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View Full Version : how do you seal transom thru bolt correctly



cerberus
07-15-2003, 12:19 PM
After drilling hole through transom, what is the correct way to seal hole with bolt ?

Liqui-Fly
07-15-2003, 12:22 PM
You'll get some wold answers here but this is what I do. I drill then coat the inside of the hole 3 times with penetrating epoxy. Then surround each hole with 3m 5200 to form a nice gasket.

David

vector mike
07-15-2003, 02:44 PM
I coat the shaft of the bolt with 3M 5200 and then under the washers on each end. That stuff is the best.

cerberus
07-15-2003, 03:21 PM
Thanks Guys.......

Techno
07-15-2003, 07:12 PM
I wouldn't ever seal the inside side of the fastener. Just my opinion but if the outer sealing job isn't working you want to know about it and reseal it. Even if it's an epoxy sealed hole. If the bolt does a bit of a wiggly dance it can chew through it, given time.

Glopping up the bolt and inserting it don't do a whole lot. I pulled one once and it wasn't anything like you would think. Most of the goop gets swiped off when inserted.

I epoxy a pipe in, still have to seal it though somehow. Now I think I'll do Liqui-Flys method of the rubber gasket deal. Was thinking of sliding a rubber washer on but didn't think it would hold up with the crush. Also considered an O-ring.

vector mike
07-15-2003, 08:33 PM
What about the upper bolts that are in the splash well? They see water on both sides.

Ronny Jetmore
07-16-2003, 08:22 AM
my two cents, 5200 is awesome. i would recommend sealing the hole with epoxy prior to the 5200, also. the best way is to drill the hole slightly larger than needed. this will give you clean light colored wood to bite into and provide a thicker epoxy surface. then you heated the wood up with a hair dryer. this causes the wood to "open up". now you want to apply your unthickened warm epoxy to the holes using either a small brush or pipe cleaner. continue doing this until the wood no longer soaks up any more epoxy. then thicken some epoxy with coloidal silica (west system product). now you coat the bolts (not the threaded section) with the thickened epoxy and insert them in the holes until it hardens. ohh, by the way, you will want to coat the bolts with a simple car wax before putting the epoxy on them. this way, when the epoxy hardens, you can simply apply some pressure with a wrench and the bolts should break loose fairly easily. if you don't wax the bolts, you can always heat them up (about 150 degrees) afterwards and the epoxy will release then. one other thing, because some time may be involved in doing this, i would recommend using slow cure hardener with the epoxy. this way you have lots of time to work. once you complete this and the stuff is hard, pull the bolts out. clean the holes well and do the 5200 trick. don't use more 5200 than needed. the stuff can really rip things up when you pull a motor off later on.

Techno
07-16-2003, 09:55 PM
Originally posted by vector mike
What about the upper bolts that are in the splash well? They see water on both sides.

Whats a splash well?

Those bolts aren't inside :D

Thats a good reason to do the pipe bonding deal though. If the bolt leaks it's only leaking through the pipe. In this case you wouldn't even need to seal the bolt.

Shadow Crazy
07-16-2003, 10:26 PM
I use git-rot even if the wood core isn't rotten. it is similar to penetrating epoxy and it is available at boaters world, cabellas,west marine etc... it seals way down deep. then squirt in some 5200.

Superdave
07-20-2003, 11:19 PM
I used a flaring tool similar to the one used to put the round brass tube for drain plugs. I used 1/2" id stainless tubing with a 0.062" wall making it 5/8" od
I drilled the holes 11/16". Inserted tubing into holes to get the length adding more to allow for the flare. The idea here is to have enough on each end to actually roll the flare over. I removed the tubes and flared one end on each one. Now I have 4 stainless tubes with a flare on one end. Then I mixed some five minute epoxy and coated the outside of the tube. I carefully pushed the tube into the hole with a 1/2" bolt with the head against the flare. I then placed the flaring attachmet in the 1/2" bolt and as you tighten it the other end will flare. After the epoxy sets you just turn thE 1/2" bolt with a wrenc and the bolt will pull out.
You now have a stainless steel insert, coated with epoxy all around and being flared on both ends it is definitly sealed!

sho305
07-21-2003, 10:44 AM
I had a boat at a friends lake once. It stormed for half an hour, and the boat had water up to the top of the battery in back. My new bilge pump had failed to kick on. Since then I seal both sides of the bolt. I really think you should just take them out every 5 years or so and reseal them, not that hard to do. The 5200 is great, and I hope I can get it off if I flip this boat....I glued the whole clamp on with it.:eek: That could have been a Homer move, but I figured it would not move around that way. It had wear marks in the glass before and I did not want to torque it down hard, squeeze the new transom too much, and crack it anyplace inside my epoxied holes or outside.

I have seen tuff rubber washers on plumbing things, with some belting in them. I think they are a good idea but could not find any when I did this boat.