Stickin' stuff to my boat

[Old Hickory]

Any of you guys use PL Premium construction adhesive? Its a polyurethane adhesive that is quick dry and waterproof.

Found some guys on Glen L forums using it w/ excellent results. 3M 5200 is hard to come by here in nashville; can't get the blue label stuff and the red label at advanced plastics is 11.95/10oz tube. Bought all they had; 7 tubes; cost me $58. and I have to buy a case at a time to get any more. Pl Premium is $3.39/10oz tube at Lowes. Think I'm going to buy a case and use it for bedding my transom, stringers and floor. Send the 5200 back except for a few tubes to use for caulking my deck to hull and to mount my transom extension. Looking at the Tech data sheets for both they are virtually identical. What do you think?

Hick

 

[Old Hickory]

sorry, heres the rest of the tech data

 

[Rob B]

Hick,
I read both and don't see were it would be a problem as long as you glass everything over real good. Being in the engineering business I've heard the same thing.

 

[teamhart2]

hey old hick, any reason you dont wanna bed the transom with some bondo like they come from the factory, or with some fiberglass putty (resin with milled fiber)????

Glad to hear its coming along, got my three transom plys cut and bonded today....... and decided to tackle replacing my pad

 

[Old Hickory]

The more I read and learn about these polyurethane adhesives the more I am impressed by them. They are different than epoxy or polyester in that they flex w/o breaking their bond. And are at their best when bonding flat surfaces (transoms) and bedding structural components. PL premium will also serve to fill voids up to 3/8" w/o compromising it's bond. Compulse170 nailed it; parts need to be encapsulated w/ glass after they are bonded w/ polyurethane. This is one of those situations that appears the sum of the parts exceeds the whole.

If I were building this boat from the ground up I would be using epoxy; period. Structurally it is superior to most anything in the market. It is best in joints and stitch and glue applications. It's weakness is tensil strength. In other words it dosn't flex as well as polyurethane. Epoxy shines w/ wood boat building and general boat repair.

Now, since checkmates are made from polyester, and I will be repairing with polyester; seperation is an issue. I was troubled by the cracks and seperations I found w/ the bondo checkmate used; it appears it dosn't have the tensil strength nessecary to withstand flexing forces over long periods of time. This was reinforced to me by the seperations I found in the transom and stringers. Polyurethane seems to answer that problem and it can't be any worse.

So to answer your question....yes I'm bedding and glueing my transom w/ polyurethane. I have also abondoned using wood in my boat repairs. I am using foam and coosa. Polyester is notorious for seperations from wood. That is why you almost NEVER see ply and wood boats built using polyester; epoxy only!

Hick

 

[teamhart2]

hmmm sounds like something I might pick up to bond some of my stuff!

 

[Old Hickory]

I'll be picking up a case of PL Premium this afternoon; and hopefully laminate the 3 pieces of my transom today. I'll let you know how it goes this evening.

BTW, I chose to use a foam similar to Mantex from Advanced Plastics for my stringers. It is 1/3 the cost of DF ply. Initially I was put off by the cost of coosa, but the savings afforded by the foam will bring the overall cost of the rebuild more in line w/ ply.

That brought me to a crossroad; had I chosen to use ply, I would have certainly used Epoxy resin due to it's superior bonding w/ wood and its ability to bond w/ the existing polyester. the down side to epoxy and wood is that it soaks it like a sponge; but you don't have the delamination issues like you have w/ polyester and wood.

Now that I have gone w/ composite materials polyester resin is the clear choice; hopefully saving me even more in materials cost.

Hick

 

[teamhart2]

well hick you convinced me, picked up a few tubes today and I hope to glue the new pad in this evening with the stuff, Dunno if Ill use it for the transom or not but I think itll work great on the new pad.

One thing Ill say, is that while poly may be weaker than epoxy in bonding to wood, it can still make a hell of a good bond, every piece of wood Ive pulled outta this boat that wasnt rotted has been a wrestling match to get it to come apart from the fiberglass usually breaking the wood into pieces and chiseling off the last layer. Even the pad was still bonded freaking well considering it was only bonded sporadically along its length and for about a half inch on each side. If the wood Im glassing in with the poly bonds as good as what was there before I wont ever worry.

 

[Rob B]

Hick I had forgotten about PL Premium construction adhesive until you mention it, great find. I'm taking notes, between you and TH2 I should have no problem replacing my floor in the fall.

 

[daren34]

Now, since checkmates are made from polyester, and I will be repairing with polyester; seperation is an issue. I was troubled by the cracks and seperations I found w/ the bondo checkmate used; it appears it dosn't have the tensil strength nessecary to withstand flexing forces over long periods of time. This was reinforced to me by the seperations I found in the transom and stringers. Polyurethane seems to answer that problem and it can't be any worse.

So to answer your question....yes I'm bedding and glueing my transom w/ polyurethane. I have also abondoned using wood in my boat repairs. I am using foam and coosa. Polyester is notorious for seperations from wood. That is why you almost NEVER see ply and wood boats built using polyester; epoxy only!

Hick

the reason boats are built with polyester is that it shrinks when curing so it will pop out of the mold
epoxy does not shink so it is better for repairs than polyester

daren

 

[wca_tim]

I just redid my stringers and floor over the past week or so and bult new "flotation boxes" as well as new engine mount pedestals...

