[nbo10]

Hi All,
I know almost nothing about finishing. I'm using an oil based poly to finish a project. What grit sand paper should I use between coats of poly? Is vacuuming enough to clean off the dust that is created? What about the final coat, should anything be done after the final coat? Thanks.

 

[Dave Paine]

Hi All,
I know almost nothing about finishing. I'm using an oil based poly to finish a project. What grit sand paper should I use between coats of poly? Is vacuuming enough to clean off the dust that is created? What about the final coat, should anything be done after the final coat? Thanks.

Questions worthy of starting a bar fight, since so many different opinions. :laughing:

I do not know what may be deemed "correct" but I have my own preferences.

For oil based, I like to use wipe on poly. Thin coat, but spreads evenly and if you pay attention you can avoid sags and drips.

After the coat has cured I use a dampened piece of wet-dry paper, 400 or 600 grit. I use very light pressure. If the piece of paper is folded do NOT use the folded edge, it will take off too much finish.

I am looking to minimize the amount of the previous coat removed. Mostly looking to take down any nibs/dust/high spots. The wet paper works well for me, I can feel when the grit has done its work.

I then wipe down with a damp sponge or damp paper towel. Vacuuming alone will not get all the dust off. You may not see the dust, but it will be present and may show or especially be felt after applying the
next coat.

For non-turning work I leave the final coat as is. Should be smooth.

For turning work I buff with Tripoli compound and my Beall buffing wheel.

 

[tc65]

I do very similar to Dave.

Wipe on (own mix of regular poly thinned with 5-10% MS). After dry I sand with 400x.

I don't wet sand though, I dry sand and use a sanding block. I used to just use a piece of paper with my hand, but I would get some places that were uneven due to varying finger pressure.

I then wipe down with a paper towel or rag dampened with MS.

Nothing done after final coat.

 

[nbo10]

Thanks for the advice. I love opening cans of worms . I knew I didn't want to take too much of the finish off I just didn't know a good starting grit. I was thinking of starting at maybe 320 but sounds like that may be too aggressive.

 

[mdntrdr]

I sand 320x between coats. :smile:

 

[nbo10]

After the first coat the surface feels significantly rougher. I would assume that's normal? I've been using a brush to apply the poly. I think I have the minwax poly.

 

[Dave Paine]

After the first coat the surface feels significantly rougher. I would assume that's normal? I've been using a brush to apply the poly. I think I have the minwax poly.

Yes, if you are brushing on the poly, the finish may not level out as well as wipe on. Hence some of the roughness is the lack of levelling. This is one reason I use the wipe on finish.

I find water based finishes work well when brush or roller, the water base has lower viscosity and so levels out better then oil based.

 

[dougj71]

Hi All,
I know almost nothing about finishing. I'm using an oil based poly to finish a project. What grit sand paper should I use between coats of poly? Is vacuuming enough to clean off the dust that is created? What about the final coat, should anything be done after the final coat? Thanks.

I like to use synthetic steel wool between coats.

 

[cabinetman]

Hi All,
I know almost nothing about finishing. I'm using an oil based poly to finish a project. What grit sand paper should I use between coats of poly? Is vacuuming enough to clean off the dust that is created? What about the final coat, should anything be done after the final coat? Thanks.

If I use an oil base polyurethane, I try to use or make a wiping version. It can be sprayed but it can run easily. I use 320x open coat paper between coats, and nothing after the final application.

I don't sand where I apply the finish. Debris stays airborne long after you can't see it. Running a vacuum can disturb the air. The exhaust will stir up the dust.

.

 

[nbo10]

I limited on space and have to sand and finish in the same area. My current SOP is: vacuum, wait a few hours, wipe down, wait till dry, then finish. Not sure how much it helps or hurts. I also have a couple fans with air filters. I think it's more amusing than useful:laughing:.

Do I need to use any special rag for the poly+10% MS mix? I have a package from the paint section at lowes.

 

[tc65]

I use old t-shirts that I cut up. They've been washed enough they are lint free and have a nice fine weave.

Edit: I should add, don't use colored shirts - depending on the dye used on the cloth it can bleed with the solvents.

 

[ricko]

between coats

I my self use 400 grit and sand very care full , wipe with a damp cloth ,then proceed to next coat. I don't vac either as to cause a stir up of dust .

 

[HowardAcheson]

The first coat will always feel "scratchy and rough.". When you scuff sand with 320 grit after the first coat has dried, you will make the surface much smoother. Vacuum off the sanding dust--no need for tack cloths or mineral spirits--and apply your next coat. If you re-coat within 10 to 12 hours, you do not need to sand between further coat unless you have some surface defect you are correcting. Three coats should do it for you.

 

[nbo10]

The wiping poly worked good. It went on much faster than a brush. Thanks for the advice all.