Jump to content


Forum problems? Contact Frank • Like our Facebook Page

Photo
- - - - -

sealing frames / marine plywood


  • Please log in to reply
87 replies to this topic

  #21 Hirilonde

Hirilonde

    Advanced Member

  • Members
  • PipPipPip
  • 2,069 posts
  • LocationCharlestown, RI

Posted 02 October 2012 - 06:10 AM

Based on the kayaks I have built I can't imagine even Jeff's largest kayaks require more than a 3'x5' piece.


If your going to cut out the 3 piece coaming it takes a 5x5 sheet. There will won't be much useful scrap left


Ah, that makes sense, I always make a laminated combing. It always seemed expensive when buying the maple, but considering the plywood it saves it really isn't bad at all.

Dave Finnegan

1967 Pearson Renegade  "Hirilondë"

Spindrift 9N #521 -  many KudzuCraft SoF kayaks


  #22 P Douglass (WA)

P Douglass (WA)

    Advanced Member

  • Members
  • PipPipPip
  • 1,088 posts
  • LocationBenton City, WA

Posted 02 October 2012 - 07:04 AM

OH YA, I also forget about the coaming. Another good reason to build a bent one.
P Douglass
1st build - Curlew

  #23 Ward

Ward

    Advanced Member

  • Members
  • PipPipPip
  • 38 posts
  • LocationNorth Georgia

Posted 02 October 2012 - 06:55 PM

I used Baltic Birch and after finishing Castaway was talking to a salesman in a local (very small town) lumberyard and he said that he would be glad to special order some BS1088 for me. He called for a price and delivery and the price was less than the Baltic Birch when considering the square footage. Delivery was three days with other lumber materials from the same supplier.
Jeff you may be interested in the latest interest in Castaway. A couple of duck hunters stopped and chatted the other day and wanted to know if I thought my kayak was stable enough to hunt ducks. The lakes are low here in Minnesota and the hunters are apparently having a hard time getting around. Might be some camo Castaways in the future.

  #24 FloatingBear

FloatingBear

    Advanced Member

  • Members
  • PipPipPip
  • 88 posts
  • LocationArkansas

Posted 03 October 2012 - 05:24 AM

An additional question for all of you keepers of the knowledge. Why are the Baltic Birch and the others you guys mentioned superior? Is it the wood itself or the assembly process and or the adhesive used for assembly? My delima is this. Do I spend 4 to 6 or even 8 times more between the cost of the wood and fuel attaining the high end ply or just buy wood from Lowes and coat it carefuly with epoxy and quality paint for a finish that should last for decades? I have already coated some 5.2mm luan on my UJ Pirogue with my epoxy from RAKA and that is some increadibly tuff stuff.

This is not intended to make any of you guys angry. I just hunger for knowledge and I like to tinker and improve! Besides I'm cheap!!!

  #25 Kudzu

Kudzu

    Advanced Member

  • Members
  • PipPipPip
  • 2,100 posts

Posted 03 October 2012 - 06:51 AM

How long do you want the boat to last?

Lowes plywood is not meant to be in the weather. Exterior grade plywood, except for that used as siding on a house, is covered with something, shielded from the weather. It was never intended to be wet. The wood used is not rot resistant, the plies in the plywood are thick and there is less of them. There are hidden holes inside that can lead to problems. It tends to warp. The only thing going for Lowes ply is the cost but that is a false savings because it will shorten the life of the boat.

Sure you can coat it with epoxy but that adds some additional weight and epoxy is not cheap. But if you miss a spot or something happens and you get a hole in the epoxy, water gets into the wood it has no way out. It will stay wet for then on and it will now rot faster than if had nothing on it. If not done perfect it won't last for decades.

This is an extreme case but this is exterior plywood I was going to use for make a form for laminated coamings. I cut it out and left. Next morning this is what I found. Do you want this in your boat?

Posted Image


Baltic Birch and MOST marine grade plywood are made of more thin plies with no voids hidden inside. Marine grades should use higher quality wood meant to be used in wet conditions. The quality of imported plywood is FAR superior to any American made plywood I have seen. Sad to say but this is one play I want imported products over US made.

As for being cheap, Fuselage Frame boats are about the cheapest boat there is out there without being a throw away boat. You should be able to build one for $400 using good materials and have a boat that will last a lifetime with just normal care. That should appeal to any cheapskate.

