GET GOOD LIGHT
Always try to use good backlighting when checking bases with a true bar, otherwise
it'll be hard to read accurately. A bright window, fluorescent overhead light,
or even a light bulb (60 watts or equivalent) positioned a foot or two beyond
the ski or snowboard tip will do the job.
TRUE BAR
TRICK
When checking for flatness on a clear p-tex base that you suspect is
concave, it is sometimes hard to determine if the light under the true bar is
from the concave area or just light reflecting through the p-tex. Try placing
the true bar in the middle of the base, parallel to the edges, and then slowly
rotate the bar 90 degrees until it sits across the width of the base. If the
base is flat, the true bar will rotate smoothly...but if it is concave, it will
catch on the edges of base material as it turns. Also, ski straps or watch bands
are handy for bundling up excess electrical cords that otherwise sprawl across
your workbench.
-Tim Mochizuki, Gardena, CA
BASE FLATTENING
TIP
When checking for base flatness with a true bar, use a water-based felt tip
pen to lightly mark high or low spots. This makes it easier to pinpoint and
concentrate on problem areas and save base material elsewhere.
-Kirk Carter, Henderson, KY
ROLLING PINS
Ever have problems with your roll pin (used to check for base flatness)
rolling off your workbench or ski? Try dripping a small blob of wax onto the
roll pin at some point...this small speed bump will stop the pin from rolling
away.
-Craig Talarico, Johnstown, NY
TWISTER
Always check skis to make sure they are also torsionally flat and true...you
don' t want a twisted ski because it'll never perform correctly. They traditional
way to check this is to hold both skis base-to-base as lightly as possible (don't
squeeze . em tight or you'll cancel out any twist that may exist). Then check
if the skis contact each other all the way across the base at both the tip and
tail. If so, good....but if not, and the bases rock slightly against one other,
at least one ski is twisted. Another way to check is to hold each ski against
a large flat mirror or window. If each ski sits flat on the glass when lightly
held against it (don't press), then they're okay. If either ski rocks even slightly,
check out another pair of skis because you can't correct this structural problem.
-Mark Sewell, Miwok, CA
TWEAKED
BOARDS
Many snowboards, regardless of core material or construction, will
warp up on the front toe edge and the rear heel edge after being ridden a few
times. This is sometimes unavoidable given the board's width. Always flatten
these bases by hand and follow this natural warpage, otherwise you'll remove
too much base material and affect the board's flex and strength.
You’ve just bought new skis and they look great…the edges shine and the bases are structured and waxed. You can’t wait to launch ‘em out of the start gate.
But are these rockets really ready to rock? Probably not, unless you and your ski shop took time to make sure they’re prepped right to meet your particular needs.
One Tune Fits All?
After construction, new skis are stoneground at the factory before being wrapped, packed and shipped off to shops. This is done to flatten bases and impart a generic structure. They’re also run through a ceramic disc grinder to bevel and polish edges, followed by a quick wax job with a buffing machine.
In short, they’re machine-prepped en masse in a time and cost-effective way, following a formula designed to meet the needs of as many different racers and snow conditions as possible. But will a “one tune fits all” approach give you all the horsepower those skis can really deliver?
In speaking with a handful of top shops around the country, all agreed that you may risk getting shortchanged in performance unless you double-check for acceptable base flatness (not to mention appropriate base structure, and accurate edge bevel angles).
Acceptable Base Flatness
Since the advent of wider shovels and cap construction, skis have more frequently arrived in shops with slightly concave bases (although less occasionally, convex)….especially near tips and tails. This is due to production, design and material challenges, such as: the inherent thinness of tips and tails; molded topsheet ridges, tubes and other design features; diverse expansion/contraction rates of various ski materials; and the way the ski ‘cures’ between the time it leaves the factory and arrives in your local shop. It is unlikely you will get the ski completely flat even after removing excessive material, and the consensus of top tuners is you don’t need to. Try for at least 3/8” (9mm) of base flatness in from the edges and be sure to bevel the edges according skiing type and you’ll be fine.
Flatness Fixes
Convexity, although not so commonly encountered, can usually be completely removed by hand or stonegrinding. Concavity, on the other hand, sometimes can’t be completely removed without also removing unacceptably large amounts of base and steel edge material…especially when it’s 1mm deep or more.
