3M marine grade silicone sealant vs 4200

bmcminn

Which one for lazarette hatches? They are a tight fit and did the overdrill and fill with 205 and the screw holes.

srbaum · Posted: Mon Feb 17, 2020 4:22 pm Post subject:

Bmcminn,
You will fall in love with butyl rubber tape. Buy it in white, 1/8" x 3/4" and you will rarely need any other caulk. Hinkley Yachts, many of my fellow boaters and I have been using it for years with great success.
The stuff remains pliable, you don't need any chemicals to clean-up and you can roll it in any shape, thickness or size.
It also does not go bad while sitting in your shop, waiting for its next use.
Here is a link to what I have purchased the last two times around. https://www.ebay.com/itm/DEHCO-COLORIMETRICS-BUTYL-TAPE-PUTTY-TAPE-BLACK-GRAY-WHITE-MANY-SIZES/231095305882?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649

thataway · Posted: Mon Feb 17, 2020 4:50 pm Post subject:

I go with the 4000, it does not turn yellow. The silicon can hold, or it cannot hold--does vary. My own experience with the butyl tape is that unless you can keep the screws and bolts tight, eventually water and dirt will get under it. I know a lot of folks like it--and it is certainly easier, faster, and cheaper for the boat builders to use....but then again, most boat builders do not properly put in solid glass or epoxy potting when they put fasteners thru a hull, into a cored structure.

localboy · Posted: Mon Feb 17, 2020 5:08 pm Post subject:

I use butyl only on thru bolted items. If screws are used, sealant. Just what I do. Don’t claim to be an expert. When I replaced our cockpit hatches I used 3M 4000.

srbaum · Posted: Mon Feb 17, 2020 6:06 pm Post subject:

Bmcminn,
Forgot to pass along the photos from my install a year ago in my 26. Did the same thing in my 22 with the same new hatches in my 26, over 7 years ago and zero leaks...
http://www.c-brats.com/modules.php?set_albumName=album2901&op=modload&name=gallery&file=index&include=view_album.php