Putting a Wood frame in Aluminum hull

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

  1. Barry
    Joined: Mar 2002
    Posts: 1,136
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    Barry Senior Member

    We rarely had to cut aluminum thinner than .100 so perhaps in the thinner gauges the wood will work.
    1/8 and up we just used a carbide tipped skilsaw blade that had 3 - 5 teeth per inch. We almost never had issues with having to clean the teeth .

    On our vertical bandsaws, 4 or 6 tpi was the norm.
    If we used anything less, the finer teeth would or could get jambed up.

    Re using WD 40 or paraffin as a lubricant. We absolutely stayed away from this as an aluminum weld really has to be absolutely clean of impurities.(certainly steel as well)
    So if you use a lubricant then you need a solvent, that will dissolve the oily/waxy surface or risk a poor weld. (as compared to a diluent that merely makes an oily surface less viscous, thinner but the oil is still exists)

    Solvents usually are a higher volatile flammable liquid, not something we ever wanted in a welding shop with multiple welding stations.

    Trichloroethylene ( used to be used in Brakeclean products) was an excellent solvent, but when an arc is present, it can turn into phosgene gas, the gas they used in
    WW1. I am not sure about toluene or any of the other solvents

    So better to lower the tpi to a point that you don't have build up.
    Slow the speed of the blade into the material. If you push saw a jigsaw quickly into the aluminum, you ask each tooth to take out more than it has room in the gullet or root
    of the tooth per stroke, then the aluminum just will fill it in. You can google tooth cutting mechanics and see that there is a certain feed rates and each tooth can only carry out so much
    material. You can also check out feed rates for horizontal bandsaws and see that they will have downward rates depending on the tpi, and feet per minute, and the THICKNESS of the material. As the blade is coming down, each tooth will begin a cut at the start of its contact, continue to cut as it moves through the material, and when it exits the cut, you need to ensure
    that the gullet has the room to carry the material that it has cut. Otherwise it will build up.

    Best on a bandsaw or jigsaw etc, to cut slow, rather than push the material into the blade beyond the ability of the tooth profile to deal with the cutting

    On thin sheet, if using a skilsaw, keep the blade at the absolute minimum of depth so the blade is moving quite horizontal to the cut. Ie cutting one eighth inch material set the blade at only a quarter inch showing. It makes a smoother cut in thin material
     
  2. mydauphin
    Joined: Apr 2007
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    Location: Florida

    mydauphin Senior Member

    I have cut a lot of aluminum and found that $9.95 regular wood circular saw works great. I go for 40 to even 24 tpi, and I don't have any problem with teeth clogging. I cut slow, and replace the blades more often than if I was cutting wood. If the edge is a little ragged then a little sanding solves that. The other option is spend lots of money on special blades and oil that may work better but ultimately method A is cheaper. So basically I treat Aluminum like a hard wood. On wood in analuminum boat, be careful of corrosion if the wood gets wet and sits on aluminum. The biggest problem I have is the termites are eating the wood. Now I have to replace the wood floor with aluminum/epoxy. Never should have put it down. The termites are eating it fast.
     

  3. Barry
    Joined: Mar 2002
    Posts: 1,136
    Likes: 78, Points: 48, Legacy Rep: 158

    Barry Senior Member

    I think that you mean 40 teeth per blade on the circular saw? We have found the carbides last an inordinately long time and if you are back gouging a weld, to ensure no voids, you are often running into aluminum oxide from the previous
    weld which can eat the edge off a regular pure metal tooth.
     
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