BarryK, question on urethane surfacer - 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 05-22-2005, 07:40 PM
Member
 
Last photo:
Join Date: Jan 2005
Location:
Posts: 3,707
Wiki Edits: 0

Thanks: 0
Thanked 2 Times in 2 Posts
BarryK, question on urethane surfacer

Barry, I've noticed on a few urethane surfacers that in the directions for use they state the primer must be painted within specified amount of time after sanding or the primer will need to be sanded again. What's the theory on this? Is this recomendation based on the probability that the primer is being rushed and not fully cured? Some of the parts I prime sit for weeks or morebefore sanding then set a few days untill the rest of the pile is sanded and readied for paint, having to resand them just before paint makes no sense IMO, or am I missing something here? Bob

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 05-22-2005, 08:02 PM
Member
 
Last photo:
Join Date: Apr 2004
Location: Georgia
Posts: 3,578
Wiki Edits: 0

Thanks: 10
Thanked 61 Times in 39 Posts
The primer can set for an indefinite time, but where the problem comes in is when you sand the part there is a rush as far as remaining solvents coming out and if you wait too long there is a chance that the scratches will seal over and loss of adhesion. Its not a total loss of adhesion but just a less than 100% of adhesion.
Down the road when companies start using the Hyper cure resins in primer this will solve the problem as they will be fully cured in a day instead of 1-2 weeks.

Interior or engine parts would not be a concern because of lack of exposure to stone chips and 70mph winds.

Exterior a good rule to follow if your not sure is overnight max.
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 05-22-2005, 09:23 PM
MARTINSR's Avatar
Brian Martin,Freelance adviser
 
Last photo:
Join Date: Jun 2004
Location: San francisco bay area
Age: 55
Posts: 13,017
Wiki Edits: 0

Thanks: 720
Thanked 1,085 Times in 968 Posts
Barry, this is an interesting subject. Back ten years or so ago when S-W came out with their first generation of urethane primers they had the warning Bob mentioned. Not only did it have a recommendation to top coat within 8 hours or something like that if dry sanded, it had a TWO hour window (as I remember) if WET sanded. What gives with that? I figured being isos are partially moisture driven the unlinked ISO's (why would there be any?) would "kick" and the surface of the sanded primer would be too hard for adhesion of the top coat?

Brian
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 05-23-2005, 05:58 AM
Member
 
Last photo:
Join Date: Apr 2004
Location: Georgia
Posts: 3,578
Wiki Edits: 0

Thanks: 10
Thanked 61 Times in 39 Posts
That is exactly why a lot of companies say don't wet sand the primer, depending on talc type (size) used and than the addition of water can really cause problems. Not for a dealership that is doing spot work but for the person that doing the allover job where its going to take a while.

The above is really more of a concern than the primer absorbing water witch is the popular opinion out there.

A good point here is like I said in first post, you do not lose all adhesion, maybe 20-30% and it won't show up until a rock chip or scratch.

There are a couple brands of cheap primer that are the worst case scenario
and I have been in shops where its been wet sanded a week before and not painted yet and they do this on a regular basis.
They say, they don't have problems. Of course they would not consider stone chips their problem.
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 05-23-2005, 06:59 AM
Member
 
Last photo:
Join Date: Jan 2005
Location:
Posts: 3,707
Wiki Edits: 0

Thanks: 0
Thanked 2 Times in 2 Posts
I've seen these directions mostly on the economy primers, the first one I noticed was with primer made by Morton? Since then I've noticed the warnings on other brands as well and always wondered if this was common with all urethane primers. But I always felt if the stuff was completely cured there wouldn't be any gain in adhesion by scuffing just before paint. I'm glad I asked-now I don't have to second guess my procedure. Barry, thanks for shedding light on this. Bob
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
Maaco vs. At-Home Paint Job nightrain_rod Body - Exterior 127 08-26-2012 03:07 AM
Question for Barryk.. turbo clear related. beemdubya Body - Exterior 5 05-09-2005 04:28 AM
Question for Barryk outlaw17 Body - Exterior 6 03-21-2005 06:18 AM
Hotrodders Guidelines -- READ ME Jon Electrical 0 06-14-2003 05:01 PM
Hotrodders Guidelines -- READ ME Jon Body - Exterior 0 06-14-2003 05:00 PM


All times are GMT -6. The time now is 05:28 PM.


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.