Trick for sealing holes thru cored deck

[kerrye]

I'm installing a couple of folding cleats and stanchion bases thru the cored deck of my A25. Wanted to seal off the foam core from water intrusion by the sealant for the fittings so I drilled the holes, reamed out the core using the bent finish nail in a drill trick, duct taped the bottoms and masking taped the tops and tried to force epoxy into the holes using a popsicle stick. Unsuccessful. It just compressed the air in the empty space and wouldn't fill up the holes. So I went to Lowes and found a Loctite epoxy product which is perfect for the job. Two part epoxy in a twin tube syringe with a long nifty mixing tube with a small exit hole. There are baffles in the mixing tube and by the time the epoxy comes out the end it's mixed. I could insert the tip into the holes and fill them from the bottom so the air escaped. Perfect. Quick and no mess. I had 12 holes and used 3 1/2 tubes. I used the longer working life version which was $4.xx per tube but the shorter lived cheaper version ($3.xx) would have been fine. I used this version but it looks like a 5oz version is also available which would do a lot of holes. There wasn't a 5oz option at Lowes.

http://www.amazon.com/Loctite-Quick-Epo ... =8-3-fkmr0

Let it dry for a couple of hours, redrilled my holes and set the fittings with 3M 4200.

[Beta Don]

Excellent idea!

If Albin had used a similar technique when they were building the boats we restorers would have lots fewer issues to deal with now 30 or 40 years later

Don

[Jeremyvmd]

Good idea but I fear your you will have issues with the epoxy you elected to use. The locktite epoxies and others you are likely to find at lowes are extremely inflexible and tend to crack easily. they are designed to hold two things together. I've had issues with them cracking and failing when used to fill spaces in the past. I would reccomend using an epoxy that is designed to fill in spaces in the future. Below is the product I used...same concept but a much larger tube, and you can buy replacemt. Mixing tips in order to use the product multiple times.
http://www.defender.com/product3.jsp?pa ... id=1152086

[kerrye]

I have tubes of that in my supply but the problem is that the mixing tips are too large to fit in the holes to fill them from the bottom. They would be ok with large holes but mine were 1/4" and 5/16".

[Jeremyvmd]

I fill up small syringes from the tube then use that to fill the holes. Seems to work well

[kerrye]

I would have tried it if I had small syringes. I couldn't find any after I started the job and my initial plan wasn't working.

[Jeremyvmd]

Gotcha. I would keep a close eye on those spots to watch for cracking either way.

[rnummi]

Did the same thing on mine. Tried the loctite as well to fill delamination between core and skin. Worked perfect. Only later did I see the pack o syringes at West. Syringes were a giant pita to use though. I witches to six10 but I was going through six ten tips by the score till I figured out you could squeeze six ten into the syringe.... In any event I ended up using pure epoxy w fast cure to fill the holes. Drilled out a new hole when cured. No matter what your using, as long as it forms a dam betwixt hole and core your in business.

[sail149]

Nice simple plan. If the epoxy has filler in it it will minimize the risk of cracking. But even pure unfilled epoxy like West system lamination epoxy will be amazingly strong and will have incredible higher compressive strength compared foam , balsa,or wood coring. I don't think you will ever have to worry!
How did you make out with the bent nail to hollow out the core? An Allen/Hex wrench is good too . It always sound easy until you hit a resin lumps from the orriginal laminating and the nail jambs practically breaking you wrist ...... Still a very good trick when you get it done. A small raveling router bit can work too if you have the room.

Don, you are so right , as boat builders we should have done this trick when we built the boats. We did actually try to add wood blocking in place of the balsa core when we knew where fittings we're going to be put and my Albin actually has blocks of cured resin/hull to deck putty put under my bow and stern rail mounting points in place of the balsa. (good job for once Albin) ...unfortunately the later additions of cleats and other fitting were just thru bolted with a fender washer behind the balsa which cannot take the compression long term.

[sail149]

I saw and bought some of the epoxy you used
It has the psi compressive strength on it! You have no worries!