Fibreglass sail boat bulkhead repairs

[Pigeon_Droppings2]

Next week I'll be tackling a job on the sail boat that I've put off for a year!

The rear (plywood) bulkheads/stiffeners have seen better days and need to be removed and replaced in places. These are the stiffeners that support the rear deck of the boat. It's only a small boat (around 7m).

Pictures will follow in due course...but tomorrow's job is loading the car with tools for the job (the boat is 3hrs drive away). So the first question I have is what tools would I likely need?

I've done a little online research which seems to suggest that the bonded fibreglass holding the reinforcements in place might come out with a sharp chisel....but failing that I'll likely need to use a grinder .

If anyone has fixed similar and has any tips please let me know.

 

[ajlelectronics]

I've done a little online research which seems to suggest that the bonded fibreglass holding the reinforcements in place might come out with a sharp chisel....but failing that I'll likely need to use a grinder .

A STONE type disc in an angry grinder is what you need. Then fibreglass mat, resin, MEK, Acetone, a box of cheap paintbrushes (ideally fibreglass bristles), rags, maybe some coarse sanding discs for keying and dust masks.

 

[500e]

Reciprocating saw with diamond blade. Lots of dust masks or air fed if possible
Done 1 or 2, can you isolate the aeria the fg dust gets everywhere tape and poly sheet

 

[Pigeon_Droppings2]

Done 1 or 2, can you isolate the aeria the fg dust gets everywhere tape and poly sheet

I was thinking the same...poly sheet and then disposable full paper suit I'm thinking.

I have the 3m adflo kit and a clear grinding air fed helmet...maybe I should take that with me!

Good idea on the reciprocating saw.

I was going to brace the deck but maybe that's a waste of time? I think the stiffeners are likely there to stop the deck flexing...4 people on deck could be 400kg if load I guess.

 

[500e]

Add flow and air fed
A corse wood blade will work as well

 

[Barking Mat]

Angle grinder, quality mask, eye protection, ear protection, a vacuum cleaner, cutting and flap disks, photos and drawings would help.

Extension cables.

I do a lot of this.

After that photos and drawings please.

You'll need acetone, resine, fiber glass sheet, brushes, spatulas and all that joy.

I'd recommend a few cold beers for you sanity....

 

[Misterg]

Definitely the chisel, if nothing else - old fibreglass bonding often separates quite easily (rather than actually cutting through it) with a bit of encouragement.

Dust mask in case you need to resort to grinder or multi-tool.

Work light.

Hammer.

Decent gloves.

Small child to send into the space to do the work for you.

 

[Barking Mat]

Definitely the chisel, if nothing else - old fibreglass bonding often separates quite easily (rather than actually cutting through it) with a bit of encouragement.

Dust mask in case you need to resort to grinder or multi-tool.

Work light.

Hammer.

Decent gloves.

Small child to send into the space to do the work for you.

Decent gloves, a good shout, and essentially a slave.

Never found a chisel a solution, but why not chuck one in ?

 

[ajlelectronics]

Decent gloves, a good shout, and essentially a slave.

Never found a chisel a solution, but why not chuck one in ?

If it comes apart with a chisel, it wasn't done right the previous time.

 

[Barking Mat]

If it comes apart with a chisel, it wasn't done right the previous time.

Sometimes heavy shock damage just delaminates in a heavy shock.

I find it you need to take a chisel to it, it's probably pretty solid.

Probably depends on what your dealing with.

Rarely do me and fibre glass involve a chisel, I prefer a grinder.

 

[Pigeon_Droppings2]

After that photos and drawings please.

You'll need acetone, resine, fiber glass sheet, brushes, spatulas and all that joy.

I'll take some pics of the before, during and after for sure .

 

[Barking Mat]

If it's not cracked or delaminated it's ok, in my books.

I grind down generally with flap disks, the affected area to what is good, then scarf in the repair.

I'll do a quick sketch, but you probably know all this.

 

[Pigeon_Droppings2]

I'll do a quick sketch, but you probably know all this.

I haven't done boat repairs before but think I get the idea from your description.

Rough plan will be...if it's not well bonded then remove back to a solid base.

Seems my sailing hobby is turning into a bit project...I guess it's always the way!

 

[Barking Mat]

So you get various thincknesses of fibreglass mat, depending on the thickness of the affected areas, go for a stepped approach, up to two or three layers of the thin stuff, per mix, if you're using heavy Matt, 2.

After prep, acetone washdone with a paint brush, attack, use a roller or paintbrush to remove all air bubbles they are your enemy.

 

[Bullet2012]

Whatever resin it was built with use an epoxy to rebuild, I personally recommend a west systems epoxy
West systems have various options that may be suitable

WEST SYSTEM Epoxy | Leader in Marine Epoxy

The home of WEST SYSTEM® marine-grade epoxy resins and hardeners for boat building, boat repair, home repair, and restoration.

eu.westsystem.com

 

[Barking Mat]

Whatever resin it was built with use an epoxy to rebuild, I personally recommend a west systems myself.
West systems have various options that may be suitable

WEST SYSTEM Epoxy | Leader in Marine Epoxy

The home of WEST SYSTEM® marine-grade epoxy resins and hardeners for boat building, boat repair, home repair, and restoration.

eu.westsystem.com

Fibreglass epoxy resin is essentially all the same.

Maybe unless your building carbonfibre super racing vessels.

 

[Bullet2012]

Also consider replacing the ply with nidaplast sheet

https://grpukltd.com/product/nidaplast8-15mm-sheet-2-5mt-x-1-22mts/

 

[Bullet2012]

Fibreglass epoxy resin is essentially all the same.

Maybe unless your building carbonfibre super racing vessels.

Agree, but if it was built with polyester then epoxy will only improve the structure

 

[Barking Mat]

Also consider replacing the ply with nidaplast sheet

https://grpukltd.com/product/nidaplast8-15mm-sheet-2-5mt-x-1-22mts/

Yep, that's the dogs danglies, but frankly marine ply generally suffices.

Depends application and budget.

We got some at work to play with, some years ago, good on decks, horizontal, but you try getting resin into that vertically, even with silica....

And getting it not to leak out.

On that note...

If you're laminating vertically and it wants to peel off due to position, get some thick plastic sheet like tarp, or plastic wrap and gaffer tape it in place.

 

[Dozzer]

Did some of this sort of work for Colvic craft when they were at Earls Colne airfield many moons ago.
100% with what Barking Mat says.
The one thing that is more important that all the other tools will be ventilation, you really need forced ventilation. when they were laying up the large moulds, they had massive fans blowing fresh air in all the time as the fumes from the resin sink and will sit in the keel. doesn't take a lot of fumes to make you quite ill.