How smooth is "smooth" ? - Hot Rod Forum : Hotrodders Bulletin Board
Hotrodders.com -- Hot Rod Forum



Register FAQ Search Today's Posts Unanswered Posts Auto Escrow Insurance Auto Loans
Hot Rod Forum : Hotrodders Bulletin Board > Tech Help> Body - Exterior
User Name
Password
lost password?   |   register now

Reply
 
LinkBack Thread Tools
  #1 (permalink)  
Old 05-04-2012, 10:53 AM
novafreek6872's Avatar
Nova Guru
 
Last photo:
Join Date: Nov 2005
Location: Central Va.
Age: 46
Posts: 395
Wiki Edits: 0

Thanks: 76
Thanked 16 Times in 15 Posts
How smooth is "smooth" ?

Hey guys, I've got 2 doors almost at the paint stage. But I noticed something at very, very, close inspection that got me wondering.

The doors have 2 fat coats of 2K high build on them and I have wet blocked them down with 320, 400, and 600. To me at least they look very good and ready to paint. But I noticed on super close inspection, (read 3 inches away), I can see tiny little pinholes all in them, very shallow and very tiny. But to run my hand over the surface, I can't feel anything, and I cant even see anything unless I get literally 3 inches away.

So what gives? Is this normal? Do I need to go back to 320 and wet block them down all over again? I'm sure there is enough high build on them to do that.

I'm painting the car black, single stage urethane. I definitely dont want to shoot paint if this is going to show

Expert advice needed!

Andy

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 05-04-2012, 11:35 AM
Stu D Baker's Avatar
Registered User
 
Last photo:
Join Date: Aug 2011
Location: Illinois
Posts: 23
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Paint will only magnify the defects in the finish. Stu
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 05-04-2012, 12:38 PM
MARTINSR's Avatar
Brian Martin,Freelance adviser
 
Last photo:
Join Date: Jun 2004
Location: San francisco bay area
Age: 55
Posts: 12,979
Wiki Edits: 0

Thanks: 701
Thanked 1,062 Times in 947 Posts
It sounds like you may have applied the primer heavy and those are air bubbles that you sanded into when you blocked it. What are your expectations? If you are after super nice stuff, I would be very careful and think seriously about sanding that stuff off (blocking it until gone) and re-priming.

If these are little air bubbles there are likely more, and even if they get "filled" by the paint or sealer, the others would likely collapse when the wet solvents from the next product sprayed over it get sucked up by the primer. I know with 2K this isn't suppose to happen but some primers are totally insoluble and will soften a little with the next product being sprayed over it.

It's hard to say without seeing them if they are small enough and never be seen or if as Stu said and they are only magnified.

Again, what are your expectations, a driver? A "show car"?

Brian
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 05-04-2012, 03:04 PM
novafreek6872's Avatar
Nova Guru
 
Last photo:
Join Date: Nov 2005
Location: Central Va.
Age: 46
Posts: 395
Wiki Edits: 0

Thanks: 76
Thanked 16 Times in 15 Posts
Well, I want to get the finish as perfect as possible so I better sand some more. Thanks much for the advice. :-)

Andy
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 05-05-2012, 08:34 AM
novafreek6872's Avatar
Nova Guru
 
Last photo:
Join Date: Nov 2005
Location: Central Va.
Age: 46
Posts: 395
Wiki Edits: 0

Thanks: 76
Thanked 16 Times in 15 Posts
Put a very light guide coat on the 2 doors this morning. blocked them again. 320 dry. 400 wet. 600 wet. If they have any tiny pits in them now, they must be at a microscopic level!

Top coat today. cleaned them off thoroughly, masked and tacked. waiting for my tack coat to flash up right now. gonna give it 15 min then a nice wet coat. then waiting 45 and another wet coat.

wish me luck!! Big Day!!

andy
Reply With Quote Quick reply to this message
  #6 (permalink)  
Old 05-05-2012, 10:56 AM
novafreek6872's Avatar
Nova Guru
 
Last photo:
Join Date: Nov 2005
Location: Central Va.
Age: 46
Posts: 395
Wiki Edits: 0

Thanks: 76
Thanked 16 Times in 15 Posts
WELL, ANOTHER DAY, ANOTHER ROOKIE MISTAKE!! SO MAD AT MYSELF!!

