Strip disc

[old soul]

Do ya'll think the strip discs, the fabric ones that go on a die grinder or drill, provide a proper surface for epoxy primer adhesion?
The surface appears to almost be polished after use, sort of like with a wire brush.

I had a '55 Chevy trunk lid media blasted (plastic) on the underside to remove 3 layers of paint. The plastic leaves a smooth finish that has to
be sanded. I have been hand sanding every nook and cranny (80 grit) and it is going to take a VERY long time, more than I can account to my
customer for. Was wondering if the strip disc would would be an option to speed things up and be able to go straight to epoxy after clean-up.
Thanks

 

[Arrowhead]

I like sanding sponges for undersides of hoods, trunks, jambs. Helps get into all the nooks and crannies without wearing the skin off your fingertips.

http://www.harborfreight.com/pack-of-10-coarse-grade-aluminum-oxide-sanding-sponges-46751.html

 

[old soul]

Thanks, Arrowhead. Haven't used those before but will give them a try.

 

[Bob Hollinshead]

The clean-n-strip discs provide an adequate texture IMO. Just don't turn them at too high of speed.

 

[old soul]

Thanks, Bob. I do like to use them on the small hard-to-get and irregular shaped places.

 

[crashtech]

I have experienced poor adhesion of some materials when applying over bare metal finishes left behind by certain clean n strip discs. When in doubt, at least scuff sand or lightly sandblast any metal that has a polished or too shiny look to it.

 

[bomccorkle]

I like to use the strip discs and have never had an issue with them but I like crash always hit the spot with some 80 grit or a 36g roloc after I'm done as well.

 

[anotheridiot]

they recommend 80 grit in the manual, so I think the polished look would be too smooth. If you dont go with the 80 grit I would definitely use a metal etching primer first.

 

[crashtech]

Etching primer is NOT recommended by SPI! DO NOT use etching primer at any point in the process when using SPI primers!

 

[anotheridiot]

Have you considered going to a different sandblast media to give bite to the primer? Aluminum oxide at low pressure will get into the corners and give you plenty of cross hatch. Being on the military side of painting there are different primers for different applications, most of mine need to be applied over anodize or chromate, so I find the primer that meets specifications for being used over those smooth surfaces. I can see the areas you are concerned with and know its pretty impossible to mechanically find a way to get bite there.

 

[Bob Hollinshead]

I have experienced poor adhesion of some materials when applying over bare metal finishes left behind by certain clean n strip discs. When in doubt, at least scuff sand or lightly sandblast any metal that has a polished or too shiny look to it.

Crash, the 3M discs have worked good for me for years but if you want one that leaves a more aggressive scratch Norton Beartex works good and lasts 3X longer than the 3M black discs. I've tried the 3M purple and not a big fan-too stiff. One thing to remember with the original 3M version is if it's spun too fast the heat will leave a clear coating that most wax and grease removers won't take off, it'll even affect welding. I run them kinda slow and that also makes for a more aggressive texture.

 

[crashtech]

Crash, the 3M discs have worked good for me for years but if you want one that leaves a more aggressive scratch Norton Beartex works good and lasts 3X longer than the 3M black discs. I've tried the 3M purple and not a big fan-too stiff.

I remember Beartex from a deburring shop I worked at as a kid. Will have to try that, thanks. I don't like the purple "Imperial" wheels either.

One thing to remember with the original 3M version is if it's spun too fast the heat will leave a clear coating that most wax and grease removers won't take off, it'll even affect welding. I run them kinda slow and that also makes for a more aggressive texture.

Yes, I have seen that effect before and it's the main reason for my advice. My thinking is that it's always at risk for being present even if we think that a slow enough speed has been used, so it's always best to go back over the finish left by such discs, especially when a less experienced hand is at the controls... jmho.

 

[rustover]

I picked these up in a 3 pack at Lowes, Kobalt brand, so who knows. They seem to be ok, but I haven't used them long enough to say if I like them. I used them on some hard to reach areas of the truck pan I was stripping the e-coat from. I was planning on using them for some hard to reach areas when I strip the shell. I will keep the speed down on them. I'm going to a swapmeet next week, hoping to get a few deals on some items like these.