Digging in the deck

Ayedunknow. Can see how many find my words eye-glazers.
I wouldn't have poured in plain epoxy to try to fill the holes.

I would have cut disks of Xmatt and/or fiberglass cloth and laid them in stacked like pancakes and then capped the stack with the well buttered disk of skin.

the butter is epoxy mixed with Cabosil or alternative. The butter can be strengthened with chopped strand, which is usually 1/4" fiberglass pieces you buy by the pound or jar.

I would have prepared the holes by scrapping out the rotted balsa (with a Bacho tri-angle carbide scraper) and discarding the stuff.
I would then excavate slightly under the rim of each hole.
I would then have inserted a disk of pvc foam.
But as an alternative I could build up the required 3/8" with rounds of Fiberglass.
I would have made sure those rounds were saturate with liquid epoxy.
I would have finished each hole replacing the disk of skin that was originally removed with the holesaw.
Because the liquid epoxy can find its way into a rotted core I would have stuffed chopped strand strengthened epoxy gel into any visible space.
There may have been caves in the balsa around the rim of each hole. I would have pushed epoxy gel with chopped strand into them. I then would have laid in the rounds of fabric or pvc and capped with the disk of skin.

After the holes were filled and hard I would tap the parts of the rotted deck that were not disked out with the holesaw. If I found hollows (dull sound) I would drill in3/8" holes into them and inject them with liquid epoxy. If the liquid epoxy did not top off, I would inject epoxy gel into the drill holes until no more goes in.

Would continue this drill and fill process until no more epoxy goes in and there are no more dull hollow sounds when tapped.

Pouring in liquid epoxy into a space in an attempt to fill the space is not considered a good idea.
If the space is large and the epoxy is there in large quantity the exothemal reaction can get very hot. The area around the epoxy can get distorted, even burn, and the epoxy will boil, get frothy, and become useless..

Imco the solid epoxy fill you have does not compromise the small area you worked on. Laminating epoxy, being very thin, is formulated to be used with fiberglass and other fabrics. It also makes great fillets and installation gel when mixed with fillers like fumed silica, glass and plastic spheres and milled glass. The epoxy in itself is brittle when set and really needs to be married with the stuff it is designed for.

If you had wet out your holes with liquid epoxy -
then filled the required interstice with epoxy gel (in place of where epoxy saturated glass rounds OR pvc would have gone -
Then capped with the original top skin disk WELL BUTTERED WITH EPOXY GEL.. that could have flown.



EPOXY GEL
You need Part A and Part B epoxy to mix together. It should be the best epoxy available.
You need fumed silica to mix into the Part A - Part B mixture.
You make your liquid and fold in the Cabocil until it starts thickening.
You control the thickness with how much of the powder you mix in.
It can be quite thin but still have some body to it - or very thick and very stiff. There is a happy medium.

Epoxy blended with fumed silica is stronger than plain epoxy.
If you need extra strength: to this gell you add milled fiberglass pieces.
You can add too much and get a hairy goop. You use this stuff to give the epoxy gel some GRAIN (as in wood grain), some structure - because plain hard epoxy is brittle.
And plain hard gelled epoxy, while very strong, gets much stronger with the addition of a little 1/4" chopped strand. It becomes 'structural'. And nearly impossible to break - or to sand - so don't build it up.

[I have learned it 's easier to fill mild hollows and imperfections with easy to sand fairing compound. The one West System product I can recommend is their 407 fairing filler which you mix with your (NOT West System's) laminating epoxy to produce a chocolate colored surface you can sand. You can use this stuff under the waterline. There is another material: 410, but this compound should be used inside only.]

You can't inject epoxy gel that has chopped strand in it. The gell will be adequate in the core repair. Inject it to fill hollows. It also will naturally fill all your drill holes.

Making gel allows you to fill tilted decks, vertical walls and holes overhead like in your liner in the boat.

Damp balsa doesn't make a good thickener. Any pieces of ANY material (even glass micro-spheres you can use to make fairing compound with) when mixed into epoxy liquid will fall out. It'll sag. You need a matrix like Cabosi to make a gell to hold added materials like balsa in suspension.
You need the Cabosil to make a filler that won't move before it can set. You need the Cabosil in your fiberglass kit. Liquid epoxy is generally only used to wet out laminations of fabric.*
If you want to make a glue as for plywood, or backing blocks, or fillets you have to add the fumed silica.

This still doesn't read CLEAR, but I really hope it is useful.
__________________________________________________ __________________________________________________ _______
*Laminating epoxy makes a great sealer and grain filler for mahogany that will be finished bright.

