Major Fillet Problems.... Please Help!

I was making great progress on my deck restoration until today. We decided to make up larger batches of Peanut Butter to expedite the fillet process. We used 2 Quarts of Polyester Resin and .9 oz of Mek(1.5%) per my calculations. We then added 2 quarts of Cabosil making it 1 to one. I used a paddle stirrer on a drill to make the mixing process easier. The working time was normal, but after 3 batches the intial applications started curling off!

WHAT HAPPENED!? I mixed it at 1.5% because the temp in the shed barely gets over 60 degrees. We let the PL bedding set for 48 hours. Before applying I wiped the stringers down with acetone to clean the dust and provide good adhesion. I did NOT use a wax or sanding agent on the intitial poly coating or the peanut butter.

Did I mix it too Hot?

Could the PL glue not be set?

My thought now is to let it cure fully, and cut or grind the cupped areas. I would use a little PB to fill the gap and then apply the 1708.


This photo shows the fillets I did on existing stingers a few days ago. The curled and cupped fillets are occuring on the new stringers that have been bed in with PL premium and resin coated 2 days ago without wax.




PLEASE HELP!

Re: Major Fillet Problems.... Please Help!

The PL gases out for 72 hours.

Re: Major Fillet Problems.... Please Help!

Wow ! Kinda yucky . My guess would be in the cool temps the pl did not cure completely . Hopefully the pro's will chime in soon ..

Re: Major Fillet Problems.... Please Help!

I'm no pro, but I think you shouldn't have coated your wood first when using the PL... peanutbutter yes, PL no.

Re: Major Fillet Problems.... Please Help!

I would have folded in some chopped fibers too...that looks like what I made for fairing on my hull...if so it will be brittle...

Re: Major Fillet Problems.... Please Help!

The PL sounds like my problem... I was going too fast and forgot about it gassing for 72 hours. I thought about adding chopped fibers but didn't do it in the end.

So, what now?

Re: Major Fillet Problems.... Please Help!

You still need to tab those in with csm/ 1708 right? Might want to wait and get an expert opinion though...

Re: Major Fillet Problems.... Please Help!

Yeah, they still need tabbed in. If I let it all set up(pl and PB)Can I just knock the high edges off and fill with resin and CSM?

Re: Major Fillet Problems.... Please Help!

Hmmmm, my understanding is that cabosil/aerosil and resin only make for a thickened resin, not too strong without the fibers, might even be as brittle as plain resin...
Definitely got to let the PL gas out for 72+ hours, depending how thick it went in the first place...

Seems like the PL out-gassed through your thickened resin, causing the blow outs...

How far along are you?...all your fillets done?...If yes, Oh well...

For now let everything cure really well for at least another day or two, then hit it...

Since the fillets are mostly a means to provide a smooth transition for the matting to follow, and you still need to add CSM and 1708, you should be OK getting rid of any really bad spots that blew open, use a combination of any of the following, whatever it takes to clear it out: grinder, dremel, die grinder, drill with carbide rotary bits or or coarse [24-40 grit] sandpaper...

If any of the fillets look like they are about to pop off the surface, use a sharp wood chisel and pry up any thing that want to come loose...

Clean with Acetone, re-fill with a proper mix of PB then rough up the remaining fillets you have with some 80 Grit, or there about, to give them some tooth [the reason being that the thickened resin mix you made tends to dry to a smooth, not too porous a surface], Acetone wipe down, then apply the layers of Mat and Cloth...

Let me add that you might be able to skip some of the fillet sanding IF, and only IF when you wipe them down with Acetone, they become sticky/tacky...meaning you SHOULD be able to get a decent mechanical bond...

Sorry, but there isn't going to be a much easier way to do this and still get a satisfactory adhesion between the fillets and the subsequent layers of mat/cloth/resin...

And I know this comes too late to help you out, but maybe someone reading this in the future will benefit from the following...

When filleting with Hairy PB, I like to add the first layer of CSM tabbing while the PB is still moist...
This does two things...
1-It makes for a Chemical/Molecular? Bond between the fillet and the CSM, and...
2-It allows you to shape the fillet using the CSM...

Also, adding the next layers of 1708, etc...while still moist/freshly kicked, is also beneficial, although not always possible...

Hope this helps and best of luck,
GT1M

Re: Major Fillet Problems.... Please Help!

