Powder coat prep question - The 1947 - Present Chevrolet & GMC Truck Message Board Network

dan468 · 04-29-2007, 10:02 PM

How abrasive can I go on my frame with grinders and sanding and still not see the grind marks after the powder coat goes on?

Thanks
Dan in AZ

Sport/Truck · 04-29-2007, 10:18 PM

I don’t think you want to leave 36 grit grinding marks in the metal by no means, just hit it with a tiger disc to blend it out.
s/t

timcos · 04-30-2007, 12:14 AM

What is a tiger disc?

GREASEMONKEY72 · 04-30-2007, 02:04 AM

use a buffing pad on the grinder

IvelDesigns · 04-30-2007, 02:18 AM

Quote:

Originally Posted by GREASEMONKEY72

use a buffing pad on the grinder

huh? i'm confused.

GREASEMONKEY72 · 04-30-2007, 02:19 AM

Quote:

Originally Posted by IvelDesigns

huh? i'm confused.

theres a wheel for the grinder called a buffing pad

i can get a pic of it if need be

IvelDesigns · 04-30-2007, 02:21 AM

ok, so i assume it's nothing like a buffing pad you would use on paint. that's what immediately came to mind for me

GREASEMONKEY72 · 04-30-2007, 02:24 AM

Quote:

Originally Posted by IvelDesigns

ok, so i assume it's nothing like a buffing pad you would use on paint. that's what immediately came to mind for me

no you deffinitly wouldnt want to use it on paint

its a buffing pad for steel instead of using a grinding wheel

BigMike · 04-30-2007, 02:37 AM

I'd say nothing coarser than 80 grit. I had some stuff powder coated that had some 36 and 40 grit marks on it that came through once they were coated.

Mike

Morgsie · 04-30-2007, 05:21 AM

Why not sandblast the frame?

cdowns · 04-30-2007, 08:17 AM

if you're going to have the frame powdercoated just powerwash it and degrease it and drop it off at the coaters they'll prep it and coat it

3/4tonterror · 04-30-2007, 09:36 AM

the powdercoater HAS to sand blast all parts before coating, even if they are new or bare metel. if not the powder wont stick.dont do it with a grinder its a waste of time.

Sport/Truck · 04-30-2007, 10:35 AM

Quote:

Originally Posted by timcos

What is a tiger disc?

Look here http://www.aaabrasives.com/shoponlin...FQ9nYAodZxQaRA
s/t

C10-Driver · 04-30-2007, 10:36 AM

I had my frame sand-blasted then did all my grinding, fabrication and pre-assembly. Before I had it powder-coated, I had the my sand-blaster hit it again. The sand-blasting provides a nice, even finish and hides a lot of the swirl marks from sanding or grinding. It's not going to hide any deep grinding marks of course but it does even things out nicely.

dan468 · 04-30-2007, 11:00 AM

Quote:

Originally Posted by C10-Driver

I had my frame sand-blasted then did all my grinding, fabrication and pre-assembly. Before I had it powder-coated, I had the my sand-blaster hit it again. The sand-blasting provides a nice, even finish and hides a lot of the swirl marks from sanding or grinding. It's not going to hide any deep grinding marks of course but it does even things out nicely.

so then what grit # would you finish with on your fab work?

jimmydean · 04-30-2007, 11:27 AM

80 grit TOPS. Even if you have it double coated (I would recommend it if they know what they are doing) deep marks can often show through powder.

Powder does a great job of hiding marks, though. Media blasting when done properly will provide the best profile for powder.

Overkill67 · 04-30-2007, 02:30 PM

I used to do powder coating. Any marks that go below the surface (like grind marks) will show up, and the more coats you do the worse it will look. yes the powder coater should be blasting it before they coat it to remove any grease and give it a good surface to adhere to. (sorry my spelling stinks lol)

C10-Driver · 05-01-2007, 01:09 AM

Quote:

Originally Posted by dan468

so then what grit # would you finish with on your fab work?

I used medium angle-grinder disks. I think they are about an 80 grit.

As many people have been saying, powder doesn't cover a lot. Any significant imperfections below the surface are going to show through. Then again, take a look at all the imperfections on a 1967-72 chevy truck frame as it came off the line 30 or so years ago.

04-29-2007, 10:02 PM	#1
dan468 Registered User Join Date: Nov 2006 Location: Sun City, Arizona Posts: 430	Powder coat prep question How abrasive can I go on my frame with grinders and sanding and still not see the grind marks after the powder coat goes on? Thanks Dan in AZ

04-29-2007, 10:18 PM	#2
Sport/Truck Sierra Grande Club Join Date: Jan 2007 Location: New Mexico USA Posts: 2,433	Re: Powder coat prep question I don’t think you want to leave 36 grit grinding marks in the metal by no means, just hit it with a tiger disc to blend it out. s/t __________________ 1971 GMC Sierra Grande, 1/2 ton short wide, original 4 bolt 010 020 block & heads. (matching #'s). 383 stroker, SMI q jet 750 cfm, Lunati Voodoo 60102 cam, Scorpion roller rockers, Spin Tech pro street mufflers with X pipe.

