Plastic Hunter Crack Repair

[H216sailor]

Thanks Crazy Dave! I read pretty much any forum post I could find on the plastic hunter repairs before making the decision to buy my 216 so I figured I'd chronicle my experience to give others who might be on the fence on whether or not to buy one of these boats yet another post to read in their consideration on whether these boats are right for them.

so far I'm very happy with my purchase and after fixing the crack with Plexus, I have no other complaints about the boat. Its a fast, fun boat that I plan on racing PHRF non-spinnaker next year. This winter I will be replacing the keel pivot pin as the board has a little play in it and I suspect its the original 14 year old pin. Not broken, just a little preventative maintenance. I have not seen a write up with pictures on that process so I'll make a new thread for that this winter.

As far as painting the repair, it is on the forward side of the coach roof and not visible when sailing so its been out of sight out of mind for now. maybe when the season's over I'll get around to it.

 

[JimInPB]

I'll look forward to reading your write up of the pin replacement. I will probably plan to do that repair on a similar boat in the near future.

Thanks,
Jim

 

[Crazy Dave Condon]

It is a pleasure to serve

 

[mdarrow23]

Thanks for sharing all your knowledge on this. I purchased a 170 in October, it has developed several cracks in the hull.
I read the whole thread and I'm trying to sift through what the consensus was on best repair method is, it seems that the process is:
1. Drill 1/8" at each end of crack to prevent spreading
2. Use Dremmel on the cracks to create some rough surface for adhesive to grip (is this required if using Plexus?)
3. Do I use the Plexus MA300 on the cracks? Mesh or no mesh? The Plexus is an 'adhesive' but can be used on open cracks?
4. Once is hardens then light sanding and use Krylon white paint.
Is the above process correct? If so, how far does a tube of the MA300 go?
Thanks in advance!

 

[H216sailor]

Welcome to the forum and congratulations on your new boat. Your process looks good to me. As for dremeling the crack, you should do this step to open the track a bit to make a larger surface for the Plexus to bond to. As for the mesh, I did not use any but I guess it depends on how big the crack is and whether it’s it a hit load area or not. I did my repair in late August of last year but did not get a chance to sail the boat in heavy air to see how it held up. Held up just fine in light air and I don’t think it will be a problem in big air. Keep in mind that the plexus does lose some volume whe it dries so the repair will be slightly concave. You can put more plexus in the crack or use an auto body filler

 

[mdarrow23]

Thanks. Does the Plexus MA300 require the plastic welder (to heat it) or does it apply like a caulk?

 

[chuckwayne]

If you buy the plexus in cartridges and the gun it's applied like caulk - the cartridge uses a replaceable mixing nozzle to mix the two parts. by far the easiest way to do a good fill. The small tubes don't go very far and are more expensive (as I recall). As H2 said, plexus shrinks as it cures so you can overfill slightly or apply a second layer after the first one sets. I use the version that has a 15-20 minute working time which works well in this repair, you can apply a bead and then smooth it with a plastic or wooden spreader

 

[H216sailor]

The 50ml cartrage I used to fill my 3’ crack used a little more then half of the cartrage. Definitely use the mixing nosle to make your life easier. I find that the cartrages don’t keep well after they are opened so I would recommend buying the small ones and using the whole thing.

 

[Shorefun]

Thanks for sharing all your knowledge on this. I purchased a 170 in October, it has developed several cracks in the hull.
I read the whole thread and I'm trying to sift through what the consensus was on best repair method is, it seems that the process is:
1. Drill 1/8" at each end of crack to prevent spreading
2. Use Dremmel on the cracks to create some rough surface for adhesive to grip (is this required if using Plexus?)
3. Do I use the Plexus MA300 on the cracks? Mesh or no mesh? The Plexus is an 'adhesive' but can be used on open cracks?
4. Once is hardens then light sanding and use Krylon white paint.
Is the above process correct? If so, how far does a tube of the MA300 go?
Thanks in advance!

