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Sanding Ski Bases - Page 2

post #31 of 46

A little concavetivity also helps skis track straight and not be so squiggly when bombing or coasting across the flats in a straight line. 

post #32 of 46
Quote:
Originally Posted by Xela View Post
 

You guys are great for keeping with this.

 

Primoz, I think the point of turning the little hairs into little blobs is that they're more likely to come off when scraped.  I have no desire to leave them there.

 

While I realize that bases don't need to be 100% flat, I do like to get them reasonably close.  This helps because my sharpening guides index off the base.  Fewer surprises.

 

I really appreciate the guidance toward the metal scraper.  I'm going to spend some quality time getting acquainted with my Sandvik.  I think a metal roto brush may be in my future, too.

 

A lot of people are recommending pads.  Should I be looking at Omni-Prep or Fibertex or some 3M product.  Or are they the same?

 

Finally, I'm not trying to make the skis faster.  I'm just aiming for a known initial state to start the season.

 

Thanks again.

 

Yes, many bevel tools do index off of the base. But unless the glide foot of the tool sits righ in the center of the concavity it is not an issue. If it is an issue I use this

Since it spans the entire base it bridges any concavity. Side bevel is not as sensitive. If your side edge bevel tool sits down in the concave portion you would end up with slightly less than a 3 degree side edge. A 2.75 would be fine. Side edge bevel is not as crucial to be exact as base edge bevel. With base edge bevel .25 of a degree makes a big difference. If you were trying to achieve a 1 degree base edge bevel and you were off by .25 a degree that translates to a .75 mm gap at 60 mm across the skis. this sounds small but makes a huge difference in skiability. Additionally, this "underbevel" assuming the rest of the ski was at 1, will make the ski feel likes it is railed, since the underbeveled portion is in the tip and tail area because of those concave areas!

post #33 of 46

Well, maybe we are all just too orthodox in our approach.  :)  Just because we a lot of us have done it successfully (and professionally/semi professionally/race techs in a lot of cases) without taking a flamethrower to the base doesnt mean it is wrong.  (This comes from the guy that once took an orbital sander to a pair that had seen a lot of rocks :eek - Hint, I never did it again :mad )

 

In fact Xela, I think you should definitely do it, provided  of course that you take a video at the same time and post it here.   Just to make it balanced, you should also take a shot of your daughter's face as you apply the torch to her new skis ....

 

:popcorn

post #34 of 46
Thread Starter 

Zenny, the torch idea comes from here:

 

http://www.tognar.com/base_flat_tips_information_ski_snowboard.html

 

Quote:
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

 

Also, can you help me decide between a steel roto brush and a brass one?  I already have a horse hair for after waxing.  I'm looking for something that will clean out gunk and hairs.

 

Thanks.

post #35 of 46

     Interesting tip......most here would advise more conventional methods that have been proven on the World Cup. What about the flatness...have you scoped them with a true bar yet? This is usually my first or second step when examining a new pair of skis.

 

   Anyways, as for my suggestions on brushes keep in mind that it is very easy to over do it with steel brushes--and especially roto versions. Remember, we want to use light to medium pressure when brushing so that just the tips of the brushes are in the structure and we are not bending the bristles in a heavy handed and/or significant way--90% (my number) of home tuners brush with WAY too much force!! Also, you'll find that the fibertex pads will be key for hair removal/polishing and they should be used in conjunction with metal brushes (see the sweet SVST roto versions I linked previously). 

 

  So, here are my recommendations: look on this page for a very nice oval soft steel/hh brush from beast tuning (I don't usually like Beast, but this IS a nice brush--I have 2) http://www.the-raceplace.com/BEAST-Oval-Race-Brush-System-p/3076z.htm?1=1&CartID=0   This is all the aggressive cutting action from steel you'll need if you use fiber pads. Here's another favorite of mine:

http://www.race-werks.com/svst-6mm-brass-roto-brush-90mm/  Larger diameter than the soft steel oval to work a little higher in/on the base.             

