Painting prep question

[Dunkut88TJ]

Top of the morning folks! I had a question regarding painting and wanted to ask the gurus here. I believe I know the answer but figured it worth a shot. It says my paint from automotivetouchup.com will finally arrive today - 4 weeks. I had planned to sand the half doors down, prime, paint etc. I was talking with a friend and he asked “why not just paint over what is there?” So I ask you guys why not? I would assume sanding it to bare metal promotes a far better result but what if I didn’t sand down the existing clear coat and paint? Would the new stuff flake off? Truly a question of curiosity from someone that had never taken on this task, please me gently

 

[defenderu]

Do it right the first time and you shouldn't have to do it again. SAND IT!! (Edit: Don't need to go to bare metal but you do need to sand)

 

[Webfoot]

If it is the factory paint on the doors and there is no sign of the previous paint peeling, flaking, cracking, etc... there's no reason to sand down to bare metal. A lot of shops would wet sand with 400 grit, put on a water based sealer/primer, sand again after that cures, then paint and clear. You may not even need the sealer/ primer, but I would use one if it were me.

 

[Juggernaut]

If it is the factory paint on the doors and there is no sign of the previous paint peeling, flaking, cracking, etc... there's no reason to sand down to bare metal. A lot of shops would wet sand with 400 grit, put on a water based sealer/primer, sand again after that cures, then paint and clear. You may not even need the sealer/ primer, but I would use one if it were me.

This. 400g followed by primer/ sealer is a safe bet and certainly an acceptable method. Sanding to bare is obviously more work and you might find it’s harder to recreate the flat substrate to shoot the new paint.

 

[P man]

If you take it to bare metal you run a high risk of making more issues than you solve...IF the current paint is rust free with no peeling etx scuff it well and paint it

 

[defenderu]

oh ya I wasn't really clear. No need for bare metal but you do need to sand with a wet sand lower grit.

 

[MutantNinjaTJ]

Wet sand the original paint and go for it, the original paint is a better base then going to bare metal and priming it. Just sayin!

 

[Dunkut88TJ]

thanks guys, here is a picture of the doors. The paint is in extremely great shape. Only two areas that need attention, first taking off the stripes easy peasy. The only area that has any chipped paint is the driver door on the bottom lip, looks like they set it down and scuffed it a bit. Looks to be easily sanded to blend, and no one will see that from the outside. I’m fine to sand them to bare metal if need be, not pumped to do it, just trying to avoid added problems and unnecessary work. Also don’t want to do it again

My plan has always been that if I f*ck this up too bad I’ll go get them vinyl wrapped black

 

[Unspokenfor]

It looks like you have a PSB paint code jeep. Let me know how yours color matches. I've tried one from Amazon and it was way too dark.

 

[JMT]

thanks guys, here is a picture of the doors. The paint is in extremely great shape. Only two areas that need attention, first taking off the stripes easy peasy. The only area that has any chipped paint is the driver door on the bottom lip, looks like they set it down and scuffed it a bit. Looks to be easily sanded to blend, and no one will see that from the outside. I’m fine to sand them to bare metal if need be, not pumped to do it, just trying to avoid added problems and unnecessary work. Also don’t want to do it again View attachment 251363
My plan has always been that if I f*ck this up too bad I’ll go get them vinyl wrapped black

No reason at all to go to bare metal. Sand down as others have suggested, prep is everything, so take your time and do it right the first time.

 

[Dunkut88TJ]

It looks like you have a PSB paint code jeep. Let me know how yours color matches. I've tried one from Amazon and it was way too dark.

It matches well, at least the touch up bottle I ordered last year did. We shall see how the aerosol pans out!

 

[Vtx531]

Bright silver metallic spray can paint job? Good luck! You are going to need it

x8 on just sanding the existing paint but I don’t think it is going to matter in this case because the results are not going to be good either way.

400 grit might be a little too aggressive and cause issues with the metal flake orientation in the sand paper scratches.

 

[Dunkut88TJ]

Bright silver metallic spray can paint job? Good luck! You are going to need it

x8 on just sanding the existing paint but I don’t think it is going to matter in this case because the results are not going to be good either way.

400 grit might be a little too aggressive and cause issues with the metal flake orientation in the sand paper scratches.

Thanks for the well wishes! someone in here used it for their silver half doors and had pretty good luck. It may look like and if so we vinyl wrap and move on. Half the fun is in trying and learning, I realize it may be a total botch job and that’s ok!

 

[JMT]

The Duplicolor Flame REd (PR4) didn't come out matching very good on my Aluminum tailgate armor. I will probably wrap it.

 

[Dunkut88TJ]

The Duplicolor Flame REd (PR4) didn't come out matching very good on my Aluminum tailgate armor. I will probably wrap it.

One thing I have learned, few things are final in this realm and can be fixed. However $$$ adds up real quick fixing bad jobs

 

[PCO6]

I'm in the process of painting my LJ. I've simply scuffed the paint with red 3M Scotch Brite pads. I'm shooting single stage enamel paint and it's worked well.

https://www.amazon.ca/dp/B00H2VX6P6/?tag=tjforum-20

 

[Dunkut88TJ]

I'm in the process of painting my LJ. I've simply scuffed the paint with red 3M Scotch Brite pads. I'm shooting single stage enamel paint and it's worked well.

https://www.amazon.ca/dp/B00H2VX6P6/?tag=tjforum-20

You using a paint gun?

 

[PCO6]

You using a paint gun?

Yes, a basic HVLP gun. I'm doing the entire Jeep.

 

[Vtx531]

Doing the original oem metallic color in single stage? What brand? Are you doing it one section at a time?

 

[pc1p]

As someone who spent 3 summers in a body shop, I can say that it's almost always preferred NOT to sand down to bare metal. The only time we ever did was for sheet metal repair.

The rule of thumb for spraying new panels is if you're trying to color match and the base color is the same color as what you are painting, we would use a base primer/sealer and respray, sanding as needed with the MFG recommended grit.

If you're changing colors, like in your case of going from green to silver, then we would sand with the appropriate grit (again, according to MFG recommendation), use 2 coats of a sealer+build up primer, and then spray color. For silver, I would imagine the proper base primer color is a 15-18% grey (what most grey primers are).

I'm in the process of painting my LJ. I've simply scuffed the paint with red 3M Scotch Brite pads. I'm shooting single stage enamel paint and it's worked well.

https://www.amazon.ca/dp/B00H2VX6P6/?tag=tjforum-20

I would be concerned about edge adhesion with just a scuff up... hopefully time will show that it was sufficient!