Repairing 54 yr old rubber exhaust hose 4.125" ID

Discussion in 'Wooden Boat Building and Restoration' started by sdowney717, Oct 31, 2024.

  1. sdowney717
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    sdowney717 Senior Member

    This joins to a copper pipe that exits the wood transom. It is joined to a black poly pipe which joins to a fiberglass muffler. Not wanting to buy new hose, I figured why not tear off the outer crappy rubber and then the rotten cotton to expose the still good inner sleeve. I have noticed the inner rubber on exhaust hoses seems to be much better quality than the outer cover. Scrubbed it clean and it looks good to me. The outer rubber layer was in rough shape, weak and tore easily. The cotton also partly rotten and where it was not rotten, with effort was able to cleanly pull it from inner rubber sleeve.
    Visible on the surface of inner sleeve is the rough cotton wrap when originally made.

    I used the poly pipe as a form. I wrapped 2 layers of paper board around the tube to make it a size that will slip onto the copper pipe.
    Slid old inner sleeve over paper.
    Then coated sika flex 291 LOT over sleeve with a plastic putty knife spreader.
    Wrapped 4 layers of this yellow drywall tape over the sleeve coating on more rubber for every layer.
    I pulled it tight as I wrapped.

    Then it's done. Took about 1/3 of a tube. I paid $6 for this tube. Amazon Sikaflex store made a price error. It is now back to $22, should have bought more than 2 tubes but wondered if it was a scam...

    Took me less than an hour to tear it apart, setup the process and finish the wrap. I have no idea how much a new hose costs, but likely lots more than what I did.

    The other hose that joins to muffler is in perfect shape.
    Either hose could fit in either spot.

    Starting out, you can see the torn off cotton, some of which was rotten.
    upload_2024-10-31_15-39-34.png

    Starting with some sika 291

    upload_2024-10-31_15-40-43.png

    Finished wrap, hose good as new. Likely stronger since it has FG instead of cotton. The FG wall tape does conform and allows you make low angle turns as you wrap ends to middle. After first layer done, I did not cut tape for the other 3 layers, just wrapped tight and coated as I made a spiral row.

    upload_2024-10-31_15-41-50.png
     
  2. seasquirt
    Joined: Dec 2015
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    seasquirt Senior Member

    Good work sdowney717, I love a home made fix, or 'macgyvering'. I hope the Sika is up to the temperatures. Get that old vice bolted somewhere, it's a pearler.
     
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  3. sdowney717
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    sdowney717 Senior Member

    it's good to 180 *F, I figured it would be ok.

    I just checked and it is curing fine. I use a Rector Seal T Plus 2 teflon pipe dope on all my rubber hoses. It keeps rubber hoses from sticking to metals.

    This one has to slide back to remove and slide up the black poly tube to install.

    I inherited that vice and it is a good old vise. I just dont have a clean work bench to install it somewhere. And I do need to clean it up, it has gotten a little rusty. The whole head can turn 360 degrees.
     
  4. messabout
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    messabout Senior Member

    I 'm with Seasquirt. That vise is a real prize that deserves some serious TLC.
     
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  5. sdowney717
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    sdowney717 Senior Member

    Took the hose off the form this morn, and it is perfect.
    There is no pressure on this tube, it just channels exhaust water out back of the boat, I figure though with all those FG layers, it could take some pressure.

    You know cotton has no stretch either does FG tape, but it can compress with a hose clamp and seal.
     
  6. sdowney717
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    sdowney717 Senior Member

    Funny thing is, here I am fixing up a really very old rubber hose, while my dad used to buy new tires every 2 years whether their car needed them or not. I told him he was wasting his money and could get 10's of thousands of more miles from them, he would just get mad, saying they were unsafe. My dad used to waste-spend money like it was nothing. Of course, when you have money to waste, that is what some people will do.
    Me, I am frugal, I save and invest money and spend it when needed. Besides all that, this hose would cost me hours of time to drive somewhere and try and get a new hose, which who knows if it would fit decently like this original. And I don't want to fight with it trying to stretch it into place in a spot hard to work with on the boat. I do have access with a plywood covering board unscrewed, to reach down with one hand couple of feet and put things together.
     
  7. comfisherman
    Joined: Apr 2009
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    Location: Alaska

    comfisherman Senior Member

    Guessing it was originally a stretched 4 inch bellows. Nowadays it's substitute would probably be a high temp 4 ply silicone hose that runs around 100$. It's always a stretch the first time it goes on, our tool of choice is a dedicated tub with a repurposed BBQ grille and a hole in the bottom. We put a kettle in the hole underneath it and start a boil. When the lid gets all wonky it means it's warm enough to slide on. Did a six inch one the other day, used some low profile tig gloves and moved fast. Took two tries to stretch it on which is pretty normal. The shields exhaust hose with wire is a bit bigger bear but can be wrestled in the same manner and is cheaper than the silicone.

    Glad the fix worked for you, most folks would conclude that the rubber on the inside is just as old as the rubber on the outside. On a wet exhaust low down, leaks aren't much fun to deal with on the water.
     