You need to use a Dremel to widen the crack and increase the surface area for the glue to adhere.
The Plexus MA300 is methacrylate (MA) adhesive. While it is 2 part it is NOT epoxy. The MA chemically 'opens' the Luran plastic and allows for the molecules of the glue to catch on the plastic.
I did all the common places on the deck side of my 170 and have used 5 of the 50ml containers. I would guess like 6 feet of crack fill.
The Hunter directions want you to do longer cracks by grinding the crack then thinning the area with a sander and placing glass. You will need a lot more MA 300. My cracks were on top and not structural. The couple real long one were up in the front bay area. I decided to try doing without the glass. Well I was able to lift the plastic along the floor and slip in some 5" by 1" glass with MA300 under the backside. My thoughts are I can always grind out and redo with glass if the crack comes back.
Any cracks on the hull I would grind and glass. Too important to want to not crack.
I bought this applicator https://www.amazon.com/COX-M25-25-m...ual+Epoxy+Ap&qid=1551060032&s=hi&sr=1-1-fkmr0

The process of glueing was kind of fun to do. The applicator was comfortable to use. The glue sets kind of fast and I prepped the cracks by taping along the edges to reduce sanding. I would lay a line and not worry about a perfect fill. Then used a plastic scrapper for autobody filler to level. This usually gave me some on the scrapper and that would let me fill the areas not fully filled. Also the scrapper will help push the glue further into the crack. You will need to work fast. You lay down a line then scrape and lay in more. You have just a couple of minutes before the glue in the mixer will set up and start coming out lumpy. So long as you keep dispensing the glue is freshly mixing. By a bunch of tips and if you need to take time just trash the current mixer and put a new one on the tube. You will also feel the mixing tube getting warm if you wait too long. Do not panic, you really get plenty of working time. I had problems after I had handled the longer lines. It was bunch of short lines of glue around the cleats, the edge of the bay and were the front jib bracket is in the front. I had to stop and take some time to limit the mess I would have to sand off and I was not putting out a full mixing tube of glue each time so the stuff in the mix tube was curing.

The glue does shrink a bit, I was surprised with how much. I sanded the areas with like 240/ 320 paper depending on how much I had to take off. I used small pieces and stayed close to the glue line. Then worked up to 600 and then some plastic polish by Novis.
I bought some marine bondo to level the areas. Great idea, but does not work so good. Remember the plastic does not let glues stick to it very good, neither does the glue. Some of the odd areas the filler seemed to work, often it came off in a piece.
I got some of the plastic paint as recommended. When I tried it was cool out and the dry time was long. The paint did not like to stick to the glue and looks ugly. I will test it again when it gets warm to see if it works better.

Keep in mind the MA300, Devcon and Locktite are all the same company. They are just different product groups. The Devcon is just a smaller size of the same MA300.
If you are going to west marine keep in mind they price match with amazon. Just show them the thing on the phone and you get the price. I found the filler for around $16 online and it was $30 at West.

 

[Rictifyit]

Hi! I’m new to this forum! I am pleased to find all the helpful information about crack repairs on Hunter sailboats, because I just bought a 2004 146. And guess what, it has lots of cracks. Fortunately, I paid minimum for this boat. My boat repair skill is “beginner”, although I ran a small auto-body shop for a while in the early 80s. I’m trying to lay out a plan of attack, and will welcome helpful hints to my plan.
From what I can tell from the forum comments, and the Hunter General ACP repair manual PDF, the basic way to repair these cracks is:

1. Drill holes at each end of the crack. Dremel a V along the crack to create a trough for Plexus (whether it’s from Home Depot Locktite, Walmart Devcon, or Plexus, it’s Methyl Acrylate)
   1. Question: Do I use straight Plexus, or combine it with milled fibers of fiberglass to give it more substance/strength. My guess is that really small cracks get just plexus, and as they increase in size, add milled fibers, and even fiberglass cloth.
   2. The bigger the crack, the more you dredge out, sometimes even down to the foam layer. And then bevel it up to the top to assist with feathering.
   3. Sand it down, and paint it with Krylon fusion. ( has anyone used that rubberized paint Flex-seal? Rustoleum has a cheaper equivalent. Just curious )
2. Part of the deck is a little “bouncy”, so I think part of it has delaminated from the foam. I’m not sure what to do there, so suggestions are welcome. Do I cut out the bouncy part, and build it up with Plexus/Fiberglass clothe, or pump Plexus under it??

