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Model Forum / General / Rockets / November 2004NC Paint Removal
I've got a 4" PML nosecone that needs refinishing due to paint chipping off. Does anyone have a good technique for removing the old paint other than sanding? Sanding just heats the paint enough to turn it to sticky goo - clogs the paper and generally just makes a mess. Suggestions?  SignatureJoe Michel NAR 82797 L2 http://home.alltel.net/jm44316/ > I've got a 4" PML nosecone that needs refinishing due to paint chipping off. > Does anyone have a good technique for removing the old paint other than > sanding? Sanding just heats the paint enough to turn it to sticky goo - > clogs the paper and generally just makes a mess. Suggestions? Hi joe, get some wet sanding paper at the auto section of your store and fill a bucket up with warm water and liquid dish detergent. Keep the nose wet and the paper wet and it does not heat up or get the paper filled up with paint to turn into a goo. Hope this helps, it will come off in just a few mins of work this way. have fun ! > > I've got a 4" PML nosecone that needs refinishing due to paint chipping > off. [quoted text clipped - 9 lines] > > Hope this helps, it will come off in just a few mins of work this way. A bit of trivia related to getting the paint to stick to a blow-molded nose cone: A couple of weeks ago, I met with the owner of a blow-molding company concerning a project that I've been considering, and the subject of paint adhesion came up. Apparently, on jobs where the finished part is to be painted, the blow molded part is flame treated at the plant. Pressing further on how this was done, I was informed that they simply pass the flame of a cheap propane torch over the surface of the part! (There is specialized equipment to do this on high-volume jobs.) According to the plant manager, it takes some practice to get the technique down (duh...), put once the part is flame treated, paint adhesion is no longer a challenge. Perhaps one of the chemical/techie types can fill us in on what actually happens to the plastic? James ________________________ James Duffy jduffy@mac.com www.rocket.aero Blow molded nosecones for hobby rockets are typically manufactured from polyolefins such as polyethylene and polypropylene. These are low surface energy, crystalline polymers that exhibit low surface energy. Flame treating increases surface energy thus promoting wetting and adhesion. Another method commonly used is corona discharge treating which accomplishes much the same thing. The latter is preferred in applications where surface oxidation cannot be tolerated although some will argue that surface oxidation is what is increasing the surface energy in the first place. The techniques are used extensively for print labeling of polymer packaging in the food industry. It's also important to note that it's efficacy is generally dependant on how soon the ink or paint is applied after the treatment. It's also not a silver bullet. Anthony J. Cesaroni President/CEO Cesaroni Technology/Cesaroni Aerospace http://www.cesaronitech.com/ (905) 887-2370 x222 Toronto (410) 571-8292 Annapolis >> > I've got a 4" PML nosecone that needs refinishing due to paint chipping >> off. [quoted text clipped - 35 lines] > jduffy@mac.com > www.rocket.aero > Blow molded nosecones for hobby rockets are typically manufactured from > polyolefins such as polyethylene and polypropylene. These are low surface [quoted text clipped - 10 lines] > > Anthony J. Cesaroni What blow molded material is? SignatureJerry Irvine, Box 1242, Claremont, California 91711 USA Opinion, the whole thing. <mail to:01rocket@gte.net> Please bring common sense back to rocketry administration. Produce then publish. http://www.usrockets.com Ebay auction deals and specials. http://tinyurl.com/6wlp8 Jerry wrote, > What blow molded material is? Jerry, My reply was in response to James's inquiry regarding flame treating. Sorry if I confused the thread. Anthony J. Cesaroni President/CEO Cesaroni Technology/Cesaroni Aerospace http://www.cesaronitech.com/ (905) 887-2370 x222 Toronto (410) 571-8292 Annapolis James Duffy wrote, > A bit of trivia related to getting the paint to stick to a blow-molded > nose cone: A couple of weeks ago, I met with the owner of a [quoted text clipped - 9 lines] > technique down (duh...), put once the part is flame treated, paint > adhesion is no longer a challenge. Blow molded nosecones for hobby rockets are typically manufactured from polyolefins such as polyethylene and polypropylene. These are low surface energy, crystalline polymers that exhibit low surface energy. Flame treating increases surface energy thus promoting wetting and adhesion. Another method commonly used is corona discharge treating which accomplishes much the same thing. The latter is preferred in applications where surface oxidation cannot be tolerated although some will argue that surface oxidation is what is increasing the surface energy in the first place. The techniques are used extensively for print labeling of polymer packaging in the food industry. It's also important to note that it's efficacy is generally dependant on how soon the ink or paint is applied after the treatment. It's also not a silver bullet. Anthony, you didn't consused the thread. You confused Jerry. 