Letramax vs plywood or card stock?

Woody's Workshop

Well-Known Member
TRF Supporter
Aug 3, 2011
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Reed City, Michigan (Lower)
Is Letramax more fire proof, or fire resistant then thin plywood or heavy card stock?
Use is in a baffle in the size of BT-60.
I'm making some adjustments to the Scrambler because I didn't like the way the shock cord was fastened.
The piece I received from eRockets is heavy pressed laser cut card stock.
It was to be glued on top of a letramax coupler with the shock cord slipped through a small hole and tied.
The ejection would be pulling at it, even though it would have been filleted in I didn't see that being enough.
So I put it on the bottom, tied Kevlar on the bottom side, threaded it through the hole and a piece of launch lug.
Glued the launch lug to the inside of the coupler. I have Letramax and thin ply for the top of the baffle that glues inside the coupler.
I'll probably cover the bottom of the baffle and the Kevlar knot with JB Weld, and the launch lug.
I'll join the Kevlar with the shock cord just below the air frame to help prevent zippering.
The holes are large enough in the card stock bottom I can get a small paint brush in to fillet the bottom side of the top baffle plate.
It will also be filleted on the top side as well as it sites 1/8" down from the top edge of the coupler.
Now the pull will be on the whole baffle, not just on the top plate. And with the launch lug between the top and bottom it makes a solid top to bottom.

Gary Byrum

Overstable By Design
Aug 4, 2011
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Lincolnton NC
I don't know about fire proof, but the Letramax is my preferred material for CR's. The cuts are usually better than some plywoods I've used, and the card stock these days is substandard in my opinion.