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Prop mold

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Joe M:
Made a propeller mold over the past week. Used a Zinger 12 x 5 wood prop.

Joe

Joe M:
Used Epoxy resin and carbon tow to make one.  The first one stuck in the mold and a few chips out in the hub area.  Waxed a few more times and the second one pulled out with no flaws. 

Joe M:
The wood prop weighs 22.7 gram  and the carbon fiber is 37.1    The cool thing on the epoxy one it can be heated up and de pitched.  It also is much stronger than the wood one.
 Joe

Joe M:
I use Resin services resin and surface coat.  The molds are waxed and a brushed coat of PVA,  When dry lay up. 

 I need to work on my lay up of tow as the prop tips take less tow than the hub area. It you dont have the lengths correct the mold takes to much force to close and compact the roving and could lead to a weak part.

Joe

Dennis Toth:
Joe,
Looks good. Did you post cure the resin? Wayne Trivin was a good friend that developed a technique for molding props and tanks. He passed away in 2005 but his website has been maintained by the speed and racing group. Here is the link:  http://www.nclra.org/TechTopics/WayneTrivin/Actualindex.html


If you are looking to just re-pitch the prop, wood props can be heat pitched just like Carbon. The way you heat the wood prop is important. The technique is to heat and soak like pitching an IC APC prop. I use a heat gun. I am a bit lazy and only pitch the 70% diameter. So what I do is heat the hub by rotating top to bottom for about 20 ish seconds then let it soak in for 20 seconds then repeat. At this point it could be a little warm (near 175F) so either use a glove or a towel, grab the hub and twist the blade and hold for 15 seconds. Now check the new pitch, repeat as needed to get the desired pitch.

Best,     DennisT

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