Sub assemblies painted, best glue to put them together

[ulvdemon]

I have to admit, I've been looking into this but I think I am just missing this most basic concept.
I understand the need to build and paint in subassmeblies, but to minimize on sanding the joins, what is the best type of glue to use? Epoxy or superglue
I'm aware that good ol' styrene glue is pain to bond on painted surfaces, but if you have to build, paint and decal in subassemblies, what is the ebstw ay to glue everything together to minimize any gaps that can occur?

[Dieghigno]

This one: http://www.anticsonline.co.uk/l.aspx?k=13754

Try to make the thinnest layer you can...
It melts paint and plastic and made a very strong bond

[ulvdemon]

Thank you. Will look into it.

[Kylwell]

Any glue has issues with paint largely because the glue attaches to the paint which then attaches to the plastic. With acrylics this leads to an exceptionally weak joint. I tend to clear the joint areas carefully and bond with my usual Tenax 7R.

[dizzyfugu]

Any glue has issues with paint largely because the glue attaches to the paint which then attaches to the plastic.

That's the main point. Whatever you glue together, make sure you have clean surfaces - not only without paint, but also without grease from your fingers, etc. Scratching away paint will suffice (and also prevent potential ugly reactions of the paint with glue!), and if you want a really clean basis use some Windex or iso alcohol, e. g. with a brush.

For the glue itself, use whatever is appropriate for the materials. I found that a clean surface on polysytrol kits is "enough" when you use normal plastic glue, so that it can meld and bond the material as it is supposed to. One (or even two) layers of paint considerably weaken this bond, so that IMHO no extra glue is necessary. But on other materials, where you do not change the material properties and just make the surfaces adhere, some super glue or even 2C glue might be the best option.

[Tankmodeler]

[quote="ulvdemon"]I understand the need to build and paint in subassmebliesquote]
Actually, I'm not sure I agree that there is a need to build and paint in subassemblies.

I only build and paint in subassemblies if I can do so and not create a joint whith a seam or where the adhesive will be seen later. If it leaves a seam, it all gets built together so I can fill the seam before I paint.

Now a separate part, like a suspended weapon on a pod or a dropable fuel tank or the like, I'll build and paint separately because I can make sure there is no gap and the seam is actually supposed to be there.

I only have to controll the gloss from any small amount of glue visible and I do that by hitting the joint with my last flat or gloss coat before weathering and then weathiering the entire model as one. I almost never weather seperate assemblies, so the final weathering give a last chance to hide any gloss from the adhesives andbelnd it all together.

That said, if you are bound and determined to bond a painted part to another, make sure you remove the paint from the joints. For most small aprts yuo really only need to remove a vers small amount of paint to get a good solit styrene to styrene join. If the glue is something else, like epoxy or CA, then you'll need a somewhat larger area.

In bonding, cleanliness of the bond line is the golden rule!

Paul

[Tankmodeler]

[quote="ulvdemon"]I understand the need to build and paint in subassmebliesquote]
Actually, I'm not sure I agree that there is a need to build and paint in subassemblies.

I only build and paint in subassemblies if I can do so and not create a joint whith a seam or where the adhesive will be seen later. If it leaves a seam, it all gets built together so I can fill the seam before I paint.

Now a separate part, like a suspended weapon on a pod or a dropable fuel tank or the like, I'll build and paint separately because I can make sure there is no gap and the seam is actually supposed to be there.

I only have to controll the gloss from any small amount of glue visible and I do that by hitting the joint with my last flat or gloss coat before weathering and then weathiering the entire model as one. I almost never weather seperate assemblies, so the final weathering give a last chance to hide any gloss from the adhesives andbelnd it all together.

That said, if you are bound and determined to bond a painted part to another, make sure you remove the paint from the joints. For most small aprts yuo really only need to remove a vers small amount of paint to get a good solit styrene to styrene join. If the glue is something else, like epoxy or CA, then you'll need a somewhat larger area.

In bonding, cleanliness of the bond line is the golden rule!

Paul

[ulvdemon]

Thank you everyone.