Gluing parts together that were painted be for assemblying a model

[midlineqb]

I would like to know everyone's thoughts and ideas for gluing a model together after the parts and body were painted before assembly.

Thanks in advance.

[NOBLNG]

Once the parts are painted, you are pretty much limited to CA, epoxy or PVA for glue. Any solvent glues will destroy the paint finish. Stuff like engine block, heads, oil pan, water pump all get assembled and painted as a unit. Same with some suspension components. 

[StevenGuthmiller]

14 minutes ago, NOBLNG said:

Once the parts are painted, you are pretty much limited to CA, epoxy or PVA for glue. Any solvent glues will destroy the paint finish. Stuff like engine block, heads, oil pan, water pump all get assembled and painted as a unit. Same with some suspension components. 

Even most CA glues need to be used carefully.

They can be prone to fogging glass, chrome, or even painted surfaces if used too liberally.

 

 

 

Steve

[Mark]

X2 on keeping CA away from anything clear.

I do use CA on some parts.  I prefer Loctite's product, not so much for the glue as for the bottle.  Its cap seals quite well, stretching the life of the glue once opened.  As you use it, though, there's more air taking the space of the already used glue, accelerating the demise of the unused portion.  Some guys just buy the small/cheap one-time-use CA tubes and throw away what's left at the end of a building session.

[Bills72sj]

I am still old school. Scrape paint carefully. Mix Testors red tube with Plastruct liquid and apply sparingly with a toothpick. Model stays together with out losing parts for going on decades.

[Bill Anderson]

Hi, 

Everytime I work on a model I wrestle with the question with many individual parts - do I paint before partial assembly or after?   Also, do I paint while on the sprue or after I remove and clean it up?  Ha, there is just no single answer for this, as I find each situation presents that question.

For motor assembly, I paint the parts and try not to paint where I know glue will hit.  Easier said than done of course.  For the chassis, I've done it a few ways.  Some I've painted by hand (brush) and tried to keep paint from where parts attach.  And some I took to the spray room (garage) and sprayed and later scrapped the areas where glue needed to be used.  Honestly, I've been satisfied or unhappy with both methods - depending on the outcome.

Of course, either way requires touch up afterwards, and I'm thankful I inherited a bunch of expensive small brushes from my Mother in Law.

 

 

 

[bobss396]

I pin most sub assemblies to reduce fumbling around during final assembly.

The pin holes are good to hold small parts for painting as well.

I just picked up dome Slo Gap CA glue that should help me out. The Loctite ones set up instantly on smooth surfaces, giving zero time for adjustments. 

[slusher]

I do paint some parts befor assembly ii us Testors Orange tube glue..

[peteski]

When I have to paint parts before assembly I mask the gluing surfaces before I paint them. I use all sorts of methods for masking.  Most commonly masking tape, vinyl tubing (heat shrink or just insulation stripped from wires), liquid masking agent.  If not, I will remove (scrape off) paint to expose bare plastic or metal (if those are metal parts).

CA glue will often attach paint (epoxy is inert and does not seem to attack paint). But remember that since the layer of paint is between glue and the part itself, the glue joint will only be as strong as the adhesion of the paint to the plastic item (which is usually much weaker than the glue joint itself).

Edited March 30 by peteski

[midlineqb]

Thanks for the info. I will try some of these ideas.

[StevenGuthmiller]

I haven't scraped a painted or chromed glue joint since I was a kid.

Call me lazy I guess, but I've never really found much of an advantage to it.

 

I suppose if your models are going to get a lot of really rough handling, or get knocked around a lot, I suppose I could see it.

But even with plenty of bouncing around and routine handling, I haven't had much problem with parts coming off.

Have I had the occasional mirror or antenna flicked off?.....sure I have, but that's going to be pretty hard to avoid in any circumstance.

 

I've been using 2-part epoxy now for pretty much everything for more than 10 years.

I don't scrape a single glue joint anywhere, and my models get more than their share of abuse and frequent handling, and I don't think I can remember the last part I lost.

Just for an example, the last model I built, (1964 Pontiac Bonneville) contains a TON of tiny parts.

It's made at least four trips to shows this past year of around 500 miles each trip, bouncing around in the trunk of a stiff riding Honda S-2000, unpacked and repacked 16 times during the course of those shows, not to mention the handling it receives at home for whatever reason on occasion.

So it's no shelf queen by any stretch, but as fragile as some of the intricate assemblies on this model are, I have not had to re-glue a single part throughout all of the abuse.

The same can be said for virtually every model in my collection.

 

Just out of curiosity, I decided to dig out a box of old stuff that has been sitting for about the past decade.

These models were packed up when we moved about 9 years ago, were thrown into the back of a U-Haul and driven 300 miles, stored in a hot storage shed for over a month, and then tossed into a pickup truck and hauled to our current home, where they were unloaded and placed in the room that is now my shop.

I think this is the first time I've looked at them since they were packed up.

The only lost parts that I see on any of them is a knocked off mirror on a '61 Impala, and a front wheel from the '53 Ford.  (the wheel is not a failed glue joint, but a broken axle instead)

 

In any case, I imagine that you're catching my drift.

A lot of my models have not had easy, pampered lives, and yet I don't scrape joints, and I don't loose parts.

 

 

 

 

 

Steve 

Edited March 30 by StevenGuthmiller

[Belugawrx]

Yep, I rarely, if ever scrape glue joints...I use mostly BSI C/A medium which doesn't melt the joints per se as Tamiya thin does.

I do use Tamiya thin for sub-assemblies before paint, engine halves, and the like

I don't paint ANY parts on the tree,..they all need to be cleaned of their parting lines and tree trunks first...

[Bill Anderson]

Yes, it can be a difficult choice for (IMO) literally every part in a kit needs some TLC to get rid of unwanted lines and tree remnants and so on.  When I can, I do like to paint portions of parts while still on the tree/sprue, but where I paint has already been cleaned up.  

My biggest challenge is decided whether to spray the chassis or brush paint.  There are always so many points of parts attachments and its either spray the chassis and scrape where the parts will be attached, or hand paint the chassis and touch up after the parts are attached.   I confess I've gone both ways......

[tbill]

I always glue together as much of any assembly that I can ( engine, chassis etc) , and then paint the assembly, keeps the touch ups to a minimum.

[Radretireddad]

Sometimes I trim off the sprue around the part while leaving the parts attached. That way I can hold on to them with an alligator clip for air or brush painting without damaging or leaving a bare spot on the part.

I apply Vallejo liquid mask on attachment points before priming and painting. Afterwards I use a wooden toothpick to remove the liquid mask so I don’t risk damaging the surrounding surface with an X-acto knife blade.

Edited April 3 by Radretireddad