It looks like Bondo!

Hi everyone,
We took on a job for a simple sole replacement on a boat with an inner liner.
When I said simple,I should have said simply buy another hull!
We got the inner liner up off of the hull on the a frame hoists.
All of the structure(3/4" plywood )for the floor was rotten.
And once we got a real good look at the rest of the hull thats where the problems began.
To make a long story short,the owner wanted the hull repaired so we were pretty much stuck.
We removed the tanks and all wiring ,motors and bracket,tabs and all accessories.
We cut out all stringers and bulkheads and started grinding down all of the old glass to prep for the re-install.
Then we found a material that looks like Bondo that was used to fill the strakes( I hope this is the correct term) that run fore to aft along the hull bottom.
They had cracks running lengthwise but not the full distance on each one.
We only found these due to the big cracks in the material where the tanks had been removed.They material was covered with chopped strand.
We are in the process of grinding all of this material out.
It is very time consuming.Could we just remove what is loose or delaminated and fill in with chopped glass fibers and some micro balloons?
I am pretty sure you all will suggest grinding all of the existing filler out and replaceing all of it with new filler.
Any suggestions would be greatly appreciated.

 

Egad. This does not sound fun.
Afraid I don't have many ideas other than what you describe. There are no cheap fixes or shortcuts with fibreglass. You either do it right, or do it again in two years.
I'm not quite sure, though, what's up with this filler. Do you have any photos you could post? If we had a better idea just what it's doing, it might be possible to find a better solution.

 

It's common to fill the strakes with putty after the skin coat, this makes the rest of the glass work go faster by not having to roll the air out them.
If the strakes are in good condition with no cracks, then I don't see why you would need to remove the putty, but if there are problems with the putty, or cracks that need to be repaired, it would be best to remove it.

 

i agree with ondarvr about the putty done it many times,even before the hull is skined alot of laminators put some paste into corners helps with the air and is easy to roll out but makes for a shity boat

 

What kind of "putty" is it that you/they use, Jack?

 

looking for the trade secrets toot, shes a homemade putty, first get your gelcoat and mix some resin into it, then add hardner, this is v important,and stir well, add milled fiber and then cabosil, and some aluminum trihydrate this will ease any exotherm, some throw in micro ballons and talc, its important to add the hardner before the powder to make sure the resin will cure and wont have soft spots but dont make it hot or it will kick on u , what a lot of guys do is have the paste powder mixed up and just make paste as they need it

 

what ive been using is premade fairing putty and adding some milled fiber and aluminum trihydrate it works good and saves me time, some places use corebond which is a pain to mix, but go easy with it just use a little to much is not good

 

Wow. If I'm going to spend my time mixing that many ingredients together, it'd damn well better taste like a twinkie when I'm done!


Seriously, interesting info. Thanks.

 

forgot to tell u on a industrial job, up in northern canada we forgot to bring cabosil to make paste , went to the general store bought all the talc they had didnt have much so we ended up using flour nice smell flour baked with resin

 

If only you would have also added a bit of baker's yeast into that concoction...

I suspect you could've gotten some extra buoyancy out of it!

 

