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Wax absorbtion of base repairs

post #1 of 17
Thread Starter 
I’m one of those people who likes nothing … well ok, few things, better than tinkering with my skis when I’m not using them. If there are any minor gouges in the base I tend to fill them with a P-tex candle. However it’s always possible to see where the repairs have been made on the base, which got me wondering if the repaired area absorbed wax as well as the original base? If not, I could see an advantage in not repairing the minor damage.


post #2 of 17
P-tex candles are a lower grade of p-tex and can not absorb as much wax and is slower than the normal sintered base on your skis. Not repairing minor scratches is fairly normal, just leave them until your next tune and they will probably end up being ground out.

The other interesting thing about p-tex candles is that they contain a significant (30%-50%?) amount of wax in them, not for speed but to allow them to burn better. The p-tex wire that is extruded out of a p-tex gun is 100% p-tex. But what wax is left in your repair will get sucked out of the base fairly quickly which causes the repair to shrink and fall out.

I don't bother with p-tex candles, if you want to do repairs at home try p-tex tape, 100% p-tex, just iron it in (but it messes up the iron) and it is more permanent than the candles.
post #3 of 17
Thread Starter 
Interesting, thanks. I've only ever used candles and have never had a repair drop out, but I'm fairly careful to clean the area well and provide a good “key” to the new plastic.

Beginning to snow up the road from you so will see you there soon
post #4 of 17
I'm a little confused with all the repair products. I've got p-tex candles, the black tape and also a powder from TOKO which I've used with some success. Does anyone know the advantage of the powder. You sprinkle it on to the section to be repaired, place a plastic film over the top so the powder will not adhere to the iron, then apply the iron and melt the powder into the repair area. Is the powder more akin to the original sintered base? Anyone else use it?
post #5 of 17
Thread Starter 
I've been told the powder is better however I just wonder what it's doing to the base given that there is enough heat there to melt the powder.
post #6 of 17
I don't know much about the powder, I presume it is just standard polyethylene (p-tex). Don't worry too much about damaging your bases with the iron though. Before that happens the repair will bubble and turn sooty (if using clear).

Yeah baby, it's snowing here. We just had a decent southerly front through a couple of days ago and I spent this afternoon watching some very black clouds bearing down on us. Winter is on its way but we have been teased by early snow before and watched it melt away. Fingers crossed for a good season.

[ May 01, 2002, 10:15 PM: Message edited by: kiwiski ]
post #7 of 17
Thread Starter 
Ok, I may try the powder next time those rocks at the top of Hutt rip the guts out of my bases.

Yes I know that image very well. I have my season pass in my hot little hand and intend using it to the max

post #8 of 17
I find that the P-tex candle is most convenient because it goes fast and you can make the repair anywhere, but the material is softer. A P-tex gun (looks like a hot glue gun) is the best since the molten P-tex is easy to control and the material is hard, but you need a power source. A narrow P-tex iron and P-tex tape does the job like the gun, but is trickier to use. I have never tried the powder, and can only assume that a larger area will get the material, and not just the damaged area.

So, to the wax absorbsion issue. Wax is not absorbed into the base as such. It is an analogy used by industry people. There are no tear shaped pores which draw wax in and release wax as friction creates heat. If you look at a new pair of skis, you will see structure line from stone grinding. Magnifiy a lot, and you will see that the base is quite cratered and hairy. The more you wax, scrape, brush and ski, the hairs are eventually shaved off. This leaves the craters on and between the ridges of the structure. When you wax and then scrape, the craters and structure valleys are filled. Brushing with a brass or nylon brush removes the wax from the structure, but the craters are still filled. This results in a smooth base. There will still be a certain amount of surface wax too. Friction of skiing removes the thin layer of surface wax first, and then the craters get emptied.

When you make a P-tex repair (powder, candle, tape or gun), you get rid of the structure where-ever the new P-tex bonds. The new material does not have any structure, and is much smoother than base. Becasue of this, there is no place other than the surface for the wax to fill. You need to get some fine emery paper or wet & dry sanding paper to re-create the original base structure in the repair area. The structure is to prevent suction. Put a drop of water onto a pane of glass and then put another glass pane on. Very difficult to move.

