3/32" Orbit Sanders for sanding Clear - 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 07-31-2013, 01:47 PM
Registered User
 
Last photo:
Join Date: Apr 2011
Location: MO
Posts: 153
Wiki Edits: 0

Thanks: 1
Thanked 0 Times in 0 Posts
3/32" Orbit Sanders for sanding Clear

Curious on other's experiences here. I've been trying to find the holy grail in finish sanding for about 3 years now and have come to the conclusion that I won't touch my final clear for 'color sanding' with a dynabrade. I sand almost everything I spray as level as glass starting at P600 Abranet, then P800 wet sanding until P2000 all with Silicon Carbide Wet/Dry (Nikkens Brand), then buff to a high gloss. This is my regular routine. Everything I spray has to be a showroom type finish (dead level and high gloss without scratches) when complete.

That said, I had seen some talk of using DA's for this job and how fast it was. I tried a bunch of different abrasives: SiCarb Wet/Dry discs, Trizact and other 3M Film discs, Mirka Abralon, Eagle Yellow Film, and a few more. And after all of this and used on Dynabrade 3/32" and 3/16" orbit sanders, I've decided that fast or not, it's not for me. I'll use them for filler, primer, or any smoothing/leveling prior to color, fixing or scuffing the first clear coat, but never after the final clear coat.

My reason being that the sanding scratch pattern of this type of sander is a pigtail or "random orbit". It's an obvious machine pattern and stands out if I miss them in buffing. Even one or two is too many.

A missed orbital sanding scratch is obvious if I watch in the reflection and move up and down a panel looking at the light source.

I originally talked to a few guys who sold abrasives and they said I must not have the cleanliness required. But I don't believe this is the case. I paper towelled each area and even filtered the water for minerals when wet sanding. I sanded fast, sanded slow (speed on the sander) and still when examined carefully in the light, there is almost always a pig tail to be found after the final buffing. Most are gone but it's near impossible to get them all. One or two are always still hiding somewhere.

Anyways, just my experience. I just don't see how it's possible to have ZERO of these through a whole car when sanded with an orbital. I mentioned on another forum that if you level sand from 800 through the grits ending at 4000 using a foam backed disc then wool buff with course compound just briefly then skip to fine compound to bring up the gloss and look at the reflection of the light at a 45 degree angle you'll see quite a bit of evidence from the sander. Obviously the point of the wool and course is to buff until the sanding scratches are gone but the point of this test being that they're there and they're obviously curly cues or pigtails. My trouble is that as thorough as I can be in buffing there are still some there somewhere if you look hard enough. It's not the sander's problem it's just the nature of the orbital pattern and it leaves an obvious looking scratch pattern. I am one who feels orbital sanders should only be used for before the last coat of clear.

I'm curious what others have experienced in this department. I'm sure there are some on here who have much more critical eyes than mine but I'm critical and if I look hard enough I see this and don't prefer this method of sanding.

Here's my post on the other forum:
Quote:
Try this, sand 1200, 1500, and 2000 (or 3000 in the case of Trizact or 4000 Abralon) with the abrasive system of your choice in wet or dry abrasives. Then buff with a wool pad and your first compound but not as long as you usually would. Then buff finer to pull up the gloss level and look at hard light source at a 45 degree angle, you'll see pigtails in the reflection as you look up and down at the panel with the light source bouncing toward you. Obviously if you spend longer on the course compound and wool, most of these will disappear. But there is NO way... and I mean absolutely no way that you can sand with an orbital and not have evidence that you used an orbital sander. If you're perfect in buffing, you'll get them all out, but nobody's perfect. Any sander (including your hand with a block) leaves a scratch pattern behind. The scratch pattern of the random orbital is the random orbits (i.e. pigtails or curly cues).

It's nothing I have against any DA manufaturer and there are several good ones (I have used Dynabrade for years and prefer them for their value/quality ratio) but it's impossible for a DA to not leave evidence in the scratch pattern that a DA was used.

