Sanding marks show under polyurethane


  #1  
Old 02-16-09, 07:44 PM
N
Member
Thread Starter
Join Date: Feb 2009
Posts: 2
Upvotes: 0
Received 0 Upvotes on 0 Posts
Sanding marks show under polyurethane

I recently applied Minwax polyurethane to an antique dining room table. The instructions said to do a light sanding in between coats with 220 grit sand paper. So, I did. After I put on the 2nd coat of the polyurethane, however, I can see the tiny scratch marks from the sand paper showing from underneath the polyurethane coat. I now have learned that this is probably because I either pushed too hard during the sanding, or maybe because I used a circular motion instead of going with the grain of the wood. Although I'd like to know why it happened, I'm now more concerned with what should I do to fix it?
 
  #2  
Old 02-17-09, 03:53 AM
M
Forum Topic Moderator
Join Date: Mar 2005
Location: USA - N.E.Tn
Posts: 45,774
Received 870 Upvotes on 761 Posts
Welcome to the forums!

When sanding stained/natural wood, you always want to sand with the direction of the grain!

The only way to fix it is to sand off the last coat of poly and sand out the scratches.
 
  #3  
Old 02-17-09, 06:03 AM
fewalt's Avatar
Member
Join Date: Feb 2001
Location: sw VA
Posts: 3,022
Upvotes: 0
Received 0 Upvotes on 0 Posts
Apply another coat after sanding with 400 or 600 paper. You can even use steel wool between coats unless you're using waterbase poly.

fred
 
  #4  
Old 02-25-09, 07:47 PM
N
Member
Thread Starter
Join Date: Feb 2009
Posts: 2
Upvotes: 0
Received 0 Upvotes on 0 Posts
If I try to sand off the last coat of polyurathane, will I be in danger of sanding off the stain? I really don't want to have to re-stain the table.
 
  #5  
Old 02-25-09, 08:16 PM
fewalt's Avatar
Member
Join Date: Feb 2001
Location: sw VA
Posts: 3,022
Upvotes: 0
Received 0 Upvotes on 0 Posts
You simply cannot sand off one coat of poly!!
Sand lightly with a fine grit paper. Apply another coat of poly.
A suggestion: thin your polyurethane with about 50% mineral spirits. It will apply easier, it will dry faster.
If you still see sanding marks - do it again.

fred
 
  #6  
Old 02-26-09, 05:27 AM
M
Forum Topic Moderator
Join Date: Mar 2005
Location: USA - N.E.Tn
Posts: 45,774
Received 870 Upvotes on 761 Posts
You need to sand until the scratches are gone. Hopeully this won't get you into the stain. After sanding, wiping the wood with a damp thinner rag will let you know if the scratches are gone. The wood, wet with thinner, mimics what the wood will look like with another coat of poly.
 
 

Thread Tools
Search this Thread
 
Ask a Question
Question Title:
Description:
Your question will be posted in: