Fixing broken plastic

Newbie question here: I am trying to repair some plastic buildings (don't know what type of plastic) that have various cracks, imperfections, and chunks of plastic missing. My goal is to repair the plastic on these buildings, sand them smooth, and then coat the entire building with some sort of plastic liquid(?) or some sort of thin liquid that will fill in the sanding scratches and any other small imperfections left behind, leaving a super smooth finish on the end product. I've kind of stumbled my way through the repairs using some clear epoxy resin. It has allowed me to fix most of the bigger cracks and missing chunks, but I need some sort of liquid that I might be able to pour on top of the building and let gravity take it to all of the low spots to fill in any of the small imperfections and give me a finished product. I hope that I am being descriptive enough. By the way, I have tried using Krylon's triple thick coat spray on an older building, but it doesn't really seem like it wants to entirely stick to everything like I had hoped it would. I prepped the building first by wiping rubbing alcohol on it to remove any dirt or greasy film. Any help is appreciated. Thanks.

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1. is it worth it? are they rare or valuable? 2. what scale and have you looked for others? 3. how much work and what is your time worth? 4. what kind of plastic?

yes it is worth it. These are actually plastic buildings off of a playfield of a twenty year old pinball machine. They do not make these game specific parts anymore and I have searched for them on ebay and other sites for years. As I said before, I do not know the type of plastic that they are made of. I believe that they were originally made from vaccuum forming if that helps? I guess that my biggest problem is finding a product that will flow over the structure evenly with a thin coat, but more importantly, a product that will bind to the plastic. The epoxy resin does a nice job, but I would have to mix a massive quantity to be able to pour it over the building and its really kind of thick for that. I know I'm reaching here, but how about KILZ paint primer? Maybe a couple of coats??? Ideas?!

Depending on what kind of plastic and how thick, Kilz might have bad effects by softening possible- how about this- can you get at the inside of the buildings? then reinforce from the inside with 2-part epoxy putty- thin bead along inside the corners. You could then use it on the outside of the edges to reinforce and restore, and then paint normally. Also, there's a resurfacing paint called Mr. Surfacer, will fill small imperfections in a surface and with a little wet sanding will make it look good again. BTW, Mr. Surfacer comes in a few grades, starting with 500 grit and working down. Keep us posted on this- sounds intriguing-

Thanks for the reply. I have another broken building that I guess I'll have to experiment on with different products. Maybe the kilz. As I said before, I fixed pretty much everything that needed fixing, I just need a final coat of something to smooth everything out. (scratches and so on) Will this "Mr.Surfacer" bond to plastics? And, where can I get it? Also, what are your thoughts on Krylon's Fusion paint?

was also thinking of possible trying fiberglass resin (without the cloth obviously) Rich

snipped-for-privacy@adelphia.net wrote:
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If these buildings are indeed hollow (as suggested by your observation that they are vac-formed); then I would second Jim's suggestion. The two-part epoxy putties would be ideal for this. They are strong, easy to apply, and little-to-no mess. They can be found under a variety of names. Check a good, full-line plumbing supply store for "A+B" or "Atlas" putties. And in the radiator sections of good automotive supply stores, look for a two-part putty that comes in a blister pack. One brand is "Super Glue" brand; and I have even found a "house brand" at Big Lots! (and cheap, too!). These putties can be pressed into the inside of the buildings using nothing but your finger, and a little water to keep it from sticking to your finger. Once cured, they are rock hard; and can be sanded and/or carved.

Greg Heilers wrote:
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My latest refinement on the process: fill such hollow cavities with the somewhat new (to me anyway) **low expansion** canned polyurethane foam, sold for use around doors etc. so they don't push the door frame out of the way. You can even find shortie cans of the stuff if you look around home depots and lowes and so on. any overfill can be easily filed/sanded off. you can't jump up and down on it like if you filled it with epoxy, but it's almost as sturdy and a lot simpler to do.
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yeah, don't experiment. check google for companies that restore such and find out what you can. or if you just want it to look ok, take a piece to a plastic seller and have them if the type. look for a plexi-styrene dealer in your phone book.

here is another thought, you guys paint your models right??? If your models are plastic, why couldn't I just use the same paint to spray these buildings with. Maybe multiple coats of model paint might do the trick?

I also restore classic video games so I can totally sympathize with you on the value you place on these parts. That's the reason why I cant stress enough that you REALLY NEED TO KNOW what type of plastic these are made of. if you use the wrong paint or even a wrong combination you could unwillingly destroy the pieces. If you haven't already, check out the Pinball forums in Google and/or yahoo, I'm sure there are other collectors who have the same game and will know what type of plastic the parts are made from. A lot of times you will actually get someone from the business who might have first hand knowledge of the actual pieces your looking to restore. (that's why these groups are so great) Good luck.....
-Dave