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P-Tex

post #1 of 11
Thread Starter 

I have noticed a difference in the decline in quality of P-tex material lately. It doesn't seem to blend in with the base anymore. I've used many guns and a lighter and a torch and welders, Now they have the soft stuff and the hard stuff, but its not the same as it used to be. Is there a definite way to know what Type of P-tex I'm getting, I used the thin Montana thread for finish and the thick thread for metal, but still unhappy with the results. I grind after the repair too. It used to be that you couldn't even notice the difference. Sticks seem to be worthless now. Any comments or similar experiences? I've also worked on Many different skis with different base materials and base qualities and still noticing the difference.

post #2 of 11

HiTunes, shouldn't you be getting the info/answers from your suppliers?

 

The "Montana thick thread for metal" that you refer to, is that another name for Metal Grip?

post #3 of 11
Thread Starter 

It seems to be more at the manufactures level. It would be nice to know what grade P-tex I'm getting so I could order the same each time.

post #4 of 11

I've noticed the same thing.

The molecular weight of the repair stick I recently used was so low it might as well as been wax.

post #5 of 11

I found the Holmenkol repair strips are better than using the repair rods for use with the Repair gun.

post #6 of 11
Thread Starter 

That seems like a step in the right direction, I'll probably try it next year. I guess I missed the story on the fx smartbase technology. I'm Gonna start a new thread on that. It seems like the same technology as plastic skating rinks. I used a special stick about 3 years ago, it was small and had a charcoal look to it. It did a good job, but I don't know what is was. I'm worried that when they change the name of the type of p-tex it will be near impossible to find the same thing.


Edited by HiTunes - 4/16/13 at 7:16pm
post #7 of 11

I believe you will need a "Smartbase" specific repair strip to repair FX-Smartbase, the normal "ptex" repair material doesn't work with Smartbase.

post #8 of 11
Thread Starter 
That's ok, so far I havn't seen any people with that base its good to have though but I am looking for a really good ptex for regular bases, but the new smartbase ptex may make a good repair for regular bases, ill have to try it next year. It just seems that its hard to find a quality ptex and its difficult to identify what "blend" of material it is in order to keep getting good ptex. I Think you are right about Holmenkol it looks like good stuff. On another note, Has anyone ever melted/dripped in sintered base patch material to do a ptex repair. I know that's not how its meant to be used and I'll lose the sintered base properties, but it may work, at least better than the current ptex i've seen around lately?
Edited by HiTunes - 4/17/13 at 10:36am
post #9 of 11

I'm sure you're aware of this, but...

 

Melted repairs (whether via iron, gun, base-welder, or the shop's poly-jet machine) inherently consist of the equivalent of extruded material. Even if the repair stick starts out as hard sintered material, the act of melting it changes the amorphous:crystalline phase ratio to basically that of extruded material. The result is that the repair will always be softer than the surrounding sintered base material, and it typically won't absorb wax or "take" structure from stone grinders very well. It will also tend to be eroded by scotchbrite/fibertex and some stiffer brushes. I've noticed these issues at basically constant severity for the last ~20 years, and there is really no way around them with "hot" repairs.

 

My guess is therefore that the repair material itself didn't change all that much, but the base material of the skis evolved. I don't think that FX-smartbase is common in skis yet (its main claim to fame is durability rather than speed, so it's more popular with the jibbing snowboarder crowd; It certainly hasn't shown up in racing skis that I know of) but sintered polyethylenes have improved quite a bit over the years. Did you actually try the old and new repair materials side by side on the same ski?

 

If you want a repair that matches the properties of a ski base, then you need to do an inlay patch instead of a hot repair. The way you do that is to:

 

1. Use a template (basically a cookie cutter) to cut out the sintered base material around the damage, all the way to the ski core. Thoroughly clean with solvent and lightly sand the exposed core/edge material.

 

2. Use the same template to cut a matching piece of sintered P-tex (you can get both templates and sheets of sintered P-tex from Slidewright/Tognar/etc). If you're obsessive like me you'll cut the inlay piece a bit big and sand the edges to exactly match the hole you made in step (1). A belt-sander is a big productivity booster here.

 

3. Glue the inlay piece from (2) into the hole from (1) with 24-hour Hysol epoxy (also from Slidewright/Tognar/etc). Clamp the repair with a rigid plate and moderate pressure and allow it to cure. Excessive pressure here will drive all of the epoxy out from under the patch and compromise the repair. A hot-box is a big time saver since heating to ~140F reduces the curing time of Hysol to 2 hrs (I actually do 130F for 4 hrs as that's my "never exceed limit" for skis).

 

4. Take the patch down to the level of the surrounding base using a file, sandpaper, or metal scraper. I use a metal scraper because I've found that does the least amount of damage (hairs etc) to the surrounding base when used properly.

 

The resulting repair has basically the same mechanical properties and robustness to further damage as the original ski base, and the "seams" are no worse than what you get when a manufacturer uses clear P-Tex in the shovel and black material through the ski body.  Don't do this for small scratches - Those don't slow you down much to begin with, so the fix is more harmful than the ailment. I put a lot of pressure on the edges of my skis underfoot (high turning forces on hard snow) so I've found that I always end up inlay-patching core shots in that area.
 

On a related note, am I the only one who finds the explanation of FX-Smartbase technology here to be a bit difficult to believe:

 

http://www.fx-smartbase.com/technology/index.html

 

They certainly appear to have the mechanics of P-Tex and wax wrong (particularly the big about "making the surface plane"), and that brings the whole exposition into doubt.

post #10 of 11
Quote:
Originally Posted by patrickjchase View Post

They certainly appear to have the mechanics of P-Tex and wax wrong (particularly the big about "making the surface plane"), and that brings the whole exposition into doubt.

 

Do you remember the surface-active "cerax nanowax" products from about 10 years ago?   http://www.azonano.com/article.aspx?ArticleID=615

 

 

 

Nanowax was then taken over by Holmenkol (and the Nanowax name kinda disappeared  from the US market)?  

I think FX-smarbase is a remarketing of that technology, and the mechanics as explained are perfectly consistent with that.   (The mechanics as explained are also perfectly consistent with the behavior of everyday surfactants.)

post #11 of 11
Quote:
Originally Posted by cantunamunch View Post

 

Do you remember the surface-active "cerax nanowax" products from about 10 years ago?   http://www.azonano.com/article.aspx?ArticleID=615

 

 

 

Nanowax was then taken over by Holmenkol (and the Nanowax name kinda disappeared  from the US market)?  

I think FX-smarbase is a remarketing of that technology, and the mechanics as explained are perfectly consistent with that.   (The mechanics as explained are also perfectly consistent with the behavior of everyday surfactants.)


Just to be 100% clear, my specific technical objection is to their description of how wax+P-tex work, i.e. the "before" part of the comparison. As noted in multiple other threads sintered P-tex isn't classically porous, and the purpose of wax is not to "make the surface plane" (otherwise we wouldn't bother brushing wax out to expose structure). When I find somebody botching the parts that I *do* know, that makes me discredit the parts that I don't know.

 

I agree that the mechanics are consistent with the behavior of surfactants, though that doesn't necessarily convince me that the result is a fast base :-).

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