SVST 6mm Brass Roto Brush - 90mm

 

 

 

  A REALLY nice brush for deep cleaning is the Red Creek ultra fine steel roto which should be available here though I can't link directly to the brush itself for some reason  http://www.canadianwintersports.com/index-25Red_Creek%20MAin.html  This is a nice, yet very spendy brush....

 

 

    zenny


Edited by zentune - 9/27/13 at 6:31pm
post #36 of 46

   FWIW, using sandpaper on skis is not quite as evil as it sounds--in fact it is indicated by some WC techs I have learned from. But it is typically reserved for smoothing the structure (knocking down the peaks) upon initial break in, not for flattening. 

 

   zenny

post #37 of 46

Zentune I doubt you got this right, but then again most of people in alpine are much less anal about this then in xc where I spend most of my time, so maybe some people actually do this what you wrote. ;) In alpine, (really fine) sandpaper is used to polish sidewalls after they were done with files and planers, but I, and more or less all my friends who were and still are in WC tech business, have never been doing anything with it on ptex. In xc skiing, where ski preparation is another 10 steps further then in alpine, sandpaper is used for sharpening scrapers and on skis only for preparing kick wax zones on classic skis (for wax to stay longer on skis, or for occasions when you have conditions for waxless skis). Other then this, sandpaper never touches base of skis, since you make skis much slower with this, and if structure is too aggressive, you have other means to do it (plastic scrapers, fibertex...).

post #38 of 46
The net result of all this is a crisis of confidence with regard to my own amateur home tuning skills. (I DO still use a torch on my woodies for the pine tar ... but it's been a while.) Xela, we should invite these guys over for an in-service. I'll provide beer and they can tune all our skis while you and I take notes
post #39 of 46

Quote:

Originally Posted by primoz View Post
 

Zentune I doubt you got this right, but then again most of people in alpine are much less anal about this then in xc where I spend most of my time, so maybe some people actually do this what you wrote. ;) In alpine, (really fine) sandpaper is used to polish sidewalls after they were done with files and planers, but I, and more or less all my friends who were and still are in WC tech business, have never been doing anything with it on ptex. In xc skiing, where ski preparation is another 10 steps further then in alpine, sandpaper is used for sharpening scrapers and on skis only for preparing kick wax zones on classic skis (for wax to stay longer on skis, or for occasions when you have conditions for waxless skis). Other then this, sandpaper never touches base of skis, since you make skis much slower with this, and if structure is too aggressive, you have other means to do it (plastic scrapers, fibertex...).

 

    Hmmmm, well I'm sure you know that not everyone uses the same methods but here's an example of what I was talking about--it's a quote from former WC tech Dave Peszek's website:

 

 

                              "You will need a range of tools – a stiff steel brush, regular steel brush, stiff brass

                            brush, Scotchbrite® pads, and sandpaper (320 or 400 grit wet/dry type aluminum oxide sandpaper). The
                            overall goal is to get the base working for you by making every edge of the micro-structure smooth, not
                            jagged (you are not trrying to erase the structure, just make it faster). The brushes will work the bottom
                            of the structure, the sandpaper the top of the structure, and the Scotchbrite® pads a little bit of both."
                              "Always work from tip to tail, and keep track of how much work you put into each step so you can repeat
                            it on the other ski! If I am trying to smooth out astructure that has tall peaks (record grooves), I will

                            start with sandpaper wrapped tightly around my true bar, working in long smooth strokes from tip to tail.

                            I always brush with a regular steel brush, then stiff brass, then Scotchbrite®. Those three items should take

                            at least 20-30 minutes per pair. When you aredone, perform a good hot scrape cleaning to remove the

                            factory gunk and your own dirt." 

 

 

     You are correct of course that sandpaper is also useful when finishing sidewalls after trimming/shaping....

