Can you fill holes in Carbon Fibre?

One of the biggest issues you may encounter when carrying out any composite work are the dreaded ‘pin holes’, minuscule imperfections in your surface finish that will drive any perfectionist crazy!

The simple answer to the question of whether these holes can be filled is yes, it is possible to fill the holes and make them virtually disappear. But as with everything related to composite work it takes time and a great deal of patience and attention to detail to get the finish just right.

We have created some simple steps for you to follow as a guide to rectifying any pinholes you may have:

1. To ensure you can see all the holes and you don’t have to come back later for any you may have missed, lightly machine sand the whole surface area of your part, with a very fine sandpaper – around 600 grit. We advise against hand sanding as the uneven pressure of this approach could damage your surface coat.  This process will highlight all your pinholes, making each one visible and easy to work on
2. Clean the area with a wipe down of alcohol or acetone
3. Take your time to create a keyed surface within each pinhole, making sure you get right to the bottom; if you don’t your filler won’t hold as there is no ‘key’ for it to latch onto. We recommend using a Dremel Multitool with a pointed abrasive tip to ensure you get right to the very bottom of the hole and make a good key
4. Once again thoroughly clean the part with your alcohol or acetone, making sure to get right into each pinhole, any dirt left in the holes will cause your repair(s) to fail
5. We recommend using a polyester filler, with high elasticity and flexibility such as BAXT CARBONfil to fill the holes as it remains black, even after sanding and clear coating. Make sure the filled holes stand slightly proud and then sand them back to a smooth finish
6. To get an idea of how the surface will look spray it with water to see if the holes have blended to an acceptable tolerance
7. Once all the holes have been filled and you are happy with your finish you can apply a clear coat and if it’s been done properly you would never know there were any holes there!

For more information on how DTC can support your composite manufacturing process, with a wide range of tools, consumables and coatings talk to us today and challenge us to save you time and money – 023 8025 1100