How do I repair a 8-ft. plastic boat????

[kmost]

I just picked up an 1988  8-ft. plastic boat, ( It is like a pond prowler).

It has some short and long cracks in the bottom. It looks like it froze and cracked. It also has 2-3 holes about the size of a quarter in the side. I don't want to just trash it :-[ ...SOooooooo....

I guess the questions are ?????

1-should I split it into two halfs to start???

2-If yes...How???

3-Will I need to use fiberglass inside out out???

4-Can I just fill the cracks with epoxy or J.B., Weld???

I'am all ears...Any and all help is welcome....

Thanks,

kmost

[cart7t]

I'm no expert on those type of boats but I have heard that the plastic in those things tends to start getting brittle as age and weathering take effect.  What you could use that would sufficiently bond to old plastic is a good question.  Splitting the top and bottom in half would be a start but the question is whether they fused them together when the final assembly took place.  If they are, getting them apart would be difficult to achieve.

I suppose you could take a sheet of something like polyethelene and cut pieces larger and than the holes and cracks and epoxy it to the outside of the hull.  

[Low_Budget_Hooker]

Getting them apart is easy, usually happens naturally anyway.  There is a plastic weld product out there but I have no idea how well it works.

[George Welcome]

It's very iffy, but this may work: A major problem is you need to do both sides and most plastic boats have a double hull.

Plastic boat repairs

By Tom Pawlak

Molded plastic canoes and kayaks are incredibly tough and durable. Occasionally though people damage them and call us for repair recommendations. Considering that plastic film is often used as a mold release for epoxy and cured epoxy easily pops out of our reusable plastic mixing cups, you can see what we're up against when we try to bond to it.

Plastic's bonding drawbacks

The most common plastics used for molded boats and other toys are low surface energy plastics such as polyethylene and polypropylene. Characteristics that make them desirable for the manufacture of small boats also make them difficult to bond to.

Low surface energy plastics are not able to overcome the surface tension of adhesives and therefore inhibit the spreading and wetting of the adhesive on the surface. These plastics are not porous and provide little opportunity for a mechanical bond. They are unreactive, or chemical resistant, inhibiting a chemical bond. Also, low molecular weight molecules tend to migrate to the surface of these plastics. Molecules with low molecular weight have low tensile strength, resulting in a weak boundary layer at the surface.

A repair that works

The repair method I'm about to describe overcomes some of these drawbacks and produces a functional repair. However, it will be fairly obvious that the boat has been repaired. In other words, it may not be pretty. Surface preparation, bonding area, and fiberglass preparation and placement are key to the success of this repair.

1. Begin the repair by forcing the damaged section of hull back to its original shape

2. Clean the area with solvent and paper towels well beyond the break. Solvents will remove oil, wax or other contaminants that would inhibit bonding.

3. Sand an area several inches beyond the break in all directions with 60 or 80 grit sand paper. Scratch the surface aggressively, making certain the entire repair surface has been abraded with no shiny places left. This step helps to overcome the plastic's low porosity.

4. Flame treat the surface. (See Flame treating a plastic surface for bonding below.) Flame treating will burn off contaminants and weak boundary layers and produce surface oxidization. Oxidation increases the surface energy allowing better wetout and makes the surface more reactive for potential chemical bonding.

5. Apply a coat of clear epoxy to the surface within an hour or two of the flame treatment. The best bonds are formed soon after flame treatment.

6. Cut the fiberglass patches, making certain each layer is staggered in size from any other layer on either side of the repair. Cut the largest fiberglass patch to extend several inches beyond the actual break in the hull and at least two inches beyond the next smaller fiberglass layer. (See the comments on fiberglass preparation below.) It usually isn't necessary to bevel the repair area.

7. Position the largest fiberglass patch into the wet epoxy and apply more epoxy to thoroughly wet out each layer prior to positioning each additional layer. Allow this repair to cure before repeating the process on the other side.

8. Repeat steps 27 on the backside of the hull. Stagger the ends of fiberglass patches on each side of the repair so they don't end in the same place as layers on the opposite side. This allows the repair laminate to bend more uniformly when it is stressed.

9. Sand the fiberglass to smooth out the edges of the fiberglass steps.

10. Fair the stepped layers of glass with an application of epoxy thickened with a fairing filler if you wish to dress up the repair prior to painting. Sand the cured fairing compound and apply 2 sealer coats of epoxy to the area and allow to cure.

11. Wet sand with 220-grit paper to prepare the surface for paint. Apply an automotive or other matching paint to finish the repair.

