PDA

View Full Version : I am stuck and could use some help!!! Wavy clear...


TheCoatingStore.com

J Early
03-10-2010, 07:59 AM
I have painted my doors, PPG DBC black with 3 coats of DCU 2002 clear. Painted the doors verticle and paint laid on OK with some ornage peel. I have blocked the doors while on saw horses with 800, 1200, 1500 and 2500 using a paint stick and/or the durablock that is about the same size as a paint stick. I am using a cross hatching pattern going from end to end, not chasing any low spots. My sand paper is either 3M or MaGuires. I am buffing with 3M rubbing compound on a wool pad then going to Sure finish with the orange pad.
I have no orange peel at all now, but the clear is wavy. If I look down the surface with my shop lights in the reflection it is terrible. Over the 5 feet of flat surface on the upper portion of the door thare are probably 6-7 waves that, when glossy and black, look realy bad. I re-cut half of that section again with the whole series of paper and re-buffed and it did nothing to help. I feel I am putting these waves into the clear but how? The paint was applied about 1.5 weeks ago with 4-5 days in a warm shop and rest of the time in my garage at around 50 -55degrees.

Bob K
03-10-2010, 08:57 AM
My first attempt to fix this if it were mine is to scuff the worst door and spray it again with clear while it is laying flat on the saw horse. Do two coats, one gun traveling north-south and then a coat with the gun going east-west. I would watch the reflections of those same lights while I spray. My gut feeling is that your gun is spraying heavy in the center and you didnít lap 50%. I could be all wrong here because when there is a problem there could be hundreds of variables that we havenít talked about. Like how fast is the hardener? I know I like to use ultra fast hardener (the kind for spot repairs) to get it out of dust as soon as possible but then the flow out gets compromised. Laying flat will let you lay the clear on thicker without getting runs and you may get better flow out.

Anyway thatís my guess, good luck I hope you find the problem and get it fixed. Oh and one other thought, put a door on the car and take it outside and view it in the real world. The mountain may turn into a mole hill if you know what I mean as the door will never be viewed horizontally under a fluorescent tube.

Bob K

Len
03-10-2010, 10:03 AM
I'm thinking that the waves are from an inconsistent application of the paint. You could probably have removed them by using a stiff block with some coarse wet paper to initially flatten the waves then a finer grit to remove the coarse scratches. If there was a lot of paint applied you may be able to do this now but you may need to apply more paint to fix this problem.

J Early
03-10-2010, 12:34 PM
I have some 600B wet paper that feels to be similar to 800p wet paper. Would this be suitable on a 12" block? If I burn through then, well I am re-painting anyway. The last thing I want to have to do is re-spray but it can't be left like this.
Is it remotely possibleto have this problem due to buffing? I don't see how it could since I just did an initial rough pass and the metal was not heated up by the buffer.

Len
03-10-2010, 01:47 PM
I have some 600B wet paper that feels to be similar to 800p wet paper. Would this be suitable on a 12" block? If I burn through then, well I am re-painting anyway. The last thing I want to have to do is re-spray but it can't be left like this.
Is it remotely possibleto have this problem due to buffing? I don't see how it could since I just did an initial rough pass and the metal was not heated up by the buffer.

Yes the 600 will work but I would start by not applying very much pressure so that you can see where the problems lay. These waves aren't caused by buffing. Remember that you want to buff on a scratch that is no more coarse than about 1500 and it's best if you can get it to a 2000 or finer scratch. So start with 600 then 1000 then 1200 then 1500 then finer. It can be quite difficult remove 600 scratches if you to jump from 600 to 1500 so take it step by step if possible.

J Early
03-11-2010, 08:00 AM
Just for a follow up;
I sanded with P600, full sheet length (11") on a long board. Made roughly 10 passes both directions carefully but thourouly. I removed about 50% of the waves, but I know I am on the edge of burn thru. I am going to flow coat the door, 2-3 more coats with the door flat on saw horses.
My best guess is this was from under the base, which is odd since I gave the high build a month to dry and block sanded with guide coat just prior to painting, same as I did for the rest of it that turned out nice??
Thanks for the help guys.

