Epoxy repair

[Eastie]

I’ve been given the job of repairing a hole in the bottom of my surf ski. I’m not concerned with the look of the board afterwards as I will never be dragging up the beach to finish an iron man, thus I’m considering doing it myself (sounds ominous).

Anyhow the hole is about 20mm across and 40mm deep – quite a neat hole from falling onto a stubby :eek:

Having a look on the net there are a few guides on how to do board repairs but the advice varies substantially. Some say use a router to clean it up – fill it with expanding foam, route it down and epoxy over it. Others just say fill it with epoxy / fibreglass?

Can anyone help?

[q9]

Depends a bit on the depth of the hole. Unless it was really deep, I would be inclined to simply fill with epoxy. In fact I would actually suggest that if it were moderate depth, then Plastibond would be suitable.

I wouldn't cut away the strands of glass, just give everything a good clean with a bit of sand paper (60 or 80), metho, or acetone if you have it. The strands will give the epoxy something to bond to. The more surface area, the higher the bond strength.

Remember, glass fibres are actually made from glass and will make short work of anything other than diamond cutting tools. And most importantly, airborne glass fibres are a SERIOUS health risk.

[Eastie]

Yep - its that other non-wood stuff (I know this is a booden boat forum, but unless you are building a traditional aussie watercraft out of bark, animal sinue and animal fat your probably going to use the non-wood stuff and may be able to give me some advice :D)

I was hoping to stay away from the f@#...ss myself and patch it with epoxy but if it's not the best way then I guess I'm stuck with the other stuff.

The hole is an inch wide (a bit wider than a long neck stubby top) and two inches deep. The board is at least 12 inches thick in that section so it won't have impacted on structural strength.

I guess at the end of the day I'm looking at whether I need to repack some foam and then rebuild the waterproof seal or just fill it with epoxy or f#@...ss/gelcoat ???


q9 - I'm aware of the health risks and already have appropriate repirators and dust/fume extraction - but thanks for the advice.

[nadcarves]

As noted in another reply,the repair is not structural.Most simple and quickest method is to pack with foam,push a piece of fibergass mat in over the new foam.Then go to a car parts store and pick up a small can of Bondo. cut another piece of mat to fit into the hole.When you open the bondo you will have resin on top .Pour a tad out,catalize it,with small brush or tongue depressor,wet the mat in the hole with the resin,put the hole sized piece on top,bit more resin,use wax paper,mylar,put on top> when resin that was mixed gets rubbery,wait two min,see if the paper/mylar comes off.,and the resin that smeared rubbery,at this point you can scrape the resin off the surface,and any sanding will only throw up clay or talc dust with resin ,no itchy glass..Use the white or,colored paste,the clear liquid hardener MEKP,if gotten in the eyes will etch the retina within 5 seconds,it will also kill a kid or animal if ingested.Not sure if you use water or acetone to flush the eyes.Fiberglass great stuff tocause you problems nad

[derekcohen]

Eastie

I'm a bit late coming to this party, so I may be too late in a few observations. I have repaired a great many surfboards and windsurfers in the past.

Just to add to what has been advised:

Use an epoxy resin - much strongly than a polyester resin. Try the West System.

Epoxy will also avoid another potential disaster, that is polysester resin and polystyrene foam (the core) do not go together - the polystyrene will melt! Also, you can't just pump in foreign foams since they may react.

It is a good idea to determine what type of inner foam is needed since most polysterenes will absorb water. Consequently, you must be careful to seal the hole well. On the other hand, if you have an extruded foam, you can be less fanatical in this regard.

Hope this helps.

Regards from Perth

Derek