Painting help needed - what did I do wrong?

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robertsfd2002

New Member
#1
#1
Did a spray paint job on new mini bike kit. This was a new kit - no rust or anything. First sanded then cleaned with mild soap and let it dry. Then three or four cans of self-etching primer (Dupli-color brand). A few minutes between each coat as the can stated. Then 5 or 6 coats of Dupli-color enamel with 10 minutes between coats as can stated. Then 3 coats of clear, again with the stated 10 minutes between coats.

Let it dry for 8 days. First 2 days were at 60 degrees or so. A couple after got in the 40s and then 50s or so the rest of the time.

Took it down today to put the thing together. The paint is coming off when barely nicked. I'm just sick about it. What did I do wrong? I read threads for several hours and thought I knew what I was doing, but apparently did not.

Is there a fix beyond sanding it all down and trying again? Colder weather is here. Honestly, I don't care if it looks great if I can ride the thing and keep it from rusting and such.

Advice please. Many thianks.
 
LSCustoms

LSCustoms

Moderator
#2
#2
on the surface of your post (without being there and seeing this personally)... it sounds as if you used way too much material... self etch primer doesnt take much for its chemicals to work in helping adhesion and helping to prevent rust... the base color only needs to be applied, where just enough coats, cover evenly... then the clear (which would all depend, but 3-4 coats is fine, especially if you are going to wet sand it)... i guess it would also depend on how heavy you sprayed your coats (whether or not you used too much material)... but could have been other factors...

again, i dont use spray cans too often, but when i do, i pretty much treat it the same way i do any other 2 stage or more paint...

anyhow, with it cracking or peeling, the only thing you can do is sand it back down and start over... you could wet sand it all smooth and as long as you do not break through to metal... just re base coat it (just enough to where it is nice and evenly covered), then clear coat it again... all this in my humble opinion...

when you respray, if you have any heat lamps, try to get your temp up a little and if its humid out there, that will make it worse also... there are many factors, but like i said, i do not normally deal with spray paint... just regular auto body type paint and airbrushing (water based and chemical based)...

if you have to buy more primer, try using the primer sealer or something other than self etching...

IMHO

do you have pics? does it appear to be very thick (as far as your coating)? take a pic of one of the spots it chipped off... when you say coming off, is it peeling off all the way back to metal?
 
R

robertsfd2002

New Member
#4
#4
Oops, 3 or 4 coats of primer, not cans.

It peels down to the metal. I just tried putting on a handle bar grip and it has to be twisted on - peeled the paint right off.

No, it isn't a thick coat. I would have thought it would be thicker, but it's the first spray paint job I've done.

I have an engine coming Tuesday and was hoping to be riding this thing by Wednesday. I think I'm going to put it all together just to ride it and later pull it apart and possibly take it to a pro to paint.

I wonder what would happen, and how long it would take to happen, if I just left it bare metal.
 
The Restore Kid

The Restore Kid

New Member
#5
#5
The humidity is probably real high.. It takes a while for paint to harden up.. I mean all day before ya even dare touch it really... WEEKS and weeks before it's somewhat HARD... Spray paint doesn't have harder in it... It takes a long long time to actually harden... years even.. a 10 year old paint job is much harder than it was when it was a day or 6 months old...
 
manchester1

manchester1

#6
#6
I think you used too much paint. I know you said you washed the frame and it was brand new, but you pobably should of sanded it a bit with some 600 sand paper. Then wipe it down with acetone.
 
LSCustoms

LSCustoms

Moderator
#7
#7
robertsfd2002 said:
Oops, 3 or 4 coats of primer, not cans.

It peels down to the metal. I just tried putting on a handle bar grip and it has to be twisted on - peeled the paint right off.

No, it isn't a thick coat. I would have thought it would be thicker, but it's the first spray paint job I've done.

I have an engine coming Tuesday and was hoping to be riding this thing by Wednesday. I think I'm going to put it all together just to ride it and later pull it apart and possibly take it to a pro to paint.

I wonder what would happen, and how long it would take to happen, if I just left it bare metal.
Click to expand...
doesnt take long for the metal to start rusting... from just touching it...

dont give up... just sand it back down real good and smooth (use 400 wet, or 500 dry)... use some regular primer (epoxy) or sealer primer, re coat and clear... try to bring your temps up if you can... what grit sand paper did you use to prep it the first time?
 
The Restore Kid

The Restore Kid

New Member
#8
#8
I wouldn't do anything to it... hang it over the top of your kitchen stove, crank the oven on to 150 degrees or something, open the door and walk away...

It just hasn't had time to harden.. if it's on there thick it is going to take a while.. Especially in the winter air..
 
S

Shadow

Banned
#10
#10
Steel absorbs moisture, drying the bare metal with a propane torch before applying the primer will pull the moisture out and warm the frame and help dry the primer coats.
 
