Household Bleach for Plastic-Safe Paint Stripper?

[hartleymartin]

I was chatting with a fellow who sold airbrushes at a recent exhibition and he suggested that I use household bleach to remove the paint from a Slater's plastic carriage I had acquired. 

 

Anyone else tried this method? Does it work?

 

[PatB]

I haven't tried it, but it might very well work. I haven't got my material references in front of me at the moment to check specifically for the properties of polystyrene but memory tells me that most plastics are fairly resistant to alkaline chemicals such as bleaches. Don't take that as a recommendation without checking, though. At least try sitting a few lengths of sprue in a jar of bleach for a couple of days to see what happens.

 

Something else you might try is sodium carbonate (washing soda), available cheaply in bulk from pool supply outlets. I haven't used it specifically as a paint stripper but I was using a concentrated solution of it as an electrolyte for electrolytic derusting of some iron components and found that everything came out of the vat completely free of paint. I'd expect it to take longer than bleach but it's safer to handle and even less likely to degrade plastics.

 

Edit: Here's a link to a compatibility table.

 

http://www.plasticsintl.com/plastics_chemical_resistence_chart.html

 

It doesn't actually list polystyrene but it appears that sodium hypochlorite (the active ingredient in most household bleaches IIRC) is not particularly aggressive to most other plastics apart from nylon (keep it away from plastic wheels) and acetal. Do the sprue test and then give it a whirl.

 

Edit again: Here's another one, this time listing polystyrene against sodium hypochlorite.

 

sevierlab.vet.cornell.edu/resources/Chemical-Resistance-Chart-Detail.pdf

 

Shows little or no effect after 30 days exposure, so your Slaters kit should be safe in a bleach bath.

[jonhall]

http://www.rmweb.co.uk/community/index.php?/topic/71372-mr-muscle-paint-stripper-opps-no-i-mean-drain-unblocker/

 

was my experiment - you need something with a sodium hydroxide component I think.

 

Jon

[Il Grifone]

If it worked sodium carbonate would be a first choice as not being corrosive to the extent of the usual chemicals, but possibly its paint removal characteristics were aided by the electrolytic action?

 

It's usually available in supermarkets in conveniently sized packets and could be worth a try. (SWMBO may already have some....)

 

I have used brake fluid in the past, but the current DOT4 type is, I understand, paint-safe, but not plastic-safe, so completely useless.

 

I used (pound shop) spray oven cleaner* with success on a Tri-ang DMU and a Piko coach recently. It has left a patina on the DMU (but not on the coach). This will not matter, of course, if the model is to be repainted. I would neutralise with vinegar or similar mild acid before further work.

 

* This contains sodium hydroxide (usually but not always the active ingredient in these sprays), which is highly corrosive and should be treated with extreme care. (The can I have suggests skin contact should be treated with running water for 20 minutes as first aid.)