Painting flexible plastic

Has anyone ever painted flexible plastic (fenders on motocross bike for instance)?? I saw that Krylon has a new Fusion plastic paint that looks to be good. Don't know.

I just used fusion on my side covers, but they don't flex as much as your fenders. I asked Krylon about the buffing, and they sid "theoretically" you can buff if, after the full curing time. I'm going to test that theory this Saturday. As far as adhesion, it is very good, even without primer...I've tested it both ways. It sprays like the enamel it is...2 or 3light coats you can see through, drying between them...then lay it on...that's how I do it. So it takes some patience to get good final results. I know it will wet sand with 400-1500 great after two days, and that you can't buff it that soon (don't ask). I also know the recoat window is very firm...follow instructions exactly regarding recoat. I was a big lacquer fan before this, and have made a few mistakes with this paint, trying to rush it like you can with lacquer. I have to say, it sprays very nicely, though, and almost doesn't need sanding/buffing. No sags or drips or runs once I got used to it, and it settles into a high gloss, too! for a dirt bike, you might be able to skip the sanding/buffing altogether. I think I would. There are pictures of my bike in paint and body, and the side covers ar not sanded or buffed. Give you an idea of the finish right from the can.

best thing to do to keep paint from cracking is scuff the part good. grey scotch-brite pad, wet or dry, scuff until your arm falls off. Of course, bare plastics are tricky though. sometimes if you do this, you get little hairs of raw plastic sticking up everywhere, looks furry when painted. I usually scuff the crap out of it, hit it with 'Bulldog Adhesion Promoter' then primer with PPG NCP-271, wetsand out to 600 grit, then shoot.

Have you determined what type of plastic it is?
It could be one of any different types of plastic. I am not sure whether or not they label the plastic type, but if they do, here are the types and the abbreviations...
Polypropylene PP
Polyethylene Terepthalate & Polyester PET
Termoplastic Olefin TPO, EPM, TEO
Thermoplastic Polyurethane TPU
Polyethylene PE
Nylon Blend PPO, PA
Thermoplastic Ether Ester Elastomer TEEE
there might be a small circle made of dots surrounding one of these abbrivations on teh back side of the piece. If so, there are different techniques for painting the two main types of plastic. Thermo and Thermo-Set are the two main kinds.
of course... I migh tjust be sputtering out unuseful stuff. If yo'd like to read more of my explaination on plastic types, let me know, I won't withhold information, if you have a use for it.

If you think scuffing the raw plastic will adversly affect it, you can just hit it with the 'bulldog' then spray it. most of the time, it's not the type of paint that makes cracks. It's either the painter laid it on way too thick, or there is not enough surface adhesion to keep it stuck tight enough to flex with the plastic.

Try this...

take a piece of masking tape, and paint the sticky side. put full coats on there until you have full coverage. after it dries, try to get the paint on the tape to crack. bend it, twist it, lick it... whatever...

chances are, if the paint is half decent, and it's not gobbed on there, it will flex with the tape. the clearcoat I spray is flexible 180 degrees on an 1/8th inch mandrel. that's like bending it in half without cracking.
Of course, I have never seen mandrel bend tests done on rattlecan paint. You could always try.

btw, 'bulldog adhesion promoter' is available in aerosol spray cans.

hope this helps.

John

Got a source for that there 'bulldog adhesion promoter' ????????? I havent seen it at Wally's, Auot Zone, or Advance Auto parts....

According to the Klean Strip website, they say that you should be able to get it at Walmart, ACE Hardware, Home Depot and Lowes. I'm gonna try that stuff and then topcoat with the Krylon fusion paint. If that doesn't hold up nothing will.

Personally, I wouldn't mess with the adhesion promoter on fusion paint. I've had my side panels on and off throughout this project, and there's no sign of any cracking at all. I just sanded it with 320 grit, painted it. If you can do it within 24 hours, you can wet sand with 400 and recoat for a really smooth finish. I did that, and am waiting a week to see if it will buff. If it doesn't, I'll post all the pertinent info. The more I see the bike with the covers on, the more tempted i am not to buff it...it reall looks great already...but I think the information is important enough to find out and pass on. if it doesn't work, it's paint, i'll fix it.

Ron...
Check yer U2U

I just read up on Krylon Fusion. I wish they had P-sheets like all the big boys. It would be helpful to know exact information. I really am not the guy to talk to about rattlecan spray paints. to me, any noncatylist paint system is not worth all the time and energy you put into prepping. Honestly, if you are a good rattlecan painter, you should be a superior spray gun painter. $19 at Home Depot will get you a 7 oz. touch-up siphon fed spray gun that is more than adequate to shoot a motorcycle. I did a whole fender for a 1964 Impala with a Campbell Hausfield 7 oz. detail gun that I paid $19 for. The gun is capable of a 9 inch spray pattern which is just as good as a "real" paint gun, and only requires 20-35 PSI to operate. You'd be very surprised at the control you have with a gun vs. a can. The magic is in the prepwork. runs can be sanded out, dry haze can be sanded and buffed to a mirror finish, and the best part, the paint never goes dull like noncatylist paints.
Anyhow, I usually get bulldog at a local autopaint store. I have seen it in Home Depot though.

good luck on that project.

oh, and something to consider. PPG DC-3000 clearcoat cannot be dug into with a sharp fingernail 90 minutes after shooting. talk about durability, and you gotta love the shine!

