Tips for fiberglassing wood base inside hull

[josrulz]

Hey, I know this isn't rocket science, but I haven't done it before. If there are any sites, threads, etc that I should look at, let me know.

Basically, I'll be installing a level platform inside the hull for a new battery, so I'll need to fiberglass a hardwood "base" to the hull at one end to give me something to screw the platform into.

I have Casey's Sailboat Maintenance Manual, which has general fiberglass info, but nothing specific to this.

Other recommendations?

Thanks!
-J

[WDS123]

Why not glass ( ie tab ) the shelf in ?

[Faster]

I'd grind off the hull in the contact area of the 'pad' plus a couple of inches all around it... be sure to radius/router the upper edges of the pad to a reasonable curve (minimum 1/4" radius) for later.

Bed the pad in a thickened epoxy and tool the excess at the edges against the hull into a nice fillet.(using a gloved finger or a tongue depressor stick). Let it set up some. Then glass over the pad with say, several layers of six oz cloth and epoxy resin for a good seal. The rounded corners will let the cloth sit cleanly on the pad rather than tend to lift as it goes over the edges. Glass down and over onto the extra area ground off before. Let cure, give a good scrub wash afterwards and slap on a coat of paint (maybe sand and paint the whole area while you're at it.. it'll look great)

Remember to caulk the mounting screw holes to keep it all dry.

[emoney]

How To Use

[tommays]

Once the glass is sanded and clean you can set the part in place in a way it will NOT move

You have to be careful if there was GOOD gelcoat on the outside of were you sanding if your doing any heavy removal as it can get HOT

I like 6" tape and once it is wet with resin in conforms pretty easy to what ever your putting in the boat

You do have to be REALLY careful about the dust and resin fumes as its real bad for your lungs and skin



If your careful and do a bit more sanding after you glass work it will look pretty good with a coat of paint

[Al Harmon]

Check out this thread from six days ago also:

http://www.sailnet.com/forums/gear-m...ighlight=bondo

[josrulz]

Thanks for the replies--these are helpful!

[rugosa]

Beg to differ, while it may look easy there is definitely an acquired skill to mastering the job. Your small project is an ideal starter to get the knack. Experienced laminators are craftsmen, like pretty well any other trade or skill.

[SloopJonB]

Originally Posted by Faster

I'd grind off the hull in the contact area of the 'pad' plus a couple of inches all around it... be sure to radius/router the upper edges of the pad to a reasonable curve (minimum 1/4" radius) for later.

Bed the pad in a thickened epoxy and tool the excess at the edges against the hull into a nice fillet.(using a gloved finger or a tongue depressor stick). Let it set up some. Then glass over the pad with say, several layers of six oz cloth and epoxy resin for a good seal. The rounded corners will let the cloth sit cleanly on the pad rather than tend to lift as it goes over the edges. Glass down and over onto the extra area ground off before. Let cure, give a good scrub wash afterwards and slap on a coat of paint (maybe sand and paint the whole area while you're at it.. it'll look great)

Remember to caulk the mounting screw holes to keep it all dry.

Faster has it pretty well covered but I'd like to expand on one of his points - it's something I've learned from hard experience. The combination of the radius on corners and the weight and type of glass fabric is where difficulties often arise. The heavier the fabric, the greater the radius needs to be. If you use something very light, like 6 oz. cloth, 1/4" radius should suffice. If you are tempted to go with a heavier weight fabric or a different weave like biaxial or a lightweight roving then you will have to make a considerably larger radius on any corners you want the fabric to drape over smoothly.

Light fabrics are slow to build thickness with - more layers needed - so you always have to choose an appropriate combination of fabric and radii for each situation.

Some final considerations - cloth is the nicest to handle and gives the best finish. Also, weight for weight, it is the strongest as well, since its finer weave holds less resin. Its only real downside is that, as noted, it is slow to build thickness with so it is more time and $$ consuming.

Don't let it intimidate you - it's really pretty easy. It just takes some experience. I find wallpapering to be far more difficult.

[TQA]

You said fibreglass in your original post. Others said epoxy in their answers. Do be aware that fibreglass [ polyester resin ] does not 'stick' very well to cured fibreglass. Epoxy although more expensive does.

Some good hints here