Ebb,

you should have do it for me! :D I knew that polyester resin by itself is useless and needs glass mat, but with epoxy I wasn't aware of that. I had also considered that no matter what, the epoxy would be stronger than just new core. The heat factor didn't seem to be as bad as you described, because I used medium hardener which took a good time to kick and didn't develop that much heat. It was pretty warm, but not hot enough to cause brittleness or worse.
I had considered somehow threading mat into the holes and beyond, but thought in the end that the mat would make it more likely I'd get air bubbles and that the epoxy wouldn't flow into all the crevices. The balsa chips (almost dust really) were dry at least.
The gap between the upper and lower FG layer is filled now and the disks are in place. I don't know if I will find somehow that the deck is not sound now - if I find it cracking of course I know I screwed up badly and will have to really remove the mess I made.

Thanks everyone for their advice, especially you, Ebb. If my job is terribly botched it will serve at least as advice how NOT to repair the deck!

I don't think you've botched it.
There are a hundred ways to fix this problem.
You may have invented a perfectly decent method.
I'm an Opinionated Old Fool, glued in my ways.

Epoxy is very forgiving stuff.

Good luck to Stretch
and great sailing!!!:cool:

If you would like to hear it, I think I have a 'compromise' fix that might work out.....

....like ebb (our OB1 epoxy guru) said, epoxy is forgiving and it may work out ok.


If you want to be more sure, you could take a router, set the bit to a little over 3/4" (or what ever seems appropriate from your core samples, and the material you used. I would not aim to bottom it out in each hole, just get near the bottom.... Might use something like the Dewalt Rotary tool as a router, so you can get much closer to the cabin top and the rail then a regular router would allow....

I would remove the stanchion and include the raised area in your repair, it looks like someone did some kind of repair there in the past...


The idea is you want to remove any 'stress points' where the repair ends, or at least spread them over a larger area.

Route the area all down.. deck and all, just outside the area of your repair.

Once you have a larger area, you will have 'milled down' these 'resin rich' repair areas. Then you can build the entire area back up with layers of epoxy and fiberglass.... fair it all back in, and you should have no worries about it in the future.

Hey Craig, that's a goodun.
For close to the toerail stanchion excavating using a 1/2" router,
you have to jig the router up to toerail height and maybe box it in to control it.
Excavation would be done with a long 1/2" straight bit that you'd lower in small increments to determine the depth you want. A bit dangerous, I think.
You could say that you are incorporating the backup pad into the upgrade.
But I think greater thickness translates to less likelihood of bending the fastenings that hold the stanchion.
Also getting a better no leak seal.

I have a Bosch 1HP router called the Colt (about the size of a malt licquor can.)
It accepts 1/4" shank bits. With an alternative base you could excavate as close as 1 3/8" from the toerail right ON the deck. This may be close enough as I think this area, on the Ariel deck anyway, is solid frp. Anything you can't get with the mini-router you can with a Dremel.

This small router in this ap, with careful lowering of the bit, can be freehanded, I think, into the deck. Two handed control. Sharpie pen the limits with a nice rounded perimeter and excavate to the depth you want. If you are lucky enough to have 1/4" deck skin and 3/8" core, I wouldn't go deeper than 1/2". Whatever depth...I'd work cautiously down to it.
In imagining about this, I think that if there is a little balsa/polyester stuff at the bottom of the excavation I would incorporate into the frp pad you are upgrading with. Not willing to cut through the flimsy inner skin.
A big plus is filling in the old wore out stanchion fastener holes and starting fresh!

There might be rot around the foredeck vent that this method would do well with.
There is certain to be a little rot under the mast. This might do well there as well.
Very well, thank you:D

I hear you. I dread redoing it immediately, I want to get on the water asap! But sure, nothing is lost for good, just time and materials wasted. I'll finish this off now and will keep an eye on whether it develops stress cracks or not.

The PO stated that the paint used on deck is Awlgrip, 'powder blue'. Unfortunately it appears that Awlgrip has dropped that particular color! Does anyone know of powder blue, and if any other blue comes close? Would be silly to have different blues on deck, and it will be a pain to do little repairs to the topsides paint (which does need some touching up indeed)

Sky Blue come close?
Maybe call an Awlgrip tech and ask which of their 15 whites you might add to which blue to get the old color. Maybe they just changed the name.
Or experiment:
Sometimes you can find one ounce touch up jars of color and white for sale. You know, so you don't have to buy $80 quarts.
Keep a record of your mix. Get a dozen graduated 100ml (3 oz) plastic measuring cups to play with.


Hmmmmm....yas...ahhh...
let's see,

20ml of SkyBlue plus 5ml of CloudWhite equals PowderBlue.
Maybe 5ml more white... Voila!
Close enough.

Once you know the proportion you can always reproduce any quantity tomorrow.
Until they change the base colors again.

