I'm still pondering how bend the chines onto the frame. Specifically I'm worried about how to cut in the angle on the chines where they meet the stem. Simultaneously I need to cut in the stringer where it terminates into the chine. Kind of a chicken and egg issue since the position of one affects the other.
Here is the process I"m thinking about:
1: Cut notches in higher bend areas of both chines (notches to match)
2: Clamp the chines into the top of the chine stringer relief in bulkhead 1
3: Support the aft ends of the chines high enough to so that the forward end of the chines hit their dimension on the stem. (not sure this step will work).
4: Cut in the indicated angle on the chines at the stem. (see tool order)
5: Make superstucture pieces to indicated angle (to hold chine down)
6: Cut stringers to match indicated chine interface (see tool order)
7: Bond Stem superstructure in place (with chines removed), allow cure.
8: Push Stringer and Chines into place on BH1 and stem
9: Practice bend everything into place (small prayer here for it not to break)
10: If that works repeat with epoxy.
Tool Order. I went ahead and ordered a Fein multitool. I have been mulling this purchase over for some time. I knew I would need something like this when it comes time to match-trim planking. I could probably get away with trimming the chines with a hacksaw or dremel. But doing the long fine cut on the stringer (where it interfaces with the chine) will be much easier with the Fein tool. The downside is that I will not arrive until Feb 4. I'll be thinking about re-doing the order above to get as much done before needing the Fein tool as possible. I will probably also scarf together the shear timbers while I wait for the tool to arrive.
BTW: I paid $294 on Amazon and got the newest model (350Q) that comes in a hard plastic case with a healthy assortment of blades/attachments.
Hi Esteban, your scarf cuts look great. As far as the chine installation goes, I cant help you with that so I hope you can get there (with a little bit of help from Bernd)
ReplyDeleteHowever I did just want to ask you what glue filler additive you are using in your epoxy mix for gluing? The reason I ask is that other than in your rudder blade photos, it looks as if your epoxy glue is very thin. In other words there is no evidence of the whitish glue line that is normally present , and which is usually smoothed out into a bit of a cove on angled joins. Maybe you are just extra careful with cleaning up your joins, but it's just that epoxy with no or hardly any filler in it is much weaker than it should be. I'm not nit picking here, it's just that I am very keen to see you on the right path.
regards
Bryan
So far I have not used any filler in the epoxy. For the scarf joints I figured I had nice flat surfaces that I was controlling with even pressure (maybe I should have for the stringer joints). I will be using filled epoxy for attaching the chines since those interfaces are more uneven. I'm using fused silica and microballoons for fillers. Let me know if you have any words of wisdom if one is better in various applications.
ReplyDeleteThanks,
-Esteban
Hi Esteban
Deletewhilst straight epoxy should be ok on perfect joints, in reality it is not. The epoxy soaks into the timber , especially end grain, or partial end grain and leaves not always enough in the joint to do the job. the procedure is to "prime" the surfaces to be glued with neat epoxy, and then add filler (fumed not fused) silica to some mixed resin to the desired consistency. For fillers, West have a proprietary glue filler, but straight fumed silica is good. Use microballoons for filler, not for glue. The white stuff is best in general as the red (phenolic) is only for fairing surfaces and is quite weak. West also have a whitish coloured fairing filler that is good for fairing glassed surfaces.
I would urge you to read the Gourgeon Bros book on boat building and epoxy usage (free download) before you progress any further.
As regards your latest post- you can use a weight lifting weight on a piece of line to pull the stringers down. But in any case you need to lock that bow piece in place with braces, clamps, screws , whathaveyou. When you go to join the stringers into the bow piece, after getting them trimmed to length and angle , attach them through the bow ply piece with temporary screws while you glue them. Most builders also add a solid timber strip on the very front afterwards too, as I did, and most other builders i have looked at, as it adds a lot of impact resistance.
I dont really have many words of wisdom to give you that arent already available free on the net. When you are planning each stage, I suggest you ask on line . For example ; how do I attach stringers onto the bow (stem). you will get a lot of hits on sites like the Wooden Boat Forum, which alone is worth spending many hours trolling through. Same for attaching ply, also doing glassing etc etc.
regards
Bryan
Yes I looked at the Gourgeon Bros manual when I was deciding to build a boat (I think it is overly broad and includes too little detail for the things Im interested in). I also got several books, but every source I find either skimps on the difficult details or simply doesn't have to address the issue because the boat they are building does not call for it. Your input is well received though, these are not new problems and its worthwhile to find out how they have been solved before.
ReplyDelete-Esteban