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best technique for smoothing inside of strip-built hulls?

Submitted by Robert Evans - Sun, 2/15/15 » 6:01 PM

I have not found a satisfactory way to smooth the inside of a strip-built hull. Does anyone have a technique they would recommend?

Has anyone tried a convex plane?

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RE: best technique for smoothing inside of strip-built hulls?

» Submitted by hspira - Mon, 2/16/15 » 8:48 AM

Robert,

let me start by saying, smoothing the interior is one of the more challenging elements of construction becuase the typical labor-saving devices (like ROS sanders and planes) are difficult to apply to the inside of the boat..

that said, there were a couple tools that have helped me along.

shaped sanding block for the tightest corners (bilges) and other highly curved surfaces. there are cheap sanding blocks i made by myself that are custom shaped to the hull curves i am working. the sanding block itself is a high density foam (picked up a cheap chunck from the home depot) and the shape is made by using forms as a guide (take two forms related to the area you are working and sandwich a six inch piece of foam on between them and cut the foam with a knife) then use 60 grit sandpaper as the surface for the block. with the sanding blocks i then worked the area. just need to be patient...and break the work down into a lot of different sessions. for the hull i was working on....i needed three different shaped sanding blocks for different parts of the hull.
shaped cabinet scrapers....you can find convex cabinet scrapers that can be useful. they typically come as a small set for ~ $20 and have several shapes from circles to more oblique curves. these were particularly useful for knocking down glue drips and getting me to the bare wood....where the shaped sander was then engaged.
small diameter circular sander....if you have some 'flat sections' of the hull you may be able to use a ross sander. i also have s specialy circular sander that uses disks that were only about 2 1/2 inches which was useful for the bottom of the hull...which in the desgin i was build pretty much flat.
Fein sander -- this is a pretty handy tool to have and the sanding head often looks like a triangle....good for corners. there are some other makes that do the same thing.

overall....i just recognized this phase was going to be labor intensive and just paced myself and over about a week or two got it to a very satisfactory conclusion.

best of luck

howard

RE: best technique for smoothing inside of strip-built hulls?

» Submitted by Robert Evans - Mon, 2/16/15 » 11:39 AM

Howard, excellent suggestions!

Did you find sanding faster than scraping?

RE: best technique for smoothing inside of strip-built hulls?

» Submitted by Rocky Mountain Boatwright - Mon, 2/16/15 » 11:51 AM

If you have the room:

ArborTech Countour Random Sander.

I have several of these mounted on electric angle grinders and smaller air die grinders. Not sure what I would do without them.

RE: best technique for smoothing inside of strip-built hulls?

» Submitted by hspira - Mon, 2/16/15 » 6:11 PM

Robert,

sanding with a high abrasive sandpaper was actually pretty quick. the scrapers, as i mentioned really seemed good for knocking down glue drips that otherwise would gum up the paper.

the boat i did was a night-heron....18 feet long...so it was just a lot of boat. if i looked at the hull only...i think i broke it down into 8 nights (four sections on the left/four sections on the right) and put in an hour or two per section). the middle sections were fairly easy and i was able to use the small ros sander to help.....the ends took longer.

i get kind of zen about the whole thing and just paced myself. when i try to do too much in one session...or use a power tool aggresively...i usually end up doing something i regret.

best

howard

RE: best technique for smoothing inside of strip-built hulls?

» Submitted by Silver Salt - Mon, 2/16/15 » 7:52 PM

This is the main tool we used on Julie's Redfish King...

http://www.leevalley.com/US/wood/page.aspx?p=54888&cat=1,310,54888

Works a treat. Hardest thing is to sharpen the cambered iron. Look to chair bottom shaping tools like travishers, scorps and inshaves as posibilities too.

Cheers,

RE: best technique for smoothing inside of strip-built hulls?

» Submitted by greg27 - Tue, 2/17/15 » 6:35 AM

spray the back of a sandpaper sheet with spray adhesive and fold it in half .cut into strips for hand sanding this way you dont need a block to sand ,it cuts surprisingly fast