Adhesives and Sealants

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From: Mike (Original Message) Sent: 9/28/2003 1:07 PM
There are as many opinions, tips and tricks as there are types of sealants and adhesives. I, being the impatient type, usually have to discover what works or doesn't work on my own, because I can't wait to ask advice. Well, I'm trying to change.

This is a good spot to talk over the various methods of sticking stuff together and plugging up holes.

From: Mike Sent: 9/28/2003 1:15 PM
First question: What is the difference between the standard and the Fast Cure 3M Adhesive/Sealants? Why would someone want to use the standard 3M 5200, which takes up to a week to cure, rather than the fast cruing stuff that sets up in 24 hours? I can't imagine wanting to reposition something a day or two after assembling it, and even if you do that, you lose some of the integrity of the bond. Why not just use the fast cure? Is there some advantage to the bonding and/or bedding qualities when the cure time is longer?

From: Mike Sent: 9/28/2003 1:32 PM
Second question: Has anyone tried this stuff called Goop Marine Adhesive for gluing stuff to fiberglass? I got a couple tubes of it at Home Depot yesterday. About the same price as 3M 5200, maybe a buck or so less for the small tube. It isn't as versatile as the 3M stuff, but it looks promising for use strickly as an adhesive for inside the cabin.

I just built a small shelf/rack that I am going to affix to the ceiling above the dinette table. It is made of oak, but I plan to glue two plastic pieces to the fiberglass and attach the rack to them with screws. The Goop stuff works like a contact cement in that you apply it to both pieces, let it sit for a few minutes, and then join them. It sticks pretty tight right off the bat, so it should be a lot easier to use than 3M 5200 because it will pretty much stay in place until you get the clamps or whatever in postion to hold it for curing. Curing time is about 24 hours.

This rack is pretty light, and it will be used to hold pamphlets, maps, and a box of Kleenex. I will also be hanging a cabin dome light from the underside of it. Not a lot of weight, but I sure don't want it shaking loose. Is the Goop good? Should I go with the 5200 instead?

It is not that I am really doing so great on my efforts at patience, here. I just finished putting some stain on the new rack, and I have to wait until tomorrow to hang it anyway (or the next day if I decide it needs some varnish).

Thanks.

Mike

From: kenonBlue-C Sent: 9/28/2003 4:43 PM
I got the Goop.....I've seen a doctor about it.....I've used it to glue a small shelf in the V berth among other things. It seems to hold good enough. I too though it would be nice to let it set up and just slap the pieces together but it didn't quite work that way. Maybe I should have let it set up longer, save yourselve some grief and be ready with some boards to prop the gadget up against roof for a day or two

From: Mike Sent: 9/28/2003 4:50 PM
Gotcha on the props. Will do. Thanks.

I'll try giving it the full 10 minutes it suggests for a max before slapping the thing up there. I used it to glue the pieces of oak together, along with a small brad in each piece, and it didn't seem to grab like real contact cement does. Shoot, maybe I should just use that.

Now I'm getting impatient again. The stain looks good without varnish, so she's going up tonight.

From: kenonBlue-C Sent: 9/28/2003 4:57 PM
Don't just use the contact cement. I used the Tree Bond contact cement (the good stuff) to glue up my stick stuff, it didn't work so good. I think that was due to the rough texture of the roof, but my dodads started falling down...them buggers are up to stay now......a couple of boards on top a throwable PFD works good for support. the PFD allows you to wedge the lumber package up against the object to be glued and it holds a nice tension against it

From: Mike Sent: 9/28/2003 6:39 PM
Thanks again. So what did you use to get them buggers up to stay? I know the 5200 works great, but it is kind of messy. This GOOP junk turns rubbery pretty quick, and it is easy to clean up the squeeze outs. Like I said, there won't be a lot of weight on this deal, but you never know - I might want to hang the dog from it someday.

From: kenonBlue-C Sent: 9/28/2003 7:26 PM
went with the serious overkill 5200, I suppose if I wished to remove those racks, a sunroof would fit in those locations.

From: Mike Sent: 9/28/2003 7:39 PM
Oh, sure, now you tell me. I just GOOPed the sucker up there. I have two sticks coming up from the table to hold it tight, one stick coming from the other side of the cabin to keep it from sliding up the slope, and two blocks in the back to keep the cross-cabin stick from pushing it down the slope. Talk about a dorky looking boat.

That 5200 is not as hard to remove between flat surfaces as you might think. The shelf I took down from above the table was glued up skookum with the stuff, and I worked a sharp knife in through the sealant and got it loose pretty easy. Then just scrape what you can of the rest off, and wipe it with a rag soaked in acetone (don't smoke them ceegars while you do that). Can't even tell it was there.

I'll let you know about the GOOP junk you talked me into using.

From: kenonBlue-C Sent: 9/28/2003 7:56 PM
Goop good...contact cement not so good. The things I Gooped are doing OK

From: Helen_O© Sent: 9/28/2003 11:03 PM
I wanted to glue rod racks to the ceiling in the cabin of my cd25. Went to Home Depot and asked to talk to someone who knew all about glue. They sent an old timer over to me...... he went over and pulled down some stuff called "J&B Weld". It's two tubes of stuff you mix together, then you have 3-4 minutes to get it applied. It hardens in 4 minutes. My rod holders are still hanging on the ceiling, so it must work purdy good. By the way, they aren't lying about the 4 minute hardening time.
I bought more of it to use with my next boat project.

