Parting out H170 in AZ

[JimInPB]

Plexsus is not an epoxy. Others have referenced this to a Plastic Welder. Please understand the difference. Remember that even Watertite which is a two part epoxy says on the can it is a filler. Others in my industry said the same thing

@JimInPB
I appreciate your response. We may disagree on specific materials but tend to agree on others. It seems we are on the same page with repairs and removal of all ACP in the cockpit floor. Great to hear from you

Thank you for the information on Plexus being considered a plastic welder rather than an epoxy. I was unaware of that.

On the rare occasion that you & I do have a difference of opinion, I think that it is usually based on the two of us having a different history of experiences from which to draw conclusions. I have learned a lot from you, here on this board & I thank you for your generous support.

 

[Shorefun]

The MA300 is not an epoxy and I do not think it wise to call it a plastic welder. It is a two-part methacrylate adhesive. It happens that one of its properties is it chemically opens up the plastic surface so that the molecules of glue can grab onto something and hold tight.
Epoxy does not do this, it needs a surface with a roughness to get it molecules into and hold.

 

[Crazy Dave Condon]

@JimInPB
Yes we sometimes disagree but we work together and respect your opinion as you have reported back results which is what this forum is all about.

Others who have worked with these products in the past have said Plexsus is the business name while for sale in stores to the public is the same as Plexsus under the name of Plastic Welder. Experience also has shown that adhesion is not as good attaching epoxy to plastics whether or not it is sanded. I am not the only one who has stated that. Plexsus and epoxy are two different materials met to work in ways different from one another. I too leaned from the wise experienced old sailors and am passing on what I was taught and experienced over the years what worked or not worked reporting in layman’s terms which others can learn too.

If anyone disagrees, then repair your boat the way you think it should be and report back to the forum the results first when repairs have been made followed by reports how the repairs held up for the following year of usage at interval reporting. This is the way to do it

 

[BobbyFunn]

Check this out...

My deck has been flexing for a while and a crack occured near the centerboard housing. i figured the foam had collapsed so began a repair. The plan was to cut out small shapes, build the foam back up, then replace the skin. The picture shows where i marked tape to section out the shapes. Can see one shape has been cut out.

Im dumbfounded as to what has happened. It appears the bottom of the decking is no longer attached structurally to the centerboard housing. There is a loose section of fiberglass with no resin of any kind. The foam is actually intact underneath.

In one picture you can see the 2 inch gap caused by the floor collapsing.

Im guessing for this repair i need to find a way to support the foam deck, glue the foam up to the plastic skin, then patch it up.

Most of the repairs are about pressing the decking skin diwn, i need to pull it up?

 

[JimInPB]

The resin-free area looks very regular. It almost looks too regular to have been an accident. I wonder if that was done intentionally to allow flex & prevent the creation of a stress concentration point.

My 212 has the same ACP construction as the 170. It had a small area of de-lamination. I drilled a small hole, filled it with 5200 & weighted the skin down until the 5200 cured. So far, so good on that boat. That was probably 2 years ago or more.

I will be following this repair with great interest. My 170 has a small de-laminated/cracked area. I will be very interested to see what you find inside there as repairs continue.

Thank you for posting.

 

[JimInPB]

Another thought -
You say that you need to support the foam. Another option might be to drill a small hole through the foam, insert a toggle bolt, then attach a cord to pull it up.

...Just an alternate way of putting upward pressure on the foam sheet.

 

[BobbyFunn]

Another thought -
You say that you need to support the foam. Another option might be to drill a small hole through the foam, insert a toggle bolt, then attach a cord to pull it up.

This...just like you say...


I was thinking toggle bolts as well. The basic premise here is to drill cores out and use pegs that are in the holes as tie off points to a 2x4 across the seats. a couple trucker hitches and the floor is pulled up. I can place glue in the gap first before tbe tie down.

The next step is to use expanding foam to form colums (think like a cave) between tbe hull and the holes.

