Why does DPS use a Carbon Pre-Preg?

[MontuckyMadman]

It's not a precure so its not pretensioned.

Is it because the layup and wet out of all that carbon is tough to get penetration so they prepreg and keep it cool prior to layup?

It would make sense if it was precured and tensioned but I guess I don't understand these details really.

Does this increase strength or does it just create a more stable laminate?

What type of advantages does prepreg give you?

Is it a dampness thing over a standard layup? Doubt it.

Not that I am considering this for my homebuilds but is this all marketing BS?

Perhaps this prepreg is able to offer a stiffness profile and increase rigidity without sacrificing additional weight?

out of box comments welcome and telling me I have no idea how this technical shit works also welcome.
I may beat you down the mountain on a powder day however.

[Alex13]

From my extremely limited knowledge, using the prepreg method of layup reduces resin waste, tends to be much lighter and has fewer cavities (pinholes) in the resin. They require high pressure and/or temps to cure, usually an autoclave.

-edit- For homebuilding, I'd be surprised if you could do it at all, and if you could, not to any great effect. The main reason a manufacturer may do it would be weight saving due to less resin.

[twizzstyle]

Alex got it spot on. Prepreg composites just have the optimum resin-to-fiber ratio, so you'll save on weight. It's unrealistic for a homebuilder, it's expensive and you need a large freezer to store it in. I did a few layups back in school with prepreg carbon and the stuff is awesome, but for what we do wet layups are good enough.

[MontuckyMadman]

so its a cost saving method? Seems strange. I have a big freezer for meat.
I said og that I was not planning on doing this but now that you guys tell me I can't, makes me want to do it.

I know they are not cooking the skis in an autoclave.

[twizzstyle]

now that you guys tell me I can't, makes me want to do it.

Hahahaha, that's how I got into this whole ski making nonsense! That's how most of my projects start actually...

Prepreg is not a cost-savings, it costs much more than wet layup. What you lose in cost, you gain in weight savings and strength/durability. For an airplane - important. For a ski? Eh... over the top in my opinion.

[twizzstyle]

I know they are not cooking the skis in an autoclave.

Autoclaves are only used when you are vacuum bagging things It's irrelevant if you're doing a pneumatic compression press.

[falls]

Prepreg gives a cleaner layup process than wet layup too?

[skidesmond]

now that you guys tell me I can't, makes me want to do it.

Hahahaha, that's how I got into this whole ski making nonsense! That's how most of my projects start actually...

Prepreg is not a cost-savings, it costs much more than wet layup. What you lose in cost, you gain in weight savings and strength/durability. For an airplane - important. For a ski? Eh... over the top in my opinion.

Same here! Saw a fellow ski instructor w/ a pair of skis from Lightning Boards and said that doesn't look to hard. Ha!

I thought using prepreg also allowed for a faster layup, so you can crank out more skis.

[Damon]

Prepreg:
+ Consistent and optimal fiber/resin ratios
+ Usually higher modulus fiber (for carbon)
+ Higher working temp epoxy
+ Faster production
+ Less chance for voids, contaminates, etc.

- Expensive
- Increased facilities (freezer)
- Working time - for lower temp cure = shorter working time out of freezer

If you can justify it economically and use a heated press, prepregs the way to go. You can get fiberglass prepreg as well - it'll probably be S-glass though.

[MontuckyMadman]

ok makes sense. Any one here of another company using any prepreg stuff? Looks like everyone goes for the wet layup, including dynastar.

If its more consistent and faster than wouldn't the big guys be doing it? or is it the nature of carbon that lends itself to the prepreg as a more viable option?

[doughboyshredder]

ok makes sense. Any one here of another company using any prepreg stuff? Looks like everyone goes for the wet layup, including dynastar.

If its more consistent and faster than wouldn't the big guys be doing it? or is it the nature of carbon that lends itself to the prepreg as a more viable option?

The "big guys" do most everything based on cost. Pre preg is too pricey.

[powderho]

It's painful for me to watch my work throw away thousands of dollars worth of scrap pre-preg material off the cutting table....especially the the uni-carbon. I have a lot of different ideas I'd like to try using uni carbon in my skis. I've been very tempted multiple times to slip in a few ski-shaped patterns into the nests I create. My work doesn't exactly allow its employees to walk out with the scrap material (even though it goes straight to the trash), but the main reason I haven't tested any of it is that it requires a heated cure of almost 400 degrees. I think this is pretty common with pre-preg materials. I would guess it would still cure at 200 degrees, but I'm too lazy and cheap to experiment much with it. Two layers of 22 oz triax glass with some QCM epoxy just works too well.

[Damon]

ok makes sense. Any one here of another company using any prepreg stuff? Looks like everyone goes for the wet layup, including dynastar.

If its more consistent and faster than wouldn't the big guys be doing it? or is it the nature of carbon that lends itself to the prepreg as a more viable option?

The "big guys" do most everything based on cost. Pre preg is too pricey.

Yeah, when we're talking a few bucks to make or break a model, it's tough to justify. I bet a lot of it is that they are stuck in their ways too, they've got the process down for wet layups, it would probably cost them a couple hundred thousand to convert over to prepreg - and I'm just talking process changes/training, not facilities.

powder, where do you work? They need to invest in an automated tape layer....

[feldybikes]

The following comment is entirely opinion without all that much real knowledge, but I gotta believe that on some level, the prepreg stuff from DPS is marketing. Now, I didn't say marketing BS. I buy the opitimum resin ratio blah blah, but I also figure that if the carbon manufacturer can get the right ratio, then someone down the supply chain can get the right ratio as well. Perhaps this is my misconception, but I don't think the resin is added exactly as the sheet of carbon is made. So, I figure if DPS were a big enough company and could invest in the right tooling, that they could buy regular sheeting of carbon and put in the perfect amount of resin themselves. They can't, so they spin their additional small-company expense as doing the best thing in the industry. Or something like that.

[twizzstyle]

There are only a few manufacturers of carbon fiber, and pre-preg carbon fiber in the world. The process isn't something a company can just pick up. There is a world-wide shortage in carbon fiber because most of is bought up by the aerospace industry (mainly Boeing and Airbus), that's why its so expensive. 10 years ago carbon fiber was not as expensive as it is now, thats just when I was getting into composites, now it sucks But of course now I work for one of the aforementioned aerospace companies so I can't exactly complain