I forgot to replace the water filter on my air line and guess what happened!!??

Yes. countless hours of prep down the tubes.

Tiny water droplets all in the paint, tiny craters that go down to the primer underneath.

Luckily I had the presence of mind to quit after one coat and not try to bury, as I know that doesnt work.

Soooo, looks like the 180 and the block will be coming out again tomorrow...

Bought 3 new water filters and I def won't make this mistake again!!

On the bright side, the doors look excellent in the straightness dept. and I actually did a pretty fair job laying the paint down. I think if it hadn't been for the water in the air supply, the second coat would have made this my slickest spray job yet. oh well.

Had some paint left in the gun, so the backside of the decklid is flashing the first wet coat right now. The water problem is solved for now. Expensive lesson for me, no so much in $$$ but in my hours I spent blocking and the hours to come with more blocking to get the doors ready again.

PICS HERE

Andy
Reply With Quote Quick reply to this message
  #7 (permalink)  
Old 05-05-2012, 01:53 PM
MARTINSR's Avatar
Brian Martin,Freelance adviser
 
Last photo:
Join Date: Jun 2004
Location: San francisco bay area
Age: 55
Posts: 12,979
Wiki Edits: 0

Thanks: 701
Thanked 1,062 Times in 947 Posts
Water usually doesn't look like that. How can we be sure those spots aren't the pin holes you have in the primer?

Brian
Reply With Quote Quick reply to this message
  #8 (permalink)  
Old 05-05-2012, 02:04 PM
novafreek6872's Avatar
Nova Guru
 
Last photo:
Join Date: Nov 2005
Location: Central Va.
Age: 46
Posts: 395
Wiki Edits: 0

Thanks: 76
Thanked 16 Times in 15 Posts
Somethings going on Brian. I think it must be too humid to paint here today. I keep draining the tank on the comp and its got alot of water in it. Last time I painted topcoats successfully without this prob, I did it first thing in the morning when it was cool and not humid.

I can tell you the craters are definitely not pinholes in the primer. I guide coated and reblocked the parts 320/400/600 and they WERE smooth this time.

I think I need to investigate getting a decent dryer/water trap... got any recommendations on that one? I'm not looking for the Pro model, just something that will get me through without this crap.

I had a few more of the little spots on the underside of the decklid, but not alot. I can let it ride under there... gonna cut n buff it too.

I need to take a couple days off this project, at least the topcoating part, this is extremely frustrating.

Andy
Reply With Quote Quick reply to this message
  #9 (permalink)  
Old 05-05-2012, 05:13 PM
Registered User
 
Last photo:
Join Date: Jul 2011
Location: motorcity
Posts: 237
Wiki Edits: 0

Thanks: 8
Thanked 20 Times in 17 Posts
You need to rethink your air pipe system. The filter shouldn't be asked to take that much water out.
Reply With Quote Quick reply to this message
  #10 (permalink)  
Old 05-05-2012, 06:37 PM
novafreek6872's Avatar
Nova Guru
 
Last photo:
Join Date: Nov 2005
Location: Central Va.
Age: 46
Posts: 395
Wiki Edits: 0

Thanks: 76
Thanked 16 Times in 15 Posts
Just a bad day to try to paint something. Lotta moisture in the air. Shoulda known better... I will next time. Gonna move the compressor from the garage to an interior storage room in the basement where it stays cool and less humid. Get a better air filter and a better one for right at the gun. Also going to drain the tank right before I spray topcoat on anything. That should help I would think. If not the compressor is going back, and I'm going to do some wiring for a 220.

Ive already sanded the doors back down with my orbital. Tomorrow its back to more high build then block all over again.

1/2 step forward and 18 steps back... I'm getting really good at blocking, I have no fingerprints left !

