Taking out window & replacing with porthole on NB with fibreglass sides

[W+T]

Hi Mitch, looks ok, nice one , takes practice as you have found out, i see you laid up to the wood frame edge without tapering back the edges, Not a big problem aslogn as the edge you bonded to was cleaned back with acetone, one way to tell if it has held properly is give the patch a good thump to see if it breaks free, should be ok as said if it was cleaned. Also it looks as if you have laminated over the inner side of the the wooden frame when you went over the insulation..Defo give it another maybe two laminations.

 

For the tubs i use paint tub type buckets, as you have found the resin melts a lot of things, even brushes which i found out once and the bristle binder melted off the brush, there fore bristles all over the job

 

I love the smell of of the stuff, it can get your head banging a bit hey lol, mine was spinning when i did the floor in the boat, even with all windows open.

 

So whats the next GRP project, cant stop now

[Mitchellmoxo]

Hi mate,

 

Thanks when you taper back the edges are you doing that on all edges? As I did so on the outside edge but not on the wood or the inner edge?

 

At least I know for next time I still have 7 more windows to fill in!! I did give it a punch test yesterday lol and it seemed pretty strong!

 

I did use acetone everywhere I went just to be sure! Next GRP project after this lol I havent found one yet!

 

hope your boat is going well

 

[W+T]

See home already and get to play out now, not all bad being p at 3am

 

The tapering is for when you laminate upto the outer GRP skin only, you start with a sheet of tissue and CSM the same size as the hole or a little bigger, then the next lamination 1/2 inch bigger all round and so on etc until the thickness is what you want or the taper is filled. Then on the outside it will be real flush with the outer edge.

I guess avfter you ahve done all windows then you will be a qualified laminator...GRP`er.....or what ever lol.

 

My boat is coming on great now, transom done, engine well about to get finished, and deck ready to fit

[David Mack]

Would the same technique work to use on a steel cabin? Welding in a steel plate would leave obvious marks due to the heat distortion, but would a fibreglass insert be more or less invisible after painting?

[Mitchellmoxo]

I'm no expert but I don't think it would work as well due to fibreglass & metal expanding at different rates in temperature changes. A welder worth their salt would be able to patch this and grind back the weld to make a seamless patch up job being just as strong as it would of been before the hole was cut.

Edited October 4, 2015 by Mitchellmoxo

[David Mack]

I'm no expert but I don't think it would work as well due to fibreglass & metal expanding at different rates in temperature changes. A welder worth their salt would be able to patch this and grind back the weld to make a seamless patch up job being just as strong as it would of been before the hole was cut.

 

Its not the strength that's the issue, its the heat distortion from welding which means that a cabin side which might have been pretty flat before will show ripples which indicate where the new panel was welded in, and grinding, filling and painting won't entirely remove that.

[W+T]

 

Its not the strength that's the issue, its the heat distortion from welding which means that a cabin side which might have been pretty flat before will show ripples which indicate where the new panel was welded in, and grinding, filling and painting won't entirely remove that.

 

 

Hi David, as Mitch says a good welder will be able to weld it up without disrietion, i am a novice welder and i can weld a plate ib 2mm sheet with no distortion, i just give very short even spread runs.

 

BUT

 

If you do go with GRP then use Epoxy resin not the Polyester, Epoxy resin is better for bonding but a whole lot more expensive, can be 4x the price,

 

Just a quick though for daft time of the morning, but maybe if the welding worried you, how about welding a 25mm run every 8-12 inch then fill the gap with bridging filler or epoxy filler better still. flat back the good. obvouilsy fillet the edges.

[captain flint]

On 9/22/2015 at 18:36, Sea Dog said:

Mitch, your boat looks quite tidy in the photo, albeit with a window where you'd prefer to have a porthole. I think it unlikely you're going to make such a drastic change without making a bit of a dog's breakfast of it. Just my 5 cents.

And yet....

heh.

[Sea Dog]

3 hours ago, captain flint said:

And yet....

heh.

Yeah, absolutely!  It was a couple of years ago now and I can no longer see the photos, but sometimes its nice to be wrong, eh?

[captain flint]

On 9/14/2017 at 21:10, Sea Dog said:

Yeah, absolutely!  It was a couple of years ago now and I can no longer see the photos, but sometimes its nice to be wrong, eh?