If you did not use chopped fibers in that PB, that might be the problem. The fibers give it strength like re-bar does to concrete. When I first saw it I thought it was PL, not PB. The bubbles however looks like the PL was still gassing off, but resin kicks off pretty quick and would not bubble like that unless you had a steady stream of gas coming up though the mixture.

It is just weird. I wouls grind it smooth and mix up some PB with fibers in it and re Apply and see what happens.

Re: Major Fillet Problems.... Please Help!

I am really thinking we need to re-think this PL thing for stringers as we have all have had issues with Pl when laying stringers.

Re: Major Fillet Problems.... Please Help!

Yep. Updated my link several months ago indicating my preference for PB. Thick PL takes a MINIMUM of 72 hours to cure and can take up to a week. If she were mine, I'd cut out ALL the fillets, Acetone wash everything and apply 2 layers of 1708.

Re: Major Fillet Problems.... Please Help!

I used PL for bedding my stringers with no problams, but I'm using epoxy.

Re: Major Fillet Problems.... Please Help!

friscoboater said:

I am really thinking we need to re-think this PL thing for stringers as we have all have had issues with Pl when laying stringers.

Click to expand...

Thanks for that info because I was just about to do that within the next two weeks.

Re: Major Fillet Problems.... Please Help!

Yeah, I have always been a fan of using PB instead of PL...quicker results and and way less problems...

Re: Major Fillet Problems.... Please Help!

Thanks for the advice. Things were just going too well I guess.

In a few days, I'll take my angle grinder with flap disc an knock the bubbled areas down. I got about 50% of the stringers done before I noticed the problem. Hopefully the CSM smoothes it out enough to apply 1708 over it. The subsequent PB will also have cut up CSM mixed in for strength.

Right now, I'm too tired to be discouraged. I took a week off PTO to repair my boat and then I did something really stupid. I took on a side job installing 450 Sqft of tile flooring. I need to have my head examined.

Re: Major Fillet Problems.... Please Help!

Badfish95 said:

Thanks for the advice. Things were just going too well I guess.

In a few days, I'll take my angle grinder with flap disc an knock the bubbled areas down. I got about 50% of the stringers done before I noticed the problem. Hopefully the CSM smoothes it out enough to apply 1708 over it. The subsequent PB will also have cut up CSM mixed in for strength.

Right now, I'm too tired to be discouraged. I took a week off PTO to repair my boat and then I did something really stupid. I took on a side job installing 450 Sqft of tile flooring. I need to have my head examined.

Click to expand...

Some people might say we all need are head examined for bringing old boats back to life that should be taken to the dump.

Re: Major Fillet Problems.... Please Help!

Badfish95 said:

Thanks for the advice. Things were just going too well I guess.

In a few days, I'll take my angle grinder with flap disc an knock the bubbled areas down. I got about 50% of the stringers done before I noticed the problem. Hopefully the CSM smoothes it out enough to apply 1708 over it. The subsequent PB will also have cut up CSM mixed in for strength.

Right now, I'm too tired to be discouraged. I took a week off PTO to repair my boat and then I did something really stupid. I took on a side job installing 450 Sqft of tile flooring. I need to have my head examined.

Click to expand...

Hang in there BadFish! When's it's done you will have a much better boat than new structurally.

Re: Major Fillet Problems.... Please Help!

Its the PL glue, the same thing happened to me. I had to grind everything flush before I glass in my stringers and bulkheads. If I were to do it again I would bed my stringers in with PB.

Re: Major Fillet Problems.... Please Help!

friscoboater said:

If you did not use chopped fibers in that PB, that might be the problem. The fibers give it strength like re-bar does to concrete. When I first saw it I thought it was PL, not PB. The bubbles however looks like the PL was still gassing off, but resin kicks off pretty quick and would not bubble like that unless you had a steady stream of gas coming up though the mixture.

It is just weird. I wouls grind it smooth and mix up some PB with fibers in it and re Apply and see what happens.

Click to expand...

The cabosil mix not containing chopped fibers is not the issue. As you say, the fibers act like rebar which adds strength, does not add or improve adhesion properties. From looking at the pic's it is not a strength issue, it is a bonding issue. I think I have to agree with the general conscensus, it is the PL off gassing causing the issue. I learned something similar on my boat build. When laying glass early afternoon, I would get air bubbles under the glass. This was due to the wood heating up along with the epoxy and gassing off. When I layed glass early in the morning or in the evening, little to no gassing issue. Of course I was outside under a tent so the sun had a bit more direct inpact on the heating for me.