How to caulk bait tank? 4200 or silicone?

TheBoyScout

Thanks doesn't buy gas...
Nov 13, 2014
305
207
San Diego
Name
Ray
Boat
Bayrunner Baja 23 "Rough Rider"
Hey guys, what is your method for sealing a fiberglass bait tank to a fiberglass deck with nonskid? I would like to make the seal look as clean as possible, ive heard of people using their finger to make a nice concave edge but ive never done a good job with that technique. Also is silicone good enough or should I go with 4200? Also what do you guys use for sealant on the bait tank fittings?
 

fly liner

I Should Upgrade My Account
Apr 10, 2009
2,222
1,438
hemet ca USA
Name
Josh
Boat
21' crystaliner /15' prowler
4200 for both . It is pretty tacky ,so if using your finger. Lay a smaller bead,then wet your fingertip before you wipe it down , keep a wet rag to wipe off your finger. Also if you cut the tip correctly on the tube of sealent and take your time you should be able to lay out a clean pass. Cut the tip at like a 45°angle and take your time. 4200 is a relatively thick product let the tube warm up a bit and it will flow easier.
 
Upvote 0
May 13, 2004
507
614
74
Long Beach and points due west
Name
Bob Ballew
Boat
2520 Parker with twin 200 Yamahas
...Many bait tanks are over the gas tank, requiring you to be able to detach the tank to inspect (alum) for corrosion and pinholes...also to change out the dip stick measuring pole if fuel readings are wrong....4200 or Boat Life caulk is both ok, as it can be scraped loose far better than 5200;, only recommended for permanent fixtures like cleats.....Lowes usually carries it..
...Consider pressing on a line of painters tape (Frog Tape is best for painting straight lines) before running the sealant on all fixtures and tanks ...let it set a while and when you pull it at a 45 degree angle, you will have a professional looking sealant job....
 
Last edited:
Upvote 0

J Woodman

I know nothing
Dec 8, 2006
1,013
562
Ventura
Name
Jeff
Boat
15' Gregor "Silver Bullet", Parker 2310 "Deep Color"
Masking tape will make a big difference. Take your time and apply tape to both sides of the caulk line. For curves either use several pieces layered on the deck to go around the radius or possibly use electrical tape but dont pull it too tight. When done, carefully caulk the seam with 4200 and smooth it out with a finger. Let it set for about 10 minutes and then carefully remove the tape, pulling diagonally away from the caulk.

4200 for all tank fittings also, even between a hose and fitting. It is the standard of the industry for a good reason.
 
Upvote 0

Spoons

USCG Master
Oct 21, 2004
1,445
935
San Diego/SF Bay
Name
Capt. Erik
Boat
21' Center Console
Life caulk is the best for bait tanks. It remains pliable but strong unless you need to cut it away. 4200 is good but a little too tough for a non permanent install. 5200 should not be used. Silicone will easily separate and not recommended.
 
Upvote 0

sickcat

Silverback
Aug 5, 2003
3,619
1,628
64
LA
Name
Kerry
Boat
Yellow spot
To smooth caulking I wear a nitrile glove and use a cup of water to dip my finger in. Applying the right amount of caulking helps minimize the mess and get a good looking bead.
 
  • Like
Reactions: TheBoyScout
Upvote 0

pescaloco

fish hunter
Aug 17, 2005
1,114
227
san diego
Name
Mark B.
Boat
27 Foot Stringari Custom
Recommend lifecaulk
Tape the tank and the deck a little wider than the thickness of the caulk bead.
Lay down your caulking evenly and use your finger to wipe it down smooth
Pull tape right away and lightly dress with your finger if your edge is rough from pulling the tape.
Lifecaulk smooths out way better than 3m caulk.
The real trick is getting an even amount of caulk layed down and the right spacing on your tape
 
  • Like
Reactions: Spoons
Upvote 0

karlow

Twins 2017
Apr 29, 2004
1,899
817
64
Duarte/Covina
Name
karl
Boat
20' skippy Topless /17' whaler Wet Ride (sold) /18' Outrage
HD has a tool for this sort of thing. It has a silicon rubber finger on it an a cutter on the other end. From what I have read you dip it in mineral oil for a clean finish. When I did my deck, I used a LockTite marine sealant. It was a hot day and by by the time I made it back around to finish it, it had set up! So much for the 1 hour working time.
 
Upvote 0

Drew Stephens

Almost A Member
Dec 6, 2017
112
72
26
Ventura, CA
Name
Drew Stephens
Boat
Sunbird Neptune 230
Just went through this myself. I ended up using straight silicon. No caulk or adhesive is going to hold it down like you make think. Plus if I have to work on the plumbing I can just peel it off. Super simple stuff. I just needed a water tight seal
48B977CA-3D3D-4EF2-904A-7FACF9BD8F16.jpeg
 
Upvote 0