Q-talk 117 - Service Bulletins
- Category: Q-Talk Articles
- Published: Wednesday, 23 December 2009 16:24
- Written by Doug Humble
- Hits: 901
Attention anyone who bought a Lopresti style cowling from Earnest Martin:
I was looking at my cowling the other day and saw what may be the signs of slight heat induced deformation on the top center of my cowling. It is so slight that I am not sure it wasn't always there. All other areas of the cowling is very stiff because of all the compound curves, but the top center wants to oil can a little. I made a minor mod on the inside of mine that really stiffened it up, and I recommend everyone else do the same. The Mod is explained below and will be included on any new cowls that I make.
Turn the top half of the cowl upside down on a very smooth surface. Sand an approximately 3" x 14" area down the centerline from back to front. Start about 2" forward of the firewall attach point. Mix a little dry micro and use it to glue a 1/4" dowel rod or similar material to the center of the sanded area. Then radius the edges with micro for a glass closeout. Place a weight on the dowel and let it cure. I used a brick for this purpose. After it has cured, sand the micro and dowel and add a little micro where needed for a smooth radius.
Next, cover this with 2 BID with a glass to glass bond of at least one inch around the edges. Peel ply and let cure. If you try to do all of this in one step the top of the cowl will probably not turn out flat because you can't put weight on the 2 BID before it cures. Good luck and call me if you have any questions.
Earnest Martin 828-230-5378
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