If you are applying raw carbon tow, epoxy works very well. Cover with Saran or similar material and apply moderate pressure to squeeze out excess epoxy and hold tow in contact with spar.
If you are using pre-cured strips, if you can see or feel a textured 'tooth' it should bond well. However, do clean well, including a warm, mild soapy water to remove any release left from manufacturing, and a clean solvent like acetone or alcohol (99%) to degrease. Apply with a lint free clean wipe and allow to dry. Once cleaned, touch only with gloves as oils on your skin may influence the bond. When bonding materials that can absorb the epoxy, the naturalpenetration provides a larger 'wetted' area to make the bond. However, when bonding non-absorbant materials, one way to increase the wetted area, and thus increase the bond is to provide a finite texture. Many manufactures of composite components use a teflon coated fabric on the outside ofthe layup. When peeled away, these leave a distinct weave pattern molded into the component. This gereatly increases the wetted area thus providing an increas in bond strength. If you sand this away, you will lose some of the material that you paid for, and which was included in your calculations of strength. A light sanding can remove one or more thousandths of an inch, and if you start of with a piece only 0.007 inch in the beginning, and you sand off 0.001 from each side, you are left with only 0.005 as your cap. I am not tr4ying to be an alarmist, but, keep it clean, use moderate pressure (you don't want to squeeze out all the epoxy) and use a good qwality, moderate cure epoxy, you will have a spar that you will be pround of and one that will last a long time, if treated with respect. .........bc AG4YQ Williamsburg, VA On Tue, 23 Aug 2005, Dick Williamson wrote: > Scott Martin asked: > > >What's the best adhesive for affixing carbon strips to wood spars? > > Epoxy works well. However, be sure to sand the carbon fiber first. > > Dick > -- > - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - > Dr. Richard C. Williamson Phone: 781-981-7857 > Room C-315 FAX: 781-981-0122 > Lincoln Laboratory Email: [EMAIL PROTECTED] > Massachusetts Institute of Technology > 244 Wood Street > Lexington, MA 02420-9108 > - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - RCSE-List facilities provided by Model Airplane News. Send "subscribe" and "unsubscribe" requests to [EMAIL PROTECTED] Please note that subscribe and unsubscribe messages must be sent in text only format with MIME turned off. Email sent from web based email such as Hotmail and AOL are generally NOT in text format
