Hi Guys,

Newbie here. Don't hate me...LOL.

So, I am painting my Taco, and have already done the box, and it went overall quite well. A small "hanger" in the paint that will be covered buy the box rail cap and on one side (the other was fine....weird....prolly gun control) I managed to create a lot of "curtains" that will likely take some careful attention, but can be dealt with (I THINK!).

Regardless of that, I am now doing the cab of the truck, and it is going REALLY poorly. Today, I tried to put on the basecoat, and my gun was doing the strangest things. Pattern on paper looked good, so got started, only to find out it STARTED good, but then it seemed like the fluid control opened right up, and I got a crap ton of runs, and WAY too much material in several spots. Tried to reset gun and keep going, but same thing happened.

In any case, I want to COMPLETELY go to a "re-do" position. That is to say, I cannot just "fix" the issues; I want to prep the panels to do a complete re-spray. I have found a crap ton of info doing searches, but the primary question I have, I cannot seem to find the answer to. That is, if I am to going to re-prep the ENTIRE area (full side of the cab) can I re-sand with 600 (I have read this is the finest grit to ensure adhesion) and how far do I re-sand down to. What I mean by this, is I already sanded out the runs, and as a result have burned thru to the primer/sealer under the paint. I would prefer NOT to go over everything right down to primer, but think I am still needing to sand the topcoat with 600 to get good adhesion.

Bottom line is to re-do, will I need to sand (presumably with maximum 600 grit) right down to the primer, or should I "scuff' the paint (keeping in mind, I have already burned thru to primer in some spots).

Sorry a bit verbose, but looking for any assistance anyone might provide....this second part of the project is giving a serious posting.php?mode=post&f=5&sid=4cef56e301909d280585e8a03cc0ab9f#headache. class="postlink" href="https://www.autobody101.com/forums/posting.php?mode=post&f=5#

My guess is that your air compressor is not big enough to handle your spray gun. Starts out good on paper and falls off quickly.

Need a lot more information before we can offer any real help.

Yeah...sorry...did not give a lot of detail around equipment because the question was more focused on what I need to do to re-prep the panels to do a re-coat.

I have an Eagle 5 HP compressor that says it will run 18 CFM @ 100 PSI, which if even it's below the advertised amount, should be plenty.

I have that compressor piped via 3/4" copper up the wall, across the top of the shop, down the other side with a secondary pipe at the top of that run that drops lower than the main line and into a drain and then another drain T'd into a decent filter and another (fresh) filter inline at the gun. The gun is an Accuspray (I have only used the cheapo's before this one) that seems to do a good job when everything is setup correctly. Like I said, the truck box was done with no real issues, other than a couple of runs. I am running just below 20 psi at the inlet to the gun, after the filter and a 1.4 tip. Using Nason 3.5 VOC Gen 2 basecoat with Nason 441-66 Mid Temp reducer. Shop and metal was warmed before painting to about 24 celcius (75 F).

Not sure what else to tell at this point in time, other than I think the nozzle maybe had some crap in it, but did not have a backup (stupid me) and went WAY too far before stopping.

Just to be sure, you are setting the psi at the gun with the trigger pulled full open correct?

Running the base coat usually means you either got too close with the gun at some point, didn't let it flash long enough, have too much fluid or not enough air in your gun settings.

Thanks for the response. And yes. Pressure checked with trigger fully depressed. Pretty sure the issue is related to rushed gun setup or a bad nozzle.

In any case though, I am still looking to understand if I need to take all the paint off, or just sand it smooth and re-shoot?

what brand and model of gun are you using?
what brand and type of paint?

just something to check, is the packing nut to tight and not letting the needle return to the close position as it should.
Jay D.

Using the 3M Accuspray PPS kit. The gun is part of the kit. The gun is encased in composite, so I do not believe it actually has a packing nut that can be adjusted. Using Nason 3.5 VOC Gen 2 basecoat with Nason 441-66 Mid Temp reducer.

You should be able to wet sand the car, wipe it clean and reshoot your base.
Set your spray gun up on paper before shooting the car.

Thank you Sir, that was the answer I was looking for. However, if you could humour me for just a bit longer....I have concerns about adhesion in doing what you suggest is my course of action but only to the extent of what grit would be best to ensure good adhesion? There seems to be some debate there around 600 max as anything finer can be asking for trouble. Thoughts?
Giving it another go tomorrow and yes, for sure will have a wall full of paper for checking settings, then double checking and then triple checking! <grin>.