This boat does not need to be perfectly pretty. I just want to make it sound, and keep water out of the foam. I bought it to sail with my 1st mate. She lives on a small 80 acre lake in N. Illinois. It’s not going to have to endure much, so I’m hoping my repairs will hold up. I have a CLC wooden dory that I sail elsewhere, and a Raider Sport that I hope to fix up also. It has some major repairs needed, and a story for another day. Thanks, If a couple of you could just let me know if I’m on the right track,, and also, where is the best place to get a good value on this Plexus stuff. It looks to me like I’ll need quite a bit of it. Being new to "SailboatOwners", I think I'm posting this in the correct place. If not, let me know. Ric

 

[Hunter216]

Hi! I’m new to this forum! I am pleased to find all the helpful information about crack repairs on Hunter sailboats, because I just bought a 2004 146. And guess what, it has lots of cracks. Fortunately, I paid minimum for this boat. My boat repair skill is “beginner”, although I ran a small auto-body shop for a while in the early 80s. I’m trying to lay out a plan of attack, and will welcome helpful hints to my plan.
From what I can tell from the forum comments, and the Hunter General ACP repair manual PDF, the basic way to repair these cracks is:

1. Drill holes at each end of the crack. Dremel a V along the crack to create a trough for Plexus (whether it’s from Home Depot Locktite, Walmart Devcon, or Plexus, it’s Methyl Acrylate)
   1. Question: Do I use straight Plexus, or combine it with milled fibers of fiberglass to give it more substance/strength. My guess is that really small cracks get just plexus, and as they increase in size, add milled fibers, and even fiberglass cloth.
   2. The bigger the crack, the more you dredge out, sometimes even down to the foam layer. And then bevel it up to the top to assist with feathering.
   3. Sand it down, and paint it with Krylon fusion. ( has anyone used that rubberized paint Flex-seal? Rustoleum has a cheaper equivalent. Just curious )
2. Part of the deck is a little “bouncy”, so I think part of it has delaminated from the foam. I’m not sure what to do there, so suggestions are welcome. Do I cut out the bouncy part, and build it up with Plexus/Fiberglass clothe, or pump Plexus under it??

This boat does not need to be perfectly pretty. I just want to make it sound, and keep water out of the foam. I bought it to sail with my 1st mate. She lives on a small 80 acre lake in N. Illinois. It’s not going to have to endure much, so I’m hoping my repairs will hold up. I have a CLC wooden dory that I sail elsewhere, and a Raider Sport that I hope to fix up also. It has some major repairs needed, and a story for another day. Thanks, If a couple of you could just let me know if I’m on the right track,, and also, where is the best place to get a good value on this Plexus stuff. It looks to me like I’ll need quite a bit of it. Being new to "SailboatOwners", I think I'm posting this in the correct place. If not, let me know. Ric

There are a number of threads that deal with fixing Hunters that have Luran as part of their layup.

I would recommend reading through at least the last portion of this thread as @BobbyFunn evolved the thinking on how best to tackle this issue.

Parting out H170 in AZ

What other boats share the mast and boom sections? Looking for a boat that needs a mast but nothing interesting popping up. Everything is in super condition - except for the cockpit fiberglass. Mik

forums.sailboatowners.com

 

[BobbyFunn]

You are up north. If the sails are shot, buy new ones and go sailing with them until the hardware rips out. Sell the sails online afterwards.

There is aready water in between the luran skin and the foam. You cant get it out so any repairs will reaapear with the freeze.

If the deck is bouncy its because the foam core underneath is no longer attached to the luran. The core probably broke somewhere and cant be repaired without access underneath.

This looks really bad. @Shorefun has the best plan for the buck. If the luran is detached from the foam at those cracks then inject adhesive about an inch on both sides, underneath. Also cut a 1/4inch notch down into the foam at the crack so that the glue grabs the foam to depth versus just a thin surface layer.

