MaterialsForBoatbuilding

[TerryKing]

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[djwkd]

Not bad actually!i havent really had a proper look at it (as im not a boatbuilder-im a raft builder!)but it does look good from the things that i did look at!

[ancient kayaker]

Very good info. Is this the right place for stuff like jigs? I have a great design for a scarfing jig that gives perfect results using a belt sander which I would like to share.

[alan white]

Thankyou! I wouldn't mind borrowing your belt sander! I can send you shipping info right away!
Sorry--- couldn't resist. And since I like ideas that save time and give good results, could you draw your jig?

Thanks, Alan

[alan white]

Originally Posted by TerryKing

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Very useful, Terry! Thanks. A boatbuilder's wikapedia.

Alan

[lazeyjack]

Originally Posted by TerryKing

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yes terry great for someone who has not really been into wood and sticky stuff
But now we are working on a canal boat (wide beam) with all ply houses and roofs,
We always used to use asbestos powder as glue mix, it was really strong, funny thing is you can not buy it now))

[ancient kayaker]

I hope the graphics turns out OK; there are two jigs, one for cutting and one for gluing. The cutting jig is ideal for thin ply where precision is extra important; the steel bar and square tube should be rotated as they wear. The gluing jig is great if you have a lot of planks to scarf.

[alan white]

Does it work well?

[ancient kayaker]

This is embarrassing. I rebuilt and retried it today and it did not work as well; the ply edge was beautifully feathered but the veneer lines were not straight. The sanding belt is very aggressive and cut significantly into the steel, spoiling the accuracy, obviously I have the wrong grade. I don't have the belt I used before so I will have to experiment. When I discover the right one I will get back to you. In the meantime I found my digital camera so I can at least attach a photo of it.

[alan white]

I can tell you, the idea of resting the sanding surface of the sander on steel will not work well because the belt will quickly wear on the steel as well as wearing the steel. You don't need to lay the belt on the steel though. You only have to find some means to attach four wheels to the belt sander------ wheels that would ride on steel guides (a pair of channel irons would be rigid enough) above and below the scarf face. Each sander would present different problems, but I imagine any sander could be modified to work that way. Adjustment would be the endwise location of the plywood itself.

Alan

[lazeyjack]

Originally Posted by alan white

Does it work well?

ACTUALLY ALL YOU NEED DO IT CLAMP A WOODEN PIECE ACROSS the ply at distance back from ply end and right height(draw it) and plane it with plane resting on on edge on wooden bar, simple
OR YOU CAN MACHINE SCREW A PIECE OF ALLOY FLAT ONTO THE SIDE OF YOUR PLANE, whoops caps,so that it runs past the flat of plane, once again calculating overlap of bar and bottom of plane
Then make clamp a piece of timber or alloy bar onto the ply and run your plane against this, the plane must be razor sharp, actually I have not a clue if this works I just made it up, but need to jig up myself so working on it!

[Landlubber]

lazyjack,

Yep, it is that simple, particularly with plywood, as you simply make the lines straight (of the veneers as you plane)

[alan white]

It's always worthwhile to listen to a new idea. Most new ideas aren't real improvements, but once in a while...
How something is done depends on who is doing it. I like hand tools that are razor sharp. Some people won't have enough time in their lives to become an expert with a hand plane. They rely more on power tools.
Tools are becoming more "versitile" (complicated) every day due to the belief of weekend warriors that such complication is a natural part of being accurate.
Thus, there are lasers on many saws now, for example. Yet, those complicated machines can often make a novice do better work. The pro will wear out those extravagent features in every day use, so he desires simple ways of getting the job done using a thing called feel.
It's all good.

Alan

[lazeyjack]

Yeppers Alan
they have this hand circular saw ad here on TV, has a laser guide, what a bunch of ole cobblers, frinstance when I use saw to cut long curving lines on plates, I take foot off the saw, hold the guard top in left hand and grip normally with right, sight over the guard to blade and can cut as accurately as a lazer, this works to 6mm, the drill is keep the saw abreast of one or slightly behind , so if it kicks it is always behind, the saw is only just penetrating the material, safe as houses 6 and over it is very hard on hands Naturally the plate is on the ground on old timber 4.2 , this works very well for ply too, much more accurate that jig saw, and abt 100 times the speed

[ancient kayaker]

I withdraw the belt sander idea! Actually the biggest problem was pointed out to me yesterday - the sparks from the steel and the dust from the wood could be a serious fire risk.

I find planing scarf joints works fine on thicker material but 3 mm ply has a tendency to curl at the edge resulting in more material removed from the middle of the cut. With cheap (luan) ply even a scary sharp plane caused tearout at edge but I will try it on some decent ply.

There is a commercial jig for adapting a circular saw to cut scarfs but again on thin ply accuracy is not good enough and tearout across edge grain can occur even with a fine finish blade. However, I use a jig on a chop saw to cut scarfs for 'wales and chine logs, the saw exits with the grain with no tearout and I glue without further finishing.The joints are hard to see. Since I use laminated 'wales the time saved is significant.

I appreciate the inputs guys; there are so many ideas around for cutting scarfs that no idea is likely to be new. We see further if we stand on the shoulders of giants but its a long way to fall ...

Lazyjack: here's an idea that actually works to make up for that other one: for cutting large ply pieces I put a sheet of insulating foam on my table, ply on top, cut with a (handheld) circular saw or better a panel saw with the cutting depth about 1 mm more than the ply thickness. For thin ply this is the way to go. The foam block is cheap and lasts for dozens of cuts.