Greg Guras (owner of A Racers Edge in Breckenridge, CO) addresses this conundrum by aiming to get bases flat across 2/3rd’s of the ski width. On a 3”-wide ski, for example, this would mean getting the base flat 1” in from each edge. Jim Deines (owner of Precision Ski in Frisco, CO) and Leif Voeltz (owner of The Fifth Season in Mt. Shasta, CA) try to get bases flat at least ½” to ¾” in along each outside edge. If the ski still exhibits any unwanted edge grab after that, a very small additional amount of base edge bevel (1/2 degree or so) can judiciously be imparted near tips and tails.
Mike de Santis (at Summit Ski & Snowboard in Framingham, Massachusetts, and former World Cup race service technician for Hillary Lindh & Volkl) deals with concavity by first beltsanding bases to slightly remove high steel edges, then stonegrinding with sufficient pressure to counterflex concave base areas until a uniform structure appear across the full width of the ski. While the ski may still remain slightly concave afterwards when unweighted, racers find it feels and performs like a flat ski once they climb aboard.
If you can’t get theflatness you want by hand tools or locally at a shop, you can send gear to one of these shops:
Summit Ski & Snowboard, Framingham, MA
Mike di Santis
www.precisiontuningcenter.com
(508) 875-6905
A Racers Edge, Breckenridge, CO
Greg Guras
www.aracersedge.com
(970) 453-0995
Precision Ski, Frisco, CO
Jim Deines
www.summitactivities.com/ads/precisionSkiGolf.php
(970) 668-3095
The Fifth Season, Mt. Shasta, CA
Leif Voeltz
www.thefifthseason.com
(530) 926-3606
FLAT SNOWBOARD
BASES?
By and
large, many snowboards have convex bases when new. If they're only slightly
convex, they can be flattened by hand or machine. If they're extremely convex,
don't try to scrape or grind them completely flat unless you really want to
see what your snowboard core looks like. Instead, strike a compromise and flatten
it part way...for freestyle riders and spinners, a little base convexity actually
makes the board easier to ride. If you're a racer, however, flat is where it's
at, so shop around until you find a board with a base that looks flat as Kansas.
FLATTENING BASES
ON SKIS & SNOWBOARDS
In the past, the bases of traditional sidecut skis were pretty easy to get flat
from edge to edge with the help of a stonegrinder, wet belt sander, or hand
tools like the base flattener tool, steel scraper or sandpaper and block. But
the advent of snowboards and wider skis has made achieving a flat base more
difficult...and, in some cases, almost impossible. Constructing wide skis as
well as snowoards makes it tough for manufacturers to prevent a certain amount
of warpage from creeping in during the curing process. The result is slightly
concave or convex tips and tails. If this curvature is very slight, it can usually
be removed with base flattening tools...but if more pronounced, it can be difficult
to completely remove without also removing unacceptable amounts of p-tex or
steel edge material in the process. Sometimes you have to accept a compromise
between what's workable and what's wreckable...but still rideable.
BINDING SUCK
Frequently you'll find two concave pockets on the base of a snowboard
that correlate directly to bindings mounted on the top. Commonly known as 'binding
suck', this is a condition created by the binding screws pulling up those sections
of the snowboard. Don't bother trying to sand or stone grind your snowboard
base perfectly flat in hopes of removing this concavity...it'll remove much
too much base and edge material from the rest of your board. Just tune your
bases as though these areas didn't exist...chances are you won't even notice
'em when you're shreddin'.
SKIVISIONS BASE FLATTENER TIP
I have a question about the steel cutting blade on the SkiVisions Base Flattener
tool. When flattening convex (base high) skis, it only comes in contact with
p-tex, which it cuts and flattens pretty easily. But on concave (edge high)
skis, won't this same steel blade contact the steel edges and get dull quick?
What do you do about that?
-Frank Wiles, Pittsfield, MA
Dear Frank-
Good question...and timely, too...since skis these days are wider than ever,
and often come from the factories a bit concave at the tips and tails. Our advice?
