Bubbling powder coat blemish

Denis99

Senior Member
Location
South Wales
I am after some advice from anyone who experience of this.

My frame was bought used and is in all round excellent condition, however, there are two areas where the powder coat is now bubbling.
More like an orange peel effect at the moment, not breaking through the powder coat yet.

I am considering having the frame re powder coated as a precautionary measure, but would appreciate any comments.
 

Sharky

Guru
Location
Kent
steel or alloy?

I had a steel frame, with bubbling near the rear ends. Ignored it for about 10 years and then discovered on the inside it had rusted through completely!
Excuse though for my N+1
 
May be a tall order but can you get the seat post out and pass a long pipecleaner or similar into the tube affected? Just to check the state of the tubes before you start with anything else

It’s not clear inthe images but is the paint that bad? It looks like a nice colour- it may be difficult to replicate
 
OP
Denis99

Denis99

Senior Member
Location
South Wales
Thanks, yes that’s a good idea.

Just out for a ride now, will check later.

Yes, the paint is nice, but not too worried about a change of colour, prefer lighter and brighter colours in the main.
 

Globalti

Legendary Member
That looks worryingly like rust under the paint, as the OP suggests. I used to work in a factory where they built cheap steel bikes and it was common for hot water to bubble out of the tiny drain holes in the frame and forks ruining the paint, when the frames were baked in the oven and the water boiled. However that happened at the ends of the forks and rear tubes, not in the middles as in those pictures. Have you tried crushing the paint carefully with a finger nail or sharp tool? What happens? Is there any sign of red rusty water dribbling out of the frame? Is the frame generally dry inside or wet? You'd know it was wet if the seatpost was oxidising badly.

Footnote: I love that paint. It reminds me of a pic of a bike I saw once, which had the most gorgeous green and purple paint:

MIKESPICS004.jpg
 
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OP
Denis99

Denis99

Senior Member
Location
South Wales
I bought the bike used, but it is getting worse.

Bike is stored in my garage, dry.

No evidence of any red rusty water inside the bb, recently had this out, looks ok.

Will try a gentle crush on the bubbling.
 

classic33

Legendary Member
I bought the bike used, but it is getting worse.

Bike is stored in my garage, dry.

No evidence of any red rusty water inside the bb, recently had this out, looks ok.

Will try a gentle crush on the bubbling.
Assuming it is powder coated, I second the rust verdict given above.

One possible reason for no rust inside the frame is because it's not yet got that far. It forms where the powder coating should meet the metal. Causes can range from grease on the frame not cleaned off, to problems whilst curing.

Does the area look any darker than the surrounding area. And is it in a place where the frame may have been handled. Common hanging points being the head tube and rear forks.
 

Globalti

Legendary Member
Yes in the top picture there's a dull area to the left of the rough section, right in the streak of reflected light, which seems to have tiny blisters under the paint. Can you crush one of them with a sharp implement and see if any rusty water comes out of if there's rust underneath?
 
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