John, I totally agree on all of that. The Krylon guy who finally e-mailed me a sheet didn't tell me anything I didn't read on the label...and caveated everything with "in theory", meaning "nobody I asked really knows".

Here's a thing to do for small projects like these, if you have a compressor, and get a gun, and can get your store to sell you quarts instead of gallons, for all the parts of the paint system (can you tell I'm in a small town?)...a four man tent as a spray booth. Doesn't comply with any regulations regarding filtration, but basically keeps the bugs out of the paint while it dries. Don't forget the respirator if you're shooting multistage paint, or cans, indoors. Oh and ppg clearcoat is mixed at what, 4:1:1 at $210 per gallon for the clear, $90 for the hardener, and $45 for the reducer. So, if you need two quarts...105 for clear, about 12 for a quart of reducer, and 25 for the hardener if they'll do it. You can get by with a quart on your fender, easy, but I doubt they'll sell tou a cup of hardener and reducer. So, about $90, plus gun, plus tent, plus body suit to keep ppg3000 out of your skin. Pretty pricey for a plastic fender...your costs may vary in your area, again, if they'll do it. Oh, I forgot the color coat, sorry.

:woohoo: :silly: :blink:

Post edited by: ronboskz650sr, at: 2005/10/12 21:56

We paint the nose piece on our race car but we apply a primer to it first. It lets the paint bond with the plastic a lot better. I'll have to get ahold of my brother and find out the exact product but I do know it's not very costly and it works great. The paint stayed on all season with the exception of running into the back of an occasional slow car here and there. I don't think that would be an issue for you right? LOL

Peace,
Rodger

wow! where do you live that you have regulations regarding filtration?
A while ago, I worked at a bodyshop in Peters Township, which is in the south hills of Pittsburgh, PA. Peters is the big money area of Pittsburgh. Chuck Noll, Mario Lemieux, Bill Cowher, Rooney Family, and lots of other big names lived in that part of the city. We were inspected several times by the EPA/DER and by local supervisors. The only thing they ever nailed us on was not having lids on our trash containers, and for some of us still having conventional non-HVLP paint guns :whistle: . As far as the booth emissions, they were unfiltered and blown directly out the back of the shop. I also worked in a shop in Washington, PA, in the middle of a city street, and same thing, paint fumes and overspray, right out onto the roof!

If you are interested in getting some cheaper PPG prices, and Matrix clears, I can help. Just let me know what you want and I'll get you a price on it. You seem to have it rough, paying that much for clearcoat. PPG DC-3000 which is their most expensive clear is mixed 4:1 no reducer(not needed at all) it's $155 a package, meaning the quart of hardener and gallon of clear total cost is $155. That's 5 quarts of sprayable material @ $31 per quart. For most jobs that I am not in a hurry to get out of the shop, I'll use Matrix MS-20 clearcoat. When PPG discontinued their 2020 clearcoat, in favor of the lower VOC 2021, Matrix picked up the formula, and calls it MS-20. It's identical to the 2020 clearcoat I used to spray, even smells the same! :sick: It's $124 a package, but it is mixed 2:1:0.5 with the .5 being optional. being 2:1 you need 2 quarts of hardener to a gallon of clear, so your sprayable paint is 6 quarts @ $20 a quart. MS-20 can be bought in quarts w/ pints of hardener (MH-005.)
Now, as far as basecoat goes, well, PPG can get pricey, but they do offer half pints @ $20 per half pint, depending on the color selected. DBU is classic and is mixed 1:1.5 so a half pint of DBU makes 1.5 pints sprayable. Basecoat reducer can be bought by the quart as well, rather than shelling out for the whole gallon. Now... If you want PPG, but don't want to pay as much for the basecoat, then go with Omni MBC basecoat. A gallon of Omni is around $60, verses $210 a gallon for DBU or $250 a gallon for DBC. they don't usually mix halfpints of MBC because it is reduced 1:1 straight, but a pint of most colors will run you from $9-14. and as far as the quality of omni...

check this out... www.cobweb.net/~mvp/000_00941.jpg
I did that 67 Mustang about 11 months ago. he had a total of $320 in paint, including a gallon of 2K build primer, gallon of basecoat(MBC), gallon of base reducer(MR186), gallon of clear(MS-20), 2 quarts hardener(MH-005), and a gallon of clear reducer(MR0870). The car is daily driven in Pennsylvania snow and salt, and still looks like the day I shot it.
Of course, I am just letting you know what I am paying, and offering you my discounts if you are interested. Although, I took a look at some of your pictures and I think you are doing an outstanding job with the way you are painting now! I hope you are wearing a good respirator :sick:

good luck on the SR!

John

Thanks, John..that's definitely better pricing! I don't think anyone would ever say anything about the tent idea..just mentioned the filtration for the sake of nearby neighbor ,if any. My closest oneis over 200 feet away, so it's no problem for me. Is there a shelf life on the unmixed components? It would be good if you can buy bulk reducer, and hardeners and just get quarts of color as needed. On these old bikes, I don't care for clearcoat, personally. I just think they look too glossy for the time frame...out of character somehow. It's true, I repainted mine a non-stock color (not a purist that way), but the repaint it had when I bought it was just too 90's for me. The gloss just seemed out of place. My new paint is reflective, but it's different..know what I mean? Anyway, thanks for the info...i have spraying equipment, so it's good to have a source of cheaper paint for future reference.