March 5, 2017
Laminating the Aft Outer Stem
The Aft Inner Stem seemed to turn out well. I will have to run it through the surface
planer to bring the overall width down to the proper dimension, but I purposely
oversized it so that I could do that.
I placed the completed Inner Stem back in the form and then
proceeded to epoxy the strips for the Outer Stem. It took 3 batches of epoxy to cover all of
the 15 strips. I then wrapped them in
plastic so that they did not become part of the form and clamped them in
place. After adjusting all of the clamps
to provide just enough pressure to hold them securely together I cut the excess
plastic off of the top and then cleaned up all of the squeeze out. Placed five 100 watt fixtures to assist in
keeping them warm so that they cured properly.
One thing I did different on the Outer Stem was to use 405
Filleting Blend instead of the 406 Colloidal Silica that I used on the Inner
Stem. The Colloidal Silica dries white
where the 405 Filleting Blend dries somewhat wood colored. I doubt it will make any difference in how it
bonds.
I will let everything cure for a couple of days and then
begin the same process with the forward stems.
Hi Russell, thanks again for your blog updates. A question about the lamination of the stems: normally these would be in thick solid timber but imagine it to be too difficult to obtain curved solid timber of that thickness, is the lamination of many slats an engineered alternative to the solid piece?
ReplyDeleteThank you
Hi Pmeriggi (please tell me your first name so that I can address you properly - thank you) - Regarding your question on using laminations verses solid lumber. It would be very difficult to obtain and steam bend the lumber for making a stem. I am sure it could be accomplished but it would take much more effort and time verses laminating. I am pretty much following the video series on Building the Caledonia Yawl on the Off Center Harbor site. They use this same technique of laminating. Using the West System Epoxy, it makes a very firm bond between the wood strips and just as strong, if not stronger than solid lumber. When I built my cedar strip canoe, I laminated both the inner and outer stems without any issues. Hope that helps? Russell
DeleteThank you Russell, that's what I thought
DeletePietro
Another question about the outer stem if you don't mind: this part of the boat usually would be made of strong resilient timber as it is most likely to be where the boat would take the hardest hits; I noticed your previous post on the recommended selection for Douglas Fir or Yellow pine, both seem relatively soft timbers. Does the lamination process harden the surface?
ReplyDeletePietro
Pietro - Thank you for that question as it now has me questioning and wondering how I got the idea of using something other than a hard wood for the stems. I know that when I build my cedar strip canoe, that I used white ash for the stems. I reread Iain Oughtred's notes on wood and I found that he does indicate to use a hardwood for the "backbone" of the boat. I then reviewed the video series on building The Caledonia Yawl and it is mentioned on there that they were using Douglas Fir for all of the stems (both inner and outer). So now I am questioning and thinking that I will rip and cut some strips of white ash to be used in the outer stems. I believe that I can still use the yellow pine that I have for the inner stems but will have to redo the aft outer stem with white ash. Thank you for bringing that up. As I indicated, I am an amateur and learning as I go. Hopefully I won't make any major mistakes as I go forward. Thanks so much again and please question things as I do this build as I appreciate any comments and input. Russell
DeleteOh no Russell, now you have more work on your hands and more material to buy. I'm an absolute novice too and questions are all I have at this point in time and could dispense them all day long.
ReplyDeleteLet's just say it's all for the good of a better build
All the best.
Pietro