View Full Version : Scuffing clear coat for respray?


jayfire
08-08-2012, 09:44:36 PM
I have 3 coats of clear on my car and a couple spots after wetsanding with 1200-1500 grit and buffing with Meguiars medium cut and rubbing compound, it looks good and shiny for a day, but becomes dull the next day. I don't know if I need more buffing or I went through the clear. If I were to re-clear it again, would I wet sand it with 600 then shoot, or use the red or grey scotch pad then shoot? It is a metallic base. Thanks

BB81Z
08-08-2012, 09:49:39 PM
If you are just going to reclear, use the gray scuff pad. The red one is too rough and you will have scratch marks after you clear. The gray one scuffs it up just enough for the clear to stick.

dgiepss
08-08-2012, 10:22:20 PM
i would sand it all flat with 600 otherwise youll be shooting over the orange peal already there and it will look fat

earlysecond
08-09-2012, 12:52:51 AM
Let's back up a minute! I am not so sure that you are asking the right question. You say you sprayed 3 coats and are worried that you sanded it all off? I am not convinced that this is possilbe without sanding every spot, even with 600 for a LONG time.

If you wet sanded the final coat of clear until it was flat using grits in the thousands and finisihing with a min of 1500 (I prefer 2000), then what did you buffed it, either something is wrong with the buffing (probably not buffed enough for example) or the clear is bad. Do you have experience with the sanding, cutting (compounding) and polishing process? If not, that is fine and folks will help you solve the issuses.

My first question along these lines, and I know from experience, how long did you wait between when you sprayed clear and when you began to sand? Too short makes a hazy finish days after you buff. Too long and it is a bitch to cut with paper.

Sadly, if the clear is flawed, putting more clear on will not make what you have on there be less hazy, especially if it is really noticablly hazy.

Post up your whole process and see if we cannot help you better determine what is going on before you spray it more. With that said, I always spray clear after I flatten the fist 3 coats by aggressive sanding BUT if you do not have to put more clear on and can solve the problem it just seems to make more sense.

To answer the original question, 600 wet is the max I would go. I am not recommending this but 400 dry works all the better, quicker and the next coat of clear will easily fill the scratches. I have done it with 360 dry but just for a test, with was successful BTW.

Let us know. I will be painting over the next couple of days but many people here could help.

Brent

jayfire
08-09-2012, 01:51:14 PM
Let's back up a minute! I am not so sure that you are asking the right question. You say you sprayed 3 coats and are worried that you sanded it all off? I am not convinced that this is possilbe without sanding every spot, even with 600 for a LONG time.

If you wet sanded the final coat of clear until it was flat using grits in the thousands and finisihing with a min of 1500 (I prefer 2000), then what did you buffed it, either something is wrong with the buffing (probably not buffed enough for example) or the clear is bad. Do you have experience with the sanding, cutting (compounding) and polishing process? If not, that is fine and folks will help you solve the issuses.
This was my first time trying the cut and buff portion of painting.
My first question along these lines, and I know from experience, how long did you wait between when you sprayed clear and when you began to sand? Too short makes a hazy finish days after you buff. Too long and it is a bitch to cut with paper.
I started cutting about 2 weeks after paint, probably too long. I did not cut it flat, just enough to get the clearcoat overspray down.
Sadly, if the clear is flawed, putting more clear on will not make what you have on there be less hazy, especially if it is really noticablly hazy.

Post up your whole process and see if we cannot help you better determine what is going on before you spray it more. With that said, I always spray clear after I flatten the fist 3 coats by aggressive sanding BUT if you do not have to put more clear on and can solve the problem it just seems to make more sense.

To answer the original question, 600 wet is the max I would go. I am not recommending this but 400 dry works all the better, quicker and the next coat of clear will easily fill the scratches. I have done it with 360 dry but just for a test, with was successful BTW.

Let us know. I will be painting over the next couple of days but many people here could help.

