Wood to use replacing keel stringer

Can anyone tell me the best wood to use to replace the keel stringer on my 1976 Glastron Carlson. I have already glassed some stress cracks from the inside & ground the entire bottom for new coat of cloth glass. I think the one I removed was pine probably cut out of a 2 x 6. Also what is the best technique to glass the stringer in with. I greatly appreciate any tips as I am sort of a novice at this but have some experience with fiber glass.

 

We would use pine or spruce because they come in long lengths without knots and with parallell grain. They also glue well and are easy to shape and plane.
As long as you use epoxy, you should be OK.

 

In addition to Raggi's advise:clean the spruce or other woodtype thoroughly with MEK, clean also the stringerbed - don't sand it - if you have to rough it up, use a Sandvik rasp, be careful not to brake the strands and treat both sides with epoxy. If you treat only one side, the glue will become cohesive instead of adhesive. The rest should be easy to apply. The older boats contain mostly mahagony as glassed-in material as this wood is more resistant against inrot.
Using epoxy, the permeability is minimal, 0,08% or thereabout therefore the use of mahagony is not su much required. Using woods in general depends on availability and pine is in Norway a natural choice.

 

Thanks a million

Just wanted to say thank you to both of you who gave me such great advice . I'm going to use spruce pine and treat as suggested. Again, thanks so much!!!!

 

I need to replace 3 stringers and I’m in the process of selecting the wood at the sawmill, they proposed me several type of wood that are used here for boating or building marinas, are much stronger then tek (hard to drill !)and don’t have that oil thing that tek has (not good for the resin) and they don’t rot even if they are left in the mod for years. They proposed to me “Cocobolo”, “Balsamo” , “Guayacan” or Kira. I ordered the Balsamo (myroxilon balsamum) because was the only one they were able to cut the 4,5mt stingers in a single piece. I was wondering if I’ll have some prob in attaching the fiber to it.. couldn’t find any info related to this question.. does anybody has any experience with those woods? Anybody tried to glass them?

 

Glassing in Stringers

Remember that there will not be a perfect fit between the new stringer and the hull. Use filler in the epoxy in the area you 'bed' the new stringer in so that there is a strong joint without gaps.

See the West Epoxy site for more info:
http://www.westsystem.com/
http://www.westsystem.com/frames/tier1/usingepoxy.htm
and then click on "Adding fillers & additives"

This info applies to any Epoxy manufacturer...

My approach is to fit the entire stringer (or Sister etc) first, and clean it well. Then coat it with Plain Epoxy first, hitting the end grains a couple of times. I even heat the end grains with a heat gun ahead of time for best penetration. If the epoxy 'dulls', coat again. After the first epoxy coat starts to gel, but SOON, mix your thickened (I use MicroFibres from West) epoxy, and apply it to BOTH mating surfaces.. the stringer AND the hull, and put the new piece in place. Push/hold/clamp it in place just enough to squish the thick epoxy out evenly, but do not clamp it hard and squeeze it all out. You want some strong epoxy between the surfaces. Finally, make a neat 'fillet' where the epoxy squeezed out, adding more thick epoxy if needed. You can cut a piece of plastic from a plastic bottle in a small radius (like .25" radius) to smooth out and shape the fillet. Or use your plastic-gloved finger, which I prefer sometimes...

Do all this in one 'session' so new epoxy is always chemically bonded to epoxy that has not totally cured yet. If you are adding strengthening 'tabs' etc. do those next, again within a couple hours or so, so that the bond is good....

And get back out on the water!

 

Thx TerryK, this clarify a lot. Can I add normal fiberglass over the stringer with epoxy afterwords, I read that fierglass does not adhere very well to epoxy. Besides, stringer wood should touch transom wood.. right?

 

Unclear??

Sorry, I don't understand... What do you mean by "Normal Fibreglass"?? FibreGlass (as cloth, roving etc) is used with either liquid Epoxy Resin, or liquid PolyEster or other resins.

Most people agree you should use only Epoxy for serious repairs, and not mix resin types...

Can you tell us more?

 

That's my problem, I can't find the epoxy resin you are all talking about, the only resin availiable in Panama for fiberglassing is the polyester (I went and asked to almost all the hardware stores and boating shops availiable in Panama. The only Epoxy I was finally able to find (in doitcenter!) is a filler, epoxy glue plus other stuff to make it thicker, 2 little bottles containing a thik material (not for fiber) that cure in 2 hrs. I was planning to use that to attach the stringers (bought a bounch of those) to the hull and fill any gap, then cover it with polyester fiberglass. Is that wrong? How should I proceede instead?

 

You can order epoxy from West Marine or a slew of other companies. A gallon would be a good start. You'll go broke buying smaller quantities. If you find someone to go in with, a 5 gallon jug and a gallon of hardener could be split up. The larger the quantity, the better the price per gallon. A gallon with hardener will cost between $150.00 and $200.00. West Marine is in California, and they post a 1-800 phone number on their website for calling 24 hrs a day.


Alan

 

Ouch!!

Ouch! We expect to be able to get quart / gallon sizes of Epoxy.

I think you should keep looking... The West System dealer in Panama is:

Abernathy S.A.**
Apartado Postal 1119
Panama - 1
Tel: +507 260-1222
Fax: +507 236-0140
email: abernaty@panama.c-com.net

See if you can find them....

 

You are great!! This forum is becoming my bible!
It is my favorite place for scuba equipment; I didn’t know they also have boat materials. They have it: the gallon and the quarter and cheap! The gallon plus the hardener is 130$ in addition to that they have all the type of fiber mentioned in this forum and more important... they use the same terminology you do!
I’ll go with epoxy and buy my first gallon then.. 1 question though: in another thread (http://www.boatdesign.net/forums/showthread.php?t=17092&page=4) Ehdrian was mentioning (and provided several sources about it), that the material to attach the stringers to the hull needs to be soft, so the hull receive less direct stress from the stringers.. while you are mentioning a strong (and rigid) bound using epoxy; So.. which one is the right way to go?

 

make sure to use #1 wood no nots and not that much more expensive #2 wood has a few nots in it. just my thought of the day whats yours

 

The stringers were set in polyester and mat originally. There is nothing wrong with that. You need to clean the surface well before glassing. MEK or acetone work well. Epoxy is OK but unnecessary.