Type of wood for stringers?

[Jeff_40]

just curious as to what type of wood everyone used for their stringer? All I can get my hands on is white spruce or red cedar

 

[AShipShow]

I used 2x douglas fir for mine, seems like the most common is to use 3/4" BCX plywood from the home centers. I think there are potential issues with cedar and other woods that are rot resistant. They are rot resistant because they contain natural oils that tend to not not allow the poly to penetrate and adhere to to wood as well. I would stick with either ply, or construction grade lumber. If you go the lumber route, I would try to get the straightest and clearest pieces you can. Also, let the wood sit in your garage or house for a while to let it continue to dry. Most home store lumber is extremely wet still, even if kiln dried. It tends to get case hardened which is when they dry it in a kiln very fast and only really dry the outside of the material which causes internal stresses which can show up as wood movement after it dries further.
I'm basically making the point that plywood is probably the better option. I only went 2x material because I wanted to make the stringers one continuous piece at 13'. But you can just as easily scab together plywood, or even double up the plywood and stagger the seams to get a long single piece of wood.

 

[Scott Danforth]

exterior grade plywood or marine plywood

 

[tpenfield]

Everyone used exterior grade plywood or even marine grade plywood, as mentioned.

 

[kcon]

I used kiln dried white oak on mine, probably overkill, a bit heavy, and pricey - but it's really strong stuff. If I had to do it over I'd have used marine grade ply.

 

[Woodonglass]

In the long run ext. grade plywood is Plenty Good for Transoms and Stringers. I highly recommend using it. IF you want dimensional lumber, I'd recommend Douglas fir. Bottom line the MOST important thing is Proper glassing technique to ensure total encapsulation of the wood. Do that, and just about any Structurally sound wood will work.

 

[AlabamaNewbie]

How doe ya'll feel about sandeply? My home depot doesn't carry a huge selection of experior plywoods, but this is supposedly a hardwood plywood. Other sites I have read recommended it, but I trust you guys more.

 

[Woodonglass]

Not MY recommendation. HD should carry 3/4" ACX plywood. If not check with Lowe's. Ask for underlayment to It will work.

 

[tpenfield]

How doe ya'll feel about sandeply? My home depot doesn't carry a huge selection of experior plywoods, but this is supposedly a hardwood plywood. Other sites I have read recommended it, but I trust you guys more.

It is all about the glue holding the plies together. ‘A’ grade sheets are perfectly fine for wood quality.

 

[AShipShow]

AlabamaNewbie don't use sandeply... if it's the same thing my home depot carries it's meant for interior projects or cabinets... you MUST use ply rated for exterior as it has waterproof glue.. take a piece of it and set it outside for a rainy day and you'll have 5 pieces of really thin wood lol.

stick to acx or bcx ply at a minimum... x is the designator for exterior rated.

 

[kcassells]

What Madman said;
stick to acx or bcx ply at a minimum... x is the designator for exterior rated.

 

[AlabamaNewbie]

Got it. I was going more off the hardwood part. I was steering clear of pine, even though it said acx. I thought I'd read somewhere that you don't want to use soft woods.

 

[AShipShow]

Nope.. "marine-grade" plywood is made from the same thing as exterior grade plywood, they are both allowed to have knots in the veneers, just no voids or knot holes in the interior plies on marine grade.

I put the marine-grade in quotes tho, because marine-grade doesn't always mean the same thing... the bottom of the barrel marine plywood will be softwood core and veneer with waterproof glue, however, BS 1088 certified marine plywood uses tropical hardwoods that are naturally more rot resistant and WBP glue which means it has to be boiled for an hour in water and not delaminate....

Point being, unless you are going to spend a lot of money on BS1088 certified marine ply, just use exterior grade, because thats essentially what you're getting with low end "marine-grade" ply.

 

[Woodonglass]

As I stated in Post #6 the MOST important thing for stringers an transoms is NOT the wood selection. It is the proper encapsulation of the wood with Resin and Glass. It this is done the proper way and then they are properly cared for and maintained.(i.e. any screws bolts, cuts scrapes etc, are promptly attended to) ANY wood structures will last a very long time. the other consideration is structural strength. Soft pine, Cedar and others are not suitable due to their softness and lack of resistance to flex etc...