Paint problems - What did I do wrong?

jporter1000

New Member
I recently stripped and repainted the top triple tree of a CB350F. Before I even attempted to put it back on the bike I noticed that the paint was beginning to chip. I can even chip parts off with my fingernails on top near the center hole, and it's been 3-4 weeks since I painted the part.

Before painting it I stripped the part to bare metal. Cleaned it with soap and water. Thoroughly rinsed it and then wiped it down with alcohol prior to painting. I used multiple coats of etching primer before applying multiple coats of chassis/roll bar paint.

Please let me know if you have any advice on how to do this properly. If I'm going to do this again I want to make sure I do it right. Thanks all.
 
Be sure to lightly scuff any surface to be painted with 220-320 grit sandpaper. Shiny metal is not a great surface for paint adhesion.

I typically use acetone to clean my parts before paint. Make sure you wear gloves during and after the final cleaning, as any finger contact with the surface will leave an oily residue which will hinder paint adhesion.

Did you follow the instructions on the can for the self etch? My process is as follows: 2 very light coats of primer 3-5 minutes apart followed by one medium/wet coat. The first coat of primer you put down is the most important for adhesion. I will usually just dust the surface so you can still see the bare metal underneath. Wait 30 minutes. Repeat process for top coat but increase the coverage slightly. You don't want to put on the paint very thick, especially if you plan to clear coat.

What brands of paint did you use? You can get decent results even with cheap paint but I prefer Rustoleum, VHT or Duplicolor if we're talking rattle can.
 
Thank you. I took the very light coating approach with the etching primer as you describe, and wore latex gloves when cleaning and handling. I think where I went wrong was in not scuffing up the surface. I'm going to give it another go, adding in the scuffing and using acetone instead of alcohol for the cleaning. Many thanks, I appreciate your advice.
 
Prep is everything.
Sounds like you did well other than scuffing it up, sandpaper or scotch bright just enough so the paint has something to grab on to.

As Nick said, light coats. Don't worry about coverage that will come with multiple coats. When paint gets thick it chips.
 
Also worth mentioning, as its winter in the states - paint doesn't like cold temps. Cold paint, cold metal is a bad combination. At the very least if you're painting in a cold garage or whatever, bring the can of paint inside to warm it up for a couple hours before painting. Bring your parts to be painted in the house to warm them up. If possible, do a coat outside and bring the part in between coats, or at least have a heater in the vicinity.

I always bring my painted parts into the house a day or two after they've been painted (to allow for them to outgas) and let them cure inside for a week or so before installing
 
+ 1 on the warm. I use hot water to warm the paint, put the can in it 10 mins or so before you use it. Wipe it off and shake it well before use. Also something like a triple clamp I'll warm that with a heat gun, or you can even bake it in the oven for a little so it's warm to touch, not hot but at or above room temp. It really helps, also you can put it in the oven after on low temp to help with curing. I use a small toaster oven out in the garage. Not the kitchen oven. I have had good luck with engine parts and VHT engine paint using the toaster oven and the instructions on the can for curing. you can get a really durable finish.
 
Thanks guys. I was wondering about temperature. I am painting in the garage. I keep the paint inside the house while storing and hung the part over a space heater while painting and drying but wonder if it may have still been too cold. I'll try your warming techniques this time around.
 
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