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Build design thoughts?

oldsparkey

Well-Known Member
Aug 25, 2003
10,444
113
78
Central , Florida
www.southernpaddler.com
I paddle the rivers and swamps in Florida so for the most part rocks are not a worry. Stumps and downed trees are the things I have to avoid. For that reason , plus being light weight , I like the Luann or door skins for my boats. I epoxy saturate the wood then glass both sides. I use butt joints and epoxy saturate and glass each side of them. The joints end up with two layers of glass over each seam after the boat is glassed. I have used heavy glass ( 10 oz ) on the bottom of one boat and my youngest daughter has it in the Canadian waters with lots of rocks and so far it is working quite well for her.
The other boats have the 3.5 oz tight woven glass on and in them. One boat I added extra glass to the mid section on the inside for a little extra strength. One other boat ( Matt's , JEM Watercraft , Swamp Girl ) I used glass all around and then added strips of redwood to the center section in a oval shape covering the middle third of the bottom. Plus on each bulkhead.

You can see a portion of it in this picture Just before the forward Thwart.
1720
 

C_Brice

Well-Known Member
May 12, 2005
48
0
Iowa
Thoughts:
Epoxy penetration/strength factor was probably insignificant or can't be determined in your comparisons. My "guess" is 5mm luan epoxy coated is weaker than non saturated1/4" bc plywood.
"butt joined/thin scarf" will work if glassed over. If not a glassed backer or a rib would be needed for max. strength.
Pine/fir chine logs work well.
If you're non glassed 1/4" ply boats have been working then why add glass/weight?
One factor not mentioned is most Luan plywood are rated for interior use only. If moisture reaches the glue it will delaminate. There are some rated exterior. If you have access to exterior rated, that would be a better choice.
Another option to consider would be to glue solid wood strips into panels and then glass over them. This would reduce the weight and eliminate the non exterior luan glue problems.
"Working" is all relative. Although it lasted many trips there are reasons the non-glassed 1/4 ply boat was turned into a couple book shelves. Just as there are reasons the luan boat is piled in an outbuilding covered in dirt. While the old ones worked it's time for a better mousetrap. I've pretty much abandoned trying to use box store plywood for any outdoor project without at least one side and edges glassed.
 

beekeeper

Well-Known Member
Mar 4, 2009
1,849
52
If you believe adding a layer of glass to a1/4" ply boat will correct the "reasons" that turned your boat into book shelves then choose that way. Most builders using interior grade luan cover both sides and edges to try to keep moisture from the wood. Both choices may give you a serviceable boat I would not consider either the best "mousetrap".
A strip built, or marine grade plywood build could give you the best possible "mousetrap". Each offer positive and negative aspects. You will have to decide which one will best meet your goals.
 
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C_Brice

Well-Known Member
May 12, 2005
48
0
Iowa
If you believe adding a layer of glass to a1/4" ply boat will correct the "reasons" that turned your boat into book shelves then choose that way. Most builders using interior grade luan cover both sides and edges to try to keep moisture from the wood. Both choices may give you a serviceable boat I would not consider either the best "mousetrap".
A strip built, or marine grade plywood build could give you the best possible "mousetrap". Each offer positive and negative aspects. You will have to decide which one will best meet your goals.
There's better mousetraps and best mousetraps and as I said I'm looking for the former not the later. Every step you take is better.
 
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