Bellows Adhesive Debate

[StevNimrod]

I'm about to replace the bellows on my boat - It's a Mercruiser Alpha One, Gen 2 drive. I was talking to a few service guys at the Merc dealer where I get parts and a bit of a debate ensued about how to use bellows adhesive.

Two "techs" said to put the adhesive on and let it set for five minutes before putting the bellows on.

One tech said put the adhesive on and assemble the bellows immediately.

I'm just trying to figure out what you guys recommend. I think the manual says to let the adhesive set up, but doesn't this kind of defeat the purpose of using a glue? Are there any real negatives to installing the bellows with the glue wet? It seems that tacky adhesive would not make for a good seal.

 

[wca_tim]

Re: Bellows Adhesive Debate

bellows adhesive is essentially uncured rubber with solvent added to let it flow. letting it get "tacky" or set up for a bit only lets the solvgent at the surface dry out - it still is very much able to "flow" together and make a good seal. as long as you get spread on both sealing surfaces, I'm sure either will work fine. Note, I'm not merc tech, but I do have some background in polymer and rubber chemistry...

 

[dubs283]

Re: Bellows Adhesive Debate

Test it.

Glue together two items with smooth surfaces.

First try pressing them together after immeditaly applying adhesive

Second let adhesive become tacky, them press them together

Third let adhesive dry, then press them together

See which process provides the most desirable results

 

[ziggy]

Re: Bellows Adhesive Debate

i think tacky too. i believe i read it on the tube of bellows adhesive and perhaps in the service manual too.. think i let mine set up for maybe 10 min prior to install...
done it twice that way. success both times with a seal...

 

[gshldon]

Re: Bellows Adhesive Debate

i recently did mine, and i put some on the bellows and then on the mating service and let them set up for a few minutes and slide them together and everything went together just fine. Just my 2 cents.

Good Luck and Happy boating.

Gary

 

[wca_tim]

Re: Bellows Adhesive Debate

oh... and I did mine this evening. I let them get tacky and I'm sure they'll work ok.Surfaces were cleaned carefully of old adhesive and then smoothed / roughed up with fine emery cloth, and cleaned again with acetone. adhesive on both surfaces, let get tacky for about 5 minutes, slipped into place and clamped tight.

Note that that's what i did last time.

last year I lost a u-joint cap under power and it broke the heck out of everything - including the bell housing wher ethe bellows attaches. i didn't even know the bel housing was broken until i started to cut the bellows off. the adhesive held it together...

 

[Robj]

Re: Bellows Adhesive Debate

On my Volvo I did not use anything. Bone dry. In my case, not sure that you need that stuff. Have not had a drop of water leak in through the bellows.

Have a great day

Rob.

 

[StevNimrod]

Re: Bellows Adhesive Debate

oh... and I did mine this evening. I let them get tacky and I'm sure they'll work ok.Surfaces were cleaned carefully of old adhesive and then smoothed / roughed up with fine emery cloth, and cleaned again with acetone. adhesive on both surfaces, let get tacky for about 5 minutes, slipped into place and clamped tight.

Note that that's what i did last time.

last year I lost a u-joint cap under power and it broke the heck out of everything - including the bell housing wher ethe bellows attaches. i didn't even know the bel housing was broken until i started to cut the bellows off. the adhesive held it together...

Nice. So how much time should I set aside for this? I have this nasty habit of grossly underestimating how long I'll be working on something, then either making it a two day project or working until 3am.

Isn't lacquer thinner the solvent for bellows adhesive? This came up at the dealer too, but I could feel my head starting to spin so I left. Personally I prefer acetone for cleaning stuff...since I have it handy in large quantity.

My U-Joint looks good so hopefully my bellhousing comes out in one piece, but I do have a leaking front seal in the upper and I'm debating on whether or not to fool with replacing it (getting something wrong and doing serious damage) or to tackle it and stop being paranoid.

 

[StevNimrod]

Re: Bellows Adhesive Debate

On my Volvo I did not use anything. Bone dry. In my case, not sure that you need that stuff. Have not had a drop of water leak in through the bellows.

Have a great day

Rob.

That's interesting. I've never heard of doing bellows without adhesive. To qualify that, there are a LOT of things I haven't heard that people do all the time. Just out of curiosity, what was your reasoning for going bone dry?

 

[StevNimrod]

Re: Bellows Adhesive Debate

I agree Rob, I just don't see the need if installed properly. Never had one leak.

I learn something new every day!

