Fiberglass problem

[skagit 25]

I glassed in a 25 gallon Topco plastic fuel tank about three months ago. I used 3" fiberglass strips and adhered them to the fiberglass shell and to the fuel tank.

At the time the fiberglass strips adhered and were holding. Recent inspection reveals that fiberglass pulling from the tank, but holding fast to the shell.

Does fiberglass adhere to plastic or did I do something wrong? I will admit that I do ugly fiberglass, but I have never had it pull before.

[Steve_Kiesel]

My guess is it won't adhere to the plastic. When I built my kayaks, I used plastic wrap when clamping, as the fiberglass would not adhere to it. I'm sure others with more experience will chime in.

[33hp_scott]

What prep work did you do? It seems to me that a plastic tank would have a closed cell serface and not want to bond to anything. If you were to scuff the surface and brake up the outer skin the epoxy would have a better chance of bonding.

[timw]

Ya I also when forming or fab'n some thing up I use wax paper or plastic bags on sides I don't want resin to stick to..But I really haven't tried to make it adhere to plastic, you would think it possible some how..

[skagit 25]

What prep work did you do? It seems to me that a plastic tank would have a closed cell serface and not want to bond to anything. If you were to scuff the surface and brake up the outer skin the epoxy would have a better chance of bonding.


No prep, just resin, glass and rolled. This will sound niave, but I thought fiberglass and resin adhered to just about everything.

I will prep the tank and try again.

Thanks

[Helmar]

I have tried Fiberglass patches in the past on Plastic.
Once things started to flex, it came loose.
I also tried to put a Fiberglass Bottom on a Grey water tank in my little RV.
All was well until drove it almost full. It started leaking again. I even scratched the surface Big time, which helped, but not for long.

Due to the gray water tank I have, my only option is to drop it and cover the whole tank with glass mat.

If someone gets this to work on Fuel or other plastic holding tanks, I am Real interested.

[sparrowhawk]

Don't waste your time. You are not going to get a permanent fix. Fiberglass does not stick to most plastics and only marginal on others. I also know that you do not want anything that has the possibility of fuel getting to most fiberglass. The fiberglass fuel tanks that have been made in the past used a special resin. Sorry I can't remember the details but my fiberglass supplier and I had a long talk about this some time ago when I was considering making a custom tank. Barry

[McSkagit Tim Jones]

I don't think polyester resin is compatable with the type plastic tanks are made from. Resin adheres well to other resin, wood, some metals. Marginal to epoxy. I had a bad experience with glassing to epoxy some years back. Cost me a bundle in court. If I remember correctly, epoxy will adhere to properly preped polyester resin, but polyester resin will not adhere to epoxy.

[skagit 25]

The FG seemed to hold until I had filled the tank with fuel and it bulged. Maybe had I glassed it while it was full it may have worked.

It seems like everything I have learned while restoring this old boat has taken me atleast 2 attempts. I am a slow learner.....

[sparrowhawk]

The FG seemed to hold until I had filled the tank with fuel and it bulged. Maybe had I glassed it while it was full it may have worked.

It seems like everything I have learned while restoring this old boat has taken me atleast 2 attempts. I am a slow learner.....

Most people that know things won't tell you how long they took to learn them.:D My Grandfather used to tell us that if you learn one thing every day then the day has not been wasted. I remind myself of that constantly. lOL
Barry