4200 or 5200?

Tortuga · Posted: Thu Jul 03, 2008 5:42 pm Post subject: 4200 or 5200?

Hi all,

I'm in the process of installing a new sounder on Tortuga and will be taking Thataway's advice on adhering Starboard to the transom and screwing the transducer into the Starboard.

I'd like the ability to remove the Starboard sometime in the future (though I don't know I will... just like the flexibility). So, do I use 4200 or 5200? I've been delighted with the 4200 on things like bilge pump screens etc. But I don't want to lose the transducer with a weaker bond than necessary.

Suggestions or advice?

Matt

journey on · Posted: Thu Jul 03, 2008 8:05 pm Post subject:

First, I believe that starboard is polyethylene. I'm not sure that 5200 or 4200 will stick to that. They do have a specific procedure you must use to get good adhesion. If you're going to glue it make sure you find out what it is and follow it. I would recommend that you screw the starboard into the hull with screws ABOVE the waterline, and then bolt the sensor onto the starboard. That way nothing can come loose. You can seal the screw holes in the stern with 4200.

Comments from Another Website :

"The supply house selling Starboard locally had a document from the manufacturer that listed 3M Scotch-Weld DP-8005 "Acrylic Structural Plastic Adhesive" as the proper adhesive to use with Starboard. The guy at the supply house specifically advised not using epoxy or 5200 so I didn't try it (maybe others have and can report results)."

"Adhesives have been used with some success, however King Plastic Corporation recommends using mechanical fasteners to ensure reliability."

Boris

Pete in NY · Posted: Thu Jul 03, 2008 8:10 pm Post subject:

5200 has a greater tensile strength compared to 4200, a lot more. Check out 3M's web site if you want more details. For permanent, never, ever to be removed installations use 5200. For sometihng that may need removal in the future use 4200.

AstoriaDave · Posted: Thu Jul 03, 2008 8:25 pm Post subject:

The other rule of thumb is: if the joint's failure will sink the boat, use 5200; if it won't, then 4200 is good enough. In any case, you will be scraping the bejabbers out of it to get that stuff off.

Catch 22 · Posted: Fri Jul 04, 2008 1:56 am Post subject:

my two cents... i crew on a hydroplane in the summer time and we have used 5200 to glue a few different plastic components (gps antenna, strobe light, and a few others) to the hull, which was painted with epoxy paint, and it holds up great, all these are above the waterline, but take a severe pounding of water and vibration anyway, also, we have never found a fastener of any kind that is truly perminant, i think if you use 5200, you could get it off again, just be prepared to spend some time on it...

i just mounted my transducer, and i shaped a small piece of marine plywood into a wedge to counter the rounded transom so that the transducer points forward, then i mixed up some west system and thinned it with acetone, and painted the wood with it, the acetone lets the resin penetrate the wood a lot further before it evaporates, then do a thicker layer on top, not too thick though, or it gets brittle, then i mounted the wedge to the hull using 5200, and 2 #8 SS fasteners, then mounted the transducer to that, it will all get painted with epoxy paint this winter when i paint the boat...

dtol · Posted: Fri Jul 04, 2008 6:10 pm Post subject: 5200 and Aluminum

How does 5200 work with aluninum???

thataway · Posted: Fri Jul 04, 2008 9:44 pm Post subject:

5200 will adhere well to well prepared aluminum.

The Starboard needs to be cross hatched (best with dove tail small router bit, such as made for a Dremel tool. It is correct that 5200 or 4200 does not adhere that well to Starboard. However with the cross hatching, the 5200 will fill the groves to give good adherence. The area for the screws of the Starboard into the hull, need to be drilled out oversized, undercut, and filled with thickened epoxy. Then the pilot hole is drilled and the screw holding the Starboard to the transom is attatched with the screw...the sealant is thus not critical, since that screw goes into epoxy, not the wood of the transom (and relitatively thin fiberglass layers).

dtol · Posted: Sat Jul 05, 2008 3:26 pm Post subject: Well prepared aluminum

Bob

I assume well prepared means degreased, wiped down with rubbing alcohol, and roughed up a bit. I have used brake cleaner to prepare aluminum housings for epoxy on my vehicles. I would think that would work well to degrease any film from the aluminum on a boat.

journey on · Posted: Sat Jul 05, 2008 4:58 pm Post subject:

When I'm mounting something on the transom that I want to keep, I use thru bolts instead of screws. Thus I feel justified in using 4200 to seal the holes.

The sole exception was the drain flange at the bottom of the transom, where I used 5200. That, I don't want to come loose AGAIN.

Just a different approach.

By the way, the Starboard Mfg. keeps rrepeating that the stuff is not a structural material. I assume that means that he/she doesn't feel it'll take any load. If it's not structural, can't figure out what is an approved application/load.

Finally leaving on our summer trip next Tuesday. Just killing time until then.

Boris