If i had to save the 146 to pass down to generations i would take all the top skin off and cover it resin and new glass.

Any precision 15's you could get instead?

 

[Shorefun]

So what are your goals? I am a beginner with not real boat experience that bought, in retrospect, a pretty good condition 170 real cheap. I have done antique car restoration work and know some more advanced autobody, I can paint but I suck at it.

Honestly, So long as the bottom is not cracked and the various brackets still have good wood that holds the screws you can likely sail it. Now the bracket on the bow needs to be held in tight. There is a lot of cracking around that area that would concern me. That is not an area where the 170 has issues it seems.

My first order of business would be to peel up the anti skid and that glass around the bow. This will let you see what you really have. Post pictures.

Base on my experiences try backing out all the screws on the bracket on the bow, where the mast mounts, where the rudder attaches and the motor mount if it has one. Back the screws out then try to tighten them down. The should come to a solid stop. If they do not then you know you do not have wood there. Hopefully you have look around enough to see the level of work needed. Next take them all out and probe with a pick an see if the wood is solid or wet and nasty. You need these screws to hold for the boat to work. The typical problems are with the rudder and motor mount.

From the automotive perspective you are used to putting a correct scratch on a material and then be able to get adhesive to stick. This plastic does not work that way. It is just hard to get a good bond if you are not 'melting' the plastic so the glue can actually stick to the plastic. Just like doing bumper covers. The MA300 melts the surface and lets the adhesive lock into the plastic. Anything else in my opinion is likely to fail over time with exception the 5200 (*failure depends on the structure and how you set it up).

Rebonding the plastic to the foam to get the floors solid is another story. You have to look at how bad yours is and make a guess as to what will work best for you. One guy cut up the floors and did some glass and other work, that is a lot of work. I used 5200 and worked it out manually. My floors were not so bad and I figure lots of 4" dots holding the plastic floor to the foam would be ok. Worse I have to cut it out later.

The way I figure it is they are crappy construction but fun capable boats for learning. If you get them cheap enough you can likely have a boat that will be fine to learn on. If you get more serious then you might want to move up so you sell this one cheap and move on.
The boats can't sink, you are not crossing oceans. So long as the screws are not falling out and the cracks are glued up it is going to work. It does not have to be pretty, just work.
I think you need to know what you are getting into before you start. You could end up putting more into this boat then if you were to find a decent O'day day sailer that is ready to go.
I would want to look closer at the bow forestay bracket. All that cracking would have me worried about strength and that needs to hold good. Plus water may gotten in and may have hurt the wood that you have to screw into. In that case you will have to cut it out and make up something new. A day sailer might start looking to be a better toy.

 

[BobbyFunn]

My first order of business would be to peel up the anti skid and that glass around the bow. This will let you see what you really have. Post pictures.

This...

The factory would have put white down. The black color could be causing the luran underneath to expand and contract, disengaging from the core below.

Im really concerned that you have cracks where there is some meaningful hardware.

Those cracks let water in, so we're all nervous about the wood under the luran.

Sometimes the cracks near hardware are there because the wood is soft and the hardware is flexing the luran.

 

[Rictifyit]