Larry S

From: Mike Sent: 9/28/2003 11:13 PM
Yeah, I remember that stuff. It's been around for ages. I just looked, and I even have a pair of tubes in the desk drawer right here. At the display for the stuff in the auto parts store, they used to have two engine valves glued together and dared you to break them apart. I guess I never thought about using it to glue two porous items together. Hmmm. I'll have to give it a try. I know it is good for building up metal surfaces. It's kind of like Devcon or other metal fillers. You can drill and machine it after it sets up. The only time I ever used it, I think, was to repair a crack at the filler neck of a steel gas tank. It seems to me it worked good for that. Hmm. I'll try it on something in the boat. Maybe a dog hook.

Thanks, Larry!

From: Helen_O© Sent: 9/29/2003 10:50 AM
By the way,
An extendable boat hook/rod works great as a prop to hold a newly glued piece in place. It has rubber on both ends to keep it from slipping and extends to any length you could possibly need.

Larry S

From: Mike Sent: 9/29/2003 9:16 PM
After just over 24 hours, the GOOP that had squished out of the joint was hard as rock, so I took the props, blocks and supports away from the rack gizmo. It stayed hanging on the ceiling, so I guess that's a good sign.

The extendo boat pole is a great idea! I will remember that this winter when I glue other junk up. Sometimes it's hard to find a just-right long stick without cutting some good stock. Cool. Thanks. Too bad I only have one.



From: C-Wolf1 Sent: 9/30/2003 4:29 AM
Mike, et al- Here are some properties to consider when choosing an adhesive that I can think of:

Strength-various types: tension, compression, shear, ...

Flexibility- Do you ned a flexible or rigid adhesive? Which type will hold the bond better?

Compatability-Will it bond to porous and/or impervious surfaces (e.g. wood vs glass)? Will it bond to oily, waxy, metal, or... surfaces? Which is the best one for the two you're bonding?

Filler- is it simply a thin, wattery adhesive, or does it fill in spaces between objects? What's the filler? Glass fibers, microbaloons, metal particles,wood, asbestos, ...?

Timing/set-up: How long does it take to bond? Is there time to line things up and clamp them? Does it take too long for you to make that fishing trip tomorrow?

Is it sandable, paintable, drillable, machinable, etc? What is it compatible with in terms of paint?

What is it's chemical resistance compared to your application? Water, oil, gas, diesel, solvents, wax, cleaners, etc.

How about it's temperature stability? Do you need a high temperature product? One that remains flexible at low temperatures?

Resistance to UV light, water, freezing, etc? Where are you using it, and will it survive that enviornment?

Color-Does it hide well or match your objects to be joined?

Can you use it in wet enviornments? How about underwater? Some adhesives REQUIRE water in the joined area or enviornment to set up. Water sometimes acts as a catalyist. The new polyurethane glue requires it.

Is it catalytic* or does it require evaporation of a solvent to dry out and bond? Epoxy is catalytic, Goop requires the solvent to evaporate. Putting Goop bewetween two impervious surfaces works, but may take days for the solvent to evaporate out at the edges of a large surface to surface bond.
* Catalytic reactions require two parts to be mixed to set off a chain reaction that cures the substance into a new product, such as epoxy and polyester resins.

Removeability- Can the bond be opened up and the adhesive removed if necessary down the line? Are there special solvents required? Can you simply scrape it off, or will it require some serious machine work?

Mechanical aids- Do you need to use clamps, and for how long? Can wax paper, Saran Wrap, or masking tape help in outlining the bonding are, matching up the two halves to be joined, or in shaping the filler? For example, matching to flat surfaces with contact cement can be difficult and a mismatch cannot be corrected easily, but a hinge can be constructed out of acrylic plastic sheeting and masking tape that allows the two halves to join "in registration". Big filler jobs with Bondo or Marine Tex can be shaped by putting wax paper or Saran Wrap over them and shaping them with your fingers or tools. The fillers themselves are sometimes so tenacious that putty knives and the like stick too much to the putty surface, making it difficult to shape a smooth surface. The w-p and S-W don't adhere to the adhesives, and peel off harmlessly once set up is done.

Clean up-Can the joint be cleaned up during or after joining? How about clean up of tools such as spreaders, brushes, etc? Will disposable brushes work? Which kind of foam or bristles are compatible? (Some "melt" in the wrong stuff!)

Fumes- Does the adhesive give of toxic or irritating fumes? Are they flamable or corrosive? Are you going to be working in a closed in area and need forced air ventilation or a breathing apparatus?

Skin sensitivity, allergic reactions, etc. Are gloves, and/or protective clothing required? What type of gloves are chemically resistant to the adhesive?

Don't be afraid to call the 1-800 number listed on the product for advice and answers to special questions. These people are friendly and PAID
with your good money to be helpful and do this kind of stuff all day.

I've seen compatability charts for adhesives before. They are helpful, of course, but putting all the information dessirable on a simple grid is impossible. Perhaps a next stage would be to locate a few and post links here.

Hope this helps. Joe.