Dug fur stringers

[Bco128]

I've heard alot in this forum of using dug fur for stringers.at least i think i did to tired to do search righ now.i have located dug fur that i may use for this purpose but have a few questions before i go spending money.they have treated and untreated.woul it be best to go with untreated?and for the center stringer.the width required is more than what is easily obtainable.would it be ok to have more than one piece glued and pressed or would this be too weak?what are your opinions on using this material for the transom as well?

 

[crab bait]

Re: Dug fur stringers

doug fir what..?? cause there's doug fir lumber an there's doug fir plywood.. <br /><br />never heard of treated fir lumber..<br /><br /> ply for transoms are best an good for stringers but lumber is best imho.. <br /><br />to glue/lam 2 pieces of wood together is always stronger,, no<br />matter what kind of wood..especially lumber/ply/lumber laminate..

 

[Bco128]

Re: Dug fur stringers

i was speaking of the lumber.didnt know there was a plywood made of doug fir.but yes there is a doug fir lumber which is treated.at least around here there is.not really for the sake of making the wood last longer though.it is an applied chemecal which helps keep the wood from turning color when used out doors like most untreated woods will grey.guess its not really a treated lumber but thats just how we refer to it.sry i didnt give better detail in the first post but was in a bit of a hurry.

 

[Terry H]

Re: Dug fur stringers

Bco128 <br />Are you working on a fiberglass boat? If so I would use the untreated lumber since they would need to be encapsulated in resin. The plywood is normally much more stable and strong so I would suggest a look into douglas fir plywood in a grade such as marine, MDO, or AB...in order of quality and price. If you need longer and or thicker boards than you can find you can laminate multiple sticks to make larger pieces...just a Thought

 

[Bass Runner]

Re: Dug fur stringers

I'm using douglas fir plywood 3/4" for my stringers,transom, and 1/2" for the floor.

 

[Boomyal]

Re: Dug fur stringers

If I end up needing to replace the stringers in my current Gulfstream project, I am going to go to a lumber salvage yard and find some 50 year old douglas fir construction 2x's. It is dry, straight grain, old growth that is tougher than nails and won't warp. Old growth Douglas Fir is also very rot resistant. You can still find houseboats, on the Columbia River, sitting on top of 40/60 y/o old growth logs. <br /><br />Then I'll saturate it in CPES before installing.

 

[Terry H]

Re: Dug fur stringers

Good idea Boomy

 

[Bco128]

Re: Dug fur stringers

Thought 101<br /> Yes it is a glass boat.It's a Pro Craft 1640 bass boat made in 1978.hull and deck are good.trailer good.but oooo the rot.would you mind giving a bit more detail on the plywood you spoke of such as what is ment by MDO and AB.im guessing it is the grade as refered to by frequency of voids? Boomyal dont think ill have much luck in finding lumber of that type around hear.nearly all of the old lumber from old boats barns fences and such has been salvaged by craft makers in their undying effort to fill the world with more un needed junk.but i guess at least they are salvaging old wood rather than using alot of new lumber.something to be said in recycling anyway you can.thanks for the info folks.anymore thoughts just throw em in. id love to hear em cus the weather is starting to be just about right for me to start puting this boat back together.

 

[Terry H]

Re: Dug fur stringers

Bco128 <br />I mentioned the 3 grades of fir ply that I would recommend for boat work. <br />Marine ply=all good laminations. I would use it for floors that would be carpeted or vinyled...and on boats stored dry. Good for transoms. <br />MDO=medium density overlay...made for sign painters(or at least used by them). Has decent laminations and is coated with paper like coating. With the edges sealed and surface painted this grade holds up well when used for floors.<br />AB=construction ply with "A"side and "B" side...not necessarily good laminations but you can find some good specimens if you look hard. Good for stringers that are well sealed...good for floors if well sealed with resin or epoxy...good for transoms, again if sealed well.<br />Actually any of these grades will work for any of these purposes if encapsulated in f/g...around here the cost is:<br />Marine 1/2"=50 bucks<br />MDO 1/2"= 45 bucks<br />AB 1/2"= 25 bucks<br />The 3/4" ply is a little more. <br />Hope this helps

 

[Bondo]

Re: Dug fur stringers

I Always use Plywood.......<br /><br />It's Stronger,+ More Dimentionally Stabil than Solid Wood........

 

[BillP]

Re: Dug fur stringers

Then I'll saturate it in CPES before installing.<br />

Remember this when glassing. Epoxy over polyester is ok but poly over epoxy isn't. Poly doesn't stick well when applied over cured epoxy.

 

[Bco128]

Re: Dug fur stringers

thought 101 <br /><br /> thanks for the info.will need to spend some more time at the lumber yard.had an odd thought earlier today that i would like to run by you folks. Cedar.spelling? i know it is great for many things actuall im remodoling house and plan to use it a good bit.very strong insect resistant as well as rot resistant.not certain if i can otain it in ply but can easily get it in lumber.an interesting thought. any openions experience?

 

[Terry H]

Re: Dug fur stringers

Bco128 ...I assume you are speaking of western red Cedar? That would be the same as you might use for a cedar fence around here. It's light, easy to work and has been used for boatbuilding since it was discovered. Mostly used hull planking, but could certainly be used for stringers, especially if encaplulated in f/g. Western red Cedar is light but not very strong, does not hold nails and fasteners well...in my opinion, if you want to use WRC, just make sure it's properly dried and encapsulated in f/g...just a Thought

 

[Link]

Re: Dug fur stringers

Bco128 <br />To answer you original question about Douglas fur/fir.<br />In our area to build a typical 10 foot wide single carport We must use 2" X 10" X 10' Joice's (sp) but to span the same 10' if we use Douglas fur/fir we can drop down to a 2" X 8" X 10' and still meet codes because it's 10% stronger. <br /><br />Hope that helps a little.<br /><br />Link

 

[JasonJ]

Re: Dug fur stringers

Just use good plywood, seal it well, and you will have a stronger, lighter end result. A person can either spend a few minutes buying ply or they can spend days running around trying to find something else. I had to use ply because I was never going to find 14 inch wide material for stringers. The ply is easy and straightfoward. Good luck...

 

[BillP]

Re: Dug fur stringers

I would use ply but white cedar is the one used for planking and Alaskan yellow for stringers.

 

[Bco128]

Re: Dug fur stringers

did some more looking around at the local lumber yards.while keeping all openions in mind.and i believe after all the help i have recieved from you folks ( thank you all btw )taking into account your thought and experience.i believe i have come up with the best option with material availability cost ease to work with and durability.so heres the plan feel free to pop in with any new ideas.<br /> my transom has two layers of plywood both 3/4 with a small bit of room to spare. i intend to use 3 layers of 1/2 inch dug fir ply using glass cloth ( best to use here? ) glass and press all together before i install. glass all in. use same cloth sandwiched between 2 layers of 1/2 inch dug ply for stringers. 3/4 inch ply for cross members. all glcassed in with mat over all this then 1/2 inch floor using roving. then 2lb foam.sound like a good way to go.if i figured it right it should be srong as h***.but another question arisses.under the stringers nearest the outside there was wood looked like 1/4 ply about 1 inch width.no glassing oer just layed in with stringer on top then glassed as a unit.not sure how to redo this as it extended out 3 inches to the side of the stringer. i see no reason for this.so ok thats my plan.openions?