 

[BobbyFunn]

The resin-free area looks very regular. It almost looks too regular to have been an accident. I wonder if that was done intentionally to allow flex & prevent the creation of a stress concentration point.

This appears reasonable. I was able to press the deck down enough to get the phone inside. Could also see the other side od the centerboad housing(foot stop). There is a consistant strip of resin free glass running along the centerboard housing. Good news...There is no water in tbe hull.

One picture shows the decking on the other side of the centerboard housing. can see the inch and a half of good looking foam and the resin free glass just resting on tbe foot stop. Can also see some plastic chunk that is the structure for the centerboad trunk.

next picture is looking up underneath the foot stop. I was thinking Hunter used a solid piece of glass fabric and used it for support, but its cut clean under the foot stop.

In essence the only thing holding that floor together is the tension of the skin between the seats and the adhesion of the skin to the foam. When the adhesion ends so does the floor.

 

[Shorefun]

You are right about the floor. Mine was very loose. The plastic had debonded from the foam allowing for the whole center structure to wobble side to side when you shifted weight back and forth.

After a lot of thought I went with the 5200 to bond the plastic to the foam. This made the whole floor rigid.
I chose the 5200 after seeing how easy it was to debond the gorilla glue from the Luran skin when cleaning up. My opinion is the gorilla glue will debond over time because it is hardly bonded. It feels great at first but my thoughts are in a few years after some heating and contracting and use it will loosen up. The 5200 will stick well to both the foam and the Luran skin. It is difficult to clean up. I recommend masking the areas you do no want to get the 5200 on as the accidents you find later are a pain to clean up.

 

[KeukaSailer]

First if you haven't had the pleasure of talking with Dave ….you should the Man is a wealth of information...and a gentleman. He helped me with my 146. Anyway Plexus is methlyacrylate, and is made by a few different makers. You can also use it inplace of epoxy for glassing with glass mat. I used this successfully for larger cracks. For delaminated skin drill holes pump with gorilla glue (it expands, fills and binds), and weight down. Clean up can be a pain afterwards but not impossible, and it's a perm fix. If your boat was mine...I'd be real tempted to sink bolts in the new glass work....and do a nice homemade teak slat floor. Hell I'm tempted for my 146......

 

[BobbyFunn]

I'd be real tempted to sink bolts in the new glass work....and do a nice homemade teak slat floor. Hell I'm tempted for my

You arent too too far off from what i am planning.

I measured out the decking and plan on covering up almost all of it with HydroTurf light grey diamond. They have faux teak, which looks cool, but it might be too dark for the plastic.

Its the same stuff they put on PWC floors only i'll have to cut out the shapes from sheets.

 

[BobbyFunn]

After a lot of thought I went with the 5200 to bond the plastic to the foam. This made the whole floor rigid.

@Shorefun is 5200 runny enough to spread out? Packaging suggest it is gummy. 5200 looks awesome for gluing a cut out panel back onto the foam, but here there is full access.

Im thinking gorrila glue might not be as strong, but it will spread more easily between the deck and the core offering strength in numbers.

 

[Shorefun]

I was getting up to 8 inches of movement 6 no problem. I would inject in and hold my finger over it while pressing around with my hands.

Honestly I can not see the gorilla glue holding up in time. I did some testing and found it will peel off very easy. I glued some acrylic plastic (lexan) and found did not take a lot to get it come off. I believe that the shear forces will and thermal contractions of the plastic will cause it to come apart in time.
I know the 5200 will never lose its bond in those conditions.

 

[KeukaSailer]

To each his or her own and your results may vary..... but the gorilla glue is a polyurethane expanding glue which does bond both to the foam core and the skin, permanently, and is completely waterproof. My own use of it from last year has been promising. My boat, was exposed to constant sun, the weigh of my family, torsion forces of being bounced around on our 20 mile long lake which builds up pretty good chop and wind, use down here at the jersey shore, salt water, and seriously cold temps outside this winter....and has remained rock solid. I know that this has been the go to way of relaminating the deck on this boats for years. So fingers crossed it'll work for me...