Ok, THANKS !! BobbyFunn , Shorefun, and Hunter216, I hope you all receive this reply. I'm still learning how to navigate this site. I've read, and re-read your replies, and feel that this project boat is going to be a challenge, but I'm excited about it! The boat has been high and dry in a pole barn all winter. The pics I posted were just take the other day, and there was nothing new since Fall, so that's good!
I'm making my shopping list. So far it looks like I will need a number ( maybe 6 to start at least) of the 50 ml cartriges of MA300, a gun, and a mixing tube. I don't have a Dremel tool, but everyone seems to think that's the tool of choice for routing out the cracks. Nobody gave me any feedback about adding fiberglass powder, or particles to help strengthen the plexus, so I'll assume it is not necessary. Does it come out of the mixing tube like caulk, or is it runny, and prone to sagging/dripping, etc.?
Shorefun, to answer your question about my Goals, they are just to make this little boat sound, and waterproof. I don't care much if it's pretty. It's just going to sail in a little Lake, and won't have to endure much. Per your suggestion, I am going to get after the bow first, and check out the wood that secure the bracket screws. If that's shot, or spongy rotten, I might just part out the whole boat. As you say, that place is all important, and if it's rotten there, it's probably rotten at the other hardware points. I paid $200.00 for the boat, so I really can't go wrong with whatever happens. We'll see when I bring the thing home from the barn.
Hunter216, and BobbyFunn, I did read through the post about parting out H170 in Az, and found lots of helpful info, Thanks. BobbyFunn, a Precision15 looks like a nice boat, but I'm kinds stocked up right now on boats. Thanks for the suggestion though.
I hope to get into these repairs fairly soon, so I can get the boat in the water early Summer. I'll try to post some more pics as I go for your entertainment. I really appreciate your suggestions! For now, it's nice here, so I'm going to go sail my Dory today, and get some stuff ordered for the Hunter later on. Thanks again, Ric

 

[chuckwayne]

it comes out like caulk, you don't need to add fillers. get a package of mixing tubes, they can't be cleaned and you'll use a lot of them!

 

[Rictifyit]

it comes out like caulk, you don't need to add fillers. get a package of mixing tubes, they can't be cleaned and you'll use a lot of them!

Chuck! Thanks for your knowledge about Plexus! I appreciate it!

 

[Shorefun]

YA the first time you are a bit slow on something while doing the glue and it dont come out.

Also cover up or have a rag to set the end of the glue gun handy. You do NOT want to drip some on the plastic where you do not want it. It starts 'melting' the plastic pretty fast. You will have to level sand spot to clean it up after the glue cures.

Also the glue is temp dependent. If it gets too cold it will not set up right. If it is hot it sets up faster. The unused stuff you can store in your freezer. One of the things I learned is epoxy and other glues can be stored frozen for some time. In fact some factory process 2 part adhesives are shipped and stored frozen and brought out and thawed just before use. Keep in mind some places are running 55 gallon drums of the stuff.

The MA300 does wonders for fixing plastic stuff you never thought you could glue. I have used it for several small repairs since.

 

[Rictifyit]

YA the first time you are a bit slow on something while doing the glue and it dont come out.

Also cover up or have a rag to set the end of the glue gun handy. You do NOT want to drip some on the plastic where you do not want it. It starts 'melting' the plastic pretty fast. You will have to level sand spot to clean it up after the glue cures.

Also the glue is temp dependent. If it gets too cold it will not set up right. If it is hot it sets up faster. The unused stuff you can store in your freezer. One of the things I learned is epoxy and other glues can be stored frozen for some time. In fact some factory process 2 part adhesives are shipped and stored frozen and brought out and thawed just before use. Keep in mind some places are running 55 gallon drums of the stuff.

The MA300 does wonders for fixing plastic stuff you never thought you could glue. I have used it for several small repairs since.

Shorefun! Great advice about the plexus burning into the deck if you drop some. I will be careful. Also, about keeping it in the freezer. If I had some left in the mixing tube, it would be nice not to let it go to waste after it's mixed. I do that with paint brushes/rollers if I want to paint later on in the day.
I just put in an order for Methylacrylate ( AKA Plexus) from a company named Infinity Bond. The price was far better than any other price for "Plexus" I could find on line. And, they had numerous choices for different working times. I bought 10 cartridges for $120. Infinity Bond Adhesives | Buy Better Glue for Less Now, I am trying to decide about buying Epoxy, or Polyester Resin to help with some of the cockpit deck issues. I'm not sure if Epoxy, or Glass & Resin would be the best for the larger flatter surfaces around the hardware on the deck. If you have a suggestion, thanks. I will review the other posts here to see if I can come to a conclusion. Thanks again for your helpful suggestions! Ric

 

[BobbyFunn]

The coefficient of expansion of luran is the same as epoxy and ma300. If you add fillers the coefficient looks like glass reinforce plastic. Try not to add filler. They reduce the expansion coefficient.