Topic 14173 Painting a plastic (polyethylene) motorcycle gas tank?   I have a plastic (polyethylene, I believe) gas tank from a motorcycle I would like to paint or at least find a way to have it colored "red" instead of the faded orange type color it is now. Is there any good places that can do so or is there a way for me to prepare and paint myself? Please let me know what materials should be used to get adhesion to this material and also a resistance to the gas fumes which breathe thru the gas tank itself. I have it painted now but two weeks and it bubbles from the fumes I believe. Thank you in advance. Clint G [last name deleted for privacy due to age of posting] - Saginaw, Michigan USA   Hi Clint ! Please see the archives # 10814 & 10626 and 6528. In short, you cannot successfully 'paint' Polyethylene. I would be much more concerned about the gas fumes that, you say, permeate through the tank's walls. Are you SURE? Was this always like this? (which I doubt). Pe is pretty good in permeability but Pe will eventually break down due to U.V. attack ... which is why it, like many plastics, is coloured (normally black) but red colours, ask any motorist, DO fade. Sorry. Can't help you. Go & ask the dealer. But please get back and let me know what make of motor bike this is, a cross country special, perhaps? Thanks. Freeman Newton - White Rock, B.C. Canada

Hello,

I can confirm this having a problem of painting a gas tank myself. I contacted Acerbis a major manufacturer of motorcycle gas tank and they told me that their tanks for off road (dirt) bikes are Reticulated Polyethylene (PE-X). According to them they are not repairable nor paintable. Painting could be performed if the tank is fluorinated (not very practical for me). The ones for street bikes are Polyamide (nylon).

Best regards,

Roberto C [name deleted for privacy due to age of posting]
- Torino, Italy

There are two issues involved in painting polyethylene. One is to "activate" or "modify" the surface chemically to allow wet out and adhesion. In industry there are numerous methods used to treat the surface of polyethylene before bonding or painting. The best are too hazardous for a small shop or garage since the chemicals involved are actually dangerous. Reasonable bond strength - enough for paint - can be achieved with very light surface roughening using detergent water and fine wet-or-dry sand paper. This must be followed by careful flame treatment. An oxygen rich flame is best and the flame must not be allowed to melt or glaze the surface. Instead, the farthest tip of the flame only should contact the surface and then only for a brief fraction of a microsecond. The flame must be kept quickly moving at all times. Every square inch of the surface must be touched ever so briefly by the farthest tip of the flame in this way. After some cooling, the surface can be retreated if in doubt - but I would suggest running the flame in a cross direction to the initial hit.

The surface can be tested with super clean distilled water. Apply a single drop with a very clean eye dropper. On an untreated tank, the drop will bead up like on a well waxed car. No adhesion. If properly surface modified, the drop will actual cling to the surface and spread out to be at least twice as wide as it is high. This gives adequate adhesion for most applications.

The second issue is to use a paint compatible with the flexibility of polyethylene. I suggest using a flexibilized paint or adding a flexibilizer as is customary for flexible bumpers. All the major paint suppliers offer this. Of course, a flexibilized clear coat can be put on top.

As to priming - I feel it just interferes with flexible performance and adds extra work. If the tank needs scratches or dings filled in this may be possible if you can find a sufficiently flexible filler. In any case if you were to sand the primer or the filler down and even lightly hit or scuff into the polyethylene, that area has to be re-flame treated. If you hit it hard enough to bubble the primer or filler, you are way overdoing it! Several light quick sweeps with the flame will do the job - a near-scorching will ruin it!

If you need optimum adhesion or structural bonding for repairs or modification that can be done too but the chemistry has to be kicked up a lot.

Jack W [name deleted for privacy due to age of posting]
- Austin, TX, USA

I have the same problem. I have a 1983 xr200. The used are the same faded color as mine. The previous owner tried the spray paint with the same bubble results. It's an old bike but a very good runner, riding it you would think it's right from the Honda showroom floor. Too bad the plastics make it look like it ready for the junk yard. If you all find a good way to restore then please let me know.

David W [name deleted for privacy due to age of posting]
- Slidell, LA, US

I have a dirt bike and I am trying to paint all the fenders and all the side panels a high gloss paint and I would like to now how or what kind of paint to use and how to paint it? I need a good paint that will hold up on a dirt bike.

Joshua T [name deleted for privacy due to age of posting]
Painter - Georgetown, Ohio, USA

I am searching for a cost effective paint or texturing process that will adhere to low density rotomolded polyethylene. I would like to create a surface texture and color similar to stucco, rock, concrete, etc.

Les C [name deleted for privacy due to age of posting]
Plastic rotomolding company - Meridian , Idaho, USA

I have had great luck with a paint product called Krylon Fusion [linked by editor to product info at MisterArt]. It's a plastic coat in various colors and it has worked very well on side panels fenders etc. I have not tried it on gas tanks.

Vance S [name deleted for privacy due to age of posting]
- MI

As with many of the questions posted, I am trying to restore a faded dirtbike gas tank to white. I was wondering if it could be lightly sanded or if the stain goes much deeper than that. Also, if the guy that used bedliner to cover would report his results I would appreciate it as that sounds like a reasonable idea.

Scott M [name deleted for privacy due to age of posting]
Hobbyist - Sheldon, MO, USA

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