Cracked hull
- Thread starter SailorHunter
- Start date
Will, great information. Thank you.
These are lovely little boats.
I will update this thread with progress, if any, with the H90 hull repairs.
These are lovely little boats.
I will update this thread with progress, if any, with the H90 hull repairs.
You might give West System G-flex plastic boat repair kit a try. I used it this year to build a water tight box for mounting my "transom mount transducer" in a through-the-hull enclouser out of HDPE and it stuck very well and made a stiff box. If it does not work you are out $50. If it does work, you have a boat!
video for fun
video for fun
More G/Flex fun
Here is a short clip where Andy at Boatworks Today shows how flexible Thixo the TotalBoat version of flexible epoxy is.
Here is a short clip where Andy at Boatworks Today shows how flexible Thixo the TotalBoat version of flexible epoxy is.
Good information, thank you.
I have used West System epoxy before (their 105/ 206 combination). That was a great product for gluing wood. Not used G-Flex till now, but will surely give it a try.
It is sort of a "what do you have to lose" thing. $50 isn't much to venture. They make two different G/flex kits. The one for plastic boats has tubes of pre-thickened G/flex and the one for aluminum boats has unthickened G/flex with and 406 thickener. You would want the plastic boat kit.
Get some MMA glue and a large dremel carbide bit.
You need to cut a channel where the cracks are to get surface area for the special adhesive to have enough bond area. The MMA adhesive is able to intertwine its chemical tenticals into the plastic for a strong bond. NOTHING else will work like you want it to work. I have tried to glue this type of plastic many times in the past to fix stuff with no luck. The MMA adhesives do the trick. Everything else may seem ok but will eventually l pull away.
Keep in mind I own a Hunter 170 and have some experience working this stuff.
The only thing I would consider doing on the long cracks on the bottom would be to also glue on top some fiber glass for some extra strength. You probably dont need it the whole length. Just every so often.
It is a small boat so it would not take much to keep it together. I would thing 3 or 4 tubes of the MMA would take care of most of it.
www.gluegun.com
You need to cut a channel where the cracks are to get surface area for the special adhesive to have enough bond area. The MMA adhesive is able to intertwine its chemical tenticals into the plastic for a strong bond. NOTHING else will work like you want it to work. I have tried to glue this type of plastic many times in the past to fix stuff with no luck. The MMA adhesives do the trick. Everything else may seem ok but will eventually l pull away.
Keep in mind I own a Hunter 170 and have some experience working this stuff.
The only thing I would consider doing on the long cracks on the bottom would be to also glue on top some fiber glass for some extra strength. You probably dont need it the whole length. Just every so often.
It is a small boat so it would not take much to keep it together. I would thing 3 or 4 tubes of the MMA would take care of most of it.
An Introduction to Methyl Methacrylate Adhesives (MMAs)
A Starter Guide to Methyl Methacrylate Adhesives MMAs - When we talk about structural adhesives, it means an adhesive, or glue, that is used to create a load-bearing joint. MMAs, are structural adhesives that have been developed to bond metals, plastics, and composites. They are designed with...
www.gluegun.com
I've used G-flex to repair a plastic crosslinked whitewater kayak and also a paddle with good results. They recommend treating the plastic surface with a propane torch just prior to application. Turns out this is a critical step, don't deviate. Use the torch, not a heat gun.
Yep, it is the exhaust gas products of the flame that makes a chemical change to the plastic that imporves the bond. The plastic does not even need to get warm. Flame treatment
Turns out the outer polycarbonate shell is almost entirely detached from the inner foam core of the boat structure. ( Initially I presumed it was detached only adjacent to the cracks, but that is not the case.)
So, first off I need to attach the outer shell back onto the core.Will contact cement work for this ? Sealing the cracks can be taken up after the core is re-attached to the composite shell.
(I bought this product in Aug 2020 for $18.71 from Amazon for use in another application. Now it costs $51.83. The price has gone up more than 277.02% in less than 2 years. Wow !!)
Thanks
So, first off I need to attach the outer shell back onto the core.Will contact cement work for this ? Sealing the cracks can be taken up after the core is re-attached to the composite shell.
(I bought this product in Aug 2020 for $18.71 from Amazon for use in another application. Now it costs $51.83. The price has gone up more than 277.02% in less than 2 years. Wow !!)
Thanks
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I don't see how contact cement could work for this application unless you completely peel the outer shell off. Contact cement is applied to bother surfaces, wait for them to become tacky, and then firmly press the two parts together. You can't just squeeze it into a gap and expect it to bond.
Are you sure the surface skin is intended to be securely bonded to the foam? I had an old Snark that had a thin plastic covering over a foam core. The plastic was not bonded to the core.
Are you sure the surface skin is intended to be securely bonded to the foam? I had an old Snark that had a thin plastic covering over a foam core. The plastic was not bonded to the core.
Not planning to pour the adhesive into the cracks. That might work only for smaller areas adjacent to the cracks.
