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Rounded base??

post #1 of 10
Thread Starter 
Hope this makes sense since I know crap-all about tuning. I've got about 100 days on a set of fully cambered Kendos. Since the end of last season, I've noticed a lack of edge hold, even though I've had basic tunes done every 6 ski days or so. During that time, I've demoed a number of hard snow biased skis and noticed how much better they were biting than my Kendos.

After demoing a couple of skis on Monday that gripped very well, I took the kendos out on similar conditions and, by comparision, they skied like a pair of banana peels, less than 3 ski days after a tune. I clicked out of them in disgust.

I took them to the tune shop at Loon, NH and explained this to the guy in charge. It turned out he's a big fan of the Kendos and was pretty keen to diagnose the problem. He performed a $50 tune and worked on them for quite some time. He said the bases were pretty messed up.

He described it to me as sort of a rounding of the bases, which cause you to wash out easily as you try to set the ski on edge. He said the cause of this are a series of poorly done tunes. His customer service was fantastic and I'm really hoping it solved my problem. I won't be able to ski for 10 days or so, so I can't be sure if his solution helped.

Does what he told me make sense? If so, is there a way I can avoid this in the future, besides taking them to a hopefully trustworthy tuner? I've owned alot of skis, and I've never experienced this before. Is there a term for this rounded condition of the bases?
post #2 of 10
What's almost certainly happened is that whoever was doing your tunes does not have a clue what they're doing and made an amateur mistake. My guess is they sharpened your base edge with every time without noticing that edges were getting worn down below their formerly flat surface. That made the bases convex or 'base high,' so the base bevel angle gave you less immediate purchase on the snow. At the same time your side edge angles were probably getting screwed up to because most side angle work is done with tools that use the base as the reference for the bevel

So what your $50 bought you was a base grind and structure and resetting your base and side edge bevels. I paid a lot more to have my skis fixed because I opted for a professional hand tune, but it was worth it for the peace of mind.

I'm astonished that tuning shop staff aren't trained (or maybe don't bother ) to alert the customer that they need a base grind. I'm not sure what's supposed to happen, but you'd think that at some point they'd tell you that your bases needed grinding. Or maybe they should just leave the base edges alone except for repairs, like I try to. At any rate, hopefully both of us have learned to monitor base flatness and avoid at least the shops that messed US up in the first place!
post #3 of 10

Yes what your new tech said is correct.  Stone grinding is your best course of action to remedy base high skis.

 

Shop tuning is all about making the ski look better than before.  The problem is which method the shop uses to process the skis. Sounds like the ski had been repeatedly base sanded.  Which will wear your base edge more than the base.  Most shops don't have modern machinery, and if they do, a stone grind is usually an extra option to the regular tune.  People will opt out of a grind due to the extra expense, but will come to realize (like in your case) that their ski desperately needs one.  

 

Sounds like your new tech knows whats up, and your skis should be way better on the hardpack.

 

If you take your skis into a shop, and the tech doesn't take a good look at them, and check with a true bar during the check-in :  I suggest you either mention any issues you are having, or walk out.

post #4 of 10
Thread Starter 
Thanks guys. It amazes me that the bases can become rounded to the point that the effect on edging was that dramatic. Learn something every day.
post #5 of 10

What do you mean by tune?--the tunes you've been getting 6 days--by my calculations that's about 16 tunes. To me a tune means flatten and structure the base and set and sharpen the base and side edges. The shop will usually wax as well. If you did that 16  times there wouldn't be any ski left. Flattening and structuring (grinding) the base yearly should be plenty. In between just sharpen the side edges and wax. The base edges should only be done after the base has been flattened--otherwise you will wind up with exactly the condition you are describing. Every time you sharpen the base edge you increase the distance from the edge to the snow, making it harder and harder to engage the edge. It's ok to very carefully file down any burrs that stick down below the base edge that aren't removed after sharpening the side edges, but the base edge itself shouldn't be touched.

post #6 of 10
Thread Starter 
Quote:
Originally Posted by oldgoat View Post

What do you mean by tune?--the tunes you've been getting 6 days--by my calculations that's about 16 tunes. To me a tune means flatten and structure the base and set and sharpen the base and side edges. The shop will usually wax as well. If you did that 16  times there wouldn't be any ski left. Flattening and structuring (grinding) the base yearly should be plenty. In between just sharpen the side edges and wax. The base edges should only be done after the base has been flattened--otherwise you will wind up with exactly the condition you are describing. Every time you sharpen the base edge you increase the distance from the edge to the snow, making it harder and harder to engage the edge. It's ok to very carefully file down any burrs that stick down below the base edge that aren't removed after sharpening the side edges, but the base edge itself shouldn't be touched.


