Is cleaning a kit in soap and water a "must" before building?

It is not always necessary,I very rarely do it and have not had any problems.

I only do it if the plastic really feels greasy,or if I really muck it up with fingerprints.

No, but not a bad idea. It is a must to wipe down the model before painting. you can use rubbing alcohol or testors plastic prep for this.

I agree with Tojo. It isn't all that necessary. It's probably more advisable to clean it before hand if you're using acrylic paint as opposed to enamel. But, I have used acrylics many times without cleaning the parts and had no problems. But, it doesn't hurt to clean it just to be safe as far as painting goes.

I never use water and soap. I use either denatured alcohol or Windex. Either one should get it clean enough.

Thanks guys! Wife just told me we may have some soap in the camp trailer. I'm sure it must be froze solid by now. We're so bored we put colored water in balloons and set them out to freeze so we have colored ice balls tomorrow after we remove the rubber of the balloons.

Cleaning the parts is always step one for me, part of my ritual.  But I've never had to risk frostbite in order to do that.  I may just skip it if it is that cold and I ran out of soap.

Been doing models for over 40 years and have never done that. If you have any grease or junk on the plastic then you can use some rubbing alcohol and a small cotton ball to clean up. But with resin I do use degreaser and a soft old toothbrush to clean up the parts so that the super glue can really grab.

No, I never wash the parts pre assembly. Certainly not a must. Every now and then you get a kit with mold release agent on it that needs to be removed, but it's not too common. I use plastic prep in that case.

Tojo72

It is not always necessary,I very rarely do it and have not had any problems.

I only do it if the plastic really feels greasy,or if I really muck it up with fingerprints.

i may wash it if it is an old kit or a reviewer recommends it. (soviet T-28 bridge tank for example)

I usually don't wash models before priming, but will clean them thoroughly after filling and sanding to get any residue off before applying any color coats.  I use dish soap and an old toothbrush and flush it off in the sink in our laundry room, then let it air dry for a few hours.

The worst new kit I can recall was a re-issue of Monogram's old F4U-4 that I built a few years ago.   Its was covered with a dark, greasy substance that took some overnight soaking to clean off.  

Mark

I will generally wash an older model or one that comes from an eastern European company that has visible mold release agents on it. Rarely with something from Tamiya, Italeri or Revell..

No

ICM kits are the worst for Mold release agent. I swear the plastic bleeds that stuff. Only degreaser takes it off.

Its not a requirement. I do a touch test where after washing my hands I run my finger on the surface of the plastic. If it streaks or I feel residue I was it. Usually bar soap suffices or rubbing alcohol.  50:50 solution of isopropyl or methyl alcohol and water gets rid of stubborn stuff. For severe residue I will wipe down the surface with denatured alcohol. I do it very rarely with plastic, more commonly with resin kits but its still a rare event even with resin.

I do wash a kit if I've been doing something to the kit that may produce fine particles. Sanding, drilling, scraping, etc. Occasionally I will also wash a kit when for some reason my hands feel greasy/oily.

Hi :

  I always wash my models .Just a habit I guess . It's just hard to get the water out of them though .OH ! I guess you mean Before building them ? He ! He!  No , Seriously I use Windex and then after drying them (airdryng ) I then wipe them down with clean " T " shirt material . Has worked great for over fifty years!  Tanker - Builder

I've never done it although I do know of a certain Zvezda kit in the stash that will have to be washed as the mold release agent is clearly visible on several sprues.

A good reason to read reviews in FSM and other model mags.  Most reviewers will indicate if kit has a lot of mold release on parts.  However, I always wash resin.  The mold release used in resin casting seems to be more of a problem than with die cast polystyrene kits.

If you're eating chicken wings or bacon while modeling, wash your model, or you risk your finger oils and grease from making "hickeys" in the paint where the paint doesn't stick as well.

This is really an important issue for glossy paints and car modeling, where you must have a pristine surface to lay your gloss paint onto, or you really can muck up a nice finish. ALso, the old automobile model manufacturers seem to use more release agents in their molds that make it smart to clean the plastic.

But really, today's paints are so good in the "Flat" genre, that they stick most anywhere.

weathering is your friend. check out the white UN UNIMOG in armor forum. yes it's mine. i've had 2 decent UN whites (this and canadian LAV-III) and one not real good  actually bad enough to buy another kit (canadian COUGAR).

I've had issues in the gear bays of a revell F/A-18.  I'm not sure if it's the recessed nature of the gear bays with all the piping, the glossy enamel, or the fact that it was white.  But on 3 kits I had issues on each one when I didn't wash.  I found the paint would almost push away from the crevices where a pipe was molded, or where the top of the bay met a wall, etc.  One would expect the paint to pool in the corners, not run from it.  Since then I've started washing all my models and haven't had any issues.

If you are really in a pinch, if you have a soap designed for oily skin, that will likely work mixed with some warm water as it's intended to deal with oils.

Groot