First time shooing a HVLP gun and paint came out splotchy. - 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 02-06-2010, 09:56 PM
Registered User
 
Last photo:
Join Date: Feb 2010
Location: Houston
Posts: 23
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
First time shooing a HVLP gun and paint came out splotchy.

To extrapolate a bit: I am using a 1.5 tip on a hvlp shooting primer-surfacer. I mixed the primer exactly the way it directions said to do. It was 65degrees out and I mixed 4 part pimer/ 1 part hardener 10% cutting agent. It was the first time using the gun (it's a cambell hausfeild) and was shooting a board with the pressure regulator on the compressor at 50psi and then dialed in the gun with a regulator on the end at 10PSI ( the gun says on the tip max 10 psi). I then shot the paint but it came out in big drops, not a fine mist. I figured there was not enough cutting agent so I put another 10% cutting agent in and it came out a bit better but still splotchy. (then shot with both a regulator on the base of the gun and with the regulator off the gun and the regulator on the compressor at 10psi.)

Is the problem the tip or is the primer not cut enough? I've read you can cut it more and it just takes longer to dry.

The primer is brand Newstar ns-700. I had previously tried to look around to buy a 2.0 tip but could not find one? Is there a place to get just a tip for my gun?

One more thing. This was my first time using the gun and it was used. I tried taking it apart before I used it to clean it (although it looked imaculate) but could not get the part of the gun behind the tip to come off. It does unscrew --lefty-loosy-- right? I would imagine so.

Need all the help I can get. any replies appreciated. thanks

UPDATE


The general consensus is that I didn't have enough pressure to the gun. I'm going to try again today but a followup question for everyone.

I did go ahead and spray my trunk last night with the sprayer sprayin like it was. It was over bare metal and very thick instead of a light coat like everyone says to spray the first time. Should I sand it all back down or just sand smooth and spray again?

Last edited by Mycophiles; 02-07-2010 at 10:02 AM.
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 02-06-2010, 10:03 PM
deadbodyman's Avatar
Registered User
 
Last wiki edit: Stripping paint Last photo:
Join Date: Feb 2009
Location: augusta,ga.
Age: 53
Posts: 5,710
Wiki Edits: 11

Thanks: 17
Thanked 274 Times in 226 Posts
Did you try incressing the pressure at the tip?
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 02-06-2010, 10:19 PM
Registered User
 
Last photo:
Join Date: Feb 2010
Location: Houston
Posts: 23
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
i believe you are talking about the knob on the bottom of the gun. if so then yes.
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 02-06-2010, 10:27 PM
deadbodyman's Avatar
Registered User
 
Last wiki edit: Stripping paint Last photo:
Join Date: Feb 2009
Location: augusta,ga.
Age: 53
Posts: 5,710
Wiki Edits: 11

Thanks: 17
Thanked 274 Times in 226 Posts
Try spraying straight thinner through it see if it works like that,then try incressing from 10lbs to 20lbs of pressure.does you fan control knob work?
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 02-06-2010, 11:16 PM
Registered User
 
Last photo:
Join Date: Feb 2010
Location: Houston
Posts: 23
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
ill try that. i couldnt really tell.
Reply With Quote Quick reply to this message
  #6 (permalink)  
Old 02-07-2010, 12:44 AM
Member
 
Join Date: Feb 2005
Location: Sheffield, UK
Age: 45
Posts: 57
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Sounds to me like you need more air pressure - what is the recommended inlet pressure of the gun?

The tip/ air cap may say 10PSI max (a HVLP standard), but you need to be giving the gun much more at the inlet to achieve that. Too low a pressure and the air cap simply won't be able to atomise properly, so it'll almost be throwing out lumps of primer, rather than a finely atomised spray.
Reply With Quote Quick reply to this message
  #7 (permalink)  
Old 02-07-2010, 05:53 AM
302 Z28's Avatar  
Last photo:
Join Date: May 2003
Location: North Texas
Posts: 10,810
Wiki Edits: 0

Thanks: 1
Thanked 81 Times in 68 Posts
Your HVLP gun is internally regulated to 10 psi at the tip, that is NOT the inlet air pressure you set. Your inlet pressure needs to be at least 30-35 psi or higher depending on what your spraying.

Vince
Reply With Quote Quick reply to this message
  #8 (permalink)  
Old 02-07-2010, 10:01 AM
Registered User
 
Last photo:
Join Date: Feb 2010
Location: Houston
Posts: 23
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Ok, I'll try more pressure today. Another question first though. I did spray my trunk yesterday. It was a very thick coat instead of a light coat like what is advised for a first primer coat. Should I sand it all down or sand smooth and spray over the primer?
Reply With Quote Quick reply to this message
  #9 (permalink)  
Old 02-07-2010, 12:48 PM
302 Z28's Avatar  
Last photo:
Join Date: May 2003
Location: North Texas
Posts: 10,810
Wiki Edits: 0

Thanks: 1
Thanked 81 Times in 68 Posts
If it was excessivly thick I would allow several more days for cure then sand it smooth for another coat.

Vince
Reply With Quote Quick reply to this message
  #10 (permalink)  
Old 02-07-2010, 01:04 PM
Member
 
Join Date: Feb 2005
Location: Sheffield, UK
Age: 45
Posts: 57
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Or a slightly different option - give it a light sand now with something like a P240 or P320 just to break the surface to aid curing and help the solvents escape. Then after a few days carry on as above - sand then recoat.
Reply With Quote Quick reply to this message
  #11 (permalink)  
Old 02-08-2010, 05:40 AM
deadbodyman's Avatar
Registered User
 
Last wiki edit: Stripping paint Last photo:
Join Date: Feb 2009
Location: augusta,ga.
Age: 53
Posts: 5,710
Wiki Edits: 11

Thanks: 17
Thanked 274 Times in 226 Posts
Are you planning on painting the trunk or using a rubberized undercoating (one that gets hard)? If your painting I"d use a 2k sealer instead of primer ,it'll eliminate the need for more sanding ,some sealers adhere to the bare metal (sand through spots) very well.If you started with an epoxy sealer from the start there would be no sanding at all,and its thinner so there wouldn't be a problem getting it out of the gun.
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
"Basic of Basics" How do I paint my car myself? Centerline Body - Exterior 5 11-07-2011 07:14 AM
Martin Senour Tech Sheets? unstable Body - Exterior 42 03-12-2011 09:09 PM
More on Orange Peel KarKen Body - Exterior 36 03-22-2009 02:18 PM
shooting clear vinvango73 Body - Exterior 3 10-28-2005 11:24 PM
Orange peel in the clear Montypierce Body - Exterior 13 03-06-2005 08:49 PM


All times are GMT -6. The time now is 01:32 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.