What is general consensus on PL Premium and

Discussion in 'Materials' started by Skua, Oct 23, 2013.

  1. Skua
    Joined: Apr 2013
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    Skua Senior Member

    other similar construction adhesives? It's used by a lot of people, there are youtube videos, attesting to it, as well as testing it. Seems to be used mostly for bedding stringers, and decking, but no long term results to be found.
     
  2. michael pierzga
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    michael pierzga Senior Member

    Good stuff. Not as versatile as epoxy and it needs clamping pressure ...it not a gap filler so your joinery should be correct. Ive used it on interior marine projects. Nice to work with, handy tubes. Point and squirt
     
  3. Petros
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    Petros Senior Member

    Quality constrution adhesives are excellent materials for use on a boat. when used in building construction it is expected to perform and keep its holding power for as long as you would expect to use the building. Most modern buildings are assumed to have a useful design life of 50 years, some will last many more years of course.

    But the quality exterior grade, water proof construction adhesive, as long as it will be used in places that will not have direct exposure to sun light (as with epoxy and other adhesives), it should last for many years. Likely longer than the boat!
     
  4. PAR
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    PAR Yacht Designer/Builder

    These are "construction adhesives" and not designed for dynamic loading situations. They're great holding paneling to a wall ion your kitchen, but not as well suited in a boat, where everything flexes continuously underway. They dry rock hard, require considerable clamping pressure and don't have much elongation properties, making their use limited. Most are polyurethanes and water resistant. There are a few different types and they do work well on lightly loaded pieces that aren't going to move much. Generally they cost a fair bit more per ounce than epoxy and don't have the strength, water resistance and other attributes as epoxy, but if gluing some cabin furniture together, it'll work fine. No, it wouldn't work on a panel seam.
     
  5. Petros
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    Petros Senior Member

    PAR, you describe properties of interior panel adhesives, not exterior grade. All wood structures flex and change size and shape with heat and moisture. Here in the western part of Washington state (the "pacific north wet"), wood framed houses can change size and shape 1 to 2" from summer and winter. Log homes can have their ceiling heights change as much as 3" from summer to winter. We have to design to accommodate these changes in size, particularly in log homes. All construction adhesives must have a certain amount of flexibility or they would break their bonds within only a year or two at best.

    There are cheap adhesives that are only water resistant and not very flexible after a few years (they get brittle), but quality exterior grade construction adhesive are water proof, flexible and durable. These cost much more than the cheap adhesives, and their properties are very different too.
     
  6. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    Florida is as wet, if not more so than your area in the summer and I was speaking directly at PL Premium, which is water proof and has good UV resistance, but is hard, doesn't have the elongation necessary for dynamic structures (long term), on a boat in structural applications. It is fine for internal furniture, seating partitions and the like, but it is more costly than epoxy and not as accommodating in uses and applications. It's fine for lightly loaded stuff, but not for immersion or highly loaded elements that receive a bit of movement. Simply put, I wouldn't use PL on planking or structural elements, but on secondary bulkheads, partitions, etc. it could be tempting only because of the convenience of a single part goo in a tube.

    Compressive strength is about 850 PSI, tensile strength is 600 PSI and it clearly states is not a structural adhesive. Comparatively, a low grade epoxy would be in the 10,000 PSI range for compressive strength, with refined epoxies being 50% to 100% better than this. A pretty dramatic difference. Tensile strength is equally as dramatic, comparatively. I know folks that have had great success on small craft. These structures are well suited to PL, mostly because the structural elements are generally over size to loading, comparatively (you can only make stringers so thin for example). On the other hand I know a builder that swore by the stuff and glued up his transom (as well as the rest of his boat) with PL and it's coming apart, from the rattle of the 30 HP high thrust Mercury hanging on it.
     
  7. Skua
    Joined: Apr 2013
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    Skua Senior Member

    Hmmm, looks like I will stick to epoxy, as i tend to overengineer everything. I like things with 200% overload capacity, as opposed to 10%
     

  8. jimmy wise
    Joined: Nov 2013
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    jimmy wise Junior Member

    i used it to bed my stringers, didnt like it. i would use something else next time. a ton of people swore by it. i should of used resin and cab....
     
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