The trick is getting all of these scratch patterns out and that's why I prefer to not let the orbital touch the final clear coat on anything I need top quality out of. If I find one curly cue scratch that I may have missed on something I care about, I consider this poor quality workmanship on my part. The problem I have is that it's very hard if not impossible to catch all of them. The customer who will spend more time with my work than I could in QC will have a good chance of seeing this over the course of many years and different lighting situations. A fine grit hand sanding scratch could just as easily be missed in buffing (I am very thorough and don't miss much but there's always the chance a small scratch deeper than the surrounding area could show). This is where a hand scratch looks much less eye catching than a pigtail. In my thinking, the customer will see a shallow hand scratch somehow missed in buffing and could think... maybe that happened in use. But a pigtail is much more obvious and obviously something done by a machine. If a customer sees that, they'll think... man, whoever did this work was either lazy and didn't care, or he wasn't paying attention. Really neither of those are true... it's just very hard to see all of them and very easy to miss one or two over a large area like a car.

But once again to recap, the random orbital will leave random orbits. That's just it's scratch pattern and there's no way around it. Turn the sander on with no abrasive and watch the pad and you'll see the pattern it makes. Or if you have a piece you don't care about or are stripping, sand with 80 grit and look at it. This pattern will be very obvious with the 80 grit. It's much less obvious at Mirka 4000, but they're still there and if you miss a spot and your customer doesn't...

But that's just my experience. I've found a few shallow pigtails in the work of some top finishers and although I don't hold it against them, it's not what I consider top quality work. I would expect a customer to be upset with me if they found this and eventually I know it would happen. Just a matter of time.

I still use DA's for most of the work before the color coat, but never after the final clear unless it's a car I don't care about in a showroom finish kind of way (mine primarily). Even then it bothers me when I catch a pigtail reflecting in the sun. They work great for sanding primer or even scuffing the first clear coat if needed. But no final clear for me... and that's just me of course and I told you why.

    Advertisement

Last edited by 777funk; 07-31-2013 at 02:02 PM.
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 07-31-2013, 02:29 PM
Faith - Respect - Trust
 
Last photo:
Join Date: Sep 2012
Location: Ontario
Age: 58
Posts: 3,508
Wiki Edits: 0

Thanks: 192
Thanked 638 Times in 572 Posts
I don't use a DA, I won't use a DA, 3/16th or 3/32. The reason being is that I am not doing production work with the time constraints that that type of work brings. I do all my color sanding by hand using a block.

The reason I don't use a DA for color sanding is that the abrasive when being used on the surface that you are trying to color sand can build up material on the abrasive, leaving those tell tale swirl marks. When using a DA and this happens, you can't hear that scratching noise and even if you could, it's to late, the swirl marks are there.

As I said, I do all my color sanding by hand and use a block. That's the only way I can get the results I want.

Just my thoughts.

Ray
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 07-31-2013, 08:31 PM
Registered User
 
Last photo:
Join Date: Jan 2005
Location: cranston RI
Age: 46
Posts: 491
Wiki Edits: 0

Thanks: 6
Thanked 62 Times in 52 Posts
Agreed with Ray on this as well. When you are doing high end paint work there is no substitute for good old hand sanding when the ultimate finish is desired. Whether it be blocking or cutting and buffing, in my opinion there just is no "machine" that will ever take the place of achieving a perfect finish. I do all color sanding as well with blocks and always finish with 2500 wet and all by hand.

Last edited by mr4speed; 07-31-2013 at 08:50 PM.
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 08-01-2013, 05:15 AM
jcclark's Avatar
The Penny Pincher
 

Last journal entry: Hanging Bumpers
Last photo:
Join Date: Dec 2004
Location: Louisville, Ky. U.S.A.
Age: 61
Posts: 1,877
Wiki Edits: 0

Thanks: 4
Thanked 19 Times in 16 Posts
I do most by hand too, but really, it shouldn't matter what you
use as long as you move up through the grits until
the previous one is gone, then the compounding will take
care of the super fine ones.
If you have scratches, then you didn't complete one of the steps
to rid them, whether by machine or hand.

Now getting the finish "straight" is another matter, long hand sanding
will definitely get it straighter than a sander, after the peel is gone.
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 08-01-2013, 07:02 AM
Faith - Respect - Trust
 
Last photo:
Join Date: Sep 2012
Location: Ontario
Age: 58
Posts: 3,508
Wiki Edits: 0

Thanks: 192
Thanked 638 Times in 572 Posts
I agree with what your saying "jcclark" about not removing the previous scratch giving you problems, the other is that when you use finer grits, the paper can clog up fairly quickly and if you don't catch it immediately, the little "balls" of clogged up material on the sanding disc can scratch the surface that your cutting.

Years ago I was given samples from a 3M rep to try...I did, the coarser grits in the early stage where Okay but, when it came to the finer grits, they did exactly that, clog up and scratch the surface...it took a lot longer to get those scratches out by hand than if I would have wet block sanded the panel.