The center of repaired sections will be stiffer than the rest of the hull, but the edges of the repair will flex and stay attached under considerable abuse. How much abuse it will handle will depend on the surface preparation, how far the first layer of fiberglass is applied beyond the break, what weight fiberglass was used and how uniformly the repair layers have been staggered.

Flame treating a plastic surface for bonding

To flame treat a plastic surface, hold a propane torch flame about 4" to 6" from the plastic (with the tip of the flame just above the surface) and move it across the surface at a rate of 2 or 3 inches per second overlapping the previous pass slightly. Keep the torch moving and only allow the exhaust gases to hit the surface. If done correctly, the surface will not discolor or burn in any obvious way. This technique oxidizes the surface and improves adhesion. For best adhesion, bond to the surface within 30 minutes of treatment.

Fiberglass preparation

Use lightweight fiberglass fabric for the repair. One reason this repair works is because a single layer of 2 to 4 oz fiberglass and epoxy is flexible enough to bend to a fairly tight radius when cured. With the fiberglass stepped down to a single layer at the perimeter, the outer edges of the repair should be as flexible and bendable as the hull itself. This flexibility is helpful if someone severely dents the hull alongside the repair. It will reduce the likelihood the repair will peel or debond from the hull.

If the break in your hull is only a split or slight tear, three layers of 4 oz fiberglass or six layers of 2 oz fiberglass are usually adequate for this type of repair. Multiple layers of light fiberglass fabric are best. Two layers of 4 oz fiberglass (or four layers of 2 oz) are applied to the inside of the hull and one layer of 4 oz (or two layers of 2 oz) are applied to the outside of the break to complete a repair for canoes and kayaks. More layers are used on the inside because higher tensile loads are expected on the inside if there is an impact on the outside.

[wagn]

don't know if this will help, but this guy fixes kayaks with duct-tape and he says that it will hold up for a long time if done right.

http://oregonkayaking.net/how_to/boat_repair.html

good luck

[Team_Dougherty]

I have a plastic boat, I am not sure what kind of plastic, and have fixed a hole in it here is a pic.

I have found the best solution is 3M 5200. I have found plastic sheeting about 1/16" thick. I then cut it to a 1/2" over lap of the hole.  I cleaned the area with alcohol, put a generous amount 5200 all around the hole. Place the plastic piece over the hole. Then cover the whole thing with more 5200. It will take a few days to dry but once it does it is very strong. The hole I fixed in on the floor. I made out well, the boat is white and so is the 5200.  There was a scrape in the bottom, where it hit a sharp rock, that I just filled in with the 5200. Both repairs have lasted a few years with out a problem.

[Fisher of Men]

Two words:

Marine Goop  (not just Goop, but get the Marine kind)

Cut out some aluminum flashing (I've even used a coke can).  After cleaning and sanding the area around the hole, apply the goop to the aluminum and apply.  Spread the goop thoroughly over and beyond the patch.  As far as the cracks, just run a bead along them and lightly spread the goop to cover 1/2 inch or so.  This may not be the prettiest fix, but I used to have an old water scamp just like the one your talking about.  I tried epoxy, fiberglass, roof cement, etc. and never had the success of the marine goop.  I had one hole in the front of my boat that I gooped a quarter over.  For 10 years that quarter stayed in place (I've since given the boat away).  Recently I even repaired a small hole in the bottom of my 12 foot jon boat and it's held up VERY well.  Hope this helps.

-Fisher

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[ww2farmer]

Two words:

Marine Goop (not just Goop, but get the Marine kind)

Cut out some aluminum flashing (I've even used a coke can). After cleaning and sanding the area around the hole, apply the goop to the aluminum and apply. Spread the goop thoroughly over and beyond the patch. As far as the cracks, just run a bead along them and lightly spread the goop to cover 1/2 inch or so. This may not be the prettiest fix, but I used to have an old water scamp just like the one your talking about. I tried epoxy, fiberglass, roof cement, etc. and never had the success of the marine goop. I had one hole in the front of my boat that I gooped a quarter over. For 10 years that quarter stayed in place (I've since given the boat away). Recently I even repaired a small hole in the bottom of my 12 foot jon boat and it's held up VERY well. Hope this helps.

-Fisher

<><

Thats EXACTLY what I was going to suggest, I have one of those 8' boats and have yet to have any problem with it, but I did call the MFG and ask what they recomended for repairs in case I needed it, and thats what they recomended. So I bought some and keep it just in case.

BTW buy some armor-all and wipe it down periodicly, that will really help keep the plastic like new, and in your case inject soem "life" back into it.

[kmost]

Thanks to all... Good luck fishing.. The dog and I  will be out on the water as soon as we do what you all said to do...

Again Thanks,

kmost