Reply
 
Thread Tools Search this Thread Display Modes
 
Old 07-27-2021, 10:06 AM   #1
Guru
 
City: Port Canaveral
Join Date: Jun 2012
Posts: 2,103
Which adhesive for mass loaded vinyl

I need to add 2lb MLV to the inside cowling of my outboard. What would be a recommended glue to use? I've had mixed results with heavy duty contact cements (like 3M 90).

Even though the MLV is rated to 180 degrees, I think the consequences if it were to delaminate and fall upon the engine could be rather severe.

The glue needs to hold up to vibration, heat and acoustic shock. I'm sorta thinking about 5200 which is permanent, and might even provide a small amount of decoupling as it would absorb some vibrations.

Thoughts?
Mako is offline   Reply With Quote
Old 07-27-2021, 11:03 AM   #2
Guru
 
GoneFarrell's Avatar
 
City: La Conner, WA
Vessel Name: Imagine
Vessel Model: Farrell 34
Join Date: Oct 2015
Posts: 585
5200 would do it, could be a real sticky mess to do, and takes time to cure.

I'm thinking how you clamp and hold the MLV to the interior so as to have good consistent bonding to be the bigger challenge of your project. Maybe shape some boards or ridged foam to clamp against on the interior? Do you have to preform or slice the MLV to suit the concave surfaces?

I downloaded a decibel meter app to my phone that works pretty good, that would give you some objective before and after data too. 'Sound Meter."
GoneFarrell is offline   Reply With Quote
Old 07-27-2021, 11:33 AM   #3
Guru
 
City: Port Canaveral
Join Date: Jun 2012
Posts: 2,103
Good questions. So I'll use my original crappy foam as a pattern to cut the MLV for the curved sections of the cowling (see photo).

Do you have any idea if Loctite PL Premium FAST GRAB (also a polyurethane adhesive) would work similar to the 5200 Fast Cure? It's 1/3 the price and this isn't exactly a mission critical hull-deck joint or anything.

Currently I read 95dB at my helm. BTW, 85dB is the threshold where you can suffer permanent hearing loss. Gotta fix this!
Attached Thumbnails
2731de16bd19a21332b9bf43ea80f1e2_1.jpg  
Mako is offline   Reply With Quote
Old 07-27-2021, 11:46 AM   #4
Guru
 
Lou_tribal's Avatar
 
City: Quebec
Vessel Name: Bleuvet
Vessel Model: Custom Built
Join Date: Jan 2016
Posts: 4,215
3M VHB 5952 double side tape, supports up to 90 pounds per inch.

L
Lou_tribal is offline   Reply With Quote
Old 07-27-2021, 12:18 PM   #5
Senior Member
 
City: Dewatto
Vessel Name: CHiTON
Vessel Model: Tung Hwa Clipper 30
Join Date: Jan 2020
Posts: 486
I think you may be using the wrong soundproofing. I bought this for a Yamaha 50. The 10 square foot amount was more than enough for the whole cowling. Has a heat reflector layer and stays stuck. Easy peezy.
__________________
Marco Flamingo
Marco Flamingo is offline   Reply With Quote
Old 07-27-2021, 12:22 PM   #6
TF Site Team
 
Comodave's Avatar
 
City: Au Gres, MI
Vessel Name: Black Dog
Vessel Model: Formula 41PC
Join Date: Jul 2015
Posts: 12,708
With 2 pounds per square foot I would go with a belt and suspenders approach. I would use the best glue you can find but also use some mechanical fasteners. They make little stick pin type that you use epoxt to glue to the surface and then stick the pins through the insulation and then put a cap on it to mechanically hold it in place. Amazon has them in galvanized and Soundown sells S/S ones. This is a photo of the Soundown ones.
Attached Images
 
__________________
Boat Nut:
If you are one there is no explanation necessary.
If you arenít one, there is no explanation possible.
Comodave is online now   Reply With Quote
Old 07-27-2021, 12:32 PM   #7
Senior Member
 
City: Cairns
Join Date: Jul 2019
Posts: 327
Quote:
Originally Posted by Mako View Post
.

Currently I read 95dB at my helm. BTW, 85dB is the threshold where you can suffer permanent hearing loss. Gotta fix this!
I've gotta ask: what outboard runs at 95db? Or are you running everywhere at WOT?

Will the extra cowling weight be a concern?

Good luck.
GoneDiving is online now   Reply With Quote
Old 07-27-2021, 01:03 PM   #8
Guru
 
City: Port Canaveral
Join Date: Jun 2012
Posts: 2,103
Some good ideas above that I will consider.

Itís a 2-stroke Mercury saltwater 200hp with carbs.