I hope this clarifies things a little.
post #9 of 17
Wax is not absorbed into the base as such.
So, Beta Racer, is it a fallacy that multiple passes with an iron are needed to get wax properly into the bases? I've been waxing my skis for all of 3 weeks now and have been doing the multiple pass thingy. From your description of base structure it would appear that a single, properly done, pass ought to suffice. Thanks.
post #10 of 17
You can iron the wax on, and let it cool, and re-iron. It helps to make sure the craters are filled, which is the important thing.
post #11 of 17
Thread Starter 
Betaracer, you provide a convincing argument about the construction of ski bases, however it goes against everything I understand about waxing. My understanding is that the base is indeed porous hence my question. I am in the process of confirming my understanding from reliable sources, however have included this link as it basically summarises what I understand.

post #12 of 17

What the article calls pores, I refer to as craters. When you think of the composition of the base, think of a large box filled with vaious sizes of balls. Marbles, golf balls, tennis balls. The balls are then placed as tightly together as possible, trying to use the smaller balls to fill voids between the bigger ones. No matter how you try, there will always be gaps, and the suface will never be smooth. Then imagine taking a quick drying lumpy paste (like bread dough) and leveling it over the top of the balls. The paste will fill the voids on the surface of the balls, but will not go further, and will be hindered by the lumps in the paste. Next, smoothen out the surface by cutting off any uneven parts of the hardened paste, to the surface of the largest balls. Not you have a very smooth surface, but it is only very thin. Next you use a brush that is stiff enough to cut through the paste, but will not affect the ball's shape in any way. The brush is dragged unidirectionally across the surface, exposing the surface of smaller balls, and leaving parallel ridges and valleys. one direction is still perfectly smooth, the other is rippled.

That is how the waxed base is at a microscopic level.
post #13 of 17
Thread Starter 
Yes this makes sense and I understand your analogy, however if the base does not absorb the wax why are sintered bases preferred to extruded? One of the advantages I understood was their ability to absorb more wax.

Here is another link I found of interest.

post #14 of 17

Carrying on with the example. The space between the balls does extend into the structure as well. If you would let the paste go in as far as possible on the first application, and then imagine if you could soften it again (like running your iron a second time after the wax has cooled) and being able to force the goo just a little bit further in, you get just that much more in the base. There is only so much that will go in though. If you've ever had to fix a nail hole in a wall, you know that the air in the hole prevents the spackle from going all the way in. The spackle goes in as far as the air compresses, and no further.

That is why sintered bases are prefered, since there is some 'absorbsion' of wax. It is not like a sponge though. Most of the wax remains on the exposed surface of the base, with a very small amount getting into the space between/within the 'balls'.

ANother brief example... Waxing your car. The wax fills the small dimples between the paint's surface molecules. This smoothens the surface.
post #15 of 17
Do this!

Wax your skis. Scrape "Thick".

Place base up in the sun (on a sunny day). i.e. Warm for a long time.

Where does the wax go??

No! The repair area with drip in stuff is "dead" But who cares?

post #16 of 17
The analogy I heard for a base is spaghetti for sintered bases or rice for extruded bases. It is all to do with the atomic length and weight of the polymer chains. The longer the chain the more tangled they get which gives them more strength and abrasion resistance, and makes them less dense and more porous.

Each grade of p-tex can be described by its atomic weight and wax absorption ability. P-tex does absorb wax and good sintered bases can absorb about 20x more wax than ordinary extruded bases. There are tables from tests where strips of p-tex have been dipped in molten wax for a couple of minutes and it does vary quite a bit and is due to more than just surface wax.

If you were really interested to see how much wax can go into a base the test would be to accurately measure the weight of a block of wax, then use it to wax a new set of skis then scrape. The difference in weight from before to after(including scrapings) would be how much wax was left in your base.

CalG - I have actually done that before and it gave a really great result.
post #17 of 17
Thread Starter 
Thanks gents, that pretty much confirms what I thought.
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