8-) >Jerry wrote, > [quoted text clipped - 41 lines] >soon the ink or paint is applied after the treatment. It's also not a silver >bullet. Anthony, I think what you call corona discharge is what I call plasma etching. We used plasma etching to clean many parts and glass ware. But I know about it activating the surface of plastic before printing or painting. We used a number of gasses, oxygen, argon, nitrogen, freon, and some times helium as a buffer. Some times I did try it on a nose cone and found that oxygen etching was best, although using gust argon did improve the adhesion. Jack > Blow molded nosecones for hobby rockets are typically manufactured from > polyolefins such as polyethylene and polypropylene. These are low surface [quoted text clipped - 15 lines] > (905) 887-2370 x222 Toronto > (410) 571-8292 Annapolis Interesting! When I paint my cones, I rough them up with a palm sander with 60-grit until they are really fuzzy. Then I prime and wetsand until they are smooth, then paint. (which takes FOREVER, BTW) Looks great when done, and you think it STICK, but no. Any hard impact which causes the cone wall to flex is enough to pop off a large chunk of paint. SignatureJoe Michel NAR 82797 L2 http://home.alltel.net/jm44316/ > > > I've got a 4" PML nosecone that needs refinishing due to paint chipping > > off. [quoted text clipped - 33 lines] > jduffy@mac.com > www.rocket.aero > Interesting! When I paint my cones, I rough them up with a palm sander with > 60-grit until they are really fuzzy. Then I prime and wetsand until they > are smooth, then paint. (which takes FOREVER, BTW) Looks great when done, > and you think it STICK, but no. Any hard impact which causes the cone wall > to flex is enough to pop off a large chunk of paint. You need to use an auto product for painting bumpers and stuff called of all things: Flexible Bonding Clear it is put on wet before your paint to make a flexible bonding coat for the paint the will stick on your bumper or cone. > You need to use an auto product for painting bumpers and stuff called of all > things: [quoted text clipped - 3 lines] > it is put on wet before your paint to make a flexible bonding coat for the > paint the will stick on your bumper or cone. It also helps to scrub the nosecone first with hot soapy water, then don't touch it again with bare hands until after it's painted -- the grease from your fingers will affect adhesion. You can also buy products for degreasing prior to painting. -Kevin > A bit of trivia related to getting the paint to stick to a blow-molded > nose cone: A couple of weeks ago, I met with the owner of a [quoted text clipped - 5 lines] > the surface of the part! (There is specialized equipment to do this > on high-volume jobs.) Bob Sanford used to pass out this "flame broil" tip for AT and other blow molded nose cones. With all the plastics now used, it's common in the auto refinishing industry. Part of it is probably removing mold release compounds, but it also does something to the plastic surface to promote adhesion. Bob Kaplow NAR # 18L TRA # "Impeach the TRA BoD" >>> To reply, remove the TRABoD! <<< Kaplow Klips & Baffle: http://nira-rocketry.org/LeadingEdge/Phantom4000.pdf www.encompasserve.org/~kaplow_r/ www.nira-rocketry.org www.nar.org I support drug testing. I believe every public official should be given a shot of sodium pentathol and ask "Which laws have you broken this week?". Although I have not tried it, a person with plastic model background told me that EZoff oven cleaner makes a good paint remover. I believe the "No fumes" stuff was milder than the regular. Obviously, I'd try it on a throw away first. > I've got a 4" PML nosecone that needs refinishing due to paint chipping off. > Does anyone have a good technique for removing the old paint other than > sanding? Sanding just heats the paint enough to turn it to sticky goo - > clogs the paper and generally just makes a mess. Suggestions? > Although I have not tried it, a person with plastic model background told me > that EZoff oven cleaner makes a good paint remover. I believe the "No > fumes" stuff was milder than the regular. Obviously, I'd try it on a throw > away first. I used EZoff years ago on styrene plastic parts and it removed the paint, after