I used pl to bed the tringers and deck, to bond everything to gether (as in flotation boxes and new boxes under the front seats held with bar clamps for a few hours until strong) and then once it cured (it can bubble a little)glassed the heck out of everything using epoxy resing and a combination of mat and cloth. 2 laters on the stringers, 1 layer on the boxes and seat bases in the front, three layers holding down the new bucket seat monuting blocks, and one thick later on the entire deck... I glued everything together and seaked all the joints with PL as i went. it took 8 or so of the 20 oz industrial tubes to do the whole thing and was as easy to do as caulking your bathtub...

why did I decide to us it? it'll last for a loooong time, comes in caulking tubes, is as waterproof as it gets, sets up in a few hours and holds lilke crazy. Note that it's not recommended for bonding to polystyrene based (I would probably include pooyesther resin in this category, but it seems to hold fine where i've tried it with polyester resin).

oh, I should mention that i did not use it on the mounts, those were made with 1x 3 in mahogany boards, using one side of the glass from around the original structure, layering the boards with mat and epoxy resin mixed with ground glass / filler to make it really rigid...

Not sure if this was overkill or not, but it sure seems solid as hell at this point...

now to decide what color to paint the deck and with what....

 

[teamhart2]

I was thinking about that polystyrene thing, but it says its good for fiberglass on the spec sheet so maybe it means polystyrene plastics or something

 

[Old Hickory]

Well I bought a case of PL premium this evening; I'm really looking forward to getting started w/ this stuff. All three pieces of my transom are sreamin at me right now I ended up fixing a bed and setting up a Wii today instead of working on the enforcer, because my sister n law and nephews will be spending the week w/ us. Always another distraction. LOL

I'm glad to hear all you guys using PL; just reinforces my decision to use it.

the reason boats are built with polyester is that it shrinks when curing so it will pop out of the mold
epoxy does not shink so it is better for repairs than polyester

daren

good point; I hadn't intended to go that deep because there a number of good reasons to use polyester for manufactered boats. Mold release; cost and ease of use to name a few. However, there are trade offs, separation being one of them. I also want to clarify my statement above by saying that I'm in no way implying that checkmate has a quality issue by using polyester and wood together. If you think about it, they really don't have much of a choice, so long as they want to keep their boats affordable and good quality.


Hick

 

[Old Hickory]

I was thinking about that polystyrene thing, but it says its good for fiberglass on the spec sheet so maybe it means polystyrene plastics or something

Thats the stuff cheap coolers are made of. If you grew up on a construction site like I did, you know real quick what this stuff sticks to and what dosen't; it won't stick to clear plastic covers(polyehtylene etc) and your cheap a$$ lunch bucket(polystyrene). But it will stick to the bottom of your boot, the seat of your pants and any part of your trucks interior(seats and floors). Oh yeah, the rubber handle of your hammer

Hick

 

[teamhart2]

Yea haha, I lost many a good estwing handles to subfloor adhesive back when i was working construction. Luckily for me the seats on my vehicle needed the extra glue.

 

[teamhart2]

forgot to mention, stuff seemed to work pretty good today, I laid it out in a few thick beads down the pad and then used a plastic spreader to spread it out to about a 1/8 inch or so and thicker on low spots etc. Gotta be careful though cause if you go to fast itll trap air underneath it, I may have a few small bubbles but itll be a whole lot better than what was there before. Stuffs pretty thick, really had to stand on it to get the plywood to set down into it. then weighted the crap out of it and leavin it till tommorrow.

Im pretty pleased with it so far, not sure if ill use it on the transom, since I already have the glass cut and everything plus it might be a bit of a pain to spread on that big of an area, Def gonna use it for pre-glueing my knees stringers and floor though.

 

[Old Hickory]

sneak peak of my next post on the blog

Finally glued up my transom; after it sets it'll be ready to glass in this weekend



3 pieces; two coosa B-26 and one B-20



PL Premium polyurethane; pic of application



this stuff trowels easily; cleans up w/ acetone; using a trowel w/ the "teeth" prevents those pesky air bubbles.



first layer after troweling



was able to get two cuts out of one 4x8 sheet; they overlapped slightly; had to cut a piece to fit the small section that over lapped. This layer went between the other two pieces.



finished w/ the glueing placed a total of 200lbs of weight to press them together.

I'll be posting on my blog this evening; I have alot of pics to edit and will go into more detail. Overall it went well; I was very pleased w/ the results.

Hick

 

[wca_tim]

the reason pl polyurethane bubbles when thicker is the reaction of isocyanate with moisture that foirms carbon dioxide gas as a by product.

also, the polystyrene that results from curing the styrene in polyester resin is not so dissimilar form the cheap polystyrene stuff when it comes to chemical stability and adhesion... That being said, i stuck some regular resin / glass to some pl when I redid my floor and stuch a few sample pieces in a tem controlled oven at work to see how they hold up under accellerated time testing conditions... they seemed to stick ok, so I'm betting that good quality poly resin will work ok... I went with epoxy to be safe... and because of the better adhesion to old poly resin...

I should have taken pictures... putting everything together using pl was a snap compared to other ways i've done it in the past...

great stuff... and nice work above - looks great!

 

[Old Hickory]

wca,

That explains why TH2 had bubbling; he was using ply, must have reacted w/ the moistuer in the wood. My coosa shouldn't hold a significant amount of moistuer; however I think using a notched trowel helps; reduces the surface area for bubbling. Just curious, what do you do for a living? Engineer?

Check out my blog; just posted the transom removal; will be posting the cutting and glueing of my transom tomorrow(tuesday) night. Thanks for all your insight; it's been very helpful

Hick

 

[teamhart2]

My bubbling was just when I smoothed out my initial beads across the pad before I put the ply in, there werent to many and I was able to work them out, It would have been a snap with a trowel like oldhick used....... guess theres always something to learn!