I found a local source of A1 grade DF ply. Does anyone know how it compares to AA grade plywood and has A1 been used for ribs?
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I found a local source of A1 grade DF ply. Does anyone know how it compares to AA grade plywood and has A1 been used for ribs?
AA is an premium grade that says the same veneer is used on both faces. It's real expensive and not all that available.
A1 is the best of the standard grade stuff, has the A veneer on the front and 1 grade (the best) for the back. Structurally it should not be a problem and ought to be pretty good appearance wide. A bigger issue is the water resistance. Usually you want something other than construction/cabinet plywood (which is represented by something other than the codes for face veneer grading).
A1 simply means it's pretty on both sides. For DF it's usually vertical grain face veneer with unknown core quality and type glue. You need something with WBP glue and no voids. Marine grade DF is probably the lowest cost option suitable for use in aircraft construction but don't use it as a plans substitute.
I agree that AA Doug Fir is the best option but aside from Aircraft Spruce (and shipping expense for large quantities), I have been unable to find AA in the Portland area. Multiple sources of AB but I cannot find AA anywhere. Crosscut Hardwoods no longer carries DF marine ply since all the boat guys are using Hydrotek and the like. Wondering if Seattle area has someone selling AA DF.
Please pay attention to what Marty and I say. AA/A1 only refers to the face veneer (which really should be acceptable either way). The core and the glue is what you should be concerned with and so you need to know more about the particular plywood than just the face rating.
There was a guy (now deceased) that had a blog that a lot of homebuilders paid attention to. I liked a lot of what he had to say, but he advocated "cheap" building and thought lauan plywood was good for ribs. Dad used some of that for some stuff in the addition Mom made him put on the house, & I helped him. It looked good on the outside, but it was 30% void, maybe more. Please make sure you use good quality plywood with no voids.Quote:
Originally Posted by FlyingRon
Don't get me wrong. I am a proponent of building something that you can fly without a shadow of a doubt of its integrity. My Kitfox revealed to me I am a bit OCD. I wouldn't be comfortable flying anything that I didn't have confidence in.
My only challenge is availability other than owning some shares in a trucking company that runs between Corona,CA and Portland.
If I could find some AA marine grade all DF ply in Oregon or Washington I would be ecstatic. Sadly, it's apparently very hard to find in the region the stuff is harvested in.
Just want to avoid the expense of shipping if possible.
Is there a local lumberyard (a real lumberyard, not a big box home center) that can add some to their next order for you?
The local lumber yard can only order exterior grade A1. Nobody locally seems able to get anything better than marine grade AB.
BD International in Tacoma has the good stuff - Finnish Birch. Waterproof and perfect on both sides. The difference in price compared to the total cost of the airframe probably won't bust your budget. http://www.bd-international.com/Quote:
Originally Posted by wadeg
Again, the letters mean SQUAT to you as an airplane builder (unless you need it to be an exposed work). It only tells you about the face veneer. In fart "C" grade veneer would be fine structurally, it just would look like crap if you were to finish it and left it exposed.
I used a place in Scappoose OR. They provide aircraft grade plywood. I put the word out I was ordering Aircraft Ply. I combined an order with a local EAA member and we split the shipping.
http://www.overallaircraftservices.com/