| Author |
Message |
    
David R Cole
Advanced Member
Username: david_ray
Post Number: 198
Registered: 02-2008
| | Posted on Monday, October 26, 2009 - 05:16 pm: | 
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Depth sensor had been "glued" for years to inside of boat bottom beneath engine. Glue appears to be something like JB Weld. Last summer it came loose, and will not bond again for long with JB Weld. Do you have any recommended adhesive for what I can use? I would also like to use the same type adhesive to mount the bilge pump switch beside this depth sensor. |
makomark
Senior Member
Username: makomark
Post Number: 1761
Registered: 09-2008
| | Posted on Monday, October 26, 2009 - 05:47 pm: |
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Your favorite flavor of epoxy.
make sure you roughen and clean both surfaces and that they are dry it the bond won't last long.
Realize that if you bond the switch in and it fails, you'll probably destroy it come removal time. |
David R Cole
Advanced Member
Username: david_ray
Post Number: 200
Registered: 02-2008
| | Posted on Monday, October 26, 2009 - 06:58 pm: |
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Of course I did clean the surfaces well - it has now been remounted three times this season to no long term success. Yeah, I realize that removal will destroy the unit(s), but they would have failed before I would remove anyway.
JB Weld is of course an epoxy with some fillers. As such it was a perfect color match for the original compound which is why I supposed that JB Weld may have been used when the dealer installed originally. Whatever original epoxy was used it did have fillers, as epoxy formulas are fairly translucent when mixed if fillers are not added. I can try some other brands, perhaps unfilled. |
C.DeF.
Member
Username: ipmarine
Post Number: 43
Registered: 02-2009
| | Posted on Monday, October 26, 2009 - 07:59 pm: |
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David, MM is correct in saying epoxy is the adhesive to use. I'll generally use Pro-Set or West Systems 6-10 epoxy adhesive. The drawback to these is that they come in two part cartridge form and need a special caulk type gun. West's G-10 should also work fine and can be purchase, I believe, at boating stores such as West Marine and come in smaller bottles. Epoxys are sensitive and must be mixed proportionally correct and thoroughly blended. Grind away ALL the old adhesive and roughen the fiberglass surface with 80 grit, clean well with acetone before and after sanding. Of course make sure the puck is set to shoot straigth down and not angled. You don't mention if this is a "shoot thru the hull" sender or an external surface mount. If it's an external, clean as mentioned (remove any & all bottom paint if used) & use 3M 5200 sealant. Temp. secure the sender in place ( blue mask, duct tape...) Give it enough time to set up and cure (you can use a finer grit paper on the gelcoat w/ 5200). If it's a "shoot thru", cutting a paper cup or a plastic mixing cup, cut to the same angle as the dead rise and taping it in place will help (cut the bottom out also). Pour in the adhesive then set the puck in place. Give it at least 12 to 24 hours to cure. That should do it. I would not recommend using JB weld for this type of install or any automotive epoxy adhesive/filler that might} contain any metallic type fillers.
If past attempts failed it's no doubt an adhesion problem & may not be specifically related to the products used. |
makomark
Senior Member
Username: makomark
Post Number: 1764
Registered: 09-2008
| | Posted on Monday, October 26, 2009 - 08:30 pm: |
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When I worked at the shop, we used to use MarineTex. Like a paint job, the prep is key.
Make sure the hull is dry and leave the covers/hatches open before and after if possible - moisture will inhibit the bond. |
David R Cole
Advanced Member
Username: david_ray
Post Number: 201
Registered: 02-2008
| | Posted on Monday, October 26, 2009 - 11:57 pm: |
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I will switch to some other brand unfilled epoxy purchased thru West or Overton (marine outlets), and fire for effect. Will wait a few days til weather warms a little first, but since boat is essentially ready to winterize the epoxy will have plenty of time to harden.
Thanks to all. |