Also I doubt if the outer composite layer is designed to be separate from the foam-core in this boat. It is just a 3/16 inch sheet and it does not look like it can take the weight of the boat ( 100 lbs ) while being moved by road on a trailer. ( I also get a feeling that some of the cracks might have developed after the sheet separated, because of the loss of structural integrity, especially while trailering the boat by road. )
Regarding adhesive, it is a bonding of a hard composite layer to a softer foam core. Don't need a super strong adhesive, but something tacky, to be applied evenly and uniformly over the entire contact area. (I read about FastBond melting some types of softer foam, in the reviews.) I had used this adhesive to cover my homebuilt airplane ( Mini-Max ) with ceconite fabric 3 years ago, with excellent results, and was impressed with its ease of application. I can do a test patch on the hull foam, but I am sure there are more suitable adhesives.
Also I doubt if the outer composite layer is designed to be separate from the foam-core in this boat. It is just a 3/16 inch sheet and it does not look like it can take the weight of the boat ( 100 lbs ) while being moved by road on a trailer. ( I also get a feeling that some of the cracks might have developed after the sheet separated, because of the loss of structural integrity, especially while trailering the boat by road. )
Regarding adhesive, it is a bonding of a hard composite layer to a softer foam core. Don't need a super strong adhesive, but something tacky, to be applied evenly and uniformly over the entire contact area. (I read about FastBond melting some types of softer foam, in the reviews.) I had used this adhesive to cover my homebuilt airplane ( Mini-Max ) with ceconite fabric 3 years ago, with excellent results, and was impressed with its ease of application. I can do a test patch on the hull foam, but I am sure there are more suitable adhesives.
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I really doubt that the foam was ever bonded to the outer shell, and they are not intended to be a composite structure.
It is more than likely not polycarbonate. The most likely it was roto-molded Polyethylene and then filled with expanding foam to stiffen it. The foam does not stick well to the polyethylene but fills the space with a somewhat solid fill and puts the skin into a bit of tension.
It is more than likely not polycarbonate. The most likely it was roto-molded Polyethylene and then filled with expanding foam to stiffen it. The foam does not stick well to the polyethylene but fills the space with a somewhat solid fill and puts the skin into a bit of tension.
This sounds like the Luran is separating from the foam core, correct?
Contact cement. No. As pointed out by DArcy, this requires application to opposite surfaces, drying, then joining of surfaces to work properly.
Some, including myself, have remedied this by using expanding foam or Gorilla glue. Which works best depends on the size of the area and how feasible it is to get the adhesive into place.
In my case, I used expanding foam. I drilled 1/2" holes at 18" intervals across the affected area. In my case, this was the floor of the boat. I injected the foam using the tubes supplied with the foam, pushing the affected area up and down to try to disperse the foam. It has adhesive capabilities that make it useful for this. After the foam had fully set, I trimmed off the parts that oozed out, and layed 1/2" dense foam decking over the repaired areas. If I had known about Seadek at the time (SeaDek - 18x74 Embossed Sheet Boat Non Skid Stick On Marine Foam 3M- Cool Gray | eBay), I would have used that.
Contact cement. No. As pointed out by DArcy, this requires application to opposite surfaces, drying, then joining of surfaces to work properly.
Some, including myself, have remedied this by using expanding foam or Gorilla glue. Which works best depends on the size of the area and how feasible it is to get the adhesive into place.
In my case, I used expanding foam. I drilled 1/2" holes at 18" intervals across the affected area. In my case, this was the floor of the boat. I injected the foam using the tubes supplied with the foam, pushing the affected area up and down to try to disperse the foam. It has adhesive capabilities that make it useful for this. After the foam had fully set, I trimmed off the parts that oozed out, and layed 1/2" dense foam decking over the repaired areas. If I had known about Seadek at the time (SeaDek - 18x74 Embossed Sheet Boat Non Skid Stick On Marine Foam 3M- Cool Gray | eBay), I would have used that.
Thanks for this observation. I assume the tautness of the outer shell possibly comes from the expanding foam filling out all internal space, and then pressing against outer material. In this boat, there is no tension in the outer shell, it has turned into just another separate layer.
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Thank you.
I have cut out a small triangular panel ,which was already separated on two edges, so I just took a dremmel and cut a third side to remove the panel. Some pictures of the innards are attached.
Attachments
Present plan is to cut out small manageable size panels, one at a time, glue these back to the foam, one at a time. Will make the cuts with a dremmel or other rotary cutter, avoiding damage to the foam, and leaving a slightly jagged edge, and a gap of 1/16 inch between panel edges. Once the outer panels are glued back all over, use a glue like g-flex to seal the gaps between panels.The jagged edges and slight gap between panels ( aim is 1/16 in gap, but even 1/8 gap should be ok I guess.) will likely ensure good bonding between panels with g-flex.
The limited goal is to extract a couple more seasons out of this cracked hull.
The limited goal is to extract a couple more seasons out of this cracked hull.
Had this boat been newer, another option would have been to remove the entire outer panel, and fabricate a new outer shell from fiber glass. But I don't think that much effort and expense is justifiable on this old boat.
Thanks to everyone for helping me with ideas and sharing your experiences. I learnt a lot. I will surely report back later with what eventually comes out of this experiment.
This is a short video of the homebuilt plane I built. ( Is it ok to post this ? )
Thanks to everyone for helping me with ideas and sharing your experiences. I learnt a lot. I will surely report back later with what eventually comes out of this experiment.
This is a short video of the homebuilt plane I built. ( Is it ok to post this ? )