What's more abrasive ?

[Marcq]

Wet sanding or dry? The reason I'm asking is, I hate dust, specially gelcoat dust. I'm sanding my floor with an electric sander with 80 grit and the casting deck by hand, seems to take forever + the dust. Would I be better off wet sanding with the same grit sand paper by hand/block?
Marc..

[slvrlng]

The wet dry paper is more agressive Each particle is shape like a sharp mountain. The dry paper looks more like a lump, of course this is on a microscopic level. When you use the wet paper the tops of the "mountains" crack off and leave a sharp edge just slighty smaller than the original. If you keep sanding 240 grit will turn into 600 grit. I have a self contained vacuum Dyabrade air sander with a HEPA filter on the end of a 6 foot hose. What I always run into with gelcoat or composites is the itch factor! I just can't handle the fibers or the powder. Get a tyvek paint suit with a hood and don't use a regular dust mask use a respirator with charcoal filters. Doing this alone will make it much more comfortable and safer! When you apply the non skid the respirator will come in handy because of the smell. You can probably get this stuff at any automotive paint store up there, I don't know if Canadian tire carries them or not.

[Marcq]

The wet dry paper is more agressive Each particle is shape like a sharp mountain. The dry paper looks more like a lump, of course this is on a microscopic level. When you use the wet paper the tops of the "mountains" crack off and leave a sharp edge just slighty smaller than the original. If you keep sanding 240 grit will turn into 600 grit. I have a self contained vacuum Dyabrade air sander with a HEPA filter on the end of a 6 foot hose. What I always run into with gelcoat or composites is the itch factor! I just can't handle the fibers or the powder. Get a tyvek paint suit with a hood and don't use a regular dust mask use a respirator with charcoal filters. Doing this alone will make it much more comfortable and safer! When you apply the non skid the respirator will come in handy because of the smell. You can probably get this stuff at any automotive paint store up there, I don't know if Canadian tire carries them or not.

So why would people wet sand ?
Marc..

[slippery73]

Wet sanding cuts down all the dust and also keeps the paper clean, surface clean, etc. Your constantly washing the surface of contaminants, chunks of dirt, etc. So you end up with a higher quality finished product. I don't know that wet vs. dry paper is faster, you don't see many wet papers below 400 grit, and you dont see many dry papers above 400 grit. So don't know if thats a good comparison, each one has its place. Wet for fine work ie polishing, dry for rough work ie leveling.

[RickK]

Wet sanding or dry? The reason I'm asking is, I hate dust, specially gelcoat dust. I'm sanding my floor with an electric sander with 80 grit and the casting deck by hand, seems to take forever + the dust. Would I be better off wet sanding with the same grit sand paper by hand/block?
Marc..

I would use a grinder/sander and put an aggressive wheel on it and hit everything with that, you'll be done in about an hour or less. You just want to rough it up for the new gelcoat/non-skid.  Where a good mask.