By the time you buy plywood and epoxy your probably going to be close to $50. Lets just say you can have $40 in both. A good sheet of the marine grade plywood is $100 +/- (I buy Baltic Birch for somewhere around $54 I think). No extra work required to it. So your going to save $60 on a a $400 boat and you will probably shorten the life of the boat.

Yes I am biased, but I think it a no brainier.
Jeff
Kudzu Craft SOF kayaks
www.kudzucraft.com

  #26 Hirilonde

Hirilonde

    Advanced Member

  • Members
  • PipPipPip
  • 2,069 posts
  • LocationCharlestown, RI

Posted 03 October 2012 - 08:10 AM

It isn't just a matter of longevity. Baltic Birch is much stronger. And when the minimum width of the webs of each frame is down to 1" or very close in the weak point, it matters a lot. Baltic Birch has 9 veneers. I bet the stuff you are looking at has 5. Huge difference in strength.

Dave Finnegan

1967 Pearson Renegade  "Hirilondë"

Spindrift 9N #521 -  many KudzuCraft SoF kayaks


  #27 Kudzu

Kudzu

    Advanced Member

  • Members
  • PipPipPip
  • 2,100 posts

Posted 03 October 2012 - 07:22 PM

Baltic Birch is much stronger.


I knew there was another point I had in my mind when I started my Epistle and that was it.

My long Shot was built with marine grade Douglas Fir which is (I think) 5 ply. That boat has a lot of miles on it. It been used, abused, reskinned and modified. The frame that supports the cockpit started to give over time and finally collapsible. It didn't break but just became soft and would bend downward several inches. It was easy to cut a brace that straddled the keel and deck beam to repair it. Now I am seeing the beam at the front of the coaming is starting to give a little. I have been strapping it across there when I use the car instead of the trailer to haul it.

These have all lead to changes in the plans but I think it is US made plywood. I was never impressed with the quality of the plywood and that it what lead me to Baltic Birch.
Jeff
Kudzu Craft SOF kayaks
www.kudzucraft.com

  #28 FloatingBear

FloatingBear

    Advanced Member

  • Members
  • PipPipPip
  • 88 posts
  • LocationArkansas

Posted 04 October 2012 - 05:25 AM

All excellent points and yes you are winning me over. Yet I have another question. Are you or have you guys in the past been coating your plywood pieces with anything other than oil? My thought is this. Coat my plywood pieces with epoxy which I already have and rubbing down all of my cedar with teak oil for even greater longevity!

  #29 woodman

woodman

    Advanced Member

  • Members
  • PipPipPip
  • 474 posts

Posted 04 October 2012 - 05:43 AM

If it is anything other than BB plywood...go for it.....

  #30 P Douglass (WA)

P Douglass (WA)

    Advanced Member

  • Members
  • PipPipPip
  • 1,088 posts
  • LocationBenton City, WA

Posted 04 October 2012 - 07:47 AM

Floatingbear, you really seem to want to coat your frames with epoxy and it is your boat, so go for it. It certainly isn't going to hurt it, that I can tell, will only add a few ounces in weight, if that. If it give you piece of mind, it well make it worth it. I think most here are implying it certainly isn't necessary.
P Douglass
1st build - Curlew

  #31 Kudzu

Kudzu

    Advanced Member

  • Members
  • PipPipPip
  • 2,100 posts

Posted 04 October 2012 - 08:25 AM

Sure you can coat it with epoxy but that adds some additional weight and epoxy is not cheap. But if you miss a spot or something happens and you get a hole in the epoxy, water gets into the wood it has no way out. It will stay wet from then on and it will now rot faster than if had nothing on it. If not done perfect it won't last for decades.


From my previous post.

If you want to really get educated on epoxy encapsulation to the Wooden Boat forum and search and read on the subject. It's not the cure all it has been portrayed.
Jeff
Kudzu Craft SOF kayaks
www.kudzucraft.com

  #32 Hirilonde

Hirilonde

    Advanced Member

  • Members
  • PipPipPip
  • 2,069 posts
  • LocationCharlestown, RI

Posted 04 October 2012 - 08:52 AM

If you want to really get educated on epoxy encapsulation to the Wooden Boat forum and search and read on the subject. It's not the cure all it has been portrayed.


I don't think you understand why most of the people at the Woodenboat forum are against it. They are against encapsulating old boats, especially plank on frame boats. And I completely agree, it is destructive. For new construction it is an absolutely superb method, just read some of the 2 categories above this one on the forum main page. There are a few purists there (Woodenboat forum) who are against epoxy for all uses, but they are just being stubborn about using old methods over technology. If I had an old classic wooden boat, and I did in the past, I would (and did) use the period techniques to maintain it. If I had the time, money and resources I would build a classic plank on frame boat using the old techniques. It would be fun and beautiful, but not practical for me. I bet if Capt. Nate were around today he would use epoxy. He was an innovator and loved technology.

