What adhesive is just a bit LESS strong as 3M 5200?

I had read somewhere that a 5200 is a bond forever. A cynical commentor called 5200 "the next owners problem." (I can't find this thread)

My recent experiences back that up as some demolition in my boat had the bond stay complete.. but the first ply of wood, or gelcoat or whatever, connected to the part was removed with it, which caused more future reconstruction than really necesary.

For my future use: is there an adhesive "almost" as strong as 5200, but not quite that strong? For interior joinery.

Something at major retailors (Walmart, Home Dept, etc.) without the marine price bump up is desired.

I've used "Liquid Nails" and "Gorilla Glue" at home with great success (though Gorilla Glue expanded and needed trimming).. but am unsure of their suitability in a marine environment.

 

Liquid nails has no business on a boat. It, like most of the other land based adhesives, just aren't intended for the dynamics of a marine environment.

3M-5200 can be removed with a hot knife and/or chemicals, though admittedly, it's a tough product to remove. 3M-4200 or 4000 UV have less tack, so do other brands. It depends on what you're doing. 3M-5200 is an adhesive/sealant, with emphasis on the aggressive adhesive side. So, if you want it to stay stuck, with a good seal, then 3M-5200 is a great product. On the other hand, if you're looking for a bedding compound, you might want a sealant or a sealant/adhesive, such as Sikaflex 291 or maybe one of the BoatLife products.

For internal marine joinery, you should probably use a glue, not a sealant, so TiteBond II or III (TiteBond III is my choice) or maybe Gorilla glue (I hate this stuff) would be better ways to go.

 

Although the brand name to me sounds ridiculous, "Gorilla glue" seems a good choice.
It fills gaps, has good bonding strength, but a box cutter can "undo" it without major damage to the wood.
This type of adhesive resists moisture very well but is not suitable for underwater use.

 

Thanks guys.

 

Gorilla Glue and similar polyurethane glues will expand in a foam and fill gaps - but the strength drops to a small fraction of the strength of the unexpanded glue.

http://www.popularwoodworking.com/article/the_truth_about_polyurethane_glue

 

Gorilla glue expands to a feeble foam unless constrained; it can be difficult to clamp flexible wood items like ply while GG sets. It is very strong when used in a well-fitted joint, but Titebond III is at least as good and cheaper.

Rather than compromising a joint (especially onboard a boat) by using a less-than-optimum adhesive, if the assembly has to come apart why not use screws?

BTW for actual inside a house ordinary white wood glue works well in a well-fitted joint and can be separated fairly easily with a little heat or steam.

 

When you contaminant a joint surface, adhesion is retarded.

A typical contaminated 5200 joint would be delicate exterior aluminum trim profile that has had its mating surface lightly sprayed with WD40 . The 5200 gets a poor bite, the hardware is removable a few years down stream.

Many other easy to use contaminates around the workshop.

 

I've never been a big fan of the Gorilla glue types of adhesives. As stated, in well fitted joints, with sufficient clamping pressure during the cure, a workable product. Unfortunately, most DIY'er projects have less then precise joints and it's often the case, that clamping is difficult if not imposable.

Gorilla glue costs more per ounce than epoxy, so does 3M-5200. Pre-contaminating the surface with oil or wax, seems quite counter productive, if interested in sealing out moisture, let alone, bonding a piece to a substrate. There are much better choices for "bedding" without using an overly aggressive adhesive and contaminating the surface. The PVA's I feel are a better choice both economically and in regard to ease of use.

 

To each his own. Another valuable contaminated joint technige is tape. Blue painters tape or thin foam weatherseal type tape. I like the weatherseal tape. 75 percent of the mating surface will be covered with tape...then the fitting is bedded into Sika or 3m. The thick foam tape keeps the joint from becoming Bog starved and acts as a bond break because only 25 percent of the surface is bonded. . This is a common way to bed Lewmar deck hatches.