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Do You Have a Carbon Fiber Laminate with Pinholes?

May 09, 2011
Have you ever seen pinholes in a piece of carbon fiber laminate? Pinholes are minor cosmetic imperfections that sometimes occur in gloss panels; they don’t affect the structural characteristics or strength of product. They look just like they sound – like a pin was stuck in the sheet.  A sheet can have one or two, they can be clustered in one spot, or all over the sheet. They’re not noticeable from a distance but if you hold a sheet under a bright light and look closely, you can see them. They can be an issue for any manufacturer making carbon fiber laminates using a vacuum infusion technique.  

What Causes Pinholes?

Pinholes occur as a result of the gases formed during the catalytic reaction between epoxy resin and hardener. In ideal circumstances, the outgassing from the reaction is completed when the resin is introduced to the carbon, producing a perfect high gloss panel without pinholes. However, circumstances can occur in which the chemical reaction not completed when the resin is introduced into the carbon and outgassing continues while the resin is being infused. When this happens, the gas bubbles are trapped on the mold surface and form pinholes.

What If I Have Pinholes?

Maybe it won’t matter for your application – no one will see them. If appearance is important, one common fix is to apply a layer of clearcoat to the sheet – it will fill in the pinholes and they’ll disappear.

Either way, if you’ve purchased a carbon fiber laminate that has pinholes, talk to your supplier about it. We inspect every piece of carbon fiber before it leaves our shop; we don’t ship product with pinholes. Some carbon fiber manufacturers view pinholes as an acceptable part of panel manufacturing, we don’t share that view. To us, they're second quality.

Questions? Comments? Write to us at info@protechcomposites.com.


Carbon Fiber Applications -- Some Do's and Don'ts

Feb 28, 2011
Okay, it’s no surprise that we’re big fans of carbon fiber. It has an impressive list of physical properties and besides, it looks great – especially in a gloss finish. But even we have to admit, there are some situations when carbon fiber isn’t a good fit for the job.

Here’s a short list of “do’s and don’ts” when it comes to using carbon fiber:

DO use carbon fiber for applications requiring:

  • a sleek, high-end look
  • an extremely strong but lightweight material
  • a heat or fire resistant material (low thermal conductivity)
  • limited expansion or contraction in hot or cold temperatures
  • corrosion resistance
  • an ability to withstand a high level of repetitive use or wear and tear

DON’T use carbon fiber for:

  • Projects with potential for high impact damage to the carbon fiber.
    Although carbon fiber is strong, when it reaches its breaking point, it shatters. It’s a potentially dangerous situation you’ll want to avoid.
  • High use applications like kitchen countertops.
    The glossy finish scratches easily and will scuff with constant use unless it’s coated with a very hard clear coat material. Polishes help, but it’ll still be a battle to keep it looking good. Carbon fiber can be used beautifully on kitchen cabinets and desks, but it’s best applied on vertical surfaces that get less physical wear.
  • Don’t use carbon fiber sheets on compound curves.
    Actually, it isn’t possible. Real carbon fiber sheets just won’t bend two ways (front to back and side to side) at the same time. If you have a project that requires wrapping around a complex curve, you’ll need to develop a mold. Carbon fiber fabric is then laid on the mold, infused with resin and heated to obtain a finished product.

If you have an application idea and you’re wondering whether carbon fiber makes sense, just give us a call or drop us an email at info@protechcomposites.com. We’ll be glad to give you an honest opinion about whether carbon fiber’s a good fit for your project.


Colored Carbon Fiber Doesn't Exist

Feb 04, 2011
Sometimes customers call us asking about colored carbon fiber sheets. Can you make it white? How about pink? (Yes, we’ve had that request.)

It’s time to set the record straight. What we call “colored carbon fiber sheets” are really a hybrid –- they’re a combination of carbon fiber and another material, often Kevlar or fiberglass. It’s not possible to make a colored carbon fiber sheet because carbon won’t hold color. The problem is, it’s black and removing its color isn’t an option. To get a colored look, weavers make a fabric combining colored Kevlar or glass fibers with the black carbon.

