Replies

1. 
   _mj_ | Aug 05, 2022 02:57pm | #1

   Before you continue take a close look at the scratches while you think about how you sanded both the raw top and the first coat. If you used a machine to sand you may see a swirl pattern... did you use a machine between coats? Are the scratches cross-grain? Did you sand only with the grain between coats?

   My guess is that the scratches were from the tabletop prep and not the between-coat sanding. If they are, now is the time to sand it back and correct it before you get in too deep with the poly. The first coat is always a little bumpy and harder to see through, that's why the can calls for the light sanding. That second coat refines the surface and lets you see through to the surface more clearly.

2. 
   bilyo | Aug 05, 2022 03:44pm | #2

   I agree. First, you should always sand with the grain and if I'm sanding finish material, I always do it by hand. In addition, the first coat is very thin and if you sand a bit too much it is easy to get into the stain or wood below it. I frequently do not sand after the first coat because it is just too thin. Add a second coat, at least, before you start sanding between coats.
   Are you sure the scratches are in the first coat and not in the wood from your prep work? I ask because 220 grit is very fine and doesn't usually leave identifiable individual scratches. Those usually happen with coarser grit particularly when your sander picks up a stray piece of grit from the previous grit.
   At this point, you probably need to sand or strip it back to the wood and start again. The last sanding before adding finish should be by hand (in my opinion) with all strokes with the grain. Then wipe it down with mineral spirits which will highlight any scratches that remain.

3. 
   user-7625930 | Aug 06, 2022 01:10pm | #3

   Thanks guys...I resanded all the way down. I sanded 80-120-180 with random orbital then sanded with the grain with 220 and re stained. I filled the pores with old masters as it's oak. Now on to polyurethane. I'm using homemade wipe on poly...I don't plan on sanding 1st coat and it's pretty thin stuff so I might not sand the second coat but if I do I'm using 400 grit just to knock things smooth...how's this sound?

4. 
   bilyo | Aug 06, 2022 06:08pm | #4

   Sounds like a plan. Let us know how it works out, please.

5. 
   _mj_ | Aug 06, 2022 06:25pm | #5

   Sounds good... do the sanding using a stiff cork block to avoid rolling over and burning through your edges.

6. 
   Go_Bills | Aug 06, 2022 09:14pm | #6

   I am not an expert - but I see guys follow 220 grit with 320, 500 and some beyond.

   Hal Taylor strongly recommends 50/50 mix of poly and mineral spirits wipe on wipe off.

   Hal Taylor sands beyond 500.

7. 
   jharveyb | Aug 07, 2022 04:03pm | #7

   I am not an expert on wipe-on poly, but I have a long experience with Waterlox, a wipe-on varnish. Wipe on finishes have lower solids contents than typical brush-on finishes. This affects their use several ways.
   I hand sand at least to 32o grit before starting the finishing process. (As mentioned, as you are going up the grits, clean the wood thoroughly to remove any grit particles so they don't scratch the surface when you are using finer grits.) The wood is noticeably smoother, which is important with a thinner finish. Waterlox recommends applying several coats before first sanding, as you definitely want to avoid sanding thru the finish into the wood. I would use worn 320 grit or finer to sand the finish. 220 is too coarse. On flat surfaces, a cork block can be helpful; I mostly just hold it in my hand.

   As I am nearing the final coat(s), I want to make sure I have minimal scratches to fill with the final coats. After sanding with fine paper, I rub with 0000 steel wool to further refine the scratch pattern. You must clean the surface very well after using steel wool, as there is the danger of water taking the iron into the wood, producing black spots. I would blow off with compressed air, then wipe down with a clean rag wetted with mineral spirits.

   The final coat or two, I apply using a "mouse". It is a cotton ball wrapped in a cotton rag (I use a rubber band to close the rag around the cotton ball.) Wet the mouse with the finish, then rub it on the surface of the piece. You are aiming for a very light coat that dries so quickly that there is very little chance of dust sticking to it. It may take two coats to get the fill on the haze/scratches that you want.

   You may want to investigate the auto-finishing rubbing compounds available from companies like Maguiar's at auto parts stores. I've used them in the past to rub out finishes. An auto body shop could probably provide advise on what level of coarseness to start with and finish with.