Primal
03-12-2010, 12:36 PM
first thing that comes to mind with wet paper is your pressing to hard. I have seen people make marks like this because they press when wetsanding. Let the tool work for you.

Alpo
11-30-2015, 02:59 PM
This is an older thread and took a lot of searching but outlines my current problem exactly. Restoring 64 Impala with looong quarter panels....took a lot of time blocking to ensure no waves on these new quarter panels. Many primer/guide coat/long blocking sessions and I thought they'd be laser straight. Paint and clear went on well but color sanding has revealed the dreaded waves. 600 wet will not get them out; I haven't burned through the clear yet but I need a plan of action now.

First thought is to long board with 120 and spray some Featherfill or Slick sand, which I did not do in the first place, then refinish. Second thought after reading this old post is maybe to re-flow the clear. Thoughts?

Len
11-30-2015, 03:46 PM
This is an older thread and took a lot of searching but outlines my current problem exactly. Restoring 64 Impala with looong quarter panels....took a lot of time blocking to ensure no waves on these new quarter panels. Many primer/guide coat/long blocking sessions and I thought they'd be laser straight. Paint and clear went on well but color sanding has revealed the dreaded waves. 600 wet will not get them out; I haven't burned through the clear yet but I need a plan of action now.

First thought is to long board with 120 and spray some Featherfill or Slick sand, which I did not do in the first place, then refinish. Second thought after reading this old post is maybe to re-flow the clear. Thoughts?

What tools and materials to use depends on the severity of the problem. On large areas of body work we almost always spray Slick Sand in order to make sure the surface is level. If you use any type of sprayable filler you want to be sure to "guide coat" it before you block sand so that you can see what you're doing.

Alpo
11-30-2015, 04:10 PM
Thanks, Len. After posting I found another thread discussing the same issue: http://autobodystore.com/forum/showthread.php?1204-Wavy-show-car-finishes/page4 . Seems this is more the problem: vertical ripples after the clear has been applied. I've used an 11" Durablock with 600 wet to try to cut these down; I've even used some guide coat on the clear but it is gone pretty quickly and does not reveal the ripples. Wax and grease remover reveals them under fluorescent lights. From here, I'm thinking to just keep blocking with the 600 to see if they go away or I burn through the clear.

Len
11-30-2015, 04:37 PM
Thanks, Len. After posting I found another thread discussing the same issue: http://autobodystore.com/forum/showthread.php?1204-Wavy-show-car-finishes/page4 . Seems this is more the problem: vertical ripples after the clear has been applied. I've used an 11" Durablock with 600 wet to try to cut these down; I've even used some guide coat on the clear but it is gone pretty quickly and does not reveal the ripples. Wax and grease remover reveals them under fluorescent lights. From here, I'm thinking to just keep blocking with the 600 to see if they go away or I burn through the clear.

This is a problem I've never experienced in spraying top coats so I'm wondering if it could be the spray guns that some people are using. What kind of gun do you use for top coats and do you have the fan pattern wide open?

Alpo
11-30-2015, 05:38 PM
I have an Iwata gun for clear; yes on wide open. For the last coat my painter friend used his Sata and you could see that it was laying down a wider pattern. Maybe my previous coats had built up in the middle, but as others have observed the ripply waves are vertical. If I go through the clear coat, should I just lay on a reflow coat or two, or sand it all down and block it again? I'm sure the prepped panel was straight before sealer/base/clear.

Len
11-30-2015, 06:32 PM
I have an Iwata gun for clear; yes on wide open. For the last coat my painter friend used his Sata and you could see that it was laying down a wider pattern. Maybe my previous coats had built up in the middle, but as others have observed the ripply waves are vertical. If I go through the clear coat, should I just lay on a reflow coat or two, or sand it all down and block it again? I'm sure the prepped panel was straight before sealer/base/clear.

So you're using good guns and spraying horizontally (?) and you're getting ridges that are vertical (?) which means that there is something like filler, primer or paint that is causing this problem. I'll say it again... The cure for this problem will depend on how severe the problem is. If it's minor then another application of clear will probably do the trick but a little more severe and clear isn't going to add enough film thickness to do the job.