adding base structure

[heferly]

before the spring temps come at us, i figured a discussion could be started on base structuring (i gotta start sooner in the midwest...)

what tips/suggestions do you all have (besides 'get a stone grind')?

there's plenty of methods...skivisions, rillers, edges of mil files, sanding, etc, and yes, stone grinds.

personally, i'd love to get a skivisions, but i'm going to have to wait until the wife approves another tuning purchase...

i've only pressed structure into my bases...definitely does the job, but with pressing, it's only temporary...that's bad and good, as the structure 'wears down' quickly (the bad), but you don't have to worry about flattening and cutting in a structure every time the snow changes (the good)

it'd be nice to know how other methods have worked out for everyone else?

[marshalolson]

what type of ski are you talking about?

alpine fat, race, all moutain, xc classic, skate, etc?

[heferly]

any and all alpine...although not much structure needed for pow....

midwest is getting some pretty heavy (read wet) snow....already thinking about structuring. i press so i don't have to restructure for trips to the east coast, but not sure if one is in the works the rest of the season

[Meathelmet]

And to piggyback on your question : in what kind of snow a coarse structure is a drawback?
I mean,hard ice and racing is kind of obvious,but on fatter skis on which you ski pow and crust etc...does it matter if you have a really big structure?

[heferly]

coarse structure w/cold snow could create static problems...the snow doesn't melt enough w/the lack of friction...not sure what an 'all-around' structure would be

edit: i don't think static would really make that much difference, compared to the suction effect w/warmer, wetter snow, though

[RShea]

There are rillers out there to add structure. Most were designed and used for Cross Country skis. However Red Creek as released a Alpine ski version. It is purchased as temperature specific model.

http://www.reliableracing.com/detail.cfm?edp=11084399

http://www.reliableracing.com/detail.cfm?edp=11084373

There are some other ways to do this also if all you want is to break up a smooth bottom ski- various courseness of sandpaper, various scotchbrite type of pads (industrial versions go much higher than the green commonly sold in a typical grocery or home store.

[marshalolson]

And to piggyback on your question : in what kind of snow a coarse structure is a drawback?
I mean,hard ice and racing is kind of obvious,but on fatter skis on which you ski pow and crust etc...does it matter if you have a really big structure?

yes, if by coarse you mean deep structure. it will make the turn really grabby and hooky and not turn right.

a standard broken linear for basically any all mountain ski in nearly any snow condition works really well. there is a reason it is he defacto pattern used.

[AlpiNord]

Nordic racers have several skis with different grinds to match snow type. Sharper crystals are found with new snow and cold snows. A finer structure is typically desired for cold.

The standard broken linear structure as Marshal stated does work well,



but a more aggressive linear has been my preference for spring skiing and corn harvesting (coupled with some LF over a durable base wax).

A riller tool presses in the structure which requires reapplication and could be a PITA.



A linear structure works very well for wetter snows to channel water. One approach if you apply an aggressive structure and the conditions get dryer and colder is to apply a very hard wax and not brush out the structure entirely.

For the DIYer, the SkiVisions structuring tool works great for applying linear structures which do work well if you use appropriate grit stones. Their are virtually few hairies, unlike sandpapering.



I have an older pair of skis that are very fast and I did all the structuring with progressive sandpapering and made sure to remove the hairs with a metal brush, scraper and fiber pad. Followed by hot scrapes and base saturation.



Here's are Base prep tips section.

EDIT:
Here are Toko's Structurite rollers (nordic) which coincides with their S3 system for temp/wax colors: blue (cold), red (mid range) & yellow (warm)

[heferly]

A linear structure works very well for wetter snows to channel water. One approach if you apply an aggressive structure and the conditions get dryer and colder is to apply a very hard wax and not brush out the structure entirely.

good to know...one of the main reasons i haven't tried anything but 'pressing' the structure in.

how bad are the ptex hairs with progressive sanding? seems like the cheapest option to attempt a new method of structuring (and one i've pondered many times). i assume pretty time consuming...

would you then need a stone grind to bring back a finer structure to prevent overworking the base?

edit: i've also heard mixed reviews on using the side of a mil/bastard file...cuts the structure in, but i would think base edge damage is probable

[AlpiNord]

good to know...one of the main reasons i haven't tried anything but 'pressing' the structure in.

how bad are the ptex hairs with progressive sanding? seems like the cheapest option to attempt a new method of structuring (and one i've pondered many times). i assume pretty time consuming...

would you then need a stone grind to bring back a finer structure to prevent overworking the base?

edit: i've also heard mixed reviews on using the side of a mil/bastard file...cuts the structure in, but i would think base edge damage is probable

Bases are just plastic and like wood, there are a lot of methods to abrade/tear/cut/scratch/grind the material, including metal file edges. Depending on how the base is textured, hairs or filaments of plastic will remain. These create drag and need to be removed. 60 grit sandpaper can abrade the bases very quickly. Following with finer sandpaper, scraping, brushing and fiber pads to mostly remove the hairs can take a while but is very straight forward and low tech.

A file edge is probably less forgiving as you noted, but as long as you are careful, you may be able to achieve an aggressive linear structure. You can always add more later if you want to start easy. You can skiver/scrape and remove coarser structure, but a base grind may be better to get you back to a finer, uniform structure, IMO.

The SkiVisions base planer lets you micro manage and minimize the amount of base material removal which includes the wax that needs to be re-saturated into the base after grinding/base removal tasks.

[heferly]

how well do the skivisions ruby stones create structure? (personal experience?)

seems like the perfect all around tool for flattening and structuring

[AlpiNord]

how well do the skivisions ruby stones create structure? (personal experience?)

seems like the perfect all around tool for flattening and structuring

See link and image above. Plus another close up:



With the SkiVisions tool, you are limited to varying coarsenesses of linear structure, whereas a base grind (by a competent tech) allows many more options, plus much less effort and time for flattening larger base problems. I have not been able to discern any substantial difference in glide or turning between a base grind and using the tool. YMMV.

Base Structuring Decisions

What is structure on a ski base? It is the process of roughening it to reduce surface tension. If your base is very smooth, surface tension, simply put, is suction from a lack of air between the base and the snow, which slows its glide. Very smooth bases tend to be very slow bases.

As a general rule, you want to use the most coarse structure to minimize surface tension, rougher surfaces have less surface tension. However, it isn’t that simple. New snow crystals are sharp and will dig into a coarse structure causing considerable drag. The rules need to be followed:

1. In new, cold snow the structure needs to be fine, the newer and colder the snow, the finer the structure.

2. As snow gets older, the crystal points start breaking down, so you can then go to a medium structure.

3. As snow goes through multiple freeze and thaw cycles the crystals loose their sharpmess and therefore a coarse structure works best.

A simple rule to follow is to use fine and medium stones in early and mid-winter, medium and coarse structures in late winter and early spring, and extra coarse in spring

Even though there are four Ruby Stone Blade levels of coarseness, don’t think you are limited to four results. With each blade, the amount of structure is not only dictated by the blade grit, but also the pressure applied to the Base Flattener when the stone is used. The best example is fine grit. If you want a very fine structure, you can achieve that result by using very light hand pressure on the tool with the fine blade, with light pressure you can get a very fine structure, heavy hand pressure gives you a deeper fine structure, you control your options.

FTR, the steel blade and planer also works well to flatten bases, reduce structure, as a true bar and finishing base repairs, plus side wall removal. The stones can also re-texture repaired locations.