Bondo question (Marine use short strand fiber)

[akintosyali]

I decided to rent a 3500 PSI powerwasher to help me speed up the sanding of the bottom. I took off all the old antifouling paint , and some of the original barrier coat. In the process, it also took off small chips off the gelcoat I went to westmarine for some ideas - there is definitely dime a dozen fillers, but they are too small in size. Then I remembered that bondo has a filling compound for marine use. They have a putty kind and also a gel. The marine putty claims to be waterproof. Has anyone used marine grade bondo below water line for small gel coat chips? How about the Gel? Any suggestions are appreciated.

 

[Boss Lady]

Bondo was used in the marine industry long before it was used on cars. It was called fairing compound, they were still using lead for body work on cars up until the early seventies. Then bondo caught on and the rest is history. Most bondo is polyester resin based. Some of the newer lightweights have fillers that may not be suitable for marine use. I would look at some websites and see what the manufacturers recommend.

 

[Maynard Rupp]

I see no advantage to bondo and plenty of disadvantages. We use West System epoxy with either their 410 filler if you will need to sand it, or 404 filler if you don't need to sand after filling.

 

[Starman]

Akintosyali,

Small chips can be repaired using 3M bondo, Premium filler. It is made to use above and below the waterline, and in the marine environment.

The advantages to bondo over west system is the quick set-up and finish time. However if the repairs include structural , which yours are not, then I would surely use the west system.

All west system patches need to be sanded regardless of the additive used. Epoxies have what is referred to as a wax film after setting. Just like varnish and most other products, the shine must be removed to insure proper adhesion of the next product.

410 sands very easy. 404 is very hard, but it does and needs to be sanded like everything else.