 

     zenny


Edited by zentune - 9/29/13 at 6:00am
post #40 of 46
Quote:
Originally Posted by qcanoe View Post

The net result of all this is a crisis of confidence with regard to my own amateur home tuning skills. (I DO still use a torch on my woodies for the pine tar ... but it's been a while.) Xela, we should invite these guys over for an in-service. I'll provide beer and they can tune all our skis while you and I take notes

 

   Beer and pizza???:beercheer:
                                                       

 

    zenny

post #41 of 46

Back in the old days we belt sanded instead of stone grinding, as belt sanders were far less cost prohibitive.  Pretty sure WC folks had them by the mid to late 70s though.  After running them across the belt to flatten them we flat filed more to smooth out the grit marks hahaha.  Then, the fine tuning took place.  I still manage all my skis with nothing but files, gummy stones, p-tex, wax, and metal and plastic scrapers... oh and a cork here and there.  However, living in the flatlands my skis never see more than two days between light tuning so there isn't a lot needed ever.

 

Still, back in the day I actually used a hand belt sander to carefully flatten skis without destroying them.  I used belt sanders on furniture for a living back then though..

 

I've really only been teasing Xela here.  A huge joy of being involved in skiing is experimenting with new or different ways to tune up your gear.  In the end it really doesn't matter as long as you're willing to accept that sometimes you may wreck something trying a new approach.  All part of the expense of skiing.

 

I'm pretty sure Xela could afford to buy his kid new skis if it goes horribly wrong and will replace the skis if that happens.

 

Post photos of it when you do it.  Might be a pretty fun "I told you so" for the critics or for the OP Xela..

post #42 of 46

Something not mentioned in this thread is that a flame will oxidize a polyethylene surface.

All the printed polyethylene bottles you see are either flame or corona treated to oxidize the surface so the printing ink will stick.

Oxidizing the surface of a ski base would make it more hydrophilic and less likely to let wax penetrate.

The best way to remove base hair is by waxing and scraping in the opposite direction of the grinding pass.

The wax immobilizes the hairs so the scraper can pull them out..

Try this experiment.

Take a piece of polyethylene and flame part of it and mark across it with a magic marker.

Then try to wipe off the mark with a rag.

You will see a difference between flamed and unflamed plastic.

post #43 of 46

Crgildart I didn't forgot those time. But things change ;) Back in days, when there was no stone grinding machines at all, we all used different things, including sand papers, but that doesn't mean sand paper does same job as stone grinding. Here it's not really about destroying skis. If you do it normally, you won't destroy ski with doing it with sand paper. But skis will be slower. Now if this matter it's up to you. But this basically goes under same category as "we used only non-fluro waxes 20 years ago". And people won all World cup, World championships and Olympics races with non-fluoro waxes, simply because there was nothing else at that time, but that doesn't mean you don't need fluoro waxes nowadays... talking about racing of course not recreational skiing. ;)

Zentune well as I said, people in alpine are much less anal about skis as those who come with xc ski background ;) And then there's huge difference between techs for speed and those who do SL/GS skis, who basically do edges and hardly ever bother much with waxing ;)
 

post #44 of 46

I used to use a propane torch to apply pine tar to my X-C skis many years ago.  Worked great.

post #45 of 46
Thread Starter 

Sorry that I won't have any juicy pictures.  The work was already done when I started the thread.  At this point, they just look like they have a slightly coarse structure.  I'll probably go back and do some more scraping, brushing and fiber-texing.

 

I'm curious about the oxidation idea.  This post suggests it's not a concern:

 

http://www.epicski.com/t/2769/base-oxidation#post_23503

 

In any case, I expect any oxidation to be limited to the surface and easily removed with a brass or steel roto brush.

 

I think it's safe to say that the skis are not ruined, in the sense that my 10-year-old daughter will be able to ski them.  It's not like 120cm skis bought for $180 (with bindings) are a work of art.

post #46 of 46

From my experience, what Xela is doing won't matter much. The bases on those skis are extruded not sintered. $180 kids skis don't come with sintered bases.They won't hold wax. The structure he is putting in them may even help a little.

 

Karl

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