 

[Shorefun]

Well actually the Gorilla does not bond well to Luran. It needs a porous surface to get any grip.

The 5200 actually is similar and if you look up the bonding strength it is like half as strong a bond to Luran. Luran is difficult for any adhesive for any glues to bond except ones that can open up the surface. The MA300 has solvents that allow the glue to get into the molecules of Luran for a bond.

Anyway your boat is done and its working, no need to worry about it. I like to try and understand what is going on with the products I am using. I have learned too many people use products wrong. In car restorations I have seen the problems people have had because they have use products wrong.

 

[JimInPB]

5200 is pretty runny when it is fresh. After a year or two in the unopened tube, it stiffens up a bit.

When 5200 cures, it expands slightly, then later it contracts a bit. Don't be surprised if you see a little bulge at seams after it hardens. That bulge can be cut off with a razor blade. It works best if you lubricate the blade with a little oil or dish soap.

The waterproof grip of 5200 normally lasts for many years, but eventually it does give up the seal & need to be replaced.

When I did the motor mount repair on my 170, I spilled a drop of West System epoxy on the deck. I still can't get that drop to come off. I therefore believe that West System epoxy does stick to clean Luran pretty darn well, even with no surface prep.

5200 is a big mess to work with. Have plenty of paper towels handy when you open that tube & consider using rubber gloves.

5200 comes in a few different flavors. The fast-dry normally cures in a day. The standard stuff normally cures in a week. There are also different colors.

3M posts spec sheets on line. They contain a lot of good information. One piece of advice that I picked up from the sheets was to not use alcohol to clean the surfaces to be bonded. Apparently alcohol prevents proper curing. They also informed me that 5200 has a moisture activated curing process. The moisture in the air can affect curing times as can temperature. They provide charts & graphs to illustrate this.

 

[Hunter216]

. I therefore believe that West System epoxy does stick to clean Luran pretty darn well, even with no surface prep.

That’s very interesting. There are lots of threads about not using epoxy on the Luran as it either doesn’t bond or worse will eat the Luran. Do you think because it was just a drop the heat buildup during curing was minimal and that made a difference?

 

[BobbyFunn]

Got a 4" hole saw and cut through the foam in the same area as the skin I removed. This allowed me to get a camera in the hull.

The unedited picture is under the port deck by the mainsheet swival, looking towards the motor mount. The drain hole is visible on right. Not sure what the expanded foam column is to the left.

This explains everything. There is no support under the deck at all and there is about 3 feet where the deck has to wrap around the centerboard and it is not attached, purposely. In my opinion, Hunter170 deck delamination repairs are only temporary fixes if the deck is not fully supported.

Im guessing that Hunter has that free floating deck after the mainsheet swival because the core would split right there. They knew it would wiggle, but hoped that the skin to core adhesive would hold.

Better construction would have been the inclusion of a stringer at the end of the centerboard trunk that spans both decks and connects or at least rests on the hull.

 

[BobbyFunn]

Here is a picture of the underside of the luran skin panel i dremeled off.

This provides evidence to me that 2 part urathane foam core barely sticks to plastic. It also shows what looks like the section closest to the centerboard housing/foot stop did not get attached to the core during the factory build.

Gorrila glue might work for areas like seats that are well structured, but it might not be great for decking. Gorrila glue expands with moisture and if the space isnt pressed together and the gaps removed the bond will be made of foam bubbles. I can see the circular bubbles on the panel.

Fun fact...As i was pulling the grip tape off the deck, i could hear the luran delaminate from the core

 

[JimInPB]

In the picture in post 38, on the left, I see bare glass cloth that looks cut. I am curious what the opposite side of the boat looks like in that area. Is it also bare glass? or is there resin on that side? If there is resin on the other side, I am going to have to conclude that somebody probably did a poor quality vacuum bag job. I am leaning towards that conclusion at this time since the resin looks significantly richer towards the stern of the boat compared to mid-ship.