Delamination due to edge material

[Bambi]

I have just been talking to the guys at CDW about their edge material.

They supply 3 types - plain, sandblasted and protected.

According to them poor bonding to the edge material is common and they said that you must always at least use sandblasted edges to create texture to bond to.

Secondly they recommend this coated edge material which is specially treated to improve the bond and prevent rust. Unfortunately the treatment will burn off if heated so you must be able to bend the edges cold.

So:

1) Are the delaminations that people experiance coming from the edge bond? Do you think that bonding to the edge material is a big problem.

2) Is it feasible to bend the edge material round the tips without anealing or is that just impossible!

If bending without anealing is a nightmare then i will just go for the sandblasted edges, but if bending cold is an option then I may try the treated edges.

B.

[littleKam]

I'm not an expert about the sandblasting issue but I've never sandblasted my edges before and they seemed to have bonded well. All of my delamination issues were a result of tipspacer problems.

As for this question:

2) Is it feasible to bend the edge material round the tips without anealing or is that just impossible!.

It's very possible to bend edges without heating them using an edgebender. Here's a simple device we use: http://www.skibuilders.com/howto/equip/edgebender.shtml. It works quite well and saves the fingers!

[Chris Downing]

All I know from the marine industy is a bare metal surface can oxidize in about 30 min.
When I protect a metal keel I will sand bare,
wash degreaser/solvent (interlux 202),
Acid wash (ospho)
and epoxy.
all within the 30 min.

[G-man]

As I have mentioned before, I used to build custom steel bicycle frames. Before painting, each frame would get glass bead blasted. When I first started out, I would transfer each frame from the blaster to the spray booth by grabbing them by the seat tube, just a few inches above the bottom bracket. About 12 months after I sold the first frames, nearly every custormer reported back to me that the paint on their expensive bike frame was blistering on the seat tube just above the bottom bracket. The paint in this area was so "delaminated' that it nearly peeled off in one large sheet. As it turned out, the acids/oils present in the skin in my hands was, over a time period of about 12 months, causing a significant amount of anerobic metal corrosion under the paint. It was immedately obvious what the problem was because I never had any corrosion issues anywhere else. I started handling the frames with clean rubber gloves after bead blasting and never had another problem in 11 more years of building nearly 500 bike frames.

I have a strong hunch that a metal ski edge will behave in a very similar manner over a similar period of time... maybe sooner due to the increased exposure to moisture, road salts, etc. Of course, I could be mistaken about the ski edge susceptibility, but it was no fun stripping and repainting all of those bike frames. So, I always sandblast my metal ski edges after bending, and then, only touch them with a gloved hand.

I hope to try a certain company's primed edges, but they've not been able to get my order right in about 4 months now. Fortunately, patience is one of my stronger virtues.

G-man

[kelvin]

I think the metal/composite bond is a big problem. On our skis, if they delaminate, they start at the edges (usually right at the end) and spread to the tipspacers. Once you get a little separation started, it's easy to get water, snow and dirt in there opening it up even further. It's hard to tell exaclty which bond is weaker, the tipspacer or edge. I'm leaning towards the edge though. Most likely it's a combination of the two. We are using the sandblasted and protected edges. You can use an edge bender, but it can only do large radius bends. If you want to bend around the entire tip or tail, you'll probably have to heat it.

After bending, I wipe the edges with acetone really well and minimize bare handed handling. Right before layup, I'll wipe down the whole edge and base with acetone again.

I working on getting a sandblaster, and hopefully it'll solve some of the bond issues.

-kelvin

[splat]

VDS rubberfoil is the key to bonding edges and, many times, tip insert material. Forget vibration. It's the necessary bonder for the resin to metal interface. Our delams have been occurring because of the heat generated on the edges when sanding our bases flat. Gotta have a light touch and some emulsion in the sander water to do it without creating a bond-melting heat on the belt.