First off, check the bases with a true bar, and note any concave sections. Next,
using a flat mill file (or an edge tuning tool with a mill file insert), file
these sections until the edges are at least flush with the p-tex base where
it abuts the steel edge.
Then, bevel the steel edge...a 1-degree base bevel should work fine. Start working
with the SkiVisions Base Flattener, using the steel cutting blade insert...but
not too much! Stop as soon as you feel it trying to bite into the steel edge.
Now, repeat all the above steps as necessary until the edge and p-tex are both
flat for about 1/2" width on each side. If the base is still a litle concave
in the very center, it shouldn't affect ski performance appreciably for recreational
riding.
The best option, of course, is simply to take a true bar with you when you buy
new skis. If the bases are concave, ask the ski shop mechanics to grind 'em
flat before you buy 'em...then it'll only take a little touch-up work with the
Base Flattener to keep 'em flat throughout the season.
BASE SANDING TIPS
You can use silicon carbide sandpaper to flatten p-tex bases. To flatten a convex
(high or crowned) base, start with a coarse (80 grit) paper wrapped around a
sanding tube or block to quickly remove excess p-tex material. Then switch to
progressively finer grits (100, 120, 150, 180, etc.) to finish. After sanding,
be sure to remove p-tex "hairs" on the base by brushing with a brass, bronze
or copper brush...followed by medium and fine scotchbrite or fibertex...followed
by an omni-prep pad. Finish by waxing bases as usual.
You can also structure bases with sandpaper. In general, use a coarser grade
(100 to150 grit) to create a coarse structure (best for wetter snow)...and a
finer grade (150+) for a fine structure (best for drier snow).
LONG SMOOTH
STROKES
A common pitfall that you should avoid when base sanding is a "back
and forth" movement...it results in twice as much sanding in the middle of the
stroke as on the ends. To sand evenly, wrap silicon carbide paper around a sanding
block and use long, one-way, overlapping strokes...always in a tip-to-tail direction.
Start with coarse grit and progressively work up to a finer grit. Be sure to
scrub the bases with a Scotchbrite pad afterwards to remove p-tex hairs created
by the sanding.
EVEN-HANDED
Sanding paper and scotchbrite pads are very helpful for base work, but if you
don't apply even pressure across the full width of the base they can do damage.
If you don't have a sanding block or tube for this, use the wood handle on your
wax brush.
-D. Salera, Mulino, OR
SCRAPING BASES
FLAT
Steel scrapers have long been used to flatten p-tex bases...especially before
the advent of stonegrinders and other new hand tools. They still are popular
among some technicians...although they require more skill to use properly. Two
important tips for using steel scrapers are...1) keep them sharp with a good
burnishing tool...and 2) if you use a thin scraper, hold a file behind it to
prevent it from flexing and cutting unevenly into p-tex material.
SCRAPER SHARPENING
To sharpen a steel scraper, I clamp a lathe file (face up) in my bench vise
so it sits about 1/8' below the top of the jaws. This ensures the edge of my
scraper won't slip off the side of the file as I draw it along to sharpen it.
To keep my steel scraper rigid so it won't flex when scraping bases, I clamp
a side edge file guide (#TEQ-0 for example) to the back of the scraper about
1/4' above the scraper edge with two 1' c-clamps. I leave this on even when
sharpening the scraper with a file.
-Lynn Johnson, Ketchum, ID
LINEAR BASE WAVES
Most commonly found on nordic race ski bases, these are ripples or waves that
appear down the length of a ski base. They can usually be spotted by holding
a ski base up with one end held up to a window or light source, and the other
end held near your eye. They detract from good glide and therefore should be
removed. This can be done by taking your skis to a shop technician who is very
experienced with stonegrinding, or by hand using a base flattener tool, steel
scraper or sanding paper and block...all of which are positioned and worked
at an angle diagonal (rather than perpendicular) to the length of the ski. This
helps remove the tops and troughs of waves or ripples.
GETTIN' RID OF RIPPLES
To remove base ripples that make your skis act funny on snow, wrap
sandpaper around an absolutely flat 10" file. Holding the file at an angle across
the base, pull it in long smooth motions down the base. Then reverse the angle
and pull in the same direction. This will help flatten a base and remove ripples.
