dulling planer knives

[Foss]

I have an old Parks 12" planer which I use occasionally to reclaim wood. I have recently tried planing the boards from an old picnic table (redwood
I believe) which at one time had a clear finish. After wrestling trying to get them through the planer I checked the blades and they were pretty badly worn. There were no nails or metal in the wood, but some knots.

Any advise would be welcomed. I currently use HSS blades....would carbide work better. I have ~ 5 more tables that I need to re purpose.

[KingwoodFan1989]

I have an old Parks 12" planer which I use occasionally to reclaim wood. I have recently tried planing the boards from an old picnic table (redwood
I believe) which at one time had a clear finish. After wrestling trying to get them through the planer I checked the blades and they were pretty badly worn. There were no nails or metal in the wood, but some knots.

Any advise would be welcomed. I currently use HSS blades....would carbide work better. I have ~ 5 more tables that I need to re purpose.

How new were the blades before you started planing this batch of boards? Not sure what kind of clear finish would wear down knives. I haven't worked much with reclaimed lumber but I think it's usually the grit that sometimes gets embedded in the surface that wears knives down fast. If there were any giant pieces of metal (which you said there weren't here, of course), you'd end up getting a decent sized nick in the knives rather than just duller knives.

[Foss]

How new were the blades before you started planing this batch of boards? Not sure what kind of clear finish would wear down knives. I haven't worked much with reclaimed lumber but I think it's usually the grit that sometimes gets embedded in the surface that wears knives down fast. If there were any giant pieces of metal (which you said there weren't here, of course), you'd end up getting a decent sized nick in the knives rather than just duller knives.

The blades were fairly sharp before I started. when I checked them they were not only dull but worn down with nicks. Can knots do this to blades................like I said , I checked for metal in the wood and found none?

[Stwood_]

I have an old Parks 12" planer which I use occasionally to reclaim wood. I have recently tried planing the boards from an old picnic table (redwood
I believe) which at one time had a clear finish. After wrestling trying to get them through the planer I checked the blades and they were pretty badly worn. There were no nails or metal in the wood, but some knots.

Any advise would be welcomed. I currently use HSS blades....would carbide work better. I have ~ 5 more tables that I need to re purpose.

Picnic table, being outside, may have had embedded dirt and grit on the surface.
Knots, hard ones, even pine knots, will dull and chip knives sometimes.
Get you an extra set of blades and have the others sharpened

[Foss]

Picnic table, being outside, may have had embedded dirt and grit on the surface.
Knots, hard ones, even pine knots, will dull and chip knives sometimes.
Get you an extra set of blades and have the others sharpened

If it is dirt, grit or knots......do you think carbide would fair better? The HSS blades I used were fairly sharp before I started and by the time that I had run 6-8' boards through on each side I was having problems.

Also, I did see in other posts, that it can be beneficial to take deeper passes........I was taking very shallow passes..........thoughts?

[KingwoodFan1989]

Foss, check stwood's comment here. I think it answers your questions about knots. Plus, his comment that grit can become embedded in the surface of finish (like I pointed out can happen with bare wood that has been reclaimed) could be the answer to the dulling planer knives.

[Stwood_]

Deeper may be better. I've done that removing paint from boards. Scientifically,  I can't really tell you whether it's better or not.
 

I've never ran carbide planer or jointer blades. Cost was an issue there.
I priced em once...and....wow o wow.
  I've always ran HSS blades

[Wild Turkey]

40 grit belt sander would be a good first step. You'll be surprised at how fast it can strip the finish which would also take off the worst of the grit, etc. that's killing your planer blades.

After a little sanding the boards will be ready for the planer

[Foss]

40 grit belt sander would be a good first step.  You'll be surprised at how fast it can strip the finish which would also take off the worst of the grit, etc. that's killing your planer blades.

After a little sanding the boards will be ready for the planer

I was wondering about that. I'll give it a try.

[mike4244]

I have an old Parks 12" planer which I use occasionally to reclaim wood. I have recently tried planing the boards from an old picnic table (redwood
I believe) which at one time had a clear finish. After wrestling trying to get them through the planer I checked the blades and they were pretty badly worn. There were no nails or metal in the wood, but some knots.

Any advise would be welcomed. I currently use HSS blades....would carbide work better. I have ~ 5 more tables that I need to re purpose.

If you have a band saw you can saw off 1/16" or more of the boards. Then run it thru the planer. I did this once with painted redwood from handrails on a cooling tower. Worked well, got 60+ 2x6 's and about the same amount of 2x4's mostly 12'-0" long.
mike