Maybe I should amend the poll to have a fourth option: "Bellows adhesive? What's that?!?!"

 

[ziggy]

Re: Bellows Adhesive Debate

I just don't see the need if installed properly. Never had one leak.

perhaps vp does it different. ie, dry. if so, that's how i'd do it too. however the oem suggests i do it. however, so far, i've learned the best chance i have for success with repair to my mercruiser is to follow mercruisers instructions in their service manual.

for my rig this is what it says.

s/m #2. pp 6A-32

" 9. apply bellows adhesive (c-92-36340A1) to inside diameter of each end of universal joint bellows. allow adhesive to dry approximately 10 minutes, or until no longer tacky.
10. install end of universal joint bellows marked 'aft-top' to bell housing. position clamp ans shown in fig. 10 and torque clap to specification."

so i stand corrected in my previous statement about how tacky. but i did wait the 10 min. + till no longer real tacky.

 

[StevNimrod]

Re: Bellows Adhesive Debate

bellows adhesive is essentially uncured rubber with solvent added to let it flow. letting it get "tacky" or set up for a bit only lets the solvgent at the surface dry out - it still is very much able to "flow" together and make a good seal. as long as you get spread on both sealing surfaces, I'm sure either will work fine. Note, I'm not merc tech, but I do have some background in polymer and rubber chemistry...

Thanks Tim. That's what I was wondering, from an engineering perspective. I know there are a few polymers that won't fully cure unless a certain initialization procedure is used.

Test it.

Glue together two items with smooth surfaces.

First try pressing them together after immeditaly applying adhesive

Second let adhesive become tacky, them press them together

Third let adhesive dry, then press them together

See which process provides the most desirable results

That's actually what I'm thinking about doing dubs, just for S&Gs. I'm trying to think about how I want to set it up, but I think I would be interested in doing peel, shear, and pressure tests. Assuming I can devise a reasonable way to set it up.

i think tacky too. i believe i read it on the tube of bellows adhesive and perhaps in the service manual too.. think i let mine set up for maybe 10 min prior to install...
done it twice that way. success both times with a seal...

And that's basically what I'm after from a practical standpoint. I'm interested in the data, but I'm probably more interesting in the bellows not leaking because I didn't do something correctly.

 

[soaringhiggy]

Re: Bellows Adhesive Debate

if you have ever put down Formica it is the same process, let the solvent flash looks dry on both surfaces then put them together and bond. It works and it works very well. Remember the old intertube on your bike? let the glue dry on both patch and tube then apply the patch, remember when you did not and it just slid all over the place?

Use the manufactures recommendations, it is the best way

 

[Zackman]

Re: Bellows Adhesive Debate

Both Merc and Volvo recommend using sealer... See attached from the manuals. Merc specifical states to let the sealer dry. The first attachment is from the Merc manual the second from the Volvo manual.​

 

[stonyloam]

Re: Bellows Adhesive Debate

Maybe, just maybe you should follow the instructions on the tube.

 

[freeone]

Re: Bellows Adhesive Debate

Maybe, just maybe you should follow the instructions on the tube.

agreed, ive had both. one tube recomends to aplly wet and other says to let dry.

 

[T-Bone Coug]

Re: Bellows Adhesive Debate

Maybe, just maybe you should follow the instructions on the tube.

Coming from an adhesives and coatings background, I agree most with this suggestion. Some adhesives will not cure if there is not enough surface exposed to the air for the solvent to flash out. This is the reason for applying and letting it dry on the surface. Others will cure when they reach a certain temperature. Some are called "moisture cure", meaning they cure only in the presence of humidity or water. And there are also some that cure by applying pressure: pressure-sensitive adhesive (most labels, decals, etc. use this type). If you want the best results, follow the directions on the tube/container of adhesive.

 

[rodbolt]

Re: Bellows Adhesive Debate

would simply using the correct service manual and the correct part number adhesive when called for, using the correct manual procedure, simply be to hard ?

 

[TowRoper]

Re: Bellows Adhesive Debate

would simply using the correct service manual and the correct part number adhesive when called for, using the correct manual procedure, simply be to hard ?

I 2nd that!

 

[StevNimrod]

Re: Bellows Adhesive Debate

Maybe, just maybe you should follow the instructions on the tube.

Good point, stony. I never thought about it that way.

If there are no instructions on the tube, then what should I follow?

Kidding, of course. The only reason I put the question out there was at the time I couldn't get my hands on any of the Merc stuff and the Sierra stuff didn't have any instructions and is somewhat different than Merc.