-Wina Sturgeon, Canoga Park, CA
DOUBLE UP
Base flatness is critical, yet flat filing is a primary source of convex
bases...even for experienced technicians and racers. The cause is flexibility
of the files, assuming you don't have a better tool for flattening since files
are really best for filing steel edges, not p-tex. Two files together, however,
are virtually unbendable...so I rubber band two files with a wood paint paddle
in between together. The wood prevents the files from dulling each other and
you still have two file surfaces to work with.
-Scott Irving, Cape Elizabeth, ME
MAIL ORDER FLATTENING
& STONEGRINDING
If you can't get the quality flattening or stonegrinding you crave locally,
here're some shops you can send your skis to for quality work. Call them for
details and rates.
Alpine skis
Precision Ski, Frisco, CO Call (970) 668-3095, ask for Jim Deines
A Racers Edge, Breckenridge, CO Call (970) 453-0995, ask for Greg Guras
Nordic skis
Rossignol Skis, Williston, VT Call (802) 863-2511, ask for Jim Fredericks
Precision Ski, Frisco, CO Call (970) 668-3095, ask for Jim Deines
AVOID THE "FUZZ"
Getting bases to glide faster is the perpetual quest of any serious tuner or
racer. One key to this is thoroughly removing microscopic p-tex fuzz or hairs
on your p-tex base. After flattening and/or structuring (whether by hand or
stonegrinder) there are literally thousands of polyethylene hairs left attached
to a p-tex base. To remove these, the base first needs to be lightly scraped
with a sharp metal scraper (Swix's razor scraper is ideal for this). Next, rub
the base with a fine scotchbrite or fibertex pad backed by a rigid scotchbrite
holder or sanding block to ensure even pressure is applied across the full width
of the base. Follow this with rubbing the base with an Omni-Prep pad. But now,
even after all these steps are taken, there may still be some p-tex fuzz left
on the base...whaddaya do?
Ski 'em off! According to the Fischer nordic technicians, the Italian Nordic
Ski Team hires people to ski 30-40km until the bases ski fast. The Norwegians
do the same, but feel it takes more than 30-40km. In any event, the snow abrades
away the p-tex hair and the skis get faster.
REMOVING P-TEX HAIRS
Here is an easy way to remove unwanted p-tex hairs from your ski or snowboard
base after sanding. Take a propane torch with a flame spreader tip, and, using
a soft (cool) flame, make one pass down the base. Keep the flame about 2' above
the base and move it along as if you were painting with a paint brush. The base
will stay cool, but any p-tex hairs will melt into little balls. At this point,
hot wax the ski, let the wax cool and scrape it as usual...the scraping will
completely remove these p-tex balls.
-Ray Yusi, Sherborn, MA
POPPING P-TEX HAIRS
You can sometimes help remove unwanted p-tex hairs after any sanding by hot-waxing
your base with a very cold hard wax (Swix blue or colder). Iron it on just enough
to melt the wax, but try not to heat up the base much. Then take the ski or
board outside to rapidly cool it. This makes the wax more brittle. When you
scrape, p-tex hairs will sometimes "pop" off with the flakes of excess wax.
FINER FINISHES
Although the finished condition of ski and snowboard bases when they leave the
factories has greatly improved over the years, it's still wise to look 'em over
good before buying. Some factories take more time finishing bases than others.
Volkl, for example, runs their race skis through a stone grinder 16 times (at
increasingly finer settings) to produce some of the silkiest bases and edges.
K2, Head and Blizzard make about 12 passes through stone grinders with their
skis, and Dynastar makes 10-12 passes with a belt sander that begins with a
rough 80 grit belt and gradually works up to a smooth 320+ grit belt.
Here's a few quick ways to check the base finish in a shop. First, check for
base flatness (side-to-side) with a true bar...run it down the base from tip
to tail looking for high or low spots, concavity or convexity. The base should
be absolutely flat.
Second, lightly drag a fingernail across the base from center to the edge. Do
this without looking at the base and try to feel any change in the finish when
you go from P-tex to steel edge. Ideally, you shouldn't...the edge should be
polished smooth without striations or roughness left by factory grinding wheels
or sanding belts.
