I put a 1 1/2" x 1 1/2" sample in hot water for five minutes last night. When I took it out, the paper was fully saturated. There was no de-lamination at all. I let it air dry on the bench all night. There does not seem to be any noticeable difference between it, and a piece of ROSS foam board that was not soaked in water!
They're Ultramicrobes' plans, but I wouldn't recommend building it unless it was for static display. It looks awesome, but flies terribly. I built 2, one scale and heavy, the other as light as possible. If you turn, they stall, if you climb, they drop either wing. They do look incredible on the ground and in the air though. http://flitetest.com/articles/swappable-stuka-dive-bomber-with-remote-bomb
Same Size: 20"x30" Same Thickness: 3/16" Weight: Adams board 4.1gRoss 4.7g Price: DTFB $1USD, ROSS $0.88 USD Flatness: DTFB is wavy, ROSS is flat as can be. Brightness of paper: DTFB dull white, ROSS bright white Paper Quality: DTFB is ok and textured more, ROSS might have a thicker(heavier weight) paper and smoother finish. Crush Test: (Pound a corner of a piece into the table). DTFB paper pealed away from the foam. ROSS paper held on to the foam and crinckled. See picture. Paper Peel: DTFB peels clean and easy. ROSS pulls up the surface layer Rigidity Comments: DTFB seems to be more rigid and prone to cracking and pulling the paper away for the foam around the area of a fracture. ROSS my be slightly less rigid and crease instead of crack. Fold Test: Piece was fold 90degrees one way, then folded 90 degrees the other. DTFB paper started to lift and made a tighter radius bend. ROSS paper held on to the foam and had a larger outer radius bend A&B style folds: Both are fine. Foam Bevels with sharp knife: Both are fine.
Cold Water 1 min soak: DTFB seems to be affected more by cold water then hot water, the paper peeled very easily. ROSS was unchanged. Hot Water 1 min soak: DTFB was slightly affected and the paper seemed to peel the same as it always does. ROSS was unchanged. Suface water splash: DTFB "raised the grain" of the paper, similar to getting a piece of wood wet and the paper may peel a bit easier(hard to tell). ROSS has no noticeable changes. Spray paint test: ROSS has a much smoother finish. DTFB paper becomes more saturated with the paint causing easier delamination. ROSS paper is still mainly white on the inside after painting. See picture.
Hot Glue Test Paper to Paper: DTFB peeled the paper off, no surprise, ROSS eventually tore the paper off but it was much more difficult. Foam to paper: DTFB pulled the paper off leaving it attached to the hot glued side. ROSS eventually tore the same but is was much more difficult. Foam to Foam: This is the hardest joint to separate for both. I would consider it a tie. Butt Joint: DTFB Pulled the paper off of the mating surface when wiggled left and right. ROSS held on great until to much force pulls the hot glue away from the foam edge. This type of failure is much easier to fix then the delamination of the surface paper.
I just built a Mustang with the Ross board. It definitely holds up better than DTFB. I couldn't even get the paper to necessarily peel off and ended up cutting/fileting with a blade where needed. I also tried soaking with water and it held up great, couldn't even tell it go wet. Also took paint very well with no warping, etc.
It is about 1mm thicker than the DTFB (at ;east the Ross and Adams stuff sold by me) so if you try to build with FT plans you need to compensate for this. My suggestion would be to get a PDF editor/Adobe Illustrator clone and go change the plans. If you make a A fold, the piece will be 1mm taller. If you make a B fold, the piece will be 2mm wider. Wings will be 2mm thicker and so on. It's enough to make a difference on fitting pieces together.
Since it is thicker, folding over the Ross for a wing is a bit more challenging and the control surfaces need a bit more beveling to get to work. The material has a bit more resistance to it as well.
All in all you have to do a bit of "tweaking" of the FT plans to get the Ross board to work. All the FT videos, plans, build techniques, etc. are geared around DTFB so you might find things dont work exactly the same with the Ross board and may need to do a little trial and error. A good example of this is the elevator on the Mustang build. Personally, I think there is a bit of a design flaw in that the control horn mounts behind a very thin part of the elevator in the middle. With the Ross board, the elevator wanted to twist at the thin part...partially because of how the foam is not quite as stiff and partially because the hinge for the elevator seems to have more resistance. I ended up reinforcing with some wood to get it to work. Had I used DTFB, I am assuming it would have worked just like it was designed.
With that said, the Ross board seems to be pretty good. It does hold up better than the DTFB (doesn't delaminate, takes water/paint/etc., creases but has a bit of memory to come back to shape, doesn't ding up as much during the build) but as noted above is not as rigid and has a tendency to crease rather than crack. Not sure if that is good or bad in the long run but this characteristic of the material plus its additional thickness certainly require some design changes along the way.
I began cutting out an old speedster from ROSS board and am pleased so far. With a sharp knife, it cuts clean and smooth. I plan on putting floats on it and really testing out the ROSS board with Adirondack lake water over labor day weekend.
I did my first build with the Ross board....liked the material but was a bit put off because I needed to tweak here and there. Probably some of this was because it was my first build and some because I was not using DTFB. I just built a tiny trainer with the DTFB and have to say I much prefer the Ross board. The paper stays on the Ross board much better where the DTFB seems like the paper wants to peel off on its own while you are building...I am guessing this will not hold up to much punishment under normal use and I will be repairing, regluing paper on an ongoing basis. I do wish the two (Ross and DTFB were the same thickness) to make following FT plans a little easier.
How did your build go? Did you notice a difference in the build one versus the other?
FYI, I just started painting my mustang with the Ross paper. Based on my earlier tests it took paint really well so I did not prep, just painted (with light coats). There are a couple of spots where the paper became wavy...not sure why if there is a coating on the paper that rubbed off during build or some defect but on one of the wing tips there is noticeable waviness in one spot a few inches long by a couple of inches wide. The other spot I noticed this was right around where the wing meets the fuselage you put a bead of glue to seal the wing. There is waviness around this glue bead which leads me to believe there is a coating on the Ross paper that evaporates with heat and/or comes off maybe with some friction. Probably need to test this which if true, you have to be careful during the build and pay attention to any spots that may have been exposed to heat or friction. You could use CA glue on any surface gluing maybe? Just a theory at this point and needs to be tested/proven.