Yes the cowling will probably weigh in at 40lbs by the time Iím done. Wonít be easy to remove. The noise is horrible though and Iíve considered getting rid of it and buying a nice new 4-stroke.
Mako is offline   Reply With Quote
Old 07-27-2021, 01:18 PM   #9
Senior Member
 
guy with a boat's Avatar
 
City: SoCal and Vancouver Island
Vessel Name: Tortuga
Vessel Model: Nordhavn 63
Join Date: Aug 2016
Posts: 291
Seems way better to use mat with peel and stick adhesive already in place. Marco lists one option above and you can find all combinations of sound and heat barriers that are made for this job and will stay in place. For sound barriers alone there are lots of choices in durable and effective peel and stick material.
guy with a boat is offline   Reply With Quote
Old 07-27-2021, 02:56 PM   #10
TF Site Team
 
FlyWright's Avatar
 
City: California Delta
Vessel Name: FlyWright
Vessel Model: 1977 Marshall Californian 34 LRC
Join Date: Apr 2008
Posts: 13,525
Try a PM to Keysdisease for advice or call SoundDown direct. He works for SoundDown.
__________________
My boat is my ark. It's my mobile treehouse and my floating fishing cabin. It's my retreat and my respite. Everyday I thank God I have a boat! -Al

@DeltaBridges - 25 Delta Bridges in 25 Days
FlyWright is offline   Reply With Quote
Old 07-27-2021, 04:03 PM   #11
Guru
 
City: US PNW
Join Date: Nov 2018
Posts: 940
If you already have the product this may not matter, but I bought some "Hoodliner" (Sounddown, IIRC) and put it on the inside of the "doghouse" on a van. It came with adhesive already on it.

This sits over/beside a big, hot engine, so I would not have been pleased if it had fallen down. It did not. (I prepped well, solvent cleaned, etc.). It's been a while, but I think I used some of the thinner (also self adhesive) sound absorbent stuff first (The type that only has to cover X percentage of the surface). Then the Hoodliner.

I was mostly going for heat reduction, with a bonus side helping of sound reduction. So some other product may work better. But the adhesive that was on it sure worked well (it was a type where you peel off a paper backing to expose the adhesive).
Frosty is offline   Reply With Quote
Old 07-27-2021, 09:17 PM   #12
Senior Member
 
City: NE Florida
Join Date: Dec 2020
Posts: 218
Quote:
Originally Posted by Mako View Post
Some good ideas above that I will consider.

Itís a 2-stroke Mercury saltwater 200hp with carbs.

Yes the cowling will probably weigh in at 40lbs by the time Iím done. Wonít be easy to remove. The noise is horrible though and Iíve considered getting rid of it and buying a nice new 4-stroke.
I had a 115HP Johnson that would make ears ring when I first bought the boat.
The exhaust pipe was leaking at the joint connecting to the lower unit. The seal had been misaligned during some service the previous owner did or had done. That thing was loud. Fixing that made a HUGE difference.
just food for thought
skyhawk is offline   Reply With Quote
Old 07-28-2021, 06:18 AM   #13
Guru
 
Keysdisease's Avatar
 
City: South Florida
Join Date: Sep 2014
Posts: 898
1lb MLV would be more appropriate for a 2 stroke OB. Has to do with frequency, 1lb works great at high to mid range frequency, 2 lb adds good lower range reduction which a 2 stroke OB doesn't really create. A lot of your noise in carj noise which is definitely mid/high range.

MLV plays nice with just about any adhesive, the Loctite product looks appropriate, but I suggest you test because of this:

https://dm.henkel-dam.com/is/content...rab-2019-12-12

"Certain materials such as rubbers and plastics may have bonding difficulties. Test before use"

The product Marco used is what the automotive industry calls Dynamat. The self adhesive is very aggressive. It appears to come as 36sqft which seems way too much for 1 OB cowling. It does weigh 1 lb sqft and should perform well. Price looks high. The adhesive is not at all forgiving re repositioning, like contact cement it sticks now.

Dave's suggestion is good, but those pins in this application would call for epoxy, and as long as you're mixing some up, epoxy is the go-to adhesive for "when in doubt" when working with MLV

Keysdisease is offline   Reply With Quote
Old 07-28-2021, 10:37 AM   #14
Guru
 
City: US PNW
Join Date: Nov 2018
Posts: 940
Great info on the 1lb. vs. 2lb. for an outboard's frequency. I have a four-stroke that's relatively quiet at low speeds but still louder than I would like in the higher rpm's. For some reason I had never thought about adding noise-reducing material.

(Would you say the same about 1lb being best for a four-stroke?)