  8. sdowney717
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    sdowney717 Senior Member

    Yeah, I don't want to wrestle on a new hose. The copper pipe is a genuine 4 1/8" OD to have a genuine 4" ID. It is inline with the muffler, no bend.

    IF the inner liner was bad, I would have bought a new rubber hose from say Hampton Rubber. They do sell fractional sizes.

    Going to use the T plus 2 teflon pipe dope to aid in sealing, plus it prevents rubber from gluing itself to metal. 2 SS band clamps on each end.
     
    Last edited: Nov 3, 2024
  9. sdowney717
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    sdowney717 Senior Member

    I should check the other side also. I got into this as 20 years ago, I mis made the transom hole for port exhaust, cut it too low by about an inch, compared to other side. What that caused was at rest, the copper sat slightly in the water all the time, not that it damaged anything, but could sink your boat.
    I moved the 4" hole up an inch, and then made filler pieces for the frame and the outer plank and glued them in place. Recut to the right size.
    I got a decent tight fit for the wood pieces, and the hole.
    Behind these outer planks is an angled 2x10 forming the framing corner support for the boat, to which I had to carve and glue in a piece as the hole intersects the top of the plank which runs at 45 degrees to the hull planks.

    Wood wedges shown holding in wood pieces while glue sets.

    upload_2024-11-3_10-40-38.png

    And it is done, above is the bottom of a teak swim platform. Bronze bracket at extreme right.
    I plan to put sika flex 291 on the wood and seal this copper pipe into place.

    I now have 2 fingers width from pipe to swim platform, same as other side.
    Somewhere I also have bronze rings for the copper pipe, lost track of those, but they have not been on for 20 years.
    upload_2024-11-3_10-43-15.png
     
  10. sdowney717
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    sdowney717 Senior Member

    So the bottom edge of this hole the wood is 3" thick, and 1.125" at hole top

    I did not use a 4" hole saw to form the hole. I ground and cut it out free hand.
    Was not an easy job, took several hours to get a good tight fit to the pipe, and to have it even all way round.

    The inner thick corner support frame intersects in the middle of the copper pipe at a 45-degree angle. When I rebuilt the entire transom more than 20 years ago, course I had to replace all the interior framing wood. I abandoned the convoluted way Egg Harbor had done it, and it has been great with no rot anywhere. And stronger I think the OEM and no leaks. OEM crazy, but they used plywood rather than solid boards. They also had a complex interior framing and it all rotted in under 30 years. When I got boat, I was reaching in by hand and pulling out chunks of wood mulch, surprised it had not sunk the boat.
     
  11. kapnD
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    kapnD Senior Member

    What type of “black poly pipe” is that?
    I seriously doubt it’s suitable for exhaust service!
    Plastic pipes get very soft when overheated, and can burn.
     
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  12. sdowney717
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    sdowney717 Senior Member

    Don't know, but it came with boat when I got it 25 years ago.
    It feels like HDPE. No markings on it.
    It's position is around 8 feet from the riser outlets past the mixer and the fiberglass mufflers. It sits between muffler end and copper pipe outlet. One rubber hose joiner on each end.
    I figured it is OEM from 1970

    I have not seen it get deformed from heat yet. Looking inside looks clean and shiny, like the outside.

    I have not had to replace any exhaust hoses or parts except for risers yet.
    Copper outlet is perfect. It does have a heavy wire soldered on the outside and is bonded to the rudders. If it's original, I don't know. But does it seem like seeing the copper pipe is perfect, would a prior owner need to replace a 4' long copper pipe sometime in the past on both sides? I would think the copper would be as good as the outlet copper pipe.
     
  13. sdowney717
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    sdowney717 Senior Member

    Went looking and approved rubber exhaust hose is rated to 200 degrees F, still under the boiling point.

    Temperature Range-20 Degrees to 200 Degrees F Continuous

    SHIELDS RUBBER Series 200 Exhaust/Water Hose, No Wire (Sold per foot) | West Marine

    And it's going to burn if the cooling water flow stops, same as a plastic pipe, although might last a few minutes longer. That kind of heat likely to also cause the hose to delaminate on the inside, fall apart. Hoses are made of layers of rubber and cloth reinforcements.
     
  14. sdowney717
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    sdowney717 Senior Member

    My guess is the 3" rubber hoses attached to risers before the bronze mixer are going to burn first on the inside, and blue black smoke from that will come out the exhaust.

    The large laid flat mufflers always have water in them, and until boiled away, that water will cool the pipes coming after them. The fiberglass plastic mufflers are like 1 foot round cylinder diameter, black color, and several feet long, and they do also have a drain plug which I have never removed. I do think they are Centek or Vetus brand and they are old.

    The look like this, with 4" outlets. This looks very familiar looking to me.

    CENTEK Muffler, 4" In/Out OD, 9.06" Body dia., 26.69" Body Length, 33.69" Overall | West Marine

    Anyhow, it has not happened yet to me.
     

  15. kapnD
    Joined: Jan 2003
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    kapnD Senior Member

    Neither poly pipe nor copper are recommended materials for exhaust pipe.
     
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