What am I looking at? (deck plug)

[egaito]

A recent survey turned up some "delamination" through hammer testing. I cut open one of the spots and found something I've never seen before. It appears to be unsaturated fiberglass over the coring.

Poking the coring with a screw driver, it's a little soft, but not mushy, and still white. Smells of resin.

Is this area "delaminated", or "never laminated"?

Should I expand the area to all margins and re-laminate or fill with CPES and fuggedaboutit?

Picture attached....

 

[thoward]

I'd guess an air void Put an air vent over it and call it done

 

[Boatsb]

Dig it out and run down to Home dipsh(t and get some hydraulic cement for patches. It will fill the cavity and never rot. worked on my driveway why not the boat.

 

[Traveler 45C]

It kind of looks like a farm with green hair. (please, no acid comments...)

Where is this section located?

You can clean it out, CPES the core, fill with thier filler and put the lid back on. Done

 

[Angela]

Where is this section located?

It's the sun pad area just in front of the pilothouse windshield on the bow area. We do not yet have the pads made for that area. Good place for Ed to practice his fiberglass skills since it will get painted and a pad placed over the area.

 

[Traveler 45C]

I’ve got a similar problem on my bow where a deck fitting lives. It leaked (for who knows how long) and a lot of the core is wet/rotted. I bought some CPES and its going in that hole along with the filler. I didn’t have to cut the deck open though.

I don’t see why you couldn’t treat this the same as a rotted core fix. Find the extent of the ‘never laminated’ area using your drill instead of your saw and use CPES and filler. Less FG work this way.

 

[thoward]

You can thin out West System enough for it to penetrate the core. West Systems makes some great fillers you can use as well. I would seal the core then alternate filler and glass to the top.

 

[Traveler 45C]

You can thin out West System enough for it to penetrate the core. West Systems makes some great fillers you can use as well. I would seal the core then alternate filler and glass to the top.

Agreed. But CPES is ready made for this kind of job. It has the consistency of water and will flow where other stuff can't go.

 

[egaito]

Dig it out and run down to Home dipsh(t and get some hydraulic cement for patches. It will fill the cavity and never rot. worked on my driveway why not the boat.

I can see it now...some future surveyor, tapping around, and hitting a plug of driveway filler...."what's that? An unfamiliar sound...the boat must be ready to sink!"

 

[egaito]

I think thoward gets the cookie for his air void guess....I followed it to the end, and there's no path in or out for moisture. Perhaps condensation over the years where a gap existed can be attributed for what little moisture is there.

This pic shows the extent of the area. You can see where it transitions to fully wetted-out glass again.

The rest will be perimeter holes, flooded with CPES, or in my case, West Systems thinned 70% with Tolulene. In reading everything I could find, CPES is bascially epoxy thinned with various components, each with various absorbtion and evaporative properties. Tolulene seems to travel further than Naptha, Acetone, or the other solvents used in various commercial concoctions.

 

[egaito]

Forgot the pics....

On the bright side, my "sounding" skills are getting pretty good!

 

[thoward]

I have used both of the following fillers with good results. I used WS on my wood Egg and never had any problems. It will penetrate just fine with the toluline. I would use a heavy cloth to sandwich the layers of 404 filler and top it off with a couple layers of mat, then faired with 410.

404 High-Density filler is a thickening additive developed for maximum physical properties in hardware bonding where high-cyclic loads are anticipated. It can also be used for filleting and gap filling where maximum strength is necessary. Color: off-white.

410 MicrolightTM is the ideal low-density filler for creating a light, easily-worked fairing compound especially suited for fairing large areas. Microlight mixes with greater ease than 407 Low-Density filler or microballoons and is approximately 30% easier to sand. It feathers to a fine edge and is also more economical for large fairing jobs. Not recommended under dark paint or other surfaces subject to high temperatures. Cures to a tan color

 

[egaito]

I have used both of the following fillers with good results. I used WS on my wood Egg and never had any problems. It will penetrate just fine with the toluline. I would use a heavy cloth to sandwich the layers of 404 filler and top it off with a couple layers of mat, then faired with 410.

