cleaning model parts

[Frank Burroughs]

When a kit is received should the parts be washed in dish soap?  I want to remove any dirt or oils before applying primer.

[Bob Cleek]

It would depend upon the model kit. One should expect that plastic parts would be clean, but it's always possible that they aren't. Handling plastic parts with bare hands prior to painting can certainly leave skin oils that may interfere with a coating. I never worried about it much when I was building plastic models, but, obviously, when in doubt, cleaning the parts is advisable and can't hurt.  A soak and rinse in an appropriate mild cleaning solution which itself is not prone to leaving any sort of residue on the part should be sufficient to remove any oils or grease prior to applying any coating to plastic parts. 

Edited August 2, 2023 by Bob Cleek

[gsdpic]

I've heard or read that the plastic parts can have some residual mold release agent as well.  I often do a quick wash and rinse of the sprues before using them and then try to not touch the actual parts (much) before paint or primer.  Having said that, I've never seen a problem arise from not doing it.  And just make sure you do not wash a small part down the drain while cleaning.

 

[JeffT]

I wash the parts right before I paint. This gets rid of any sanding dust or other particles that may be on the parts. I dry off the parts with my airbrush or a blow dryer, then paint immediately.

[Pirate adam]

I have a lot of experience painting plastic airplane models over the years.  I think it is especially important to clean plastic parts if you will be using acrylic paints.  There are a several things this helps with:

 

1) oils from your skin or mould release can prevent the primer or base coat from adhering properly causing sections to peel off later especially if you will be doing any masking.  This will cause extreme frustration when it happens.  (BTW, you can usually get a do-over with acrylic by soaking the painted part in windex and rinsing the paint off)

2) oils from your skin can leave fingerprints that show up when you paint

3) cleaning helps get rid of hairs, dust, etc.

 

I use liquid dish soap and rinse with cool water.

 

Adam

[Kelp]

I have heard of rubbing alcohol also being used to clean the plastic parts.  Any comments on the use of alcohol vs. dish soap?

[VitusBering]

I use both - a weak detergent solution and full strength alcohol. Sometimes on the same parts, mostly not.

It sounds confusing but here's the deal.

 

I use soap and water on the sprues.

I put a sprue in a baking sheet and use a very soft bristled paint brush dipped in the soap solution to clean the parts then rinse them really well.

I use a baking sheet to make sure any parts that may come loose from the sprue during cleaning don't go down the drain.

 

I use soap, then alcohol on the larger pieces, like hulls and decks. That's mostly because they pick up oils after soap cleaning and because the alcohol will ensure a good surface for paint adhesion. I wipe them down with a lint-free cloth saturated with alcohol immediately before painting (I let the alcohol evaporate before painting, of course).

Edited August 3, 2023 by VitusBering

[Frank Burroughs]

Thanks for the replies.

 

The model kit has been around since 1972 and is opened.  Who knows how many times the parts have been handled.

[Canute]

I like DAWN dishwashing liquid on plastic and resin parts. After washing you can wear cotton gloves to keep finger oils off. For resins, I wipe them down with alcohol prep pads before priming. And some resins may need a second washing to get the mold release really cleaned off.

[Jaager]

For a water rinse, if your supply is hard water, it may be wise to use distilled water.