Epoxing Mounts to Engineroom Wall/Floor

I am in the process of planning out my water maker install and need to install some mounts in the engine room for the motor and filters. Since my hull is cored I assume the proper thing to do is to use wood epoxied to the current hull but could use some specifics. I have West System epoxy, the engine room paint is old in the area I want to mount it, any specific cleaning instructions?
Also any specific woods better than the other? I was thinking something with a bit more density would be important. Once epoxied I was going to hit it with a coat or two of bilgecoat paint.

I might have the wrong idea or process here so advice appreciated.

Thanks
Arthur

I would recommend that you first sand the paint off to an all fiberglass surface. Then you have 2 options, IMO.

You can build the surface up with alternating layers of bi-axial cloth and matt, using polyester resin (fiberglass). This goes faster than you would expect as you can cut multiple layers and put a number of them down with each batch of polyester.

The second choice would be to bond a piece of Coosa board to the hull using polyester resin thickened with bonding powder (West system product). I would cover the Coosa board with at least one layer of bi-axial cloth with maybe a 2" overlap on the hull.

Either method could be done with epoxy instead of polyester. IMO, wood blocks laminated to the hull are a poor choice.

Ted

There are COTS (commercial off the shelf) stickers made to hold pipe, wiring , whatever.

Check Hamilton Marine and other boat building sources.

When we redid our engine room, I used 1/2” or 3/4” marine plywood depending on the loading. I made templates first then fabricated the platforms. I sealed the edges and then tabbed them to the hull after sanding the hull to get to clean glass, using 2-3 layers of biaxial fiberglass cloth and polyester resin. I like working with polyester since it’s easier to sand, cheaper and there’s no blush to deal with.

Teak accented engine room with mitered corners on the trim


That's some Hobo

Keysdisease said:

Teak accented engine room with mitered corners on the trim


That's some Hobo

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Its a very impressive engine room! I have seen it before,during refit and after..

You can sand off the old paint and sand with a 60 grit to scuff up the fiberglass, wipe with acetone and then epoxy a plywood block to the hull. I would coat the plywood with unthicken epoxy to seal it. Then wash the plywood off with water to remove any amine blush. Thicken some epoxy with some structural filler and trowel it on the plywood block about 1/4” thick. Push it in place and work it back and forth a bit to make sure that you have good contact with the hull. Tool the edges and make a nice radius with the thickened epoxy so that it looks good. You may have to brace it in place until the epoxy goes off. You can put wax paper between the braces and the block so the braces don’t get glued in. After it goes off wash it with water to remove any blush and then paint.

Like Comodave said but I just tape the ply in place while the epoxy cures.

Duvie said:

Like Comodave said but I just tape the ply in place while the epoxy cures.

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I leave a clean spot in the middle of the piece on the back and on the corresponding bulkhead and then use a few dots of hot glue on those areas to hold it up.

I like to glass over the entire block and around the edges/fillets.

I have had great results with epoxying large enough pieces of mahogany to the hull and then screwing directly into the mahogany. Very strong, good looking, no rot and no screwing around with layers of glass.

First sand the area with 40 or 60 grit, then attach the mahogany using thickened epoxy.

Ken

kchace said:

I have had great results with epoxying large enough pieces of mahogany to the hull and then screwing directly into the mahogany. Very strong, good looking, no rot and no screwing around with layers of glass.

First sand the area with 40 or 60 grit, then attach the mahogany using thickened epoxy.

Ken

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Second this. Depends on weight of equipment being hung. 1hp motor with pump, structure should be pretty beefy. Tubing/membranes/filters, hard to go wrong with blocks of mahog and peanut butter epoxy.

For bigger stuff or stuff I wanted to isolate, I've used lead faced plywood (painted for safety) mounted with vibration isolating mounts. Then attached pumps etc to that vibration isolated plywood.

Ken

This is the quick and easy method I use for installing deadwood:

Clean off any non-adhering paint on the hull, seal the edges or paint the deadwood (I use exterior grade plywood), put an appropriate number of dollops of 5200 Fast Cure on the back of the deadwood, add a couple of patches of hot clue and put in place.

The hot glue will bond quickly and hold the deadwood in place while the 5200FC cures; typically in about 24 hours.

Neophyte question: What is 'lead faced plywood'?

kchace said:

For bigger stuff or stuff I wanted to isolate, I've used lead faced plywood (painted for safety) mounted with vibration isolating mounts. Then attached pumps etc to that vibration isolated plywood.

Ken

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Wil said:

Neophyte question: What is 'lead faced plywood'?

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Sorry, it's not a boat thing but it's excellent for vibration damping. It's used at my work to create X-Ray shields. I got a small scrap piece which comprised 3/4 plywood with 1/8" lead bonded to one side. I painted it and used it along with some rubber islolation mounts to mount my fresh water pump. Almost completely eliminated any noise or vibration from the pump.

Ken

For mounting the high pressure components, e.g. the HP pump, the membranes, and supporting the high pressure lines, you'll appreciate later any effort you put into vibration isolation. Those components can set up a really obnoxious resonance that is terribly annoying. The good news is it's pretty easy to mitigate, and not a lot of cost involved. It does take a bit of effort to determine the correct isolators, but this website is helpful- Vibration isolation.

Try to mount either hanging or standing vertical. Shear mounting isolators requires a special shear isolator, otherwise, they'll fail.

I installed membranes in a lazarette, they hung from the overhead, I used rubber isolator grommets to hang the mounting frame, nearly silent when running. The 1st iteration was solid mounting at the client's request for cost saving. The modification to isolate made an astounding difference in the noise.

Supporting high pressure hose to keep it from transmitting the pulsing of the pump is easy, I use a piece of silicone rubber hose and fabricate a simple isolator. (Photo) These gizmos are very effective at isolation, and inexpensive. Don't try to use plain rubber or plastic hose, it transmits the noise.

If your watermaker is a unitary frame mounted design, it will be easier to isolate the frame than if you must treat individual components.

Maerin, I think that is brilliant!