So are you saying you're not a fan of the hydraulic patch option? Fix enough patches with that, on the right side of the boat, and I might get rid of that annoying list!

Am I close to the mark with a 70% dilution?

Thanks,

-Ed

 

[thoward]

I used that % on mahagony so it will do just fine with balsa. Make sure to let each layer cure as they will continue to release heat and mess with your workable time. Epoxy can dump lots of heat. The cool thing is you will not have to sand between each layer....

No, I do not think I would use "cement" on a boat

 

[Starman]

This is no more than an area where there was not enough resin during the layup process. This is why we see the white, unsaturated cloth. Many times the resin may not have been mixed with the hardener very well, hence the sticky and strong resin smell.

Fiberglass by nature conducts heat, and fiberglass does have some flex.

After time, the heat from the surface will cook the interior. It is like putting a lid on a pot of boiling water, but not letting the steam escape. Something has got to give, IE...the top layer flex's outward, creating this "blister".

I would clean out any soft spots of foam or balsa. Then , if these are large, I would replace with a like product, epoxied into place. It has been my experience to do this step by step, day by day, instead of trying a one day layered patch.

So once filled, sand it.

Now grind about a two inches all the way around the opening. The fiberglass should be ground so that it tapers to very thin near the opening.

Now pre-cut your fiberglass cloth , placing the largest sections ( covering the newly ground glass ) on first, then subsequent smaller pieces on next until close to or just above the level mark with the rest of the surrounding area.

Use a roller to press out air bubbles and excess epoxy. This adds strength.

Sand it down the next day, removing all shine.

For this area, 410 or 407 will be just fine. Squeegee on a nice thick wide layer.

The next day, sand it flush.

Prime and paint.

Done deal !

 

[Starman]

On another note.

Acetone should not be used to thin epoxy. Many times this will cause the epoxy to never fully harden.

I have used lacquer thinner, about 10% mixture to thin epoxy with great success.

 

[egaito]

I would clean out any soft spots of foam or balsa. Then , if these are large, I would replace with a like product, epoxied into place. It has been my experience to do this step by step, day by day, instead of trying a one day layered patch.

I was careful cutting the patch out with a dremel...any reason not to put a layer of cloth or mat over the balsa, then bond the original parts back in place on top of that?

I thought I would take them down with a sander a bit to account for the new layer underneath, fill the cuts with epoxy/filler.

I soaked the area including some holes I drilled, with the thinned epoxy last night, and it seems to have hardened up pretty well. It'll have a few more days to cure as the weather is @#%^ down here for the weekend.

Thanks for all of the help offered.

 

[thoward]

Like starman said, I would radius the hole and rebuild. You could, most likely, get away with using the high density filler under the plugs and fair them in but I would be concerned about cracks. I am also not sure you could get it to look factory.

 

[egaito]

Well, the first layer is in. I found a "layered" mat that has a diagnal strnded layer over a chopped layer. The sun is out, and it's hot, so working time was reduced even more than I had anticipated, but it's wet out pretty well, and I got most of the extra epoxy out before it got too sticky to work with.

Does this layer need to cure a full 24 hours before the next? If so, I'm running out of days in town.....

Also, is it OK to put a splash of xylene in the epoxy to increase the working time in the heat, or will that ultimately decrease it's strength?

 

[jim rosenthal]

Ed, I don't think you need to cure each layer before putting on the next. I never have. I think if the previous layer is not fully cured the new layer will cross-link to it better, frankly. Like T said, a lot of heat builds up in the curing process, which is why it's better to build it up one layer at a time and not have too much mass there, curing all at once.

I wonder how many of these I have. Probably better not to know. Ed, what do you charge to come sound a deck with the educated hammer?