ressources:
* [http://werkstatt-lastenrad.de/index.php?title=Long-Andr%C3%A9:_description_en_fran%C3%A7ais#Peinture wiki Werkstatt Lastenrad]
* [http://www.firstindustries.ch/cms/init.php/page/content?l=fr&id_page=660 First Crissier] (fournisseur de prestation, mais lire leurs infos pour les imiter éventuellement)
* http://www.sheldonbrown.com/paint-prep.html
** sur le débarras de la rouille:
*** Sand rust patches lightly with fine sandpaper -- #320 grit or finer. This reveals where there is deeper rust.
*** Follow the sandpapering with a solution of phosphoric acid -- the mild acid which gives Coca-Cola its tang. In fact, sometimes Coca-Cola has been used to clean metals. (I don't recommend Coca-Cola for rust removal: it leaves a sticky residue, and the acid concentration is low.) Phosphoric acid eats rust but not steel, and you can leave a rusted part Phosphoic acid solutionsof a frame soaking until all the rust is gone. Avoid getting phosphoric acid solution into your eyes; also, rubber gloves are advisable -- but short-term contact is harmless. You need only wash with soap and water. [The photo at the right shows two phosphoric acid products.] Loctite Naval Jelly is pink and gooey and will stick to surfaces at any orientation. Better hardware stores carry this. Purple Power rust remover or another watery phosphoric acid treatment is typically used as a wash for metal panels in auto-body shops. You can brush this onto bare metal parts of the frame to remove light surface rust and prevent further rusting, or you can soak parts of the frame in a diluted solution to remove deeper rust. One useful way to soak is to saturate a rag with the solution and wrap it around a frame tube. [...] The object is to remove rust right down to bare metal. You should see only gray, no brown or orange rust. The frame may be left with rust pits. If they are not too deep and not located where they weaken the frame, good enough. They can be filled before painting.
*** Another way to remove rust is by electrolysis, by connecting the rusted piece and another iron or steel object to the two poles of a battery charger and immersing them in water. The liquid electrolyte is simple -- baking soda or washing soda in water. To get an entire frame into the electrolyte solution, you might lay a sheet of polyethylene plastic on the floor inside a rectangular frame. Electrolysis works much faster than phosphoric acid, and is more practical if there is pitting. Links at the end of this article go to Web pages giving instructions. Reading into the last paragraph on one of those pages, I think that electrolysis is safe for brazing, though I'm not sure.
*** The phosphoric acid solution or electrolyte can be washed off with clean water. Very little rusting will result if the frame is dried quickly.
** It is common to clean paint off a steel frame using abrasives. Sandblasting is the generic term for this work, but sand does slightly erode steel tubing. Glass bead blasting is much gentler. Major cities have shops which do this work. Before taking a frame in to a shop -- unless it is a shop experienced in work on bicycle frame -- you need to protect surfaces which you do not want to be abraded, or where you don't want particles to lodge. Thread old bottom-bracket cups partway into the bottom bracket and wrap them in tape, install an old headset,.and block off ventilating holes with toothpicks. Duct tape is sturdy enough to resist blasting and keep abrasive particles out of the frame. Also, either you or the shop needs to clean off oil, grease and deruster residues before blasting. Blasting may not entirely get rid of these and may propel them into pores in the metal. Derusters can be washed off with water. (The phosphoric acid leaves a rust-preventive coating which will withstand a rinse). A solvent cleaner works for grease and oil. If the frame has been waxed, a special cleaner such as PPG DX330 Wax and Grease Remover, Sherwin Williams R7K156 Solvent Cleaner, or Dupont 3919S Prep-Sol is recommended, because blasting can leave a wax residue in pores on the surface.
** Primer and finish coat
*** Any finish for steel must start with a rust-preventive primer coat. This works like an electrical battery, but on a microscopic scale. One component gets eaten away as an electrical current passes between it and the other when they are wet. If the two components are zinc and steel, the zinc gets eaten away, protecting the steel. Primers contain zinc, which slowly gets eaten away.
*** "Acid etch" primer is popular now for use on auto body panels, and adheres especially well to steel, but it is not suitable alone under some paints. If used, it should be followed by the primer designed specifically for that paint.
*** The finish coat or coats prevent moisture from getting in, as much as possible -- but a finish coat alone will not prevent rust. Sooner or later, moisture will get in somehow, through a crack or scratch or chip, or by absorption, and without the primer, rust will spread under the paint.
*** A fine paint job won't last forever -- but with proper preparation, and primer under the finish coat(s), it should be good for many years.
** Brushing
*** You can brush on enamels. Brushing is simpler, less messy and less of a health hazard than spraying, but generally doesn't produce great-looking results.
*** Most enamels use a petroleum-based solvent and dry by evaporation, taking weeks to harden completely. Additional hardening occurs through chemical cross-linking, which builds bigger molecules. Baking can greatly speed the drying and hardening, but is not a practical choice for do-it-yourself work.
*** '''Marine epoxy enamel -- primer and topcoat -- can be purchased at boating supply stores. It largely avoids the drying issue, because it has two components which you mix together like epoxy glue. Most hardening occurs within a few hours through a chemical reaction.'''
*** '''A marine-epoxy enamel coating is thick -- so only a couple of coats are needed -- and very durable. If you brush it on, it can get very ugly because of its tendency to sag and drip. Ugliness is an advantage, though, where it deters thieves. Because you can apply the coating yourself, the cost is low.'''
*** Despite its low solvent content, marine epoxy enamel is smelly and toxic enough that you should mix and apply it outdoors or in a detached shed or garage.
** Spraying
*** Spraying, followed by air drying or baking, is the traditional way to apply finish to a bicycle frame. It may be anything from "rattle can" work to auto body shop work, to very fancy artistic fades from a specialty bicycle refinishing shop.
*** With spraying, there is unavoidably overspray. Droplets of liquid paint are carried in the air. These are smelly and unhealthful. There are even horror stories about workers who, with repeated paint spraying, coated the inside of their lungs until they could no longer breathe properly and had to use an oxygen tank.
*** For occasional, small jobs with the rattle can, you will probably get away with spraying outdoors with the wind blowing away from you, but if you use spray paint more than occasionally, you should wear a face mask -- preferably not just a simple fiber face mask, but a professional-grade respirator with dust and mist filters, activated charcoal elements and a one-way exhaust valve. The mask needs to form a tight seal against the face so that all the intake air comes through the filters.
*** Safety glasses or goggles are a good idea too: you don't want to get spray on your eyes, or eyeglasses. Professional painters use a ventilated spray booth with exhaust-air filtering, which also minimizes air pollution.
*** Sprayed enamel, followed by baking, is the traditional treatment for everything from new cars to refrigerators to bicycle frames.
*** A good spray-painted enamel finish requires several coats -- first, the rust-preventative primer, then color coats and often, a clear finish coat to add gloss. An auto body shop or professional bicycle frame shop can spray more efficiently than you can. The paint of choice for bicycle frames is Dupont Imron enamel.
*** Spraying two-part marine epoxy enamel is not practical for do-it yourself work, because it requires specialized equipment and careful clean-up to avoid clogging. Because droplets of sprayed epoxy harden inside the lungs, it carries a high health risk. I suppose that you could take your frame to a boating contractor to spray on marine epoxy enamel, for a better appearance, and to avoid the mess and exposure to chemicals, but I've not investigated this myself.
** Internal rust protection
* vendeurs de peinture
** grand public