Is plywood a good materials for detonating mortars with inverted fuse type?
not unless it is a good thickness like 3/4 or 5/8
¼-inch plywood 0.31 3/8 inch plywood 0.47 ½-inch plywood 0.62 5/8 inch plywood 0.78 This is taken from http://www.sizes.com/units/rvalue.htm, which also has some other materials that could/would commonly be used alongside with plywood to increase the R Value such as building paper and insulation... if both sides of the frame are ply then you must also include the void.
What kind of plywood should be used on a pontoon boat deck Is there a plastic sheeting that would be better?
What is the difference between marine grade plywood and treated and will paint stick to treated plywood?
Marine grade plywood and treated plywood aren't the same thing. Marine grade plywood has special glues and woods that will withstand constant immersion in water. Treated plywood is regular plywood that has been run through a pressure treating cycle. Paint will stick to treated plywood if you make sure to let it dry for a few months before you paint.
Here is a great link: http://koti.mbnet.fi/~ijl/amerikkalaista_tekniikkaa/jonboat.pdf I am working on my onm plywood Jon boat right now and am about 2/3 finished. I created my own plans based on the link and various other photos I found. The trick is taking your time and using the right materials. Be careful, it is addictive...