final finishing step

[jimmy986]

I have been woodworking for about a year and half so I'm still teaching myself a lot of the basics. I would assume I have a similar issue as many newbies and that is finishing. While it's not always perfect, I think I've gotten it down to not getting runs and drips in it. My main problem comes at the very end. I get the finish to be pretty smooth overall from an HVLP sprayer with poly but there are obviously still going to be irregularities. In order to break those down a little I used 1200 sandpaper and a sanding block. After sanding, the finish because scratched and milky even after wiping with a microfiber cloth. Am I doing something wrong? Too much sanding? Too much pressure? Should I move up even higher in grit? Is there a way to get this to go away after sanding? I've been told its too soon to wipe it down with mineral spirits but I thought that might work.

My other question for this step is whether it is better to use a sanding block or a ROS? I have a bosch ROS and I also have a Rotex 125. I have 1200 grit granat paper for the rotex. I have the bosch if I want something smaller than the rotex until I save to get an ETS. I also have the standard and soft pads for the Rotex.

Any other insights into getting a good finish would be much appreciated. I'm trying to get it under control.

 

[polarsea1]

1200 grit is too coarse for what you want to do. If you are talking about very small imperfections, try a nib file, otherwise start with a finer grit or plan on going through the grits until you get to the desired sheen.

 

[live4ever]

If you leave it at 1200 grit, it will probably be cloudier than you are wanting. 

My recommendation (at least how I figured out this stuff when I was getting my finishing feet wet) would be to get this set of micro mesh pads:
http://www.amazon.com/Micro-Mesh-Soft-Touch-Pads/dp/B003ELH7AI

You would use these wet by hand, working up through the pads to get to your desired sheen (after you've used whatever method to remove any nibs).  Manual labor, but not that bad depending on how much you need to do. 

Once you have an idea for what kind of grits work for you and what kind of sheen you like, you can invest in [more expensive] abrasives and pads for your Rotex for larger projects (e.g. Platin 2, interface pad, polishing compounds, buffing pads, etc.).   

 

[jimmy986]

On my current project, I've been experimenting with different mixtures of poly and mineral spirits to achieve both flatness/smoothness and to keep runs from developing. It seems like I've found that if I add too much mineral spirits it is too runny and will pool up on the undersides of aprons and such. On the other side, if I spray too heavily without diluting it will be too thick to flatten out completely or will run just enough to be uneven.

I'm sure these are common things that happen to new finishers. Once I'm at the stage I am and have applied numerous coats what is the easiest way to rectify the runs? Can sanding work or would it be easier to take a sharp chisel and slice off the high spots and then spray another thinned coat?

And then would I sand with something like 2000 grit paper?

 

[live4ever]

On my current project, I've been experimenting with different mixtures of poly and mineral spirits to achieve both flatness/smoothness and to keep runs from developing. It seems like I've found that if I add too much mineral spirits it is too runny and will pool up on the undersides of aprons and such. On the other side, if I spray too heavily without diluting it will be too thick to flatten out completely or will run just enough to be uneven.

I'm sure these are common things that happen to new finishers. Once I'm at the stage I am and have applied numerous coats what is the easiest way to rectify the runs? Can sanding work or would it be easier to take a sharp chisel and slice off the high spots and then spray another thinned coat?

And then would I sand with something like 2000 grit paper?

Sanding can work, especially if it's a larger area to flatten.  Then yes, you'd work your way up the grits to the desired sheen.  You're not going to be able to use a single grit.

For slicing the high spots, I find a card scraper to work better than sanding.  The thing about card scrapers, as you may know, is they are a little bit of a pain to learn how to sharpen, but once you get the hang of it, they're incredibly useful in so many ways.  A light pass with a card scraper gets rid of nibs between coats and can also work wonders when you have little high spots to slice away.  A chisel can work, but it's easy to go to far and leave a gouge.

 

[mmyachts]

I have been woodworking for about a year and half so I'm still teaching myself a lot of the basics. I would assume I have a similar issue as many newbies and that is finishing. While it's not always perfect, I think I've gotten it down to not getting runs and drips in it. My main problem comes at the very end. I get the finish to be pretty smooth overall from an HVLP sprayer with poly but there are obviously still going to be irregularities. In order to break those down a little I used 1200 sandpaper and a sanding block. After sanding, the finish because scratched and milky even after wiping with a microfiber cloth. Am I doing something wrong? Too much sanding? Too much pressure? Should I move up even higher in grit? Is there a way to get this to go away after sanding? I've been told its too soon to wipe it down with mineral spirits but I thought that might work.

My other question for this step is whether it is better to use a sanding block or a ROS? I have a bosch ROS and I also have a Rotex 125. I have 1200 grit granat paper for the rotex. I have the bosch if I want something smaller than the rotex until I save to get an ETS. I also have the standard and soft pads for the Rotex.

Any other insights into getting a good finish would be much appreciated. I'm trying to get it under control.

To remove 800+ grit scratches you must buff it out with wool/foam pad and the appropriate polishing appropriate compound.  800-1500 grit scratches I would recommend a rotary action tool, a good DA will take care of higher grits. Polishing compounds have grit ratings that people are unaware of. Match the compounds grit rating to your final sanding grit and you won't get frustrated. Also, buying cheap compound is like buying cheap sandpaper,you don't save. Not all finishes are "buffable" so if yours isn't then you must re-coat. Make sure your tuning your gun before usage with a regulator connected directly to gun. The first tack coat should be sprayed fast , it looks bad but its purpose is to hold the following coats. Let it flash off (in my climate its 2-3 min) then spray next coat half speed of first. I let flash for 4-5min then spray the 3rd coat nice and slow. I consider that one full coat. With 2-3 part finishes you can typically repeat that process after a couple of hours if in warmer climate. Hope this helps.