Small rock damage

[1FASTLASER]

Last night had a brief encounter with a rock which forced me to get back on the trailer. I now have a small maybe 1" wide by 8"long bad place in my hull. What I need to know is I have 2 different resins that I have used in the past for doing transom replacements and stringer repairs etc..etc.. They are polyester and epoxy resins. What I need to know is which resin I need to use to make this type of repair(Hole in bottom) for the most strength. It has been awhile since I did repairs and dont remeber which resin is used for what. Thanks in advance.

 

[firehog6305]

Re: Small rock damage

I would use the polyester resin, with two layers of glass matt, first sand down the area and clean the hull in the damaged area, then spread your mixed resin over the area on the inside, then apply you matting to extend at least one inch over the edges of the hole, roll out all bubbles, then apply more resin, and anthor layer of cloth larger then the first one (by another inch) roll out any bubbles and let dry 24hrs. That should do it

another trick that I have learned working with fiberglass, before you try and remove the bubbles after you'd laid the last cloth and resin, put a piece of wax paper over the repair and smooth it down that way, it makes it very smooth, and wont have to sand repair very much if any. just leave the wax paper on for the 24hrs, it will come off very easy, good luck

 

[KnottyBuoyz]

Re: Small rock damage

Epoxy will have a slightly better bonding to the existing glass hull which is probably a poly or vinylester resin FRP. I know polyester resins definitely won't bond to cured epoxy FRP's.

Here's a good instructional video on repairing a hole in a FRP hull.

http://www.youtube.com/watch?v=6N7YMr6E564

 

[ondarvr]

Re: Small rock damage

If it is a hole, then try to get at it from the inside to do the repair, it will be easier and stronger, you'll get a better idea of how much damage there is from the inside too. Either product will work, the epoxy is stronger, but if you plan on using gel coat to finish of the repair on the outside, then use the polyster resin, gel coat won't stick to the epoxy all that well.

 

[1FASTLASER]

Re: Small rock damage

Being that I have just recently repaired the floor and dont want to rip that out again is it possible to repair this hole from the outside only. The hole is approx.4ft in front of the console and approx.18' off the keel. 75% of the time this repair will be out of the water and not really taking any abuse. I would also like to know if I need to flip the boat over or can I do it on the trailer. I know I am asking alot of questions but I wanna repair this bad spot as quickly as possible but also want it to be as strong as possible. I have done lots of glass work in the past such as transom replacements, stringer repairs etc..etc.. so I am not new to glass work ............just never repaired a hole in the bottom of a hull.

 

[ondarvr]

Re: Small rock damage

Yes it can be done from the outside. Sand an area about 4 inches larger than the crack, taper the glass so that at the crack it's very thin. If you can see more damage when you remove the gel coat, you will need to grind out a larger area. If you go through it's OK, but if you just leave a very thin layer then you have some backing and a shape to start from. Build it back up to a little higher than the surrounding area with glass, then sand it down to the shape you need.

Use epoxy when doing it from the outside, polyester will work, but you would need to do it correctly, epoxy will be more forgiving.

You can do it without flipping the boat, it's just a little more of a hassle.

 

[firehog6305]

Re: Small rock damage

or you can get away with useing duraglass filler if you dont need the strenth in the repair, its a fiberglass bondo, I've had very good luck with it, then just airbrush some color over it

 

[1FASTLASER]

Re: Small rock damage

Well went ahead and prepped the boat to flip her over. Just got remove the big engine. Everything else is out. Gonna do it right ........dont need no problems outta my boat especially running at speeds. Ill let ya'll know on the progress.

 

[checkeredflags]

Re: Small rock damage

I have a 16" aluminum boat and I need to drill two holes through the aluminum 1/2 " in diameter in order that I can install two extra bolts to secure a 25 horse engine. There are two bolts going through the transom above the water line that go through the wood; however I need aditional reinforcement and this will require that I drill two holes through the thin aluminum below the wood transom to bolt the lower portion of the engine mounting bracket. I thought I would use a thin piece of steel on the inside like a steel plate...drill the hole and run 1/2" bolts through the aluminum and the plate and bolt it down. My concern is leakage since this will be right at or a bit below the water line...not sure what to do.