PL Premium & Strip Construction?

[kbowen]

I was reading some old posts and wonder what the current judgement is on Loctite PL Premium Construction Adhesive? Some of the old posts liked it in general, and also liked it for moderate gap-filling as an alternative for beveling in sheathed strip construction. Any Updates?

[StevenBauer]

It would be god-awful messy for strip construction. Some have reported great success using it for glued lapstrake construction.

Steven

[kbowen]

It would be god-awful messy for strip construction. Some have reported great success using it for glued lapstrake construction.

Steven

I just did a test and it seems less mess than epoxy + thickener + mixing container + putty knives + cleanup, etc, etc. It comes out of a tube in a bead. My test hasn't cured yet, so I don't yet know whether it will harden / sand / fair etc. ..still groping....

[Paul Pless]

Hasn't erster built a few boats strip/plpremium?

[StevenBauer]

I don't bother with the thickeners much anymore when I'm using epoxy. GelMagic is so much easier to use. Mix the two parts and you're ready to go - just the right thickness for most jobs.


There is a liquid PL Premium, now, too. Like Gorilla glue but much more reasonably priced.

Steven

[James McMullen]

Alternative to beveling? Why not go bead and cove? No beveling and perfect tight fits every time.

[kbowen]

Alternative to beveling? Why not go bead and cove? No beveling and perfect tight fits every time.

I don't have the space or machinery to shape the strips efficiently: 275 square feet means about 10 times that in lineal feet depending on the strip dimensions. I have gotten several quotes for this milling which more than doubles the price. fwiw, the bids have gone from $4700 to $6600 delivered to Chicago.

[Paul Pless]

I don't have the space or machinery to shape the strips efficiently: 275 square feet means about 10 times that in lineal feet depending on the strip dimensions. I have gotten several quotes for this milling which more than doubles the price. fwiw, the bids have gone from $4700 to $6600 delivered to Chicago.

What design are you building? What are the strip scantlings? and what species of wood?

[kbowen]

What design are you building? What are the strip scantlings? and what species of wood?

The plan is the "Western Lakes Mackinaw" per Chapelle, 26' 7" x 7' 8" (in a shop space 19' x 31'). Scantlings are a moving target: Chapelle drew a 3/4" rabbet and provided no other construction specs. I have been working with a N.A. who has convinced me that I should probably go to 7/8" WRC or Spanish Cedar with 12 oz of glass inside and out. I have completed test sections using: 3/4" x 1 3/8 bead and cove WRC, 3/4 x 1.5 beveled WRC & Spanish Cedar, and 7/8" square strips in both WRC & Spanish Cedar. I have experimented with Titebond III, Microfiber thickened epoxy, and PL Premium. Tomorrow, I will do a test with "Speed Strip" T&G Spanish Cedar. So-far, I would prefer 7/8" Bead & Cove WRC set in Titebond & glassed, but my best bid for the wood for this option is roughly $5600.00 local.

[Bob Smalser]

... moderate gap-filling as an alternative for beveling in sheathed strip construction.

Don't bet your grandchildren on that one. Even with ground limestone fillers, poly doesn't match epoxy in its ability to fill gaps with any strength. Either mill or buy bead-and-cove, or use marine epoxy per the instructions provided.

Plus it sounds like you haven't studied open times. On a project as large as yours in summer, you'll have problems with PL and Titebond.

Further, you're concerned about epoxy and glass sticking to the PL, yet you say you prefer Titebond. There's literature out there you need to read. While epoxy sticks nicely to the poly glues, it doesn't at all to Titebond.

[James McMullen]

5k for lumber really ain't no thing for a boat of this size. You need to get used to the fact. It's going to take at least 10-15k or more to build this boat correctly. But building it incorrectly will be far more costly in the end. Don't skimp on the irreplaceable essential structural elements of the hull itself.

Do you not have a router table? You don't need a 5hp shaper with a powerfeeder for mere 7/8 cedar. This is totally within the capabilities of a moderate home wood shop for a guy who has more time than ready cash.

[Gib Etheridge]

Using PL and not beveling I would be concerned about the epoxy used in sheathing not bonding well to the PL in the open seams. Lee Valley has the router bits for beading and coving, and you can mount your router and a fence in a long 2 x 8.

[Paul Pless]

who has convinced me that I should probably go to 7/8" WRC or Spanish Cedar

My wife and I have a small stash of Spanish Cedar. Really nice and quite lightweight stuff, but pricey. . .

[Ron Williamson]

I don't have the space or machinery to shape the strips efficiently: 275 square feet means about 10 times that in lineal feet depending on the strip dimensions. I have gotten several quotes for this milling which more than doubles the price. fwiw, the bids have gone from $4700 to $6600 delivered to Chicago.

Any guesses on the labour/material/trucking split?
I'd make pretty good money charging you $500 to machine it.
If I had moulder knives, it would be $100-ish for setup and about $150 to run,which would take less than two hours.
To run with a planer and shaper it would take most of the day.
R

[CJ]

I took some bead & cove cedar (3/4" x 1-1/4") and glued them together using PL Premium a year ago. Each time I've taken a sample of these and tried to break the glue interface, the wood breaks instead - and these were glued together on a bench without applying pressure to them as suggested.

So, mechanically PL seems strong enough to me, especially if you edge nail the strips or plan to fiberglass the hull afterwards. Scrape away any squeeze out during the cure when it's rubbery (not wet, not fully cured) for a clean joint. It will sand off if you miss any. Put unused PL in the fridge for later use.

Gap filling isn't it's best quality, but it will to a degree.

CJ

[wizbang 13]

Beveling? Bead n cove? PL caulking?
Ug, just learn how to use epoxy.

[Bill Huson]

So from $4700 to $6600 - does that mean machining B&C was $1900? Dude, you can buy a router, table, proper bits, and a few featherboards for a few hundred bucks. I've run strips through my router table set up for bead & cove and had piles of them before my first coffee break. Not to mention the router is one of my fav tools now, on and off the table.

[kbowen]

There are other considerations: this is a very curvy design, not remotely like the canoe-body hulls that all the books on strip construction show in their illustrations. I built a 1:8 scale model to study the plank (strip) lines and ended up with stealers all over the place. It's deceptive: there is so much sheer that the midships girth is not very different from the height of the (nearly plumb) stem rabbet, so you would think the plank lines would be simple, but the best way to negotiate the twist from the deadrise to the ends seems to be to let those planks sweep upward and then correct the runs both above and below. Due to this, the benefit of B&C would be severely reduced by the number of times I would have to rip tapers in some strips or rip a sweeter line through a bunch of strips to start a new course. So my current plan is square strips & plastic nails. I would prefer working with the PL premium glue, but am beginning to think I should get serious about refining my epoxy technique.

[timo4352]

I at first considered PL premium for the boat I'm building now. I worried about the compatability of the fiberglass/epoxy over the PL, and decided it wasn't worth taking the risk. I'm so glad I didn't - I'm coming up on 100 hours into this thing and I'm not near done yet. Why risk it? Also, I compared the cost per ounce of both PL and epoxy - the epoxy won again. First time I've used epoxy and I've had no problems at all (knock on wood (boat) )
I have used PL on my kayaks and was very happy with the result - even sealed the nylon skin on one of them with it - but those are quick and easy to build too. Not hundreds of hours and thousands of dollars.
Tim