If done well FloatingBear it will add many years to the life of your frames, but here is why I do not bother:

1. It is not necessary, the frames simply oiled, probably even if nothing is done last longer than I will if I dry the boat between uses.
2. Epoxy coating is expensive, (even though I own some, it will be used later, so it does cost) it is messy, tedious, won't look as good as natural (I am surely vain) and adds build time that is ...see #1.

As Paul has mentioned, do it if it makes you feel better, but I think you are just adding work and sacrificing looks.

Dave Finnegan

1967 Pearson Renegade  "Hirilondë"

Spindrift 9N #521 -  many KudzuCraft SoF kayaks


  #33 Kudzu

Kudzu

    Advanced Member

  • Members
  • PipPipPip
  • 2,100 posts

Posted 06 October 2012 - 01:28 PM

I don't think you understand why most of the people at the Woodenboat forum are against it.


Actually I do. And I think there is good reading on the forum on this subject.
Jeff
Kudzu Craft SOF kayaks
www.kudzucraft.com

  #34 FloatingBear

FloatingBear

    Advanced Member

  • Members
  • PipPipPip
  • 88 posts
  • LocationArkansas

Posted 08 October 2012 - 11:43 AM

Thanks again for the info and insight guys. I just want to learn as much as I can as I am just a newbie at boat building and I do greatly appreciate everyones input.

  #35 Hirilonde

Hirilonde

    Advanced Member

  • Members
  • PipPipPip
  • 2,069 posts
  • LocationCharlestown, RI

Posted 08 October 2012 - 12:47 PM

Whether you use West System brand epoxy or not (there are many good epoxies), the Gougeon Bros. have probably made more good info available to modern wooden boat builders on the subject of gluing and waterproofing with epoxy than anyone.

Here is a link to their book in pdf. format:

http://www.westsyste...Book 061205.pdf

Here is the address to their online magazine Epoxyworks:

http://www.epoxyworks.com/

If you want to read up on epoxy, these should keep you busy. There are a lot of "wives tales" out there about epoxy, and lots of good advice. It is often very hard to discern one from the other. When in doubt, these are both good resources to verify info.

Dave Finnegan

1967 Pearson Renegade  "Hirilondë"

Spindrift 9N #521 -  many KudzuCraft SoF kayaks


  #36 FloatingBear

FloatingBear

    Advanced Member

  • Members
  • PipPipPip
  • 88 posts
  • LocationArkansas

Posted 08 October 2012 - 01:03 PM

Holy crap I may have found a source for Baltic Birch without driving. Woodworkers Source sells 1/2" Baltic Birch in 20" X 30" pieces per dozen for $126 shipping included!!!

Thanks Dave!!!

  #37 Kudzu

Kudzu

    Advanced Member

  • Members
  • PipPipPip
  • 2,100 posts

Posted 08 October 2012 - 02:22 PM

That is not big enough to make a coaming from. Sorry......
Jeff
Kudzu Craft SOF kayaks
www.kudzucraft.com

  #38 Hirilonde

Hirilonde

    Advanced Member

  • Members
  • PipPipPip
  • 2,069 posts
  • LocationCharlestown, RI

Posted 08 October 2012 - 02:35 PM

He might be able to make a laminated combing, but I am not so sure about the scrap from using small pieces either. It could make a good square foot price disappear. Definitely needs some thinking through.........

Dave Finnegan

1967 Pearson Renegade  "Hirilondë"

Spindrift 9N #521 -  many KudzuCraft SoF kayaks


  #39 FloatingBear

FloatingBear

    Advanced Member

  • Members
  • PipPipPip
  • 88 posts
  • LocationArkansas

Posted 08 October 2012 - 06:49 PM

A laminated combing was what I was planning on. Jeff does your book cover that? If not I was planning on tracing the dimentions from my dagger and making a form from a piece of 3/4 birch that I have had for a few years.

  #40 Kudzu

Kudzu

    Advanced Member

  • Members
  • PipPipPip
  • 2,100 posts

Posted 09 October 2012 - 09:15 AM

Yes, it is covered in the book.
Jeff
Kudzu Craft SOF kayaks
www.kudzucraft.com




0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users