Ski Builders Forum

if you don't mind me asking... where did you get your titanal???

cheers
billl

Chubz,

I've been away product testing (otherwise known as skiing the spring corn). I agree with many of the responses above regarding the results of your test samples, but I'll add just a couple of things. You mentioned that you didn't scuff the base material on your test piece, then later indicated that you planned to do that on the next test. That leaves me wondering which side of the base material you bonded in your test... was it the smooth side, or the dull/rough side? It should have been the dull, rough side which has been prepped for bonding (abraded and flame treated) at the factory. Also, you shouldn't scuff the dull side of the base material because the flame treating is only a few molecules thick, and scuffing the surface will result in removing the flame treatment. At the factory, they first abrade the base material surface to increase overall bond surface area, then they flame treat the abraded surface to increase the surface tension for improved bonding. Flame treatment is more important than abrading in improving bond strength, so you don't want to scuff it away.

Titanal, or any other aluminum alloy, oxidizes very quickly... like in seconds... so you have to be quick in getting your treated titanal covered with epoxy. There's tons of info on the web regarding bond surface prep techniques for aluminum, both physical and chemical.

Thanks for sharing your initial test results and I'm looking forward to hearing how the next test goes.

G-man

Thanks

Bill, if you read earlier in the thread , I share why I cant reveal my T source. I wish I had a stack in my garage to share, but my resource is even a delicate scenario.

G-man
Wow I figured the pre-scuffed side is the exterior of the base, because it looks most like base material of boards I have. You are telling me that the smooth side is the outside that is then sent through a base grinder to create the base pattern?

I will research further for T bonding, it is my biggest challenge right now, besides getting my core profile accurately cut. I have a fairly decent core core cut, but my research has shown that if it is not within 1/100's or 1/1000's of an inch across the board width it can effect the flex characteristics from toeside to heelside. Keep in mind I am building alpine boards, not freestyle, so I am trying to be a bit more concise. Its fun tooling with the micrometer anyway. I just gotta figure out how to take such small thicknesses and get even thicknesses across the core, while also following my tip to tail thickness scales.

Also debating on what weight and weave fiberglass to use. I know glass boards are typically made with 22 oz, but building with T, CF (Uni), create new build characteristics. I have been told with T and CF I wont need a core as thick and the glass wont need to be as heavy, so I am considering something lighter (7 oz.)to put between the CF and T, as I have also been told that CF and T do not work well when directly bonded to each other.

Lastly, now searching how to heat my rib cage press. I know some stuff is out there, but so many variables in building.

If I were single and didnt have my family mouths to feed, I would be going nuts building boards and skis all week long in the evening, but I have to eek my way along on my limited budget.

Heading to the garage to clean it up a bit, prepping for warmer weather.

Wow I figured the pre-scuffed side is the exterior of the base, because it looks most like base material of boards I have. You are telling me that the smooth side is the outside that is then sent through a base grinder to create the base pattern?

Yep, the smooth side gets surfaced on the base grinder (unless you leave it really smooth like I do... then you never have to wax). Just be sure to give the factory treated side a quick wipe with acetone right before lay-up.

G-man

Guys

Just a follow up question regarding bonding. It was mentioned (and to be honest I have only scoped around on the net for an answer and not throughly researched it) that carbon fiber 'cannot/not the best at' bonding directly to a metal layer. Is this due to different contraction properties in relation to temperature?

The second Q is for those members that have used metal laminates. Did you go with a chemical etching solution? How did that work and what are your tips on making a secure bond with metal laminates.

Thanks

SCHÜSS

I think the issues of metal lamination bonding might be titanium specific.
http://www.engineeringtoolbox.com/linea ... -d_95.html

This chart doesn't exactly show the coefficient of thermal expansion for glass reinforced epoxy, but it shows epoxy at 50x10-6 m/m K, lower than most polymers. Fiber reinforcement seems to bring most polymers down to 25-30, so I'd guess cured fg would be somewhere in the low 20's. On the other hand, aluminum is about 22, and titanium is about 8.

I'd guess an aluminum-fg bond would not be put under much stress by temperature change, but a titanium-fg bond would, especially if the skis were, say, cured in a heated press, then skied at subzero temperatures.

It looks like there's some googling in order to find the thermal expansion coefficients of cf in epoxy.

As I recall, the amount of titanium in Titanal is <0.

As I recall, the amount of titanium in Titanal is <0.

which might be why it's more commonly used in ski manufacture, as opposed to titanium.

coefficients of thermal expansion for CF and FG composites in Table 1:
http://www.performancecomposites.com/gr ... nguide.pdf
note the units of in/in-F, as opposed to µm/mm-K from the other link.

So carbon fiber composites have a much lower coefficient of thermal expansion than fiberglass or aluminum/Titanal, and slightly less than titanium. Hypothetically, if thermal expansion was the only issue under consideration, it would seem that carbon laminated with titanium or fiberglass laminated with aluminum (Titanal) are the better combinations.

I've used aluminum for binding mounts in a few pairs now.
Just sand it with 80 or 100 grit just before you lay it in the ski.
Wipe off the dust with a clean rag.
I've washed them with acetone, but don't use it anymore.
Alcohol would probably be ok.
I put a layer of vds above and below.

So far no issues with it.
I'm vacuum pressing with no heat so no thermal issues.
ymmv

sam

Great work guys. You provided me with the information and the answer.

I have ordered Gr2 Titanium sheet at 0.6mm (will document all this when we finally start this build in coming weeks).

So my design is specific to CF/Ti. Not so much GF/FG

So i guess my only drama will be the actual bonding itseld. I am planning to either prep with a chemical etch or acetone with a light sanding. I def will test it first though!

Not much info for the average punter online about bonding titanium. figures aye?

Thank you so much guys

G-man wrote:
Yep, the smooth side gets surfaced on the base grinder (unless you leave it really smooth like I do... then you never have to wax). Just be sure to give the factory treated side a quick wipe with acetone right before lay-up.

G-man

Now that this has been bumped back up, I wanted to note that Acetone should absolutely not be used on flame treated material. It damages the flame treatment on a molecular level. Air and water are all that should be used after flame treating.

(Yes this has been verified by Crown, so it is not just my experienced opinion anymore)

Acetone can leave an oily residue. It's not all created equally, stuff from the bottom of the barrel can be pretty gunky.
Alcohol might be a better bet.
And remember aluminum oxidizes very quickly, not sure about ti.

sam

Strange to choose ti. Let us know. Significant abrasion and mek will clean any metal. Acid etch is pretty nasty stuff, sure it works well.

sammer wrote:Acetone can leave an oily residue. It's not all created equally, stuff from the bottom of the barrel can be pretty gunky.
Alcohol might be a better bet.
And remember aluminum oxidizes very quickly, not sure about ti.

sam

It's not about the residue.

Also, per crown Alcohol should not be used either after flame treating. Water and air ONLY.

I clean all of my pieces with alcohol and then I flame treat them immediately before layup.

doughboyshredder wrote:

sammer wrote:Acetone can leave an oily residue. It's not all created equally, stuff from the bottom of the barrel can be pretty gunky.
Alcohol might be a better bet.
And remember aluminum oxidizes very quickly, not sure about ti.

sam

It's not about the residue.

Also, per crown Alcohol should not be used either after flame treating. Water and air ONLY.

I clean all of my pieces with alcohol and then I flame treat them immediately before layup.

This I know, although it is worth repeating,
The issue with oily residue comes into play when wiping your freshly treated metal with acetone then throwing it into the layup.
Just trying to help avoid costly disaster, ti ain't cheap.

sam