Quote:
Originally Posted by Keysdisease View Post

Dave's suggestion is good, but those pins in this application would call for epoxy, and as long as you're mixing some up, epoxy is the go-to adhesive for "when in doubt" when working with MLV

I am not sure how hot the inside of the cowl gets, but I might be worried about high temps and epoxy. I think it starts softening at 150ļ F. Or are there special epoxies for heat (I'm speaking of your typical WEST System, System Three, etc. marine epoxies).
Frosty is offline   Reply With Quote
Old 07-28-2021, 08:26 PM   #15
Guru
 
Keysdisease's Avatar
 
City: South Florida
Join Date: Sep 2014
Posts: 898
Epoxy will serve very well in adhering MLV to the inside of an O/B cowling, probably your best choice. Any 2 part epoxy will tolerate the temps of this environment.

As an example of frequency transmission, consider this:

When you pull up to a red light and some kid is cranking his stereo 2 lanes over, your rear view mirror is vibrating and you can almost feel...the bass. The band is playing organ, guitar, they are singing, but all you hear is bass.

The high and mid range frequency is being reduced by closed car windows, the low frequency bass goes right through everything.

The lower the frequency, the more mass you need in order to reduce it.

A carbureted 2 stroke has significant intake noise from the carburetors. 4 strokes are quieter, but as a general rule gasoline engines produce noise in a frequency appropriate for 1 lb mass products. For diesel engines the lower frequencies call for 2 lb + products.




Quote:
Originally Posted by Frosty View Post
Great info on the 1lb. vs. 2lb. for an outboard's frequency. I have a four-stroke that's relatively quiet at low speeds but still louder than \
Keysdisease is offline   Reply With Quote
Old 07-29-2021, 10:54 AM   #16
Guru
 
City: Port Canaveral
Join Date: Jun 2012
Posts: 2,103
Not to be too argumentative... so I've heard that before about 1lb and higher frequencies typical of a gasser. So let's say that 1lb MLV is adequate for an outboard, but that does not mean that it is better than 2lb. The 2lb should provide similar performance in the high frequencies, but in addition, will do a better job of knocking down the low frequencies. I don't think the lows are as significant as with a diesel, but they would exist in some form.

In any case, I have the 2lb so am not going to get rid of it. At this time (Thursday) I'm planning on installing this weekend and am leaning towards the Loctite Fast Cure product. I like the idea of the slight flexibility afforded by the polyurethane versus epoxy products.

I'll report back when I have performance measurements taken in about a week.

Thanks to everyone for the input.
Mako is offline   Reply With Quote
Old 07-29-2021, 11:10 AM   #17
Senior Member
 
City: NE Florida
Join Date: Dec 2020
Posts: 218
for clamping
I'm picturing lining the cowling with a trash bag or similar, and filling with sand (or water).
skyhawk is offline   Reply With Quote
Old 07-29-2021, 11:31 AM   #18
Guru
 
City: Port Canaveral
Join Date: Jun 2012
Posts: 2,103
skyhawk, I've been giving that same thought as well. Will have to apply in small sections (say 5) and would go with sand in order to avoid leaks. I also have some scuba weights which will give good local pressure. Will heat the vinyl with a hair dryer and hope that helps to soften it.
Mako is offline   Reply With Quote
Old 07-29-2021, 03:23 PM   #19
Guru
 
Keysdisease's Avatar
 
City: South Florida
Join Date: Sep 2014
Posts: 898
Quote:
Originally Posted by Mako View Post
The 2lb should provide similar performance in the high frequencies, but in addition, will do a better job of knocking down the low frequencies. I don't think the lows are as significant as with a diesel, but they would exist in some form.
This is absolutely true, but the difference for a carbed OB may only be measurable and not significant. I was making the point more to save weight on the cowling than dispute 2lb not working.

I understand, you got it, use it

Keysdisease is offline   Reply With Quote
Old 08-01-2021, 04:31 PM   #20
Guru
 
City: Port Canaveral
Join Date: Jun 2012
Posts: 2,103
Coming along real well. The front 2/3 is completed. The fast cure Loctite sets quickly. Iím stopping here and will launch it tomorrow and take sound measurements. I still have a few square feet of MLV to work with. Btw, a hairdryer on it for 5 minutes allowed it to bend very nicely. Click image for larger version

Name:	E6C6D21F-B2DA-403A-A821-35D75CD24B98.jpg
Views:	9
Size:	81.2 KB
ID:	119780Click image for larger version

Name:	IMG_0900.jpg
Views:	8
Size:	94.3 KB
ID:	119781
Mako is offline   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


» Trawler Port Captains
Port Captains are TF volunteers who can serve as local guides or assist with local arrangements and information. Search below to locate Port Captains near your destination. To learn more about this program read here: TF Port Captain Program





All times are GMT -5. The time now is 06:55 PM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2021, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2006 - 2012