Putting a Wood frame in Aluminum hull

Discussion in 'Materials' started by jlmclean, Nov 8, 2016.

  1. jlmclean
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    jlmclean New Member

    I have a 15' Aluminum hull (Bass Boat Design) that I picked up at a scrap yard. It has no frame work at all, just the bare hull. I am a pretty decent woodworker and have actually built a plywood skiff. I am thinking about putting a wood frame in the aluminum hull. I really don't want to do any type of through hull fasteners since they would be going into the wood. My idea is to glue the framework to the aluminum. If anyone has actually glued wood to aluminum and had good results, I'd like to have some suggestions on the best adhesive to use. I want to do it right the first time instead of realizing I should have used something else later on down the road.
    Thanks in advance for any help.
     
  2. mydauphin
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    mydauphin Senior Member

    First don't use pressure treated wood , it will rot your aluminum. 5200 caulking will work well on aluminum and wood. I would also do a couple of stainless steel nuts and bolts somewhere. It may not be the best thing but it will get you out fishing.
     
  3. upchurchmr
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    upchurchmr Senior Member

    Don't do it.
    When the aluminum heats up it will expand a great deal more than the wood, putting the glue under a great deal of shear.

    I put an aluminum V track in a piece of fir once before. Out in the Texas sun it broke the bond as soon as I put load on the track.

    Very bad idea.

    Fasteners would be a much better idea.
    Or do it right and use aluminum for the frame.
    Aluminum cuts pretty much like wood, except for the noise, and the chips which are like extremely sharp knives, and the fact that you have to scrape aluminum slag off the blade every few minutes.
    That is because of the woodworking blade speeds and construction of the wood blades.
     
  4. Barry
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    Barry Senior Member

    There is not a problem with cutting aluminum with woodworking saws. A 7 1/2 inch circular saw with 40 to 60 carbide teeth, reciprocating blades at 6 teeth per inch and bandsaws at either 4 - 6 teeth per inch will give you clean tooth service. Do not use a wax as some people recommend if you are going to weld the pieces in as the wax will cause problems making up a joint. There are aluminum specific cut off abrasive discs and grinding wheels. Do not use an abrasive steel disc/blade for aluminum or you might have it explode. The aluminum can melt into the outer rim, solidify when cold, then when you start grinding it can tear the disc apart.You will find for that for sanding you will use maybe a 60 to 80 grit for final sanding.

    You could go down to a boat dealer to see what framing is required and copy it as the reinforcement design will be proven. Then cut all the pieces to fit, and a welder in a couple of hours should be able to weld in all the pieces that you need.

    When cutting any aluminum, you should use two levels of eye safety, a set of safety glasses and a face shield as the chips come off hot, sharp and travel a good distance
     
  5. Ad Hoc
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    Ad Hoc Naval Architect

    Make sure your wood is well treated and 'sealed' and that the ally hull contact is treated and sealed too, otherwise you'll run into bad corrosion.
     
  6. mydauphin
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    mydauphin Senior Member

    I have built several aluminum boats from 8 feet to 70 feet. Welded of course. Cutting is like cutting wood, I just use regular wood blades you just have to change them more. I do go for more teeth per inch just so they don't jam. Cut flat on aluminum, not on edge. I have also glued aluminum to aluminum using either epoxies or fancy caulks. Both work. I used 3m 5200 caulking to create shock mounts for things like instrument clusters and solar panels. . After many years I have to cut them off. I also use wood internally for walls, etc. I bolts them on and use cheaper caulking for vibration. So if the guy wantsaid to putter along in his bass boat, why not mix mix together. It is not a spaceship or a yacht, nor is he crossing the Atlantic.
     
  7. Barry
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    Barry Senior Member

    Re welding,
    I made two assumptions, 1) that the hull is thick enough to take a weld, say on the bottom .100 and 2) that the hull is not a riveted construction where they will use a mastic/gasket between the two pieces before they RIVET the hull together. You never want to run a weld bead even close to this joint as the mastic will just melt out and you will have leaks
     
  8. jlmclean
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    jlmclean New Member

    Thanks for all the info. I need to add a little more to the situation. I do welding myself. Grew up and still live on a farm. Fixed everything from plastic to steel and have welded quiet a bit of aluminum. I have built a plywood skiff and have always been fascinated with wooden boats and the methods of building them. I've had this old hull laying around for years and thought it would be neat to have wood inside instead of metal. The wood frame is a personal preference more than anything else. I am capable of going either way but to me, wood is more pleasing to the eye and to the touch than aluminum is. I appreciate the opinions on what and how to do it and I hope some more people reply. Thanks to all.
     
  9. Barry
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    Barry Senior Member

    It would be helpful if you sent some picts and what you are trying to accomplish. From the first post, it appeared that perhaps inside stringers etc are not in existence and you are trying to strengthen the boat.
     
  10. jlmclean
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    jlmclean New Member

    Yea, it's just a sheet aluminum hull. It has a "V" probably 1 1/2" wide crimped in full length of each side and I think maybe 5 in the bottom running full length, all for strengthening purposes. I've not checked the gauge but it's probably around 1/16" to 3/32". I'll try to snap a photo of it and post it but it will be tonight or in the morning before I'll get a chance to do it.
     
  11. Irie
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    Irie Junior Member

    Aluminum cutting tip: place scrap wood underneath the aluminum where you plan to cut and cut both the aluminum and wood. The wood will clean the teeth as you go. No more stopping to clean the blade. My preference is metal cutting blades, 14 tpi.
     
  12. jlmclean
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    jlmclean New Member

    Here are a few pictures of the hull, not the best but maybe you can see what I have.
     

    Attached Files:

  13. PAR
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    PAR Yacht Designer/Builder

    Wooden slats would be all I'd consider and these would be removable. Bonding wood to aluminum has it's issues and isn't recommended on a boat like this, mostly because of the weight. Most aluminum boats do have some wood, commonly in the transom or under seats, but is to offer some stiffness to a relatively flexible material. It's typically through bolted, screwed of bonded, with polyurethane adhesive/sealant. That little jon can't take a lot of weight, before you really hurt its capacity and performance. Think cedar slats on the bottom and move on.
     
  14. mydauphin
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    mydauphin Senior Member

    Cool tip.
     

  15. alan craig
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    alan craig Senior Member

    I've just been looking at West System epoxies, they do a couple of flexible ones which which are ok for metals; they even give achievable tensile strength. Morgan cars are made with a wood (ash) frame and aluminium skin. I'm sure you are familiar with cutting ali. but paraffin or WD40 make good cutting lubricants.
    I think your boat would look great with wood framing.
     
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