Andy
Reply With Quote Quick reply to this message
  #11 (permalink)  
Old 05-05-2012, 09:02 PM
deadbodyman's Avatar
Registered User
 
Last wiki edit: Stripping paint Last photo:
Join Date: Feb 2009
Location: augusta,ga.
Age: 53
Posts: 6,025
Wiki Edits: 11

Thanks: 22
Thanked 431 Times in 362 Posts
No need to sand anything when you get a problem like that ,just wash the paint off (before its completely dry) with lacquer thinner ,then W&G and start painting again right away...or when you get the water problem solved and if its dry 400 is what you want to use not 180, 180 would need more primer or the scratches will show...
Reply With Quote Quick reply to this message
  #12 (permalink)  
Old 05-06-2012, 06:37 AM
novafreek6872's Avatar
Nova Guru
 
Last photo:
Join Date: Nov 2005
Location: Central Va.
Age: 46
Posts: 395
Wiki Edits: 0

Thanks: 76
Thanked 16 Times in 15 Posts
Quote:
Originally Posted by deadbodyman
No need to sand anything when you get a problem like that ,just wash the paint off (before its completely dry) with lacquer thinner ,then W&G and start painting again right away...or when you get the water problem solved and if its dry 400 is what you want to use not 180, 180 would need more primer or the scratches will show...
I was under the impression I would have to sand the little divits completely out because they go all the way down to the primer.

I did try some 400 first on a block in one are and I could still see and feel all the divits. If I can do that, wont they show in the next topcoat? I wouldnt be too worried if it was white, but I'm painting the car single stage black and EVERYTHING shows.

I've already sanded the panels back down to primer level with my orbital and going to shoot more high build today and basically start over.

But I would appreciate you input on what I'm saying about the divits. If I can see and feel them, they will show, correct??

Andy
Reply With Quote Quick reply to this message
  #13 (permalink)  
Old 05-06-2012, 08:07 AM
Registered User
 
Last photo:
Join Date: Oct 2009
Location: Seattle
Posts: 312
Wiki Edits: 0

Thanks: 0
Thanked 14 Times in 11 Posts
" If I can see and feel them, they will show, correct??"

Water spots blister UP, fish-eyes pucker DOWN.

It sounds like you have a contamination problem is your air system. You really do need a PRO quality air filter in the system as close to the gun as possible, only use that air line for the paint gun AND a disposable filter on the gun.

OR 'practice makes perfect' and you like working for free.
Reply With Quote Quick reply to this message
  #14 (permalink)  
Old 05-06-2012, 10:01 AM
novafreek6872's Avatar
Nova Guru
 
Last photo:
Join Date: Nov 2005
Location: Central Va.
Age: 46
Posts: 395
Wiki Edits: 0

Thanks: 76
Thanked 16 Times in 15 Posts
OK, thanks so much for this info.

I believe I have traced the problem to contamination in the gun itself. I used a different gun on my last project and did not have any of these problems.

Just for good measure, I did relocate my compressor to a cool dry room. and am using new filters.

I am getting LOTS of practice in now... back to square one

Andy
Reply With Quote Quick reply to this message
  #15 (permalink)  
Old 05-06-2012, 04:19 PM
Old Fool's Avatar
Registered User
 
Last photo:
Join Date: Jan 2008
Location: spokane,wa.
Posts: 1,343
Wiki Edits: 0

Thanks: 8
Thanked 40 Times in 34 Posts
I have read a number of posts over the last year of people buying china guns and having fish eye problems due to machining oil in the internal air passages of the gun.

If a guy is going to use one of them it is probably wise to take it completely apart and wash all passages out.

Do not know if this was your problem or not, just passing along some info that may help someone to not have this problem.
Reply With Quote Quick reply to this message

Recent Body - Exterior posts with photos

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Hot Rod Forum : Hotrodders Bulletin Board forums, you must first register.
Please enter your desired user name (usually not your first and last name), your email address and other required details in the form below.
User Name:
If you do not want to register, fill this field only and the name will be used as user name for your post.
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
How smooth is smooth?? ryork Body - Exterior 52 11-25-2009 11:22 AM
Q-jet not smooth???? speedydude Engine 2 04-19-2007 08:05 AM
what is best to smooth body to paint wiretwister Body - Exterior 3 12-24-2005 07:17 AM
problems getting it smooth project66 Body - Exterior 8 09-17-2004 08:53 PM
Smooth firewall GearHead69 Body - Exterior 17 07-25-2003 10:26 PM


All times are GMT -6. The time now is 09:14 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
Copyright Hotrodders.com 1999 - 2012. All Rights Reserved.