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Base grind alternative?

post #1 of 10
Thread Starter 

Hi guys, 

 

Is this technique a valid alternative to base grinding? Or is it more intended as maintenance between grinds? Also, silly question, but his sandpaper is black; mine is brown. Is sandpaper colour coded and does it mean anything? 

 

post #2 of 10

that concavity is so minimal, ya got the tail wagging the dog in that video. 

 

As long as the ski is flat about 10mm in from each base edge, the ski will ski perfectly. 

 

The point of a grind is to bring the base relatively flat but also bring  base edge back to 0 degrees so you can impart a new accurate base bevel of .5 to 1 degree on the base edge metal. 

 

 

You won't ever see me doing this by hand!

post #3 of 10
Quote:
Originally Posted by Metaphor_ View Post
 

 Also, silly question, but his sandpaper is black; mine is brown. Is sandpaper colour coded and does it mean anything? 

 

 

His sandpaper is probably (didn't recognize the markings on the backing) wet/dry and yours is probably not wet/dry. Yours would be used for - well - wood. And other things too. Wet/dry is used where you need to flush the sanding dust away as you sand, such as color sanding auto paint. I find wet/dry to typically be more durable than the other.

post #4 of 10
Thread Starter 
Quote:
Originally Posted by Atomicman View Post
 

that concavity is so minimal, ya got the tail wagging the dog in that video. 

 

As long as the ski is flat about 10mm in from each base edge, the ski will ski perfectly. 

 

The point of a grind is to bring the base relatively flat but also bring  base edge back to 0 degrees so you can impart a new accurate base bevel of .5 to 1 degree on the base edge metal. 

 

 

You won't ever see me doing this by hand!

 

OK, and would you say you won't do it by hand because a human can't do it as accurately as a machine? The base grinder actually takes off the base edge at the same time to flatten to 0?

post #5 of 10
Quote:
Originally Posted by Metaphor_ View Post
 

Hi guys, 

 

Is this technique a valid alternative to base grinding? Or is it more intended as maintenance between grinds? Also, silly question, but his sandpaper is black; mine is brown. Is sandpaper colour coded and does it mean anything? 

 


This is how I do it.  I also don't come from the "perfect flat" camp.  Some are and some are not.  Slight concave tips and tails engage fast and quick.  Slight convex (boat shape) will be easier and more fun.  They will engage once the ski is tipped up on edge though.
In this case the skis have convex tips and tails.

post #6 of 10
Quote:
Originally Posted by Metaphor_ View Post
 

 

OK, and would you say you won't do it by hand because a human can't do it as accurately as a machine? The base grinder actually takes off the base edge at the same time to flatten to 0?

Yep!  Yes the base grinder brings edges and base flat and level with each other to 0

post #7 of 10

Wet or dry bonded abrasive paper is often black but can be found otherwise.  The abrasive used is Silicon Carbide (SiC) and is favored over Alumina (Al2O3)

When metal is encountered.  Al2O3 is often termed garnet, and is very useful for wood working needs.  (note: Ruby and Sapphire is also Al203 but "dirty" ;-)

 

I can comment from experience,  If one expects to see a visible change in base profile due to the hand manipulation of abrasive paper, one should be very, very patient.

 

The effort goes tediously slow.

 

Add to that the "rounding" effect on the metal edges of abrasive paper backed by any hand held support, and the effort is even less rewarding.

Those fancy "stone grind" ski tuning machines are  real labor saving contraptions!

 

A properly formed burr on a cabinet scraper can move p-tex in good time,  but those metal edges.... opps.  there went the burr!

Jaques,  how do you deal with dull scrapers?

post #8 of 10
Quote:
Originally Posted by Cgrandy View Post
 

Wet or dry bonded abrasive paper is often black but can be found otherwise.  The abrasive used is Silicon Carbide (SiC) and is favored over Alumina (Al2O3)

When metal is encountered.  Al2O3 is often termed garnet, and is very useful for wood working needs.  (note: Ruby and Sapphire is also Al203 but "dirty" ;-)

 

I can comment from experience,  If one expects to see a visible change in base profile due to the hand manipulation of abrasive paper, one should be very, very patient.

 

The effort goes tediously slow.

 

Add to that the "rounding" effect on the metal edges of abrasive paper backed by any hand held support, and the effort is even less rewarding.

Those fancy "stone grind" ski tuning machines are  real labor saving contraptions!

 

A properly formed burr on a cabinet scraper can move p-tex in good time,  but those metal edges.... opps.  there went the burr!

Jaques,  how do you deal with dull scrapers?


I either place them in a vice and run the file over them, or place the file on a flat surface and run the scraper over it.  For the cutting scrapers I sometimes then burnish the edge with one of those rods used for knives.  I forget what those are called.  One can also use a good hard screwdriver shaft in a pinch too.

For my wax removal scrapers I remove all burrs with sandpaper.  I want those smooth as not to affect the base structure.

post #9 of 10

You don't find the base scrapers dulling too quickly when they come in contact with the metal edges?

 

Perhaps " base high", is a more common situation for your methods.  I seem to observe snarfed up and "railed" bottoms as a result of "typical Eastern conditions" .

 

Oh!  With edges that are banged, bruised and rounded over from encounters with infinite exposed ledge. ;-)

post #10 of 10
Quote:
Originally Posted by Cgrandy View Post
 

You don't find the base scrapers dulling too quickly when they come in contact with the metal edges?

 

Perhaps " base high", is a more common situation for your methods.  I seem to observe snarfed up and "railed" bottoms as a result of "typical Eastern conditions" .

 

Oh!  With edges that are banged, bruised and rounded over from encounters with infinite exposed ledge. ;-)


In my video you will see i do a long base bevel first.   This prevents edge contact.  When contact is made, you stop and stone the edge and plastic interface and do a bit more.

In this way once the edge is hit again you hit a smooth edge without burrs.   The video is long, but if you have time take it in.

 

With the wax removal metal scraper it's the same.  You need a smooth edge.  Check this.  It will start at a point you seem curious about.  It will only take a moment for you too see.

https://youtu.be/q-p1vYXQOOM?t=16m34s   

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