Balsa wood outdoors

[Greg Elmassian]

 Yep, you live in the UK, I live in the USA.

 We most certainly do not shop in the same place.

Greg

[cabbage]

Hmmm... Obviously you do not shop where I do Greg, as a I normally purchase my sheets of Marine Ply (3mm thick) from the local wood merchant -less than 3Km away. I normally buy a std 30cm by 90 cm sheet for £4.95p. I normally use Phenol-Resorcenol based glues -although my late father always used two pack Urea-Formaldehyde based glues. My son is building a boat with a hot melt epoxy glue gun, (he is 10). It is not actually the glue that is the defining property of the grade "Marine Ply" but the woods that it is made of and the layering of the direction of the grains. Normal plywood is cross grained while "Marine Ply" is grained at 120 degree to give it the flexibility to form curves as required in the shaping of a hull. regards ralph

[Greg Elmassian]

Thin plywood might easily delaminate in the outdoors. Hard to find marine grade (better glue) in that thin I believe.

Regards, Greg

[cabbage]

Pressure treated timber relies on the fact that you don't saw or drill into it. If you do you have to treat the "wound" with something like "Endseal" or similar. What you are looking for is a hardwood that will take exterior use -as stated above cedar or oak. I use "Marine Ply" and boat building glue. http://www.cabbagepatchrailway.co.uk/buildings.html regards ralph

[IRB Souther Engineer]

What if I used 1/4" plywood sheets cut into 1/4"x1/2" strips?

[IRB Souther Engineer]

Would this work? http://www.homedepot.com/Outdoors-Fencing-Wood/h_d1/N-5yc1vZ1xg4Zbb2w/R-202051003/h_d2/ProductDisplay?langId=-1&storeId=10051&catalogId=10053

[rpc7271]

I've used balsa as shims between my concrete roadbed and track. Mostly to superelevate the outside edge of curves. Some has been out in the weather for 5 or 6 years with no problems. I use it because it sands down real quick and I don't spend all day sanding.  I glue it down with GE Silicon II caulking which I also use to glue down my track.

[ttrigg]

IRB: I’ve seen that balsa will not stand up to the weather and constant contact with dirt. You will most likely need to pull it up every year to retreat with Thompson’s. Have a look at cedar or redwood fence boards. They run about two bucks a board, which need not be treated. Untreated, they should last about 6~10 years in your environment. Adding a sealant or preservative will extend their life use. In the long run you should save a pocket full of change over balsa. Cedar ages nicely with a very good-looking patina. Redwood will hold its natural color a bit longer but also develops a nice patina. After building my bridge (redwood) I got a balsa birdhouse (gift) to put among my other buildings. The birdhouse fell apart in just a few months (glue failure), the "floor" had some serious rot after a year, and that was after treating with preservative. The bridge still stands strong with no signs of rot.

[Chopperthedog]

Uhhhhhhh, I personally wouldn't even think of it . Any time earth comes in contact with wood I go AC2. Balsa is best left for rolling stock, buildings, and those little airplanes you used to get at Rexall Drugs for .79 cents with the rubber band prop. 

 

good day 

[Rex in Pinetop]

Balsa expands like crazy when it gets wet so I don't think it would last long outdoors even with a water seal.  I would recommend redwood or cedar.

Rex.

[IRB Souther Engineer]

If balsa wood is treated with something like Thompson's water seal will it be okay for outdoor use (to make a retaining wall as shown in the Oct 09 GR mag.)?