Tried to call Awlgrip tech support, there's some kind of mess with their telephone numbers, basically I can't find anybody so far.
But I'll keep trying. Your idea with the touchup bottles is nice, although they charge $20 for each, so that's another $40 for a few ounces of paint. Bloody expensive stuff, I could get 4 liters of Bacardi for the same money.

Allocate your funds properly and you won't care what color your decks are. ;)

Stephan, You did read about thickening (?) the epoxy to where it has the consistency of a cake frosting or some say peanut butter? Silica , cotton mill fiber, etc. etc. as a thickening agent.

Carl, I added a lot of the 'sawdust' from the excavation. I didn't want it to be too viscous, to encourage it to flow into all the open spaces, so I didn't achieve that cake-frosting feel. I was worried too that I was running out of time. Unfortunately, that meant it was too thin to not seep out from the lower areas. I guess I should have realized I can't have it both ways.
However, I think that this will be just a nuisance to fill the not completely filled gaps. I hope that it's structurally sound, else I have a real mess.

The only epoxy I know that is "viscous" is 'structural epoxy'.
It is thick epoxy you get when you want to glue things together like wood.
You cannot use this stuff for deck or deck/core repair.

For that you must have very runny 'laminating epoxy' - which is like warm maple syrup, not viscous.
The only thing you can use to thicken that stuff is fumed silica. (Aerosil, Cabosil)
With that you can make infinite 'gels' - ranging from flowing to stand-up stiff.
None of these gel mixes that you make with epoxy liquid and fumed silica are viscous in any way.

This NOT opinion, OK?
If you mix any other material into runny epoxy, no matter how thick it seems to get, it will not stay stiff. It will move. The only exception is cotton flock. And most proprietary powdered products like West SDystem's 407 and 410. Which have fumed silica as part of the ingredients.

If you mix balsa bits into the correct epoxy liquid for core repair ie: laminating epoxy, the resulting peanut butter will not be stable.
This may be what you want.
You may want the mix to wet out its leading edge. It maybe that there is enough surface friction in the hole you are filling to hold the mix.
But as the mix heats up in exotherm it will loose its body and sag.
That is what happens, OK?
If you want balsa bits or any other material like micro spheres to wood flour to fiberglass fibers you have to include fumed silica in you ingredients. Otherwise it'll move before it sets.

This will not happen if you make your filler with enough fumed silica.
Enough fumed silica: you probably have to mix up fillers a number of times to find out for yourself.
EG, enough fumed silica in a fillet mix (this means a stand alone gel mix you'd use to form inside corners in fiberglass work) could be described as 'medium peaks', as if you were beating up eggwhites for a recipe. When you lift the mixing stick out of your goop, the peaks will just fall over at their peaks. But of course the material has more body than beaten eggwhites - this metaphor only describes the look of your fumed silica/epoxy mix.
In one sense this mix is relatively 'dry' - you can scoop up gobs of it like egg whites - it leaves no trails - not viscous.

If you are mixing up gel to stuff into excavated holes under the deck, you can make the material much looser. It will fill such narrow spaces better if it is looser.
But you don't want it runny because then it will not fill the space and stay in place.

If you want the work you are doing to marry with the repair you should
FIRST wet out the area you are stuffing or laminating with laminating epoxy liquid. Then you mop up the liquid with towels until the surface or hole is damp but not running with liquid epoxy.
Then
SECOND you butter your filler into or onto whatever you're doing.
Leave this step out at your peril.

There is no 'viscous' to this. Except for your hands and tools you can do this work with your best suit on. Viscous is polysulfide and most of the other tube rubbers and two-part rubbers that create long strings of material and are messy in the extreme.

See post #16 for 'epoxy gel'.
Look, if you don't trust crazy ole ebb, then get yourself a book or pamphlet on the subject.

Ebb,

I'm a total noob when it comes to epoxy, and I'm glad you giving me all those tips and set me straight. I really don't doubt you are 100% right. Unfortunately I thought this saw dust would be just good enough - and you were proven right indeed. I didn't understand the difference between 'viscous' and 'thick', or used the words wrongly.
The MAS epoxy and hardener is very 'thin' indeed, and the saw dust didn't change that much. I didn't pay attention to your tips to use fumed silica, forgive my ignorance.
Anyways, the stuff is in, it didn't burn or warp anything, and unless it cracks, I hope I didn't do serious damage. If I did, I have to get a big fat grinder and remove some or all and glass it properly, as you suggested all along. But I'm desperate to get into the water, with the season in Chicago being short enough as it is.
On top of it I have still numerous other projects, including finishing the fridge insulation and new inner liner. Since I have to work my 5 days a week, that doesn't leave me much time...

Fiberglass and epoxy is very forgiving to work with, while at the same time being a fast learn with a little guidance. I have no doubt that you did no further damage or weakening of the deck. Nothing is weaker than wet tuna fish balsa which is what you had. Carry on.