Engine noise abatement

[jbruce]

I am upgrading the soundproofing insulation in the engine compartment (hatches, mostly) to reduce engine noise on my 2012 Cutwater-26. The new insulation has a peel-off layer to expose the sticky-back adhesive. To ensure good adhesion with the new product, it is necessary to remove the previous adhesive materials that held the original insulation in place. Job success requires an absolutely clean surface for the newly-installed materials.

Question: Trusting that you know (or can find out) the chemical composition of the adhesive materials that held the original insulation in place, can you recommend a high quality solvent that will remove it easily and completely?

 

[Andrew Custis]

Hello there,

The adhesive comes on the sound insulation so I wouldn't know what is applied from our supplier. Your best bet here is to contact Brandon@soundtechco.com.

Hope he is able to answer your question.

Best regards,

Andrew Custis

 

[jbruce]

Thank you, Andrew.

 

[SGIDAVE]

it is necessary to remove the previous adhesive materials that held the original insulation in place. Job success requires an absolutely clean surface for the newly-installed materials.

can you recommend a high quality solvent that will remove it easily and completely?

Hello jbruce,

In my amateur opinion, use acetone.

But don't smoke whilst using the acetone.

And wear gloves and eye protection. 😉

etc, etc.

Good adhesive residue will not come off "easily" with any namby-pamby solvents (grin).

Seriously, let me know how that works out. I'll be removing the factory insulation from my R21 engine box to install thicker material.

/david

 

[jbruce]

David, Thank you this. Others have mentioned it too (along with Goop Off), and I certainly aim to avoid the namby-pamby! Appreicate your tip on gloves too, Jim

 

[SGIDAVE]

Well...the gloves are 'optional' as acetone is the main ingredient in "nail polish remover" which my wife and daughter liberally smear the ends of their fingers with several times monthly. So, it can't be THAT toxic, right? :?:

/david

 

[RProffer]

It is very toxic ... and flammable. Acetone is also the ingredient in lighter fluid. I would use it in a well ventilated space with no heat, sparks, etc. Make sure the bilges are well aired out before starting the engines, generator, etc.

 

[Captmike]

we have an R29. we notice quite a bit of noise emanating from the aft door frame. has anyone used spray insulation to reduce engine noise?

 

[Scottfree]

I've used acetone to clean up fibreglass projects, it dissolves the resin nicely! Use heavy rubber gloves not nitrile gloves sold at automotive stores, they swell and dissolve too. Put liberally on a rag and wipe on and wipe off. Don't spill the acetone in the boat. Yes it's is very flammable. Finger nail Polish is not pure acetone and therefore safe for the girls fingers. I'm not sure how diluted it is but I have given my daughters acetone and it removed the polish much faster! They said it burned but it didn't bother me much 😀 .

I like a combination of mechanical fasteners and adhesive. More complicated but doable.

Good luck, I'm curious how much quieter you could make these engine bays.

Leon

 

[baz]

I am upgrading the soundproofing insulation in the engine compartment (hatches, mostly) to reduce engine noise on my 2012 Cutwater-26. The new insulation has a peel-off layer to expose the sticky-back adhesive. To ensure good adhesion with the new product, it is necessary to remove the previous adhesive materials that held the original insulation in place. Job success requires an absolutely clean surface for the newly-installed materials.

Question: Trusting that you know (or can find out) the chemical composition of the adhesive materials that held the original insulation in place, can you recommend a high quality solvent that will remove it easily and completely?

Any chance you can measure the noise level before and after you add the new soundproofing material. I would be most interested in knowing the difference.

If you have an iPhone there are several Noise-level measuring Apps to be had.... using one of them would make taking the measurements very easy.

Thanks in advance. 🙂

 

[LADYBUG TOO]

We did not bother with removing the old adhesive; however, we did use a spray on adhesive and mechanical fasteners. Our original equipment sound material had fallen off. We found it on the engine when we opened the hatch. We just added the spray adhesive and used fender washers with screws to make sure it stays in place. One needs to be careful when using screws to make sure you don't penetrate the deck. There are also fasteners made specifically for this purpose and they were supplied in a kit we used to increase the sound dampening around our generator. They are aluminum perforated squares with a pointed aluminum pin. We fastened ours with short screws through the aluminum squares. We applied adhesive, then pushed the material on over the pins. A "one-way" washer is then pushed onto the pins and the pin cut. Another "one-way" cap is then pushed onto the cut pin to protect you from scratches from the cut offs. We do not recommend using the mylar tape provided for the seams. Get a good 3M aluminum tape for this as it will adhere much better. Also, the is a duct seam coating material for A/C ducts that will help protect the seam. It is messy and the finished product is not pretty but very effective. We have not applied that yet as we are hoping the 3M tape will do the trick. The sound reduction was noticeable(we think) although we did not measure before and after. Maybe it is just the "placebo" effect! After all that work, we wanted to believe!

