Flat bases

[backyardskier]

After a basic clean up I take my skis to shops to have them work on the bases and edge. Each shop I have been to tells me that they had to spend a good amount of time grinding the skis in order to get them flat. I have been trying to improve my techniques to get a better ski, but still keep hearing the same thing. The mold is flat, the cores are rabbeted, the bases arent warped and the edges are locked down nice and smooth. The only thing I can think of is that I'm using a vacuum press which is leaving behind little pockets of epoxy. The skis do come back from the shops completely flat but I want to go in with a near flat base, any ideas or tips for this?

[pmg]

Is your fibre layup symmetric? Same fibres below and above core?

[backyardskier]

Is your fibre layup symmetric? Same fibres below and above core?

Yes using a 22oz glass above and below.

I was thinking a little more about it, and I think the problem might be I'm not doing anything to the bases before I take them in. I'm leaving on the epoxy that was pushed through the gap on the tape for the edges. Next time I'm going to do a light sand on those spots and see if that helps.

[vinman]

Most shops are not used to grinding skis with an unfinished base, of course it take longer/more passes than a pre-finished ski.You will need to do a bit of grinding to get them flat no matter what.

I usually spend 30-45 min per pair. Also depending on how new their sanding belt is it could take longer if the belt is getting dull.

Try putting a true bar on your base prior to grinding to see just how good you did. It will give you an idea on where the inconsistencies in your molds are and how much grinding will be needed.

Also if possible see if they will let you watch them grind your stuff. You'll lest something about how flat things are from seeing what spots require more grinding.

[backyardskier]

Most shops are not used to grinding skis with an unfinished base, of course it take longer/more passes than a pre-finished ski.You will need to do a bit of grinding to get them flat no matter what.

I usually spend 30-45 min per pair. Also depending on how new their sanding belt is it could take longer if the belt is getting dull.

Try putting a true bar on your base prior to grinding to see just how good you did. It will give you an idea on where the inconsistencies in your molds are and how much grinding will be needed.

Also if possible see if they will let you watch them grind your stuff. You'll lest something about how flat things are from seeing what spots require more grinding.

I always take a flat edge to clean spots on the bases after they are out of the press. They are pretty flat each time. Next time I'm going to see if I can stand around and watch to see what is going on when they run them. But they all turn out flat after they are tuned so I must be doing something right.

[pmg]

I always take a flat edge to clean spots on the bases after they are out of the press. They are pretty flat each time. Next time I'm going to see if I can stand around and watch to see what is going on when they run them. But they all turn out flat after they are tuned so I must be doing something right.

Did you control the flatness or do they just look even? Depending on their machines and settings they can grind with very high pressure and just press everything uneven flat on the stone.

Many (probably all major ones) ski companies do this in their factories. Pressure, Pressure Pressure. Lowers machine time. Especially one Austrian company is reeeeeally good at making concave tips and tail, sometimes around 0.5mm off. So the have to use a lot of pressure to get a nice even grind on the base.

But the most important thing is: If the grind feels good for you everything is alright.

BTW: I have the feeling that our homemade bases have about the same flatness when fresh out of the press as commercial ones. We just notice our uneventies much more because we take a close look.

[backyardskier]

Did you control the flatness or do they just look even? Depending on their machines and settings they can grind with very high pressure and just press everything uneven flat on the stone.

Many (probably all major ones) ski companies do this in their factories. Pressure, Pressure Pressure. Lowers machine time. Especially one Austrian company is reeeeeally good at making concave tips and tail, sometimes around 0.5mm off. So the have to use a lot of pressure to get a nice even grind on the base.

But the most important thing is: If the grind feels good for you everything is alright.

BTW: I have the feeling that our homemade bases have about the same flatness when fresh out of the press as commercial ones. We just notice our uneventies much more because we take a close look.

The shops I go to all use machines like this
But yeah the skis are coming back with dead flat bases. Sounds like it is normal for them to take a while to get there and I shouldnt worry.

[vinman]

I'm grinding on a grind rite belt/stone combo and it takes a while. The advantage to bring write is I can do some places by hand as needed if some areas need more attention than others. But yes it takes at least 30 min to do a pair 45+ with a worn belt.

Does that Wintersteiger have a belt or is it just a stone?

[pmg]

These Robots are available in almost any configuration you like, w/o belt, 2 Stones, automatic waxer and and and...
This one should be a nice video of one of the many Wintersteigers
https://www.youtube.com/watch?v=ba_dBMnNb9M

@backyeardskier: Then you definitely got a good ski service station :) As far as I can tell from the way the grind looks, the manufacturers mostly use Wintersteiger, but definitely with a different setup (much more pressure).

Cheers