Hi everyone,
I hope the pics that I'm posting come out alright.
We got the rest of the grinding done where the stringers and bulkheads were attached today.
I even went to the trouble to grind out the fillets that were for the main stringer.
I found alot of hairline cracks in the fillets, so we didn't want to leave any room for doubt.
Marshmat ,the pics of the hull are about 8' fore of the stern where the fuel tanks are placed with a 19" tall center stringer.
I am beginning to believe the cracking of the filler was due to heavy use in rough seas.
I don't remember that many of the fillers from the late 80's early 90's,but the one they used in this boat stunk!
The last pic is of the filler with a blacktop background.
Ondarvr,is it a common occurrence for filler materials to crack like this,or is it just another case of shoddy prep work.
Also we did not find any cracking in the underlying mat nor from the bottom side did we find any gelcoat cracking.(we were lucky)
I talked to the owner today,and needless to say he was not pleased.
He made a 50mi. roundtrip just to see for himself and to cry on my shoulder about the potential costs.
And to top it all off when he was there, he was tapping the transom where we removed the engine bracket and found a whole lotta voids.
So tomorrow, after I get finished grinding out about 80' of filler (6 strakes along hull),I get to remove the transom too.
Fiberglass jack is the aluminum trihydrate available at most marine supplies? Or do I have to get it from a specialty store?
And lastly the hull is sitting on its trailer and is supported pretty well on its bunks up about 12' from the stern(30' hull).We also placed another cross support between the two that are forward on the trailer. It seems pretty sturdy and level.
I was just concerned that with all of the material that we have taken out of the hull that we should build a rack to set it on?
Thanks for your time everyone!

 

My suspicion is that if it stinks, it's probably got something biological in there. Flour, probably. I have never done a rehab on anything like that, but that's just my hunch.

In fact, that's always been my concern with using flour- is the rotting issue. Of course, most of it is encapsulated in resin, so you don't have the problem right off the bat, but over time, as that resin cracks and lets air and moisture in, I'd imagine it could get stinky just as you've described.

It's just my hunch though.

 

you can get trihydrate at most fiberglass sulply shops, the pastr should have plenty of milled fiber and some lose chop strand this will stop cracking. if they put the paste in thick it is natural for the paste to crack during the cure from the heat fiber will stop this

 

Hi everyone,
Toot, I didn't mean that the filler stunk, I mean't the job stunk! Sorry about that .
Thanks for the info on the aluminum trihydrate fiberglass jack.
I guess when they built this hull in 1990 they were probably mixing their filler pretty hot,that would explain the cracking filler which is all over the place, even in the resin they used.
As I started grinding again today, I found that as I ground through the top layer of chopped strand it would slowly delaminate until I reached the filler.
Tomorrow starts another full day of grinding to finish removing the filler.
Now when we mix our filler material what is our best mix ratio? I will add the aluminum trihydrate like fiberglass jack said. The epoxy resin to milled fiber to cabosil ratio I'm looking for I guess is one that won't do what the original filler did.Any suggestions? Hopefully as soon as the owner decides on the stringer, transom materials we can get that done.
We want some weight savings so we're going with 1" NidaCore with 2 layers of bi-directional with epoxy resin to support the inner liner floor/deck/sole.
I just haven't decided on the fiberglass weight (6oz,12oz or 24oz) and the orientation of the 2 layers.
Should we roll the bi-directional out fore to aft on the first layer and on the second layer, roll it perpendicular to the first layer.
I would really like to try and vacuum bag the inner liner part of the job.
The inner liner main section will use about 48 sq.ft. of NidaCore in section no more than 3-4 sq.ft.,and the nine hatches will be about 48sq.ft..There are (6) 14"x24" deck hatches, (1) 36"x72" fish box (1)24"x24" livewell hatch and three 16"x72" center fuel tank covers under the center console.
We 'll experiment on the smaller hatches first to get the procedures down. If you all need a better idea of the inner liner I'll take some pics of it.
I have been reading and seeing alot about vacuum resin infusion and thought that this might be the right job to try it on .
The boat won't go back in the water until spring anyway according to the owner so we have time to work out any problems.

If you all think we're going about this wrong please let me know, epoxies and core materials aren't cheap and I dread costly mistakes.
If any of you have suggestions throw them at me,you guys have way more knowledge than me about the finer types of fiberglass repairs.
Thanks again.
I'll post more pics if anything interesting turns up.

 

glassr

The putty really doesn't do anything but take up space, I've seen scrap wood, foam, card board and other things used to make the hull flat over the strakes, I don't think junk putty is a great way to do it, but you would be amazed at how many boats are made that way. Most use a low cost, light weight putty.