Tips and tricks for dry sanding film

Lizer said:
Ok, I went out and gave buffing a try over lunch and am disheartened. Lots of pigtails and little scratches that didn't buff out.

I used Chem Guys V32 with Hexalogic orange foam, then switched to twisted wool to see if that made it any better.

Either my random orbit polisher needs a shorter orbit, or I'm getting too many contaminating particles causing scratching (which is hard to tell when dry sanding because you can't hear or feel it like you can when wet sanding by hand), or I need to spend more time with 1500 and 2500.

Tried to take a picture but all it showed was a shiny reflection and can't get the scratches to show up.
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unless its just a single random deep pigtail on the surface when your done, which would be dirt then i can almost guarantee that your seeing 1000 grit scratches that werent worked out with 1500. when i am teaching a new guy here how to do it, that is the #1 cause of headache. it does take some getting used to the paper. your da should be a 3/16 orbit.
 
Jim C said:
unless its just a single random deep pigtail on the surface when your done, which would be dirt thei can almost guarantee that your seeing 1000 grit scratches that werent worked out with 1500. when i am teaching a new guy here how to do it, that is the #1 cause of headache.
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It is many pigtails. Is it my sander itself or just the fact that I need to spend more time with 1500?

I would be willing to buy a better sander that would do a proper job but I only have a 60 gallon 13 CFM compressor so if it’s pneumatic it needs to be easy on the air. I like to use electric.

How fast are you sanding with the dry films? Slow rotation speed or fast rotation speed?
 
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i only use air sanders. they have such more of a precision feel to them and i have one dedicated to wet sanding as well. i run all my sanders at about 2/3 speed so i think 13 cfm would do it. i have a gas backup compressor here, 5hp that is around 13-14 cfm and that will run a sander. it runs non stop but it does keep up with it. if you buy a sander then as i said 3/16 orbit not the 3/32 one. those are terrible. all my sanders are either dynabrade, 3m and i have 3 kovax/eagle sanders as well. all are good. the kovax seem a little more bulky though. not saying its your sander specifically causing the issue but it could be in an indirect way where its not cutting as efficiently, its loaded with contamination from years of heavy sanding use of other products or it could be that it just deosnt have a precision enough feel for you to get in all the area evenly...who knows. i do know i couldnt imagine using an electric for the job but the last electric sander i used was old school and 20 years ago.

generally its easy to tell a dirt pigtail from a sander. dirt will be bigger and they will be random. could be all over or just localized but generally if its dirt then the panel will buff and shine up like butter and you are left with just these few random pigtails. if its a sanding issue from other grits then its generally more "area" based. it could be a whole area that may buff hard and your left with dull spots or areas like that. that is typically 1000 grit that hasnt been worked out with 1500.
 
No longer valid........ said:
So last night I tried using water with the bufflex deal. I blocked this out halfassed with 1000 wet, then da'd it with sunmight 1500 dry. Then green and blue bufflex wet, then 3000/5000 sunmight. Then buffed. I think it took me a total of 30 min.. Honestly quite surprised how well that worked out. Only gripe was the bufflex paper would come off the supplied interface pad when wet.
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When you say green and blue Buflex are those K2000 for green and k2500 for blue? 6" with the 15 holes?
 
alex1970 said:
When you say green and blue Buflex are those K2000 for green and k2500 for blue? 6" with the 15 holes?
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16976528670907312347162392515832.jpg

That's correct. They also make it in a 3" and 5" without holes as well
 
Man, I don't know. I'm ready to toss this stuff aside and go back to wet sanding by hand. I hate that, but I've just completely resanded this hood going back to 1500. This time when I buffed I used Megs M100 on a wool pad and it looks very shiny, but if I look across the surface just right I can see a haze of thousands of little DA swirls in the finish. I sprayed 4 coats of single stage on this hood but don't know how much more sanding I can go before I start taking too much off.
 
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Try going over it with the pad and compound one more time. Work it pretty good, mist some water in a spray bottle to keep a section from drying out. That "should" get them.
I've been fighting sand scratches and urethane wave pretty much for the last 3 weeks from hand sanding. Nightmare. I empathize my friend.
 
Lizer said:
Man, I don't know. I'm ready to toss this stuff aside and go back to wet sanding by hand. I hate that, but I've just completely resanded this hood going back to 1500. This time when I buffed I used Megs M100 on a wool pad and it looks very shiny, but if I look across the surface just right I can see a haze of thousands of little DA swirls in the finish. I sprayed 4 coats of single stage on this hood but don't know how much more sanding I can go before I start taking too much off.
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This is the fear I have when doing my upcoming first cut and buff. Either I have scratches I can’t seem to get rid of that don’t show up until I finish buffing, or I start burning through to primer. Sorry to hear you’re having problems and hope you get it figured out.
 
@Lizer If going over it again doesn't get it, then go over the panel with the last sanding step in your process. No need to go all the way through again, just the last step then compound again. That will get it.
 
I did pick up an air sander but haven't had a chance to use it yet.

I have been finally having success with Megs M100 and a Wizards wool pad, it's taking a lot of buffing but I'm removing all the haze deep into the finish. Now all that's left is rogue pigtails and scratches...and there are quite a lot of them.

By the way I absolutely hate cutting and buffing. By the time I'm to this point of a project I just want to be assembling.
 
I am also cutting and buffing and not loving it. I am using 3D yellow wool pad and white wool pad on a rotary. I hate how many times I have to wipe it all down with a clean micro fiber to check progress only to discover more to do, and checking progress is tough with 54 YO eyes.:(
 
To me it’s all in the sanding. And personally I’d rather spend more time sanding and refining my scratch and make my buffing life much easier. I guess I’m fortunate, I’ve never had scratches fight me too much. Even an original hard clear I can usually make 1500 scratches disappear quite easily with a gear driven flex, Nevermind a rotary. But obviously pad and compound play a huge role in that.
 
I haven’t had a chance to revisit my sanding yet. It’s getting there with the buffing, it’s just been a slow process but I don’t think it would have been possible with foam and CG V32. I’ve had to go back and hand sand some rogue scratches but all it takes is 1500 then 2000 and the wool and compound takes care of the rest.

Hopefully my next panels will sand better and buffing will be faster. Thos dry sanding is all new to me but I loathe hand sanding.

This is the hood which was my first panel. It’s just compounded, I still need to polish.

IMG_3345.jpeg
 
pretty happy with my doors. still some small micro scratches here and there not bad- also what I guess is some urethane wave. I can always buff again in a year or two. Now on to the fenders, hood, Deck lid, etc... Ive been using Super Bufflix dry K1500, K2000, K3000 by hand, that paper is insanely effective despite having to clean it out every 20 seconds.
P Door after polish.jpg
 
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