The Restore Kid

The Restore Kid

New Member
#11
#11
paint shouldn't fall off unless it was over the top of something wet / greasy, or old flaky paint that is already flaking off.. I just paint rite over old paint when doing the same color... Just wipe it with a rag and hit it, and never have any problems.. Duplicolor is about all I use..

I say if it's on thick, just let it set up real good before beating on it... virgin paint will come rite off easy as can be..

I painted this engine a year and a half ago, and STILL haven't touched it with a wrench, although I'm sure it's probably safe by now.. :laugh:


 
jeep2003

jeep2003

#12
#12
if its smooth and not peeling off you did it right I think. Sounds like its just not fully cured . just be careful assembling it and it should harden up over time. or put it in a warm place for a while . like on top of your boiler
 
mlanzoni

mlanzoni

#13
#13
Nothing you can do now but strip it down to the metal. If its peeling off down to the metal, means its not sticking to the metal. Strip, sand, wash, wipe down with acetone, let dry, spray self etching primer (two coats). Let dry for a min of 24 hrs at a min of 70 degrees. Then paint - at minimum of 70 degrees, 2 to 4 coats, then clear coat. Paint can be tricky with temperature, humidity, dry times, but most important is the prep. I've learned, the hard way. Good luck.
 
george3

george3

Active Member
#14
#14
It was too cold for spray can paint. The chemicals got traped only the last coat fully dried if that. Read the can. It lifted the etching primer. Believe it or not you etching primer is the weakest link. scratch the paint bare metal? It will scratch to the weakest point.
 
LSCustoms

LSCustoms

Moderator
#15
#15
LSCustoms said:
you could wet sand it all smooth and as long as you do not break through to metal... just re base coat it (just enough to where it is nice and evenly covered), then clear coat it again... all this in my humble opinion...

when you respray, if you have any heat lamps, try to get your temp up a little and if its humid out there, that will make it worse also...

if you have to buy more primer, try using the primer sealer or something other than self etching...

IMHO
Click to expand...
LSCustoms said:
doesnt take long for the metal to start rusting... from just touching it...

dont give up... just sand it back down real good and smooth (use 400 wet, or 500 dry)... use some regular primer (epoxy) or sealer primer, re coat and clear... try to bring your temps up if you can... what grit sand paper did you use to prep it the first time?
Click to expand...
george3 said:
It was too cold for spray can paint. The chemicals got traped only the last coat fully dried if that. Read the can. It lifted the etching primer. Believe it or not you etching primer is the weakest link. scratch the paint bare metal? It will scratch to the weakest point.
Click to expand...
:thumbsup:
 
TomH

TomH

New Member
#16
#16
I would give it a week to dry in a dry warm..over 50 degrees place. Test the paint in a spot that doesn't show and see if it has hardened. I would sand back the bad place, protect the rest of the bike from overspray, feather it back and spot it in. Light coats on the primer with the can back a foot or so. I like to dust on a couple of coats to just cover the metal and let it dry for a half an hour or so until it is dry to the touch, same with the top coats, a beginners mistake is getting in a hurry and re coating it too soon before it can de-gas, takes forever to dry, and it can bubble and all kinds of nasty stuff.
 
R

robertsfd2002

New Member
#17
#17
Okay, thanks for all the tips and advice.

I did sand it as the first step. Perhaps not enough though.

I think I know what I need to do now. And the oven idea...maybe I can do that - the fumes were strong and the wife and kids might not like it.

I really wanted to be riding this later in the week...oh well.
 
TomH

TomH

New Member
#18
#18
robertsfd2002 said:
Okay, thanks for all the tips and advice.

I did sand it as the first step. Perhaps not enough though.

I think I know what I need to do now. And the oven idea...maybe I can do that - the fumes were strong and the wife and kids might not like it.

I really wanted to be riding this later in the week...oh well.
Click to expand...
grab the wife's hair dryer and heat it up. that works too.
 
manchester1

manchester1

#19
#19
Believe me, I know how hard it is to wait:laugh: I have been working on this project since feburary and have to wait a few more days for the paint to set up so I can put it back together:thumbsup:

 
ogygopsis

ogygopsis

#20
#20
While I'm no expert when it comes to painting; I'm going to weigh in on this one. I think the answer lies in his third sentence. "I cleaned it with soap and water and let it dry". Many soaps are petroleum (oil) based and depending on which one he used he may have inadvertently left a nice film of oil on the bare metal. The fact that it is peeling off down to the bare metal including the self etching primer makes me suspect that. Robert, When you finish sanding you can wash it down with soap and water if you wish but before painting you ABSOLUTELY MUST wash it down thoroughly with Acetone, Kwik Prep, or some other metal prep. prior to priming. Then one thin coat of self etching primer. After that one or two coats of the color. And finally; two coats of clear. I've done this for years and have never had a problem. Good luck. Ogy
 
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