04-30-2007, 12:14 AM	#3
timcos Chief Honcho In Charge Join Date: Aug 2006 Location: Bentonville AR Posts: 970	Re: Powder coat prep question What is a tiger disc? __________________ 1992 1500 4x4 Shortbed 1984 Ford F250 Supercab Longbed 6.9L Diesel 1972 K10 Cheyenne Super Fleetside Short Bed - 350 - A/C 1971 VW SuperBeetle 1960 Wife 1984 Son 1986 Son 1989 Son Previous Trucks 1967 C10 SWB (1980-1981) 1971 C10 LWB (1998-2004)

04-30-2007, 02:04 AM	#4
GREASEMONKEY72 Registered User Join Date: Aug 2006 Location: Bakersfield,CA Posts: 7,893	Re: Powder coat prep question use a buffing pad on the grinder __________________ -steven Alte Seele S.S. "Allison" '72 C/10 LWB 350SB/TH350 - DD PITBULL IS NOT A CRIME

04-30-2007, 02:21 AM	#7
IvelDesigns Commander Taco Bello Join Date: Sep 2006 Location: Des Moines, Iowa Posts: 2,232	Re: Powder coat prep question ok, so i assume it's nothing like a buffing pad you would use on paint. that's what immediately came to mind for me __________________ Bagged '50 3600 - Bumper punchin' road kill since 2009... Bagged '69 C10 Longbed - Bumper punchin' road kill since 2007...

04-30-2007, 02:37 AM	#9
BigMike Registered User Join Date: Sep 2004 Location: Rancho Santa Margarita - SoCal Posts: 1,432	Re: Powder coat prep question I'd say nothing coarser than 80 grit. I had some stuff powder coated that had some 36 and 40 grit marks on it that came through once they were coated. Mike __________________ Mike My 69 SWB Project Father/Son 72 Nova Project My Airbrushed RC Car Bodies

04-30-2007, 05:21 AM	#10
Morgsie Registered User Join Date: Apr 2005 Location: BC, Canada Posts: 122	Re: Powder coat prep question Why not sandblast the frame?

04-30-2007, 08:17 AM	#11
cdowns Senior Member Join Date: Jan 2003 Location: daytonabeach Posts: 22,956	Re: Powder coat prep question if you're going to have the frame powdercoated just powerwash it and degrease it and drop it off at the coaters they'll prep it and coat it __________________ 71c-10 350/2004r/4:11 lowered3/4 longbed/dead by hurricane MEANING OF DEATH::::: SOMEBODY ELSE GETS YOUR STUFF DONT BELIEVE EVERYTHING YOU THINK TAKE MY ADVISE;I DON'T USE IT ANYWAY

04-30-2007, 09:36 AM	#12
3/4tonterror Registered User Join Date: Dec 2006 Location: jaffrey,NH Posts: 325	Re: Powder coat prep question the powdercoater HAS to sand blast all parts before coating, even if they are new or bare metel. if not the powder wont stick.dont do it with a grinder its a waste of time.

04-30-2007, 10:36 AM	#14
C10-Driver Chevy Truck Addict Join Date: Aug 2006 Location: Kelowna, BC Posts: 1,176	Re: Powder coat prep question I had my frame sand-blasted then did all my grinding, fabrication and pre-assembly. Before I had it powder-coated, I had the my sand-blaster hit it again. The sand-blasting provides a nice, even finish and hides a lot of the swirl marks from sanding or grinding. It's not going to hide any deep grinding marks of course but it does even things out nicely. __________________ . 1970 Chev C/10 SWB, 355 SBC, 700R4, 3.73 Posi, Air Ride (Click to view Build Thread) (SOLD) 1978 Chevy C/10 SWB 1970 Pontiac Lemans .

04-30-2007, 11:27 AM	#16
jimmydean Registered User Join Date: May 2005 Location: Beaverton, OR Posts: 3,728	Re: Powder coat prep question 80 grit TOPS. Even if you have it double coated (I would recommend it if they know what they are doing) deep marks can often show through powder. Powder does a great job of hiding marks, though. Media blasting when done properly will provide the best profile for powder. __________________ New Project: 1966 LWB C20 Plans: 1/2 ton conversion Dropmember front Dropmember rear Corvette discs Restored raised bed http://67-72chevytrucks.com/vboard/s....php?p=4295210

04-30-2007, 02:30 PM	#17
Overkill67 Registered User Join Date: Apr 2007 Location: Roselawn, Indiana Posts: 60	Re: Powder coat prep question I used to do powder coating. Any marks that go below the surface (like grind marks) will show up, and the more coats you do the worse it will look. yes the powder coater should be blasting it before they coat it to remove any grease and give it a good surface to adhere to. (sorry my spelling stinks lol)



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