Pat & Carolyn, Ladybug, Too

 

[baz]

Yes.... that "placebo" effect can be quite attractive/persuasive.... 😉

 

[jbruce]

Reply to baz and Ladybug Too:

First, what I did: I replaced the factory-installed sound insulation on the two engine hatches (C-26) with much superior sound dampening insulation from Sailors' Solutions. It comes in one-foot squares (I bought 12), making intallation pretty easy. It has a great sticky-back, but I also reinforced adhesion with fasteners (9 on the big hatch, 1 on the small one), and taped the seams with a good (matching shiny aluminum) duct tape. The fasteners were stainless steel screws with flat washers, which screwed nicely into the first fiberglass layer of the covers. With my two brothers steering the committee and doing the work--and my mostly keeping out of the way--it's a professional-looking job. I also added other sound insulation to a below-decks air passage between stern and bow, and recycled a layer of factory insulation I had removed and installed it as a sound blanket right over the engine (with no change in operating temperature, which I watched closely).

The results? Good, but not a showstopper. We did record decibel levels beforehand (my wife did that part with a hand-held decibel meter) across the entire RPM range at intervals of 500, and we also took some readings in different parts of the boat. Then we took them again afterwards. So I have comparative data. Unfortunately, I am out of town now and the data are not at hand, so I can't get too specific. But the DB range ran, as I recall, from the high 60s to about 95 at full throttle before the change. (This is a 180 Yanmar). After the fix, we definitely had a reduction in all the readings, but not dramatically, and all in single-digits, all or most below 5, as I recall. Are a few digits noticeable? At those levels, when noise matters, every little bit helps. And all agreed that it was worth it, even for only a few DBs.

So is there a placebo effect? Well, maybe that too. But when even modest data support a hoped-for conclusion, it's reassuring enough to continue. I next plan another 12-square purchase from Sailors' Solutions and will replace the factory insulation on the two battery hatch covers and generator cover in the cockpit. Any place I can easily dampen engine noise, I will. It makes for a more quality experience and happier first mate. For my part, that's worth a lot!

Hope this helps,

Jim (Gallivant)

. . .

Any chance you can measure the noise level before and after you add the new soundproofing material. I would be most interested in knowing the difference.

If you have an iPhone there are several Noise-level measuring Apps to be had.... using one of them would make taking the measurements very easy.

Thanks in advance. 🙂[/quote]

 

[Tugalong]

3M have an aerosol adhesive cleaner, this is a lot safer and easier to use than using bulk liquid adhesive remover like acetone etc.
The product is 3M adhesive cleaner 700. This should still be used in a well ventilated area and also no naked flames as it is highly flammable. You need to be careful around "plastics" because most of these types of solvents can attack plastics.

 

[baz]

Jim (Gallivant):

Here are a few snippets of info that I gathered a year or two back, and I believe I did post my results.

For me the worst part of engine noise is the noise level within the cabin. In a previous post I measured dB in and around the cabin at various cabin location, and with cabin door closed and open (all hatches and windows were closed all the time measurements were taken, and the boat was on the water and moving along).

I found there was a huge reduction of cabin noise level when the cabin door was closed, as you would expect. The big surprise was that if a person stood on the cabin side against the closed cabin door and was large enough to obliterate/hide the cabin door's surface area, the noise level was abated even more. This told me that a large amount of engine cockpit noise is transmitted through the glass door via vibration and line of sight. In fact, if the cabin door's glass were to be more rigid and thicker I would suspect the cabin noise could be reduce significantly without having 1st Mate glued to the door. :lol:

If the cabin door glass were to be 5" thick, just like Obama's Beast limo, there would be total silence inside the cabin. 😉

Most Ranger Tug cabin doors I've examined do not close snuggly and even some gap in the lower corners. This allows much of the cockpit engine noise to filter into the cabin space unfortunately.

I agree with you --- any few dB reductions is well worth the trouble.