But be aware of imposters! “Colored carbon fiber” will always have some black tows (or yarns) in it – that’s the carbon fiber.  If it’s one solid color (not black), you’re looking at 100% Kevlar, fiberglass or another material.  It can be deceiving  -- they have the look of carbon fiber, but they’re not.

Recently I saw “carbon fiber” jewelry in solid colors – it had the carbon fiber look, but it definitely wasn’t carbon fiber. Sometimes it matters, sometimes it doesn’t. Either way, it’s better to be an informed consumer and know when you’re getting carbon fiber… and when you’re not.

If you’re looking for the real thing, we stock red and blue carbon fiber/Kevlar sheets in .25mm and .5mm thicknesses. Visit our website for more information on sizes and pricing. If you’d like to order, just give us a call.


Applying Adhesive to Carbon Fiber Sheets

Dec 16, 2010
When a customer orders carbon fiber with adhesive, we provide them a two-sided sheet of adhesive to apply as they wish. One of the most common questions we get from customers is “how do I apply the adhesive to my carbon fiber sheet?”

Our adhesive of choice is a clear two-sided high temperature vinyl adhesive made by 3M.  We like it because there’s no mess, it’s easy to work with and it creates an extremely strong bond.  However, there ARE a couple tricks to working with it.

Here’s how we like to apply adhesive:

  • First, pull the protective paper off the back (non-printed) side of the adhesive sheet.
  • Lay the sticky side down onto the back side of the carbon fiber sheet and press into place.  Apply it carefully – the adhesive is very strong and you won’t have a chance to try again.
  • Gently heat the adhesive sheet with a hair dryer, hot gun, or place in the oven on low heat until warm (or approximately 120 degrees F.)
  • When warm, firmly press the adhesive onto the carbon fiber.  Peel off the remaining paper.  Apply the carbon fiber to the desired surface and press into place.

That’s it! Pretty simple. The heat’s the real secret to creating the best possible bond. Just be careful not to overheat.

Have a question? Drop us an email at info@protechcomposites.com or give us a call at (360) 573-7800.

 

How to Identify High Quality Carbon Fiber Sheets

September 8, 2010 
So you’re in the market for carbon fiber sheets. Maybe you like the way it looks, or you’ve got a project that requires a material that’s strong and lightweight. You’ve looked online and seen the websites selling carbon fiber sheets and you’re ready to pull the trigger. Carbon’s not cheap, so once you’ve made the purchase, how will you know if you got your money’s worth and received a good quality product?

Here’s what to look for:

  • It should lie absolutely flat on a surface. No waves, warping, bends, or creases. Flat!
  • The surface should be as smooth as glass. Sheets with a gloss finish should have a completely smooth, level surface – no bumps, ridges, or fabric indentations.
  • You shouldn’t see any scratches. Not even a little one. No nicks or marred edges either. The standard you should expect for your purchase is “perfect”.
  • You shouldn't see pinholes.If you reflect light off the surface of a gloss finish and you see tiny imperfections as if it were poked by a pin, you’re looking at “pinholes”. They’re caused when gas bubbles are trapped during the production process. One of our competitors states on their website that pinholes are a normal part of carbon fiber sheets that have “optimal resin content.”  We strongly disagree – you should never see pinholes in a top quality carbon fiber sheet. 
  • The backside of the sheet should be slightly textured and flat. There should be no rough spots or clumps from excess resin. These will create visible irregularities when adhering the sheet to another surface.
  • The dimensions should be correct. Cutting tolerances should be no more than ± .125 inch. In other words, your sheet should be within 1/8” of stated dimensions.

If you order a carbon fiber sheet online and it has any of the problems above, consider returning it to the company. By doing so, you hold manufacturers to a higher standard and you’ll get the high quality carbon fiber sheet you’ve paid for!

Tags: carbon fiber sheets, carbon fiber sheet, carbon fibre sheets, carbon fiber panels, high quality carbon fiber