PDA

View Full Version : Pigtail ........ Abralon sanding


TheCoatingStore.com

stanclub
06-06-2011, 02:05 PM
I got a lot of pigtail when wet sanding with Abralon disc, especially on the hood. What did I do wrong?

I used a Harbor Freight palm sander with 3/16", but I added a valve control on the air intake, so I sanded with reduced air to get slower speed out of sander. I also run a garden hose rinsing water while sanding on panel, but it helps only when sanding the vertical panels such as door & fender; not the hood. The backing plate is flexable, not hard, so I did not use interface pad at all. Can someone suggest any solution?

Someone have told me that 3M trizact is better, so I ordered P1500 and hoping it can solve my problem. What will be advantage using Trizact? Can it flat the surface when sanding w/o interface pad?

Len
06-06-2011, 02:58 PM
I find that the biggest generator of pig tails is dirt nibs in the paint. You should sand out the nibs by hand using a small block then use a sander to level the orange peel. If you try to remove the nibs using a sander the dirt can cause pig tails when it gets between the sander and the paint. The sander you're using is a little too radical for this job but it can work if you're careful, it would be better if you had a 3/32" throw sander.

Bob K
06-06-2011, 03:11 PM
As for pigtails, your sander may have a lump in the backing plate that only shows up when you put pressure on the sander. Are you changing the paper often enough? The way you can tell that dry paper needs changing is when it starts making pigtails. Paper lasts a little longer when used wet but it doesnít last forever. Do you get pigtails right away when you put new paper on? If so then look for a better backing plate. Check your wet surface by dragging a squeegee across where you just sanded and the pigtails will show up.

A 3/32Ē sander works better for this kind of sanding.

Bob K

stanclub
06-06-2011, 04:43 PM
Never thought about the nib but I did sand the panel flat by hand with P1000 before I air sand, so I think the nib shouldn't be the threat, yeah?

About the sander, what is the difference in between 3/32 vs 3/16? I am planning on getting a good one later, but I hope that I can get my current sander works out on this project. So, am I suppose to sand fast with full throw of 3/16? Or, I should reduce the air flow to send slow? I did sand slow, but very slow, is it why I got pigtails?

One thing that have just caught my attention is that the pigtails I got was formed in swirl shape; they were so many of them, and together they looks like swirl. Am I suppose to get that many? By the way, they are not the swirl marks from buffer because I was able to get perfect result with hand sanding.

Bob K
06-06-2011, 05:15 PM
The 3/16Ē is the amount of distance that the pad moves on each stroke. A 3/32Ē pad will only move half the distance compared to the first one I mentioned. If you leave the paper on too long then the grit wears away and paint dust starts clumping up on the surface of the paper. These paint pills get to be quite thick compared to the height of the sand paper grit to the point that they are the only thing touching the car as the machine spins. These paint pills on the paper are what cause the pigtails changing the paper often prevents them from doing damage. I havenít seen them on my work when I use running water though so I am thinking you may be sanding outside the area of the running water.
The flip side of the coin is having too much water. The sander wonít hit the paint because it is floating on water if you use lots of water. I just like to have a small flow from a hose I hold in my other hand and keep enough water flowing that a milky white liquid is flowing away from the sander. That tells me the paper is cutting but the flow isnít so heavy that I am floating the sander.

Bob K

Len
06-06-2011, 05:29 PM
You're right, if the nibs were sanded by hand then they were not the cause of the pig tails. The difference between the 3/16" and the 3/32" is that the action of the sander is half the length and works better for this application. Also a palm sander is better because it has less tendency to tilt and put pressure on the edge of the pad. If you're in the market for a good sander for this application check out the AirVantage linked below. I'd recommend the 6" hook face pad.


http://autobodystore.net/Merchant2/graphics/00000001/avnon.jpg
AirVantage Sander Link (http://autobodystore.net/Merchant2/merchant.mvc?Screen=PROD&Product_Code=AVS61100S&Category_Code=T)

stanclub
06-06-2011, 06:40 PM
I don't recall getting milky white color while sanding, but some bubbles ...... I will try again tonight with reduced amount of water. By the way, should I sand with reduced speed? Or, full speed?

I am looking into the 6" AirVantage palm sander now, and definitely will be getting it in the future when I am ready.

Bob K
06-06-2011, 08:35 PM
My AirVantage is almost always throttled to half speed or less. It is a short throw sander and I donít use it as a mud hog.

Bob K

Robert
06-07-2011, 09:02 AM
Never thought about the nib but I did sand the panel flat by hand with P1000 before I air sand, so I think the nib shouldn't be the threat, yeah?

About the sander, what is the difference in between 3/32 vs 3/16? I am planning on getting a good one later, but I hope that I can get my current sander works out on this project. So, am I suppose to sand fast with full throw of 3/16? Or, I should reduce the air flow to send slow? I did sand slow, but very slow, is it why I got pigtails?

One thing that have just caught my attention is that the pigtails I got was formed in swirl shape; they were so many of them, and together they looks like swirl. Am I suppose to get that many? By the way, they are not the swirl marks from buffer because I was able to get perfect result with hand sanding.


If what you're getting is swirls, then it's likely the pad on your buffer got dried out and has chunks of compound or is dirty.