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Cleaning plastic structures prior to painting/weathering

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  • Member since
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  • From: Winnipeg Canada
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Cleaning plastic structures prior to painting/weathering
Posted by Blind Bruce on Wednesday, December 24, 2008 9:52 AM

I gave Rambo some advice to clean his projects before painting. I said to scrub lightly with dish detergent. That's OK for kits where you can paint before assembly but what about built up plastic structures that need weathering? AKA my cornerstone water tower? There are a lot of inacessable parts of this structure. Should I just dunk it in a basin of detergent water and hope for the best?

73

Bruce in the Peg

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Posted by CNE Runner on Wednesday, December 24, 2008 10:50 AM

Hmmm, I have "dunked" a completed plastic structure in detergent and water and the paint seemed to adhere quite well (although I usually clean before assembly). I purchased a unpainted, but completed, plastic enginehouse at a train show this past spring. My intention was to paint the building, add some detailing/weathering and resell it at the next show. I ended up using Polly S Plastic Prep Solution - which I obtained from Micro Mark (Item # 60873). The Plastic Prep solution was sprayed on the model using one of my wife's old spray perfume bottles (I cleaned it throughly before slipping it back on her dresser). You could use a brush to get the solution into all the nooks and crannies...I didn't.  After allowing the stuff to air dry overnight, I then painted the building without any trouble.

 "Keeping my hand on the throttle...and my eyes on rail."

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Posted by TMarsh on Wednesday, December 24, 2008 1:13 PM

CNE Runner
using one of my wife's old spray perfume bottles (I cleaned it throughly before slipping it back on her dresser).

LaughBowLaugh

Todd

Todd  

Central Illinoyz

In order to keep my position as Master and Supreme Ruler of the House, I don't argue with my wife.

I'm a small town boy. A product of two people from even smaller towns. I don’t talk on topic….. I just talk. Laugh

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Posted by Kenfolk on Wednesday, December 24, 2008 4:07 PM

using one of my wife's old spray perfume bottles (I cleaned it throughly before slipping it back on her dresser).

Eau de plastiqueLaugh

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Posted by loathar on Wednesday, December 24, 2008 4:22 PM

I wouldn't worry about cleaning before weathering. I don't think I'd dunk an entire building in any kind of water/cleaner.

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Posted by wjstix on Thursday, December 25, 2008 3:11 PM

Washing is really for before you apply the first coat of primer. If the building's already painted you don't really need to wash it to apply some weathering.

I prefer to weather "dry" with chalk or powders etc. rather than paint - nice to be able to wash it off if you don't like it!! Unless you're going to be handling the building a lot after it's on the layout, you don't really need to seal in the dry weathering.

Stix
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Posted by Last Chance on Thursday, December 25, 2008 7:30 PM

Careful with prepping the wife. YOU might get prepped yourself LOL.

I clean parts off the sprue with dish soap and warm water, hoping for the best before painting. When it's ready it recieves the powders. Although I tend to use a extra part or two and test, throwing away those that didnt turn out so well and recording the good results and how I got them for later use.

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Posted by CNE Runner on Friday, December 26, 2008 8:27 AM

Last Chance
Although I tend to use a extra part or two and test, throwing away those that didnt turn out so well and recording the good results and how I got them for later use.

What a great idea...so simple I never thought of doing it! Just about every kit (craftsman or plastic) ends up leaving several bits and pieces that arent' used. In a craftsman laser-cut kit the outside of the plates would do as "test pieces". I assume you than write the paint or weathering mixture on a 3"x5" file card and keep for future reference? Thanks for the tip.

Ray

 "Keeping my hand on the throttle...and my eyes on rail."

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Posted by doctorwayne on Friday, December 26, 2008 9:57 AM

If you're using water-based paints, washing before painting is a must, unless the model is wood. Wink Solvent-based paints are more forgiving, but there's no reason why you can't toss a plastic or brass model, either built-up or as parts, into the sink with some warm water and dish detergent.  Make sure to rinse thoroughly when done.  Most plastic kits have mould-release agent on them and all models that you handle will have skin oils on them, neither conducive to good paint adhesion. 

Wayne

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Posted by pastorbk on Wednesday, June 10, 2015 10:33 PM

What do you use since the Plastic Prep appears to be unavailable, even on eBay?

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Posted by modelmaker51 on Thursday, June 11, 2015 9:55 PM

I've never heard of mold release being used in injection molding. The moltenplastic is injected into the molds and the part is then just popped out6 - no mold release. The plastic doesn't stick to the stainless steel molds.

Now resin casting is another story. Most commercial resin casting do have mold release on them but not all. It depends on the silicone used for the molds. For my own castings I use Micromart One-To-One silicone and I do not use a mold release, however the casting process does create oils that have to be washed off.

Jay 

C-415 Build: https://imageshack.com/a/tShC/1 

Other builds: https://imageshack.com/my/albums 

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Posted by dstarr on Friday, June 12, 2015 8:12 AM

pastorbk

What do you use since the Plastic Prep appears to be unavailable, even on eBay?

 

Dawn liquid dishwash works for me. 

 

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Posted by cedarwoodron on Friday, June 12, 2015 8:26 AM

I work with a lot of new and old plastic frequently, as I pick up used built and un- built NIB rolling stock and structures at swap meets.

What I do for new plastic is to use a dish soap wash+ rinse first; same for old plastic that I have removed original paint from. I follow with this by letting the model or parts air dry on a paper towel, and then I use my air brush to push out any remaining moisture that may be trapped in crevices.

I use inexpensive nitrile disposable gloves (Harbor Freight) when I do my cleaning, so I don't re- soil plastic surfaces with body oil from my handling, but also do a quick wipe of my hands again with alcohol before working with plastic on the workbench. Subsequent partial and final assemblies get the dish soap and air brush treatment again before any paint is applied.

 

Cedarwoodron

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