installed is painted afterwards, using a brush...

In general, careful examination of what you're going to paint will usually suggest the degree and method of assembly and the best point at which to apply paint - one method seldom works for all situations.

Wayne

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Posted by Attuvian on Friday, March 10, 2017 12:53 AM

Wayne,

Really nice stuff here, both in suggestion and product!  But thanks especially for all the labor in putting together this response.

I was musing about an hour ago - before I jumped back into the forum - on the tremendous efforts that so many accomplished modelers have made over the years in these "pages" by freely sharing their expertise with folks they've never even met.  And I also wondered what percentage of those countless recipients are not club members or have other friends that are into the hobby from whom they can learn first hand.  Books are great, but only to a point.  It's folks like you that have helped more than just newbies stay focused and active by extending both the personal touch and the time it takes to deliver it.  To all of you, from all of us, here's a big nod of gratitude.

John

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Posted by Attuvian on Friday, March 10, 2017 12:57 AM

Wabashbanks,

Thanks for your response.  I note that it's your first posting.  Keep it up and enjoy your ride through the forums, friend.

John - an old neigboring (?) Michigander.

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Posted by doctorwayne on Friday, March 10, 2017 1:40 PM

Thanks for your kind remarks, John. Embarrassed

Forums such as this offer a window into the accumulated knowledge of its members, and even though I've been in this hobby over 60 years, I'm still learning new stuff from the generous craftsmen who share their experience so willingly.

Wayne

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Posted by ROBERT PETRICK on Friday, March 10, 2017 2:22 PM

Attuvian

Wayne,

Really nice stuff here, both in suggestion and product!  But thanks especially for all the labor in putting together this response.

I was musing about an hour ago - before I jumped back into the forum - on the tremendous efforts that so many accomplished modelers have made over the years in these "pages" by freely sharing their expertise with folks they've never even met.  And I also wondered what percentage of those countless recipients are not club members or have other friends that are into the hobby with whom they can learn first hand.  Books are great, but only to a point.  It's folks like you that have helped more than just newbies stay focused and active with the personal touch - and the time it takes to deliver it.  To all of you, from all of us, here's a big nod of gratitude.

John

Absolutely.

One of the great things about this forum is that craftsmen are willing to share their work before it is finished and ready for presentation. This behind-the-curtain look is invaluable to others, both novice and experienced. We are all hobbyists here, and I look forward to the day when I can contribute something worthwhile, meager though it may be.

Robert

LINK to SNSR Blog


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Posted by NYBW-John on Friday, March 10, 2017 4:28 PM

Generally I find it is easiest to paint before assembly. For most plastic kit assembly I use the liquid solvent and that needs to have bare plastic to form a tight bond so I will scape away the paint on the surfaces that need to bond together.

One exception to the above is the shell of the building. If it is going to be sprayed one solid color I will assemble it first to make sure the joints are good and tight and then spray both the inside and the outside. I'll still need to scrape away paint when installing the windows and doors but that is no big deal.

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Posted by BigDaddy on Friday, March 10, 2017 5:20 PM

Dr Wayne, not only a great post, great craftsmanship and excellent photos.  Thanks for sharing.

Henry

COB Potomac & Northern

Shenandoah Valley

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Posted by SeeYou190 on Friday, March 10, 2017 10:14 PM

I paint ALL THE TIME.

.

Stuff is painted on the sprue, then at times during assembly. After the model is assembled...  paint even more. Then I dot filter or wash, which is just more paint.

.

Painting is modeling. Painting is every step in modeling. When you model is done, all you really see is the paint. That last layer of paint that is only a couple of thousandths of an inch thick. Nothing matters more. Paint early, frequently, and often.

.

-Kevin

.

Living the dream.

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Posted by MisterBeasley on Sunday, March 12, 2017 11:28 AM

BigDaddy
The downside of assembling then painting is that the masking can be very tedious and blue painters tape sometimes doesn't prevent bleed underneath the edge and sometimes removes the underlying paint (assuming you are using muliple colors)

I agree, but I think the results are well worth the effort.  Masking mating surfaces, such as between wall sectons, gives me a clean place for glue.  I spend a lot of time masking.

Corners are always difficult.  I mask the joints to keep them clean and use plastic cement, but it's always hard to get a perfect joint that's secure and light-tight.  I make a practice of using balsa strips from a craft store in all 90-degree corners, even the roof.  I attach those with CA since I'm using dissimilar materials.

I put an interior into this DPM "MT Arms" hotel, so I also use the strips to support the floors and inside walls.

It takes an iron man to play with a toy iron horse. 

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Posted by Doughless on Sunday, March 12, 2017 1:01 PM

I paint while on the sprue then just use testors orange glue and it bonds through the paint, or scrape the edges part on fine sand paper a couple of strokes just before gluing if there is a lot of paint on it.  It takes seconds.

- Douglas

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