Varathane, the dope or resin alternatetive.

[mrwzrd59]

I thought I'd post some info on the Varathane brand Urethane resin that I use in place of polystyrene fiberglass resin. It barely has an odor and seems to bond perfectly to both Depron and dollar tree foam board. If my pictures come thru you can see that it is available in small quantities like the dispensing tube shown. I also included a pic of the elevons on my RV Jet that were so floppy from the factory. I reinforced them with 1.5 oz. light glass mat using the Varathane and now they are strong enough for even the highest G pull-outs without folding. If you look close, I added a .06" diameter carbon rod to the trailing edges too. I've done this to several FT designs and the increase in stiffness without much weight penalty is well worth the effort. I also just run a bead of the Varathane along the exposed foam board edges and they become tough to resist dings. I also use it OR White glue to run heavy fillets when I want the cantilevered stabilizers to stay put like on the FT22 raptor vert stabs.
I'm sure that most if not all of you work inside your homes and polystyrene fiberglass resin smell is most unwelcome! Varathane fills the bill and is available at Menards and Lowes. Sands up nice to a high finish if that's your deal too! I made my own complete motor cowl for my Sbach 342 after the factory vac formed replacements were shipped to me cracked.
If you have an inclination to build with fiberglass, use Varathane and breath easier! It also is safe with polystyrene foam and Cleans up with water too!

 

[RAM]

I wonder if it can be thinned.

There is a good video out there on using foam-tac and drywall mesh to do something similar but foam-tac is liquid. I didn't have foam-tac so I tried the same experiment with polycrylic and drywall mesh, it worked very well.

Here's the video, I don't think he was trying to improve stiffness but impact resistance:
https://www.youtube.com/watch?v=7eIPqCwHlnI

 

[mrwzrd59]

No thinning required.

I don't know why you would wish to thin it but I guess you could add some water.

1.5 oz. fiberglass mat can be had at very low prices from http://www.fibreglast.com

Drywall tape just isn't very dense and I wouldn't ever choose it for any of my models! Looks awful too!

The elevons that I modified on my RV jet were done with a couple of their (fiber-glast) sample packs....Very cheap to figure out if its what you're looking for.

I discovered Varathane after seeing a video on the use of some foam-kote from Delux Materials. The more I studied what they were supplying, I found out that Varathane was the same stuff for one third the price and available 2 miles from my house!

I do use their "Foam to Foam" adhesive but nobody stocks it locally so I have to order it in....Works very well as a sub for mixing epoxy, the 30 minute variety that dosent get so hard.

 

[RAM]

I don't know why you would wish to thin it but I guess you could add some water.

I saw the picture of a tube and assumed it was thick stuff, like caulking. Went on the web and searched it and found it as a paint in a can. Seems like the same stuff as minwax's polycrylic. I'll have to give it a try once I run out of the polycrylic.