The other thing that I'm concerned about is the fact that these disc go on a foam pad, not a block, you just can't get a vehicle straight without using a block. For color sanding I use several different sizes of machined billet aluminum that I've had for years now. I made sure that when I got them machined that I had the edges slightly beveled...about 1/8th of an inch around the perimeter of the block. This way the edges don't drag or cut in when I'm sanding...and if I do get crap between the paper and the surface, I can hear it before there is to much damage.

Ray
Reply With Quote Quick reply to this message
  #6 (permalink)  
Old 08-01-2013, 09:03 AM
jcclark's Avatar
The Penny Pincher
 

Last journal entry: Hanging Bumpers
Last photo:
Join Date: Dec 2004
Location: Louisville, Ky. U.S.A.
Age: 61
Posts: 1,877
Wiki Edits: 0

Thanks: 4
Thanked 19 Times in 16 Posts
Quote:
Originally Posted by 69 widetrack View Post
.it took a lot longer to get those scratches out by hand than if I would have wet block sanded the panel.
Ray
That is so true!!!
When I do use a sander for clear sanding, a lot of times
I'll hand sand the for the finer grits.

One thing that does help with that problem,
When using an orbital, slow it down to about half speed
and sand with soapy water. that helps a lot.
and of course, change the pads often.
Reply With Quote Quick reply to this message
  #7 (permalink)  
Old 08-01-2013, 02:04 PM
Registered User
 
Last photo:
Join Date: Apr 2011
Location: MO
Posts: 153
Wiki Edits: 0

Thanks: 1
Thanked 0 Times in 0 Posts
I hate that when you think you found something that's saving so much time then it comes back to bite you. There's a lot of things like that in finishing where the long way is really the shorter way.
Reply With Quote Quick reply to this message
  #8 (permalink)  
Old 08-01-2013, 04:24 PM
302 Z28's Avatar  
Last photo:
Join Date: May 2003
Location: North Texas
Posts: 10,840
Wiki Edits: 0

Thanks: 1
Thanked 86 Times in 73 Posts
I used some pads wet on my DA for final color sanding they were 5000 grit and when finished using them they left a dull sheen. It was perfect for buffing and polishing. This was used of course after first color sanding by hand to level the clear.

Vince
Reply With Quote Quick reply to this message
  #9 (permalink)  
Old 08-01-2013, 04:54 PM
Faith - Respect - Trust
 
Last photo:
Join Date: Sep 2012
Location: Ontario
Age: 58
Posts: 3,508
Wiki Edits: 0

Thanks: 192
Thanked 638 Times in 572 Posts
I can see a super fine grit like 5,000 grit (I've never used 5,000 grit, the fines I've used is 3,000 grit, didn't realize that they made 5,000) work on a machine. Your not taking enough material off to either ball up on the pad or to cause any waves in the panel. That being said, if someone is going to try this, some good advice would be to be absolutely certain that the panel is free from any dirt, lint or anything that can get between the pad and the panel. If your using water for this process, the water source must be cleaned and changed regularly, the bucket that your water is in has to be clean...housekeeping, housekeeping, housekeeping, is of utmost importance,

I'm still going to keep doing it old school, by hand, even when I use 3,000 grit Trizac, it's all hand sanded.

Ray
Reply With Quote Quick reply to this message
  #10 (permalink)  
Old 08-01-2013, 05:26 PM
Registered User
 
Join Date: Dec 2010
Location: Destin FL.
Posts: 46
Wiki Edits: 0

Thanks: 0
Thanked 2 Times in 2 Posts
when is SHINE going to get in this
Reply With Quote Quick reply to this message
  #11 (permalink)  
Old 08-01-2013, 05:59 PM
Registered User
 
Last photo:
Join Date: Apr 2011
Location: MO
Posts: 153
Wiki Edits: 0

Thanks: 1
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by fenderless 33 View Post
when is SHINE going to get in this
I stole the filtering the water idea from him a few years back. He mentioned in a thread grit from the water (minerals etc) could cause some havock.

I do know the sediment in the water heater wouldn't be something I'd want in the sandpaper.
Reply With Quote Quick reply to this message
  #12 (permalink)  
Old 08-01-2013, 06:24 PM
Faith - Respect - Trust
 
Last photo:
Join Date: Sep 2012
Location: Ontario
Age: 58
Posts: 3,508
Wiki Edits: 0

Thanks: 192
Thanked 638 Times in 572 Posts
Quote:
Originally Posted by 777funk View Post
I stole the filtering the water idea from him a few years back. He mentioned in a thread grit from the water (minerals etc) could cause some havock.

