Disc Sander or Grinder

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Disc Sander or Grinder

Postby marcusg » Tue Jun 30, 2020 7:48 pm

Mid-way through a project, I lost use of my neighbor's heavy duty orbital sander and bought my own (this one: https://www.lowes.com/pd/Bosch-120-Volt ... ag/3735191) that seems to have much less power. I know I could buy a 3 or even 4 amp sander to help me finish sanding the boat before I die, but I'm not wanting to keep buying tools if I can get one tool that does two things. I also have a good bit of fiberglass repair to do, which will require being ground down to 1/20 or whatever it was, and I remember seeing in a bunch of videos they mentioned grinders being better for that than sanders. Or does it not matter either way?

Any tool recommendations that can QUICKLY remove paint & do the fiberglass jobs would be great. I'd even consider getting an air compressor if the pneumatic ones make enough of a difference. I've been sanding for like 2 months, and I still haven't touched anything below the cockpit/deck, lol.
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Re: Disc Sander or Grinder

Postby GreenLake » Tue Jun 30, 2020 8:17 pm

Are you grinding paint, or are you grinding the gelcoat? The latter doesn't have to be removed for painting, in fact should not.
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Re: Disc Sander or Grinder

Postby marcusg » Tue Jun 30, 2020 9:52 pm

Sanding off the paint for the re-paint job. And then for the fiberglass repairs I'll need to do sand/grind the gradient to fill in the repair.
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Re: Disc Sander or Grinder

Postby GreenLake » Tue Jun 30, 2020 11:21 pm

I forgot. Did you already use chemical stripper to get the paint off, or was that some other boat?

I've used a longboard for most of my sanding, with a simple Dewalt? orbital sander (that one, with 36 grit) worked well for doing what you call the gradient.

For a sanding board you need sandpaper that comes on a roll and is adhesive backed. You take a length of lumber (not too thick, so it can bend a bit) fix two handles on it, and apply a strip of sandpaper on the back. Works really well in preventing low spots.

I also used a shorter manual sanding pad - larger than the typical "soap bar" sized ones.
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Re: Disc Sander or Grinder

Postby marcusg » Wed Jul 01, 2020 11:39 am

Greenlake. I'm using a combination of CitriStrip and sanding to remove the paint, as it wold require about 30 gallons of citristrip to strip all the old, baked-on paint and sanding is way faster. Good to know a sander is up to do the gradient, maybe I'll just suffer through using my underpowered sander for now, we'll see.
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Re: Disc Sander or Grinder

Postby GreenLake » Wed Jul 01, 2020 2:26 pm

Don't underestimate the power of manual sanding board that you can use with two hands. Definitely once you fair your hull, you don't want to use any "point sander" like an orbital sander. You are going to fair your hull?
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Re: Disc Sander or Grinder

Postby TJDSII6630 » Sun Jul 12, 2020 2:03 pm

When removing fiberglass and gel coat I favor a side grinder with a sanding disk.
Its made of layers of sandpaper and can take the RPM.
This in not like the paper disks you put on a drill.
Can be aggressive or not depending on the angle and pressure.
If you need to get into crevices or want to cut more than grind use the cutoff wheels.
It is not for finish work you intend to paint and look pretty.

Teddy
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