Third, if you have a small hand lens, check the base for the presence of any
loose P-tex hairs...none should be visible (although they may be hard to spot
since the bases were probably buff-waxed at the factory).
And speaking of this, be aware that new skis are only buff-waxed at the factory...not
hot-waxed with an iron. Buff-waxing is fast and convenient for manufacturers,
but does not melt wax deep into the base material, so it wears off very quickly.
Take time to hot wax your new bases repeatedly before taking them out on the
hill.
AFTER THE GRIND
According to World Cup technicians, you'll win or lose a race more
because of the preparation you do after a stonegrind than from the grind itself.
Right before a race, don't go get a stonegrind because your skis will actually
be slower until you've spent enough time fibertexing, waxing, scraping , brushing
and skiing on 'em to achieve a really polished and fast base.
CROSSCUT TALE
I maintain trails in the Sawtooth Wilderness Area and use your snowboard
true bar to check for kinks, bumps, and bends in the blade of my crosscut hand
saws, which must be perfectly straight to glide swiftly through the saw kerf
with a minimum of resistance. Sawing with a well-tuned saw is as elegant a pleasure
as skiing on well-tuned skis.
-C. Jay Dorr, Hailey, ID
WHERE HAVE ALL THE SKI GROOVES GONE?
Only a few alpine or telemark skis are still made with a center groove down
the base. Most manufacturers claim it's unnecessary for recreational skiing
and most racing...unless you ski at extremely high speeds when it helps a ski
track better.
CONSISTENT TUNING
Find a tuning system that you are comfortable with. Create one through the
advice of people who have respectable results, write it down, and follow it
every time you work your bases and edges. Consistency and repetition are the
key factors in World Cup tuning.
-Paul Guimond, Salomon Serviceman for Melanie Turgeon
GETTIN' A GOOD SHOP TUNE
If you take your gear to a shop for tuning, check out the quality of their
work by asking to see other examples of their work...like on a recently tuned
demo ski or snowboard. Check the edges with your fingernails to see how well
it's been filed, deburred, and polished; ask how much the base and side edges
were beveled (and why); check the base with a true bar to see if it's been stoneground
flat, and if the structure is clean and crisp (with no p-tex hairs visible).
The shop tech should also ask you questions...such as where and how well you
ski or ride to determine the best tune, and also inspect your ski or board to
diagnose and suggest appropriate repairs. If you don't like what you see or
hear, go to another shop, or better yet, do your own work at home and get the
tune you deserve.
P-TEX OXIDATION
Dear Tognar,
I have begun to notice areas of oxidation on my ski bases, usually along the
edges. I know I have probably not been waxing enough to prevent this. But I
also can't convince myself as a beginning tuner to scrape the oxidized p-tex
away with a steel scraper, since the bases are already flat in these areas.
Other than a pricey shop stonegrind, do you have any suggestions?
-Greg Still, Radford, VA
Dear Greg,
Sure, there's several home remedies you can try. A light sanding with sandpaper
and a sanding block will do the job, but it takes longest and also creates lotsa
unwanted p-tex hairs. A steel scraper with a sharply burnished edge can be used
with very light pressure to carefully shave the oxidized surface away. The SkiVisions
Base Flattener with a fresh structure stone in it will also do a good job. But
perhaps the safest and most effective tool would be the SkiVisions ski structure/skyver
tool...a few light passes with this will remove the oxidation as well as refresh
the base structure, without creating p-tex hairs or removing too much unnecessary
material.
INNER CORE
Snowboard cores are usually made from wood...about one square foot
(1 foot x 1 foot x 1 foot) of it, in fact, including waste material. It provides
about 25% of the board's structural integrity, with the fiberglass wrap and
topsheet providing 70-75%. Usually the wood core is made of one or more types
of wood with varying degrees of hardness laminated together. These laminates
can be as few as 10 veneer layers, or up to 80. The strength of the board is
found in the glue of the veneers, which is usually a wood glue. Some manufacturers
use soft woods in the middle and harder woods elsewhere...while others use a
medium hardness wood for the entire core. An example of a softwood is aspen;
maple and pine are hardwoods; poplar and spruce are medium. Hardwoods usually
come from older-growth forests, while medium or softwoods come from younger
forests.
denotes a good basic starter tool