# Painting - Sanding between coats?



## Greebler (Jun 28, 2006)

I am rebuilding a cheap bike into a SS and started painting last night. So far I have sanded the whole thing down to the paint and sprayed a base coat/primer coat on. There are a few spots that I need to wet-sand down to smooth them out. I am going to sand the bottom coat with a damp 1000 grit before I put down the main color. 

My question is do I need to wet-sand between each coat that I do? I am using a 1000 grit paper that I picked up at VatoZone and use a spray bottle with water.


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## VernDog (Jan 17, 2004)

*re: sand and paint*

Here is how I did my frame/s a while back, 
first, hotbath in a some form of paint removal tank, I had a engine rebuilt/machine shop in town here that used to do this, cost around 15 bucks, way better than sanding, you would get a very clean frame to work with.

next, would be to wipe frame down with fine steel wool around all the tubes, welds and braze ons, then a fine light wipe down with sandpaper.
Then a good wipe down with varsol/rubbing alcohol, this removes all traces of fingerprints/oil traces, a good idea to have the frame clamped internaly by the seatpost in a stand.

use a compressed air supply to finally clean the frame,
ready for priming, let dry really good, then a light touch with fine sandpaper.
start your first "rough" coat, let dry reaaly good.
then second coat, let dry
then third, let dry, apply decal set
then a clear coat.

I used automotive paint rattle cans and had really good results, much better than the tremclad or other chepo rattle cans

This procedure takes longer, but the end results are worth it
Note, Hottanking or acid washing/acid bathing carbon or aluminum/boned frames (older trek frames) is not recommended, this will soften and weaken the frames bonding agents


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## Greebler (Jun 28, 2006)

Sounds good, since I have already started I don't think I will hot-tank the frame. I should have rubbed it down with alcohol thought... O well, this isn't going to be a show stopper but it is coming along.

$15 to hot tank this thing half of the price that I paid for the bike! =P

Thanks for the advice!


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## aka brad (Dec 24, 2003)

*Don't sweat the stripping..*



Greebler said:


> I am rebuilding a cheap bike into a SS and started painting last night. So far I have sanded the whole thing down to the paint and sprayed a base coat/primer coat on. There are a few spots that I need to wet-sand down to smooth them out. I am going to sand the bottom coat with a damp 1000 grit before I put down the main color.
> 
> My question is do I need to wet-sand between each coat that I do? I am using a 1000 grit paper that I picked up at VatoZone and use a spray bottle with water.


.

If you take the trouble to strip then you have to clean and prime; screw it up and the paint will peel and flake. But, you should sand between every coat. Paint, especially gloss paint, does not like to stick to itself. A little sanding between coats help the adhesion. Don't worry about the water sanding until your ready for the final coat; 500 grit should do the grunt work.

1G1G, Brad


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## Greebler (Jun 28, 2006)

aka brad said:


> .
> 
> If you take the trouble to strip then you have to clean and prime; screw it up and the paint will peel and flake. But, you should sand between every coat. Paint, especially gloss paint, does not like to stick to itself. A little sanding between coats help the adhesion. Don't worry about the water sanding until your ready for the final coat; 500 grit should do the grunt work.
> 
> 1G1G, Brad


So are you saying that I should start over? Strip it with some aircraft stripper or something like that?


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## FlatFender (Aug 28, 2006)

spray your primer, spray your paint, let the paint dry, dip your 1000 grit into a pail of water and carefully sand the bike. wipe w/ alcohol, and spray your clear. 

If you really want it to look nice, you can sand and spray clear a number of times and it will have a really deep glossy look to it. ( Did that on my cadillac a number of years ago...)


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## CB2 (May 7, 2006)

aka brad said:


> .
> 
> Don't worry about the water sanding until your ready for the final coat; 500 grit should do the grunt work.
> 
> 1G1G, Brad


One of the main reasons for wet-sanding is so your paper doesn't clog, and become useless prematurely.


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## logbiter (Dec 30, 2003)

Greebler said:


> So are you saying that I should start over? Strip it with some aircraft stripper or something like that?


OK, so you sanded it all the way to the metal and then sprayed the tie coat? you said you "sanded it to the paint and sprayed primer/base coat"

if you went all the way to bare metal you need to make sure the primer is a metal primer & will work w/ whatever you're spraying on top. 
For rattle can jobs, it's not necessary to go to bare metal, just to rough up the underlying paint so the new paint will adhere.

as brad said, if goin' glossy paint, you need to sand between coats... if flat paint, it's not as important.

once it's all done, the longer you can let it dry before putting the bike together, the better! (assuming you can't bake it in a warm dry place)

edit- make sure you're painting according to instructions - ie proper temp & humidity range


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