 




By tune I mean a quick wax and sharpen the edges at the mountain. These usually cost between $25 and $35 where I ski.
post #7 of 10
Quote:
Originally Posted by ed_d View Post
 
Quote:
Originally Posted by oldgoat View Post
 

What do you mean by tune?--the tunes you've been getting 6 days--by my calculations that's about 16 tunes. To me a tune means flatten and structure the base and set and sharpen the base and side edges. The shop will usually wax as well. If you did that 16  times there wouldn't be any ski left. Flattening and structuring (grinding) the base yearly should be plenty. In between just sharpen the side edges and wax. The base edges should only be done after the base has been flattened--otherwise you will wind up with exactly the condition you are describing. Every time you sharpen the base edge you increase the distance from the edge to the snow, making it harder and harder to engage the edge. It's ok to very carefully file down any burrs that stick down below the base edge that aren't removed after sharpening the side edges, but the base edge itself shouldn't be touched.

 




By tune I mean a quick wax and sharpen the edges at the mountain. These usually cost between $25 and $35 where I ski.

The only way that kind of a tune would be mess up the bases is if they are sharpening the base edges, which as I said they should not be doing. The only thing they should be doing to the edges is hand sharpening the side edges. Even if they don't touch the bases running the skis through a machine that often is not going to leave much edge. Suggest you talk to the first shop and find out exactly what they are doing and how. Better yet get an edge guide and spring clamp, a couple of diamond stones, a wax iron, some universal wax, a scraper and a brush and do it your self. A vice is nice but can be done without if you are resourceful. And a couple of heavy rubber bands to hold the brakes out of the way. People use old clothes irons, but you have to be very careful to avoid burning the bases. Lowest setting that will melt wax, and make sure the temp selector doesn't move. You'll pay for that stuff very quickly. Even if you just buy the edge guide and stones and let the shop do the wax you'll come out way ahead. 

 

I have my rock/groomer skis ground and shop sharpened about once a year, because they get very beat up and because the tune matters most on hard snow. My off piste skis I have ground when they look like they need it, no more than yearly and often less (haven't gotten to use them much the last three winters here).  If you want to get scientific get a true bar or other accurate straightedge and have the bases ground if they're not flat across. Bases that are high in the center will be hard to edge, bases high on the edges will be grabby and hooky. Scratches that don't expose the core don't hurt anything.

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

The only way that kind of a tune would be mess up the bases is if they are sharpening the base edges, which as I said they should not be doing. The only thing they should be doing to the edges is hand sharpening the side edges. Even if they don't touch the bases running the skis through a machine that often is not going to leave much edge. Suggest you talk to the first shop and find out exactly what they are doing and how.
"Should" being the operative word. I'm not going back to the culprits who made my skis all wonky to ask them what the hell they were thinking as they wore my base edges down. I've voted with my feet and my checkbook. Mostly my checkbook, actually, because I'm a tool slut. Some women buy jewelry or shoes or jackets; I slaver over files and clamps and gee, I already have perfectly nice Swix aluminum-backed stones, but isn't there some justification for buying a Moonflex stone?drool.gif

Anyway, Ed_d, you might want to toy with the idea of doing your own waxing at least. A decent wax iron costs $50 or so, and there are plenty of excellent universal waxes for normal recreational use, so picking the right wax for the day isn't the big deal it used to be. Add a $3 plastic dropcloth to protect some kitchen chairs and the floor from wax drips, a $5 plastic scraper, a $20 hard nylon brush, and $30 worth of all-temp wax, and for less than $100 you're in business to zoom past your friends and make them all jealous. Throw in an $8 gummy stone to soften up small burrs and remove rust or corrosion from the steel, and maybe a natural stone to polish up rough spots, and who knows, maybe you'll start thinking about taking charge of your edges. So long as you don't have a household of skis to maintain, regular waxing and basic edge care doesn't take a lot of time, and if you don't blow money on tools the way I do, you will save some scratch that would be better spent on other things.

OTOH, I've been the busy worker bee who thought doing my own ski maintenance was just too overwhelming and time-consuming, and that $30 or $40 (at a good shop) for an edge sharpening and wax wasn't a big deal, so I understand that not everyone has the time or inclination.

Let us know how the skis feel next time out. I'd bet good money you'll be delighted. biggrin.gif
post #9 of 10
Chenzo, thanks for mentioning the bit about base sanding as opposed to base grinding. What are sanders meant to do when used properly? Are they intended to take the base down to allow the edge to be sharpened? Seriously, I'm curious.
post #10 of 10
Base sanders can flatten a ski with proper use, but that is rarely the case. They are mostly used to bevel/clean rust from base edge. They are very good at removing excess ptex from a repair. In the old days they were used to remove structure, and then subsequent final stone grinding. There's generally two types of sanders, one has a bevel plate which can set base edge bevel. The other is a rubber wheel that conforms to previous set bevel. Bottom line is that if your shop uses a base sander in their tune, make sure they finish with stone grind.
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