Brent

This was my first time with doing a BC/CC on a full car. I have done a few vehicles in single stage and a couple hoods and part with BC/CC and all have turned out pretty good. I think this would have turned out ok, if I would have watched Wookie's paint DVD's before hand instead of after. I think I had to much air pressure, no air/water separater, and I didn't lay down the clear as I should. I had a little extra in the cup and only sprayed a few spots with it (t-tops, spoiler) and the overspray on the other panels is what I was trying to cut down to make it more shiny. I am using a wool pad and compound on these spots, maybe since I waited so long, it need a LOT more buffing in that area, but thats what I was afaid of burning through the clear. I used the base and clear from the Restoration Shop line through TCPGlobal. Thanks for the help.
http://i737.photobucket.com/albums/xx20/jaydukek/5I85L75Mf3M93I93Jfc85c05d061f6e4e180a.jpg
http://i737.photobucket.com/albums/xx20/jaydukek/5N35Ld5J93Ke3F23Lbc85b539dd6c369a10e4.jpg

chauncey1970
08-09-2012, 05:28:42 PM
You have probably got a dry edge you will get rid of it with buffing try and use 2000 paper then a compound coarse (g3 or similar) then a fine (chroma 1500 or similar) should do the trick was the clear ms or hs? Either one will take some work cutting all the way through with 1200-1500

jayfire
08-09-2012, 07:50:16 PM
You have probably got a dry edge you will get rid of it with buffing try and use 2000 paper then a compound coarse (g3 or similar) then a fine (chroma 1500 or similar) should do the trick was the clear ms or hs? Either one will take some work cutting all the way through with 1200-1500
I don't know what ms or hs is! Here is a link to the clear I use: http://www.tcpglobal.com/restorationshop/itemdetail.aspx?itemno=KUS+KIT-KC210/212-GL
Should I use the 2000 wet, then try buffing again? All I have around here for compound that could be any good is Meguiars Medium cut and Meguiars rubbing compound. Should I look for something else? Where? Thanks

earlysecond
08-10-2012, 06:20:42 PM
jay,

I see what you did and why you are asking what you are asking. If the vette is the car in question, nice job.

Doing spot repairs with clear on panels is a common practice in collision work BUT those dudes are really good at it. What is used to avoid the problem that you have is a blending agent which "melts" the edges of the new clear into the old. If you did not use this or did not do it properly, you will always have what you are trying to avoid.

In order to overcome the issue you could scuff and reclear the entire panel or make tape edge breaks in hidden areas like body lines. Any other approach, especially without a blending agent, will yeild less than satisfactory results.

Good luck.

400-600 wet to scuff or a dry scochbrite will be just fine.

1981gMachine
08-10-2012, 07:13:53 PM
When you sprayed the extra spots. When was this? 5min after your last coat? Hours, days?

If it was within the range for the clear, you should just have to sand and buff the finish. If it was outside your clear's window, then you'll have to do what earlysecond said above.

Fact: Red scotch brite will not show scratches in a reclear. If the clear is not broken anywhere into the base layer. No matter what the scratch depth, it'll be shinny when recleared.

Example; look at some fine scratches on your cars finish. Now pour water over that spot. If the scratch is only in the clear you'll see only shine. If it breaks into the basecoat layer, you'll still see the scratch, or the protions of it that are deep.

Using a red scotch brite comes no where near going through 2 layers of clear. Normal non hood bending force is all you need.

What does using a red scotch brite give you over say 600-1000? Well it allows you to spray it normally without the clear being more prone to running. The smoother the finish, the more the clear will lay out. The red scotch brite gives the surface more bite to hold the clear. You also don't have near the arm fatigue when compared to using grey when your done scuffing a whole car.

I feel sanding in 600 is about the limit (fineness) I'll want to clear over for a reclear. Especially when talking about vertical panels. Also start crossing the line of not giving the new clear enough surface tooth, when you get much finer.

chauncey1970
08-11-2012, 10:59:51 AM
Yes 2000 wet sand the area you don't have to go mad just a light rub over that meguiars may be too light get some a bit rougher you can use that for the second polish use foam pads at least for the second polish don't stay in one place for too long but don't rush so keep the polisher moving but take your time on the panel
Are you using a rotary polisher or something else