2 questions on sanding scratches - 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 08-02-2013, 06:27 AM
Registered User
 

Last journal entry: Still running strong
Join Date: Dec 2011
Location: Lakehills Tx
Posts: 519
Wiki Edits: 0

Thanks: 47
Thanked 36 Times in 35 Posts
2 questions on sanding scratches

I know I might be wrong but wouldn't it be hard to see sanding scratches in metallic base, such as if I didn't sand with 600 after 400. It would seem that the metallic flake would lay on top an hide any 400 gr. scratches, don't really know what the answer is.
Do sanding scratches show up more like months later after everything is done? If they did show up is it because the bc/cc shrinks an tighting up? I can't see or feel the difference between 400 & 600, this is on top of primer surfacer..

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 08-02-2013, 07:47 AM
Faith - Respect - Trust
 
Last photo:
Join Date: Sep 2012
Location: Ontario
Age: 58
Posts: 3,508
Wiki Edits: 0

Thanks: 192
Thanked 621 Times in 561 Posts
There are 2 types of sand scratches that show up. There are sand scratches, as you said that show up in the base coat from not sanding fine enough. These sand scratches will show up immediately when you put the base on and will be visible. Usually 400 grit is fine enough, however, I like to go 600 wet, for the added insurance of not getting sand scratches and I can get a better reflection in 600 wet to make sure the car is straight, compared to 400 dry.

The other type of sand scratch happens when to coarse a paper is used when doing body work and the primer is expected to fill these scratches. The primer does go into the scratches, but, the primer will top cure and trap the solvents that are in the primer and the solvents aren't released as the top cures. The car is sanded and top coated with base coat. After the car is cleared, the solvents in the base coat and the clear coat, go down through the primer and release the solvents that are in the sand scratch. As the solvents that where trapped in the sand scratches that where filled with primer are released, there is a void where the solvents where, causing the original primer substrate to sink, leaving a sand scratch that shows up 6 months to a year down the road.

So, the moral of the story is that it's very important to finish sanding with the proper grit to endure that you don't get sand scratches in your base coat and to finish your body work with fine paper so that the primer that your using doesn't lay down deep in the coarse scratches, not totally cure and give you trouble months down the road.

Hope this answers your sand scratch question...if you need any more clarification, feel free to ask, I'll try and explain further.

Ray
Reply With Quote Quick reply to this message
The Following User Says Thank You to 69 widetrack For This Useful Post:
dogwater (08-05-2013)

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
Filling sanding scratches... wyomingclimber Body - Exterior 15 06-08-2010 08:41 AM
sanding scratches showing esahlin Body - Exterior 10 07-29-2009 12:42 PM
DA scratches when color sanding MrsBondoQueen Body - Exterior 31 10-26-2005 06:41 PM
wet sanding and scratches shine Body - Exterior 11 10-25-2005 02:46 PM
How can I eliminate sanding scratches jpd37 Body - Exterior 4 06-02-2005 10:35 AM


All times are GMT -6. The time now is 01:13 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.