some effort, without destroying the styrene. It's been awhile since I messed with it, but as always use it on a similar piece of unneeded plastic first. The other method in the modeling world was to soak it in brake fluid for a week or so, I seem to recall I didn't have to much success with that method. Chuck > I've got a 4" PML nosecone that needs refinishing due to paint chipping off. > Does anyone have a good technique for removing the old paint other than > sanding? Sanding just heats the paint enough to turn it to sticky goo - > clogs the paper and generally just makes a mess. Suggestions? Wet-sanding is the best method I've found. -Kevin Lacquer thinner will remove most paints. Dumo some in a zip lock bag, throw the nose cone in & let it do its thing. >I've got a 4" PML nosecone that needs refinishing due to paint chipping off. >Does anyone have a good technique for removing the old paint other than >sanding? Sanding just heats the paint enough to turn it to sticky goo - >clogs the paper and generally just makes a mess. Suggestions? I just whack the nosecone with the handle of a screwdriver until most of the paint flakes off. Then I scrape the rest off with an X-acto knife held perpendicular to the surface . Just to update this thread, I tried the suggestion to whack it off ;-) with a screwdriver handle. No dice - guess I'm not a good whacker. ;-) After that, I tried wet-sanding. All the grit came off the sandpaper - hey, guess I should use wet-or-dry paper, huh? DOH! Next, I tried the suggestion to strip the paint with Easy-Off. Had a can laying around, so I thought what the hey. Sprayed it and, wrapped the NC in a bag, and let it sit for a couple of hours. Uh-huh. That worked like sh*t. So, I ended up scraping it off with a utility knife, following up with a palm sander to get the primer that would not scrape off. The primer sands off without gooing up at all. SignatureJoe Michel NAR 82797 L2 http://home.alltel.net/jm44316/ > I've got a 4" PML nosecone that needs refinishing due to paint chipping off. > Does anyone have a good technique for removing the old paint other than > sanding? Sanding just heats the paint enough to turn it to sticky goo - > clogs the paper and generally just makes a mess. Suggestions? Sorry I didn't catch this earlier Joe.. I've done several AT nosecones in the past and stripped them down with Brake Clean.. Auto store stuff made to clean up pads/rotors/drums (i guess i'm no mechanic) the thing is it takes anything off then dissolves away to nothing. I've not had a Krylon or an Enamel that it didn't just take right off, spray some on, give it a few seconds then paper towel it off. Then i just wash in soapy water and resand, repaint. Jason www.firemanrocketry.com I would have tried that if I would have thought of it before I attacked it with a razor blade. Brakekleen certainly would strip it! I'm sure this won't be the last dinged up NC I'll have, so I'll try it next time. Good to hear from ya!! If you're not busy, come to chat 'round 8:30 tonite so we can shoot the breeze. SignatureJoe Michel NAR 82797 L2 http://home.alltel.net/jm44316/ > Sorry I didn't catch this earlier Joe.. > [quoted text clipped - 11 lines] > Jason > www.firemanrocketry.com I just removed the paint on a couple nosecones that I painted in a hurry and the paint started to chip off. My method was sticking shipping tape to the cone and pealing it off. It took a little time to get all the paint off but it worked quite well. > I've got a 4" PML nosecone that needs refinishing due to paint chipping > off. > Does anyone have a good technique for removing the old paint other than > sanding? Sanding just heats the paint enough to turn it to sticky goo - > clogs the paper and generally just makes a mess. Suggestions? >... nosecone ... needs refinishing ... paint chipping off ... >anyone have a good technique for removing the old paint other >than sanding? I just manually flake off the really loose paint around where it originally chipped. Then I run some thin CA around the edges of the paint chips. After that I fill in the paint chips with Squadron putty, sand them smooth, prime the touched up area and then repaint the NC to restore it to its unblemished state. ...Rick > I've got a 4" PML nosecone that needs refinishing due to paint chipping off. > Does anyone have a good technique for removing the old paint other than > sanding? Sanding just heats the paint enough to turn it to sticky goo - > clogs the paper and generally just makes a mess. Suggestions? If it is canned spray paint, you may want to try this. I get a Scotch Brite pad soaked with rubbing alcohol. The alcohol disolves the paint, while the pad doesn't gummed up like sandpaper and it can be washed out. |
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