Cutting Fiberglass

[Bill Sellers]

I just purchased a fiberglass hull (Oboy Oberto) that will need some minor construction work to finish it. I have never worked with fiberglass so I'm not sure how to handle this one problem. Now I am asking the forum to help me out. I am a fairly decent builder with a good collection of tools.

What is the best way to cut a slot in the bottom of the hull for the stuffing tube to fit through?

Bill

[vicman]

If you have a spiral saw, I would suggest blocking both sides along your cut line with wood and using the spiral saw. Once your done with that use a small flat file to open it up to the size you need, so you dont take too much off with the saw. If you dont have a spiral saw, do like it has been done for years and drill a series of holes along your cut line and then, use a small file to open the slot up to the size you need. Lastly, you could use a dremel and a fiber cutoff wheel to cut along the cut line and open it up as mentioned before (if theres enough room). It really isnt important how you start the slot, as long as you do it small and open it up slowly from there. this removes all the bad areas that are caused from the initial holes or cuts.

vicman

[Bill Sellers]

vicman,
The "slot" is really long rectangle that is more than 3/16 inches wide. Do you just drill a 1/16 slot down the middle and file to the required width? Also, will the fiberglass fray, and if so, how to seal the edges?
Bill

[AndyKunz]

I use a Dremel tool with a DuBro cutoff wheel in it. This makes a nice slice about 1/16" wide. If you don't move the cutter it will burn the resin - just keep moving.

Abrading is a much better way than cutting in my opinion.

Andy

[vicman]

It is best to cut the slot smaller then open it up. As Andy said abrasing is the best method when working with either fiberglass or epoxy, but a FINE small file will work. You could also use a small piece of wood covered or wrapped in sandpaper or emery cloth to get the same outcome. If you encounter any fraying, just use a fine sandpaper to clean it up but rub it gently to do this. Normally fraying is not a problem with either material when cutting with a fine file or spiral saw, unless the layup of the glass was done improperly (too dry) when it was molded. As far as fixing the "FRAYED" portion, once it is cleaned up wipe the area with a solvent then let it set for a while. At this time get your stuffing tube ready and asemble it in the boat. When you glue it to the boat, this will permanantly repair the frayed opening. And as a note to keep in mind, epoxy does work on fiberglass, you just have to sand it and wipe with solvent just like if it where an epoxy hull.

vicman

[Sheltered]

If you're doing anything major or fancy make sure that you know if the hull was constructed with polyester or epoxy resin. Sounds like 5 minute epoxy etc.. should work for what you are doing.

[Bill Sellers]

Guys,
Thanks for the advice. It shouldn't be too hard to do and I had planned to use epoxy to glue it the stuffing tube.

But I do have a follow-up question about the positioning of the tube. Does it get centered in the slot (front to back) and then the teflon tube extends back to the front of the strut?

Bill

[vicman]

That one will have varied answers. I have run the teflon back and the tube itself back, which if I recall is how andy does his piano wire flex's. either way works, but you need to seal the teflon to the tube if you run just the teflon back. Water will find a way in between the tube and teflon if you dont have a tight fit or sealer.

vicman