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1Back to top Go down   Paint resistance to Fuel Empty Paint resistance to Fuel Mon Jun 28, 2021 4:02 am

jjefferies

jjefferies
Gold member
Gold member
(May be US specific issue due to environmental laws) I just noticed tonight that a section of paint around the fuel cap had bubbled up and turned soft. Now the gas tank was painted almost a year ago and has been subject to minor splashes of fuel in the filling process for some months. The paint itself was one of those from a spray can with hardner. In the past I've had almost no problem with paint with hardner added. But that was back when we could get the hardner as a separate product and mixed it with the paint in a gun. So let me differentiate. This is the rattle can which has hardner in a separate compartment and you strike a button on the bottom to allow the hardner to mix with the paint. And this paint is a one coat, not the two part which has, a can of color and then a can of clear coat.  I'm wondering if anyone else has had this problem arise and if so what their solution was and how well did it work.

 Know any products that will prevent or cover up such problems?

thanks
jjefferies

    

2Back to top Go down   Paint resistance to Fuel Empty Re: Paint resistance to Fuel Mon Jun 28, 2021 8:06 am

Point-Seven-five

Point-Seven-five
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Life time member
It's the chemistry in the paint. As near as I can tell, the OEM paint is a polyurethane based where most aftermarket paint, especially rattle can is acrylic based. OEM paint is also baked to further crosslink the molecules, making a stronger film.

There's not much you can do beyond being careful not to splash fuel when filling the tank, not using the side stand with a full tank, and making sure your gaskets are in good condition.


__________________________________________________
Present:
1994 K75RT
1991 K100RS
1988 K100RS SE

Past:
1994 BMW K75S
1992 BMW K100RS
1982 Honda FT500
1979 Honda XR185
1977 Honda XL125
1974 Honda XL125
1972 OSSA Pioneer 250
1968 Kawasaki 175
    

3Back to top Go down   Paint resistance to Fuel Empty Re: Paint resistance to Fuel Mon Jun 28, 2021 8:26 am

robmack

robmack
Life time member
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The same thing is happening to my paint.  I had my tank professionally sprayed with a two-part epoxy primer and two-part polyurethane finish.  After several years, this is what has happened to the paint around the filler cap:
Paint resistance to Fuel 20180910
I had the painter repair that spot and the same thing has occurred again, and it's slightly worse now than when this picture was taken.  I don't know why this is happening other than there is something in the fuel that eats away at paint, but it is frustrating.


__________________________________________________
Robert
1987 K75 @k75retro.blogspot.ca
http://k75retro.blogspot.ca/
    

4Back to top Go down   Paint resistance to Fuel Empty Re: Paint resistance to Fuel Mon Jun 28, 2021 2:28 pm

jjefferies

jjefferies
Gold member
Gold member
@robmack wrote:The same thing is happening to my paint.  I had my tank professionally sprayed with a two-part epoxy primer and two-part polyurethane finish.  After several years, this is what has happened to the paint around the filler cap:
Paint resistance to Fuel 20180910
I had the painter repair that spot and the same thing has occurred again, and it's slightly worse now than when this picture was taken.  I don't know why this is happening other than there is something in the fuel that eats away at paint, but it is frustrating.
Other than the color that looks exactly like mine. I was wondering if there is any product out there sort of like a gasket (wrong word) looking that could be glued around the fuel filler opening. Yeah! Yeah! lots of reasons not to. Just trying to think out of the box.

    

5Back to top Go down   Paint resistance to Fuel Empty Re: Paint resistance to Fuel Mon Jun 28, 2021 3:20 pm

Point-Seven-five

Point-Seven-five
Life time member
Life time member
If indeed a Polyurethane finish was used, the problem may be due to the lack of curing before exposure to the fuel. Unless the paint is baked immediately after application or allowed to air cure for at least a month before exposure to fuel you will probably have issues with paint breakdown.

The ethanol and additives in modern gasoline are brutal to paint. Prolonged exposure will damage almost all aftermarket paints. The only defense is to get a good cure of the paint and scrupulously avoid fuel contact. Even then, some damage is to be expected, it's the price to pay for having the benefits(?) of having ethanol blended in our fuel.


__________________________________________________
Present:
1994 K75RT
1991 K100RS
1988 K100RS SE

Past:
1994 BMW K75S
1992 BMW K100RS
1982 Honda FT500
1979 Honda XR185
1977 Honda XL125
1974 Honda XL125
1972 OSSA Pioneer 250
1968 Kawasaki 175
    

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