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f/bird 04-28-2013 04:46 PM

clearcoat wetsanding
I've recently had my f/bird painted and the clearcoat never really got smoothed out all the way . My nephew painted it and it looks great but the c/coat had runs in it . On the sides I can notice the wavy areas in the right light . It's shines but I'd like to smooth the surface out if possible . Would I be able to use some 1500 s/paper on a longer s/block then step up to 2000 s/p to finish and then wheel it to a finish ? He's been busy w/kids and things and I thought I might be able to do it a little at a time but I don't want to mess it up and have to c/coat it agin ???

33Willys77 04-28-2013 05:27 PM

Runs are hard to get straight again. If the car was sanded already, you will need to know how much clear was put on to begin with. The best way to get runs out is to hit them first with a coarse grade sandpaper. 600-800 depending on the severity, then work to finer grit. I would be scared to go back at them again since it was sanded already. You may or may not go through the clearcoat, so be prepared to repaint if you do. You will need a hard flat block to get it straight again, but really, 1500 is too fine (in my opinion) to get that surface flat again.

f/bird 04-28-2013 05:56 PM

If I sanded through the clearcoat would it be able to be hit with c/coat again or the paint would need to be done again also ? It might just have to good enough !!

69 widetrack 04-28-2013 06:06 PM

33Willeys77 is correct, start of with either 600 or 800 wet with a hard block...apply no pressure on the block at all, let the paper cut the run. When the runs are knocked out of the clear, graduate up tosay 800 then 1,000 1,500, 2,000 and I prefer to finish my clear with 2,500 grit before polishing. If you sand through the clear coat, it needs be re based, especially if it's a metallic color.

Hope this helps


f/bird 04-28-2013 06:49 PM

Yes, It helps to get all the info I can ! Here's another ? ; If it goes throgh the clear and needs the base again ,can the base just be done on the panel or panels that you go through or the whole car has to be done ? Thanks

69 widetrack 04-28-2013 06:54 PM

You could blend the base over any area that had a burn through (sanded through) the clear coat, however, your better off to clear the entire panel rather than just trying to clear over the area that you re-applied base. Clear is much harder to blend than base coat and clearing the panel should eliminate polishing back a clear blend.


f/bird 04-28-2013 09:08 PM

Thanks for all the info; I think I've got the general direction to get the job going !!

JoAnnBortles 04-29-2013 06:00 AM

One of my favorite tools for removing runs are little metal blocks called Run Blockers. They are made by Motor Guard and they have saved my butt numerous times over the years. Basically, they allow you to focus your sanding on the run itself. But you have to be careful as you can end up sanding too much in that area and go thru the clear.

Sanding runs in clear is not beginner stuff. Its not easy so don't get frustrated when you sand through, cos you will. When I have to sand a run in clear, 60% of the time, I go through. This is why I always opt for having to buff some slight orange peel rather than get it too flat and having to sand a run. Getting clear to flow perfectly every time is unreal hard. Gravity is not your friend.

TucsonJay 04-29-2013 08:46 AM

You will also need to make sure the job has died completely. Some brands of paint are stable in 2 days. Other brands can take weeks.

If you sand those poor brands too soon, the run will shrink later, after you flattened it, creating a depression in the surface.

Don't let famous brands fool you. From my experience, even some of the best known are not forgiving at all. Talk to someone familiar with them.

MARTINSR 04-29-2013 01:47 PM

I have found that great care has to be taken when sanding a run. You must sand ONLY the run, it is very important to sand ONLY the run. Think about it, you have three coats of clear right next to that run, the run it's self is the thickness of 6-10 coats of clear. So while sanding that 6-10 coats you can't sand the surrounding area that is only 3 coats at all. If you only sand it a little bit, a little bit of the 6-10 coats is your 3 coats and you are THRU like right now.

So using a hard narrow block where you are ONLY sanding the run and keep an eye on it by squeegeeing off the water so you can see what you are doing often you can keep from sanding the surrounding area.

These 3M squeegees work the best I have found. They make all different sizes so you can get into tight areas.

3M Wetordry Rubber Squeegee, 05518, 2 in x 3 in-Shop 3M

Keeping an eye on what you are sanding is the best advice I can give. Sanding that run without paying very close attention and you will wipe off the water and residue to see that you have sanded thru the clear sure as poop stinks.


scottersrods 04-29-2013 05:22 PM

MARTINSR just gave you some really great advice. You really want to not rush it and concentrate your effort on the run only! It seems to me,the condition you've described is actually more of a Sag. So,as a little help,I like to guide-coat any Run or Sag;that's how I was taught and can be a huge help.

A "Run" to me, is like a kid with a very runny Nose.It kinda charges its way down to his lip hopefully stopping just before it enters the mouth. It may have a bit of a Ball on the end,sometimes at the end of that Ball,it'll look like a thin little Rappelling Rope and a tiny Man sliding down safely where it touches the floor of your shop.That,is just a couple of different types of "Runs" where I like to employ the "Razor Blade"technique.

jcclark 04-30-2013 04:56 AM

These stone sanding blocks work really good.
It makes it easy to feel the run and not sand the surrounding area.

tech69 04-30-2013 07:58 AM

I personally like a bent razor blade on a fully cured run. You just tilt it at an angle and shave it with a backwards motion to not allow it to dig in but to only shave off what you want. If you do it carefully and the clear is properly cured it will only take a second of 1000 to get any marks out. I outta try a run block but have had great success with a razor. I just can't knock it.

f/bird 04-30-2013 08:40 PM

Yep, The runny nose described it pretty close on most of it and yep, it's got sags also . Sounds like alot of work to me !!!! Tanks guys

roy2486 05-02-2013 01:05 AM

yup. turtle wax is good. i prefer 3m. i do it in 3 steps. rubbing compound(coarsest) polishing compound then a good carbauna wax. dont buy that ice crap its junk. remember wax on wax off. if you dont have a buffer make sure you buy compounds that can be hand buffed otherwise the abbrasives in it wont break down as you polish.


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