Washing of model parts?

[seadude]

Ok, from time to time, I hear how washing of the model parts/sprues is essential for removing mold release agents and so forth. So I need to ask the following:
1. Is it ESSENTIAL for every time a model kit is built?
2. Can unpainted parts be washed even after they are glued together?
3. Best temperature for water?
4. How long should the parts soak/sit in the water?
5. Best deterrgent to use or not use?
6. Any special advice for dealing with resin parts?

[scooter]

I can honestly say that I've actually never washed an IM kit.  Unless you count wet sanding as "washing"

[PR19_Kit]

1.  No..........I don't think I've ever washed a mainstream plastic kit.
2. I don't see why not, but I've never done it.
3. Warm, not hot.
4. Just long  enough to get them wet, but swirl them about a bit too.
5. Who knows? I use one drop of hand wash when I do it.
6. It's more important with resin parts so I scrub them with an old nail brush.

[McColm]

I've used Persil washing up liquid in warm water, rinse in cold water and leave to dry naturally or dab with kitchen towel.
This also helps on resin parts before gluing.
I find after filling/sanding I wipe the surface arears with a warm damp cloth before painting.

[Dizzyfugu]

I can honestly say that I've actually never washed an IM kit.  Unless you count wet sanding as "washing"

Me, too. I only do this on resin kits/parts, where you frequently encounter silicone separation agents.

[loupgarou]

I usually forget (in the rare instances when I am building something), but it helps paint to stick properly.
And in IM kits, I'd say it's necessary to wash the kit before painting, not the single parts.
When a kit is handled in building it, skin oils will be left on the surface, even if your hands feel dry. That's what's necessary to remove.
I use a few drops of dishwashing detergent in lukewarm water, and a soft flat brush to scrub the model, rinse under running water and  dabbing with a paper towel to help drying on large surfaces (wings etc).It would help using an an airbrush (without paint or anything) to blow dry cavities.

For removing separation agents from resin, it's possible to use stronger means then water and detergent, like alcool or thinner.

[Gondor]

I have started to wash IM kits more often than not now, but only prior to painting when I use an old toothbrush to help clean out any detail that has got clogged with dust.
I agree with everything else said by my esteemed colleagues.

Gondor

[zenrat]

I don't bother to wash.  Kits that is.
Never had a problem with plastic but then I prime almost everything.
Resin on the other hand I always wash having had some nasty cases of fisheye when i've forgotten/been in a hurry/couldn't be bothered.  I use a weak solution of washing up liquid and bleach in puke-warm water (that's a typo but it's apt so i'll leave it), scrub the parts gently with someone else's toothbrush and then leave them to soak overnight.

[Hobbes]

It mainly depends on what paints you use.
For Humbrol and Revell enamels on injection moulded parts, washing isn't necessary, the paint will adhere anyway. For acrylics, washing is required as the agent will interfere with adherence.

For resin, washing is necessary.

[NARSES2]

I always wash resin and normaly wash IM after I've built the bulk of the air frame prior to painting. warm water, not hot, and Fairey Liquid 

Some older limited run kits do have the parts washed whilst on the sprues but that is only for those that feel "soapy" to the touch.

[Army of One]

Can honestly say I've never washed an IM kit ever.....I never had any problem paint wise after.....hardly ever used resin, but have wiped that over.....

[Steel Penguin]

I generally wash IM kits, and always wash resin, ive had some troubled  paints with wargames stuff where the resin was still fresh enough to stink smell pungently of monomer, and being inherently lazy  ( I only want to do anything once  ) washing is a  good idea
I normally use warm water and washing up liquid, and an old toothbrush on smaller parts, and just turn the shower on larger parts
soak, spray for a couple of minutes and let air dry, some times in the bath, sometimes on a towel,  I think on one occasion ive propped them up outside,  and im now going to have to try hanging at least one lot on the line 
as for washing assembled parts, that will depend a lot on the glue you've used to assemble them, and weather you want to risk any long or short term debonding.

of course as with any thing like this,  your mileage may vary,  the 2 Jag kits im working on at the mo  one looked fine and felt ok, the other had some kind of brown gunk on it  but both got the bath and toothbrush treatment.

[zenrat]

I just opened a Hasegawa Mazda kit and will be washing it as it feels very slippery.

[Sticky Fingers]

I always judge weather to wash IM kits when I first handle the sprues. Most often I don't feel it necessary but sometimes, usually with lesser known makes, I give them a quick scrub with water and washing up liquid.
Resin: always!

[Old Wombat]

I don't but I do know of a number of guys who do & swear by them (not only for handling but several have developed sensitivities to the chemicals used in glues, paints, etc., over many years of modelling) but they're mostly over on Starship Modeler.