I do know the sediment in the water heater wouldn't be something I'd want in the sandpaper.
It's funny you should mention filtering water (which is a great idea)...I have a dehumidifier in my home. When I'm wet sanding, I use the water that is collected from the dehumidifier...I get about 10 gallons a day, it's pure and clean. I store a few days worth in plastic 5 gallon pails with lids and I have great wet sanding water for my color sanding. I know that this may sound anal but, get a piece of grit between your paper and the panel and then you realize how important having everything as clean as possible is.

Ray
Reply With Quote Quick reply to this message
  #13 (permalink)  
Old 08-01-2013, 08:45 PM
Registered User
 
Last photo:
Join Date: Apr 2011
Location: MO
Posts: 153
Wiki Edits: 0

Thanks: 1
Thanked 0 Times in 0 Posts
Quote:
Originally Posted by 69 widetrack View Post
It's funny you should mention filtering water (which is a great idea)...I have a dehumidifier in my home. When I'm wet sanding, I use the water that is collected from the dehumidifier...I get about 10 gallons a day, it's pure and clean. I store a few days worth in plastic 5 gallon pails with lids and I have great wet sanding water for my color sanding. I know that this may sound anal but, get a piece of grit between your paper and the panel and then you realize how important having everything as clean as possible is.

Ray
In a perfect world, paint work is almost clean room level clean. So I know what you're talking about there. There's always a notch to take it up on. I'm no where near clean room with my budget and know how but still am always looking for ways to make things cleaner/better where I can.

I never thought about the dehum water. I wonder if it could be used as distilled water where needed (radiators, irons, things you don't want residue, etc).
Reply With Quote Quick reply to this message
  #14 (permalink)  
Old 08-01-2013, 09:29 PM
Faith - Respect - Trust
 
Last photo:
Join Date: Sep 2012
Location: Ontario
Age: 58
Posts: 3,508
Wiki Edits: 0

Thanks: 192
Thanked 638 Times in 572 Posts
I also have a friend who is on oxygen, he needs distilled water for his apparatus. When I'm not saving the dehumidified water, he gets as much as he needs...He's supposed to use distilled water and this works well for him...not that this has anything to do with the thread but yeah, the water that comes out of the dehumidifier is pretty pure.

Ray
Reply With Quote Quick reply to this message
  #15 (permalink)  
Old 08-02-2013, 11:19 AM
302 Z28's Avatar  
Last photo:
Join Date: May 2003
Location: North Texas
Posts: 10,840
Wiki Edits: 0

Thanks: 1
Thanked 86 Times in 73 Posts
Quote:
Originally Posted by 69 widetrack View Post
I can see a super fine grit like 5,000 grit (I've never used 5,000 grit, the fines I've used is 3,000 grit, didn't realize that they made 5,000) work on a machine. Your not taking enough material off to either ball up on the pad or to cause any waves in the panel. That being said, if someone is going to try this, some good advice would be to be absolutely certain that the panel is free from any dirt, lint or anything that can get between the pad and the panel. If your using water for this process, the water source must be cleaned and changed regularly, the bucket that your water is in has to be clean...housekeeping, housekeeping, housekeeping, is of utmost importance,

I'm still going to keep doing it old school, by hand, even when I use 3,000 grit Trizac, it's all hand sanded.

Ray
This is a shot of a 4000 grit pad, I used that same pad in 5000 grit with my DA and I kept a constant flow of water over the surface I was working on. I never wet sand with water from a bucket, only a free flowing hose.



Vince
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
Sanding orange peelin clear before final clear coats 67Elcamino Body - Exterior 4 05-25-2012 12:47 PM
3/32" orbit DA with professional results Possible for Color sanding? 777funk Body - Exterior 1 04-02-2011 10:22 PM
sanding clear then repaint with base clear agian questions tiptopss Body - Exterior 8 04-20-2010 07:09 AM
does it matter "sanders" bigrobdog Body - Exterior 4 08-17-2009 06:50 AM
Wet Sanding Clear Coat: DA vs Hand Sanding? off2wildblue Body - Exterior 8 05-25-2009 07:05 AM


All times are GMT -6. The time now is 02:58 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.