Found a few threads that discuss using 3M 5200 marine sealant for installing finboxes & leash plugs.
It just seems so easy, especially for a retrofit. I have a request to add side bites - maybe even a quad / versa-plane set of proboxes - to a Surftech single fin.
I’ve read some raves (Herb, Tomatdaum, Lavarat, Soulstice ) about the 5200, especially wrt FCS & Lokbox. But also some cautionary posts (Stingray, Kokua), and a recommendation against using it with Probox specifically (Resinhead).
Since that’s pretty much a who’s-who of the guys I tend to listen to about glassing/box installs around here, I wondered if any further testing had been done. Especially for either Probox or Tufflite construction… and if you had failures, maybe something about the foam / skin system they were matched with.
5200 is not too great w/ poly/poly boards,unless you glass over and around the boxes.Same goes with epoxy/eps , except epoxy has better flex-memory,So the two work hand and hand.
Regardless of the materials ,when using 5200 to box with , always reinforce the box holes first.
Thanks, Herb…that’s pretty much what I suspected. Flexible materials need more planning & the right support structures, not just slapping them in.
I used it for a longboard center box once. I actually even wrapped a couple layers of glass cloth around the box as I mashed it into the glue for some reinforcement. And then I capped over the install with another layer of cloth, after the grinding. No issues at all with that one (2# EPS core, 1/16" balsa skins with 4 oz cloth both sides) but I was hoping I wouldn’t have to cap over on the surftech…
What would you think about FCS with close-tolerance holes?
Yes, I know I’m being lazy. But you haven’t seen the other repairs I’m working on right now. Its amazing what some people will do to their pop-outs!
Again 5200 works fine for installs ,as long as you seal the box holes w/ resin…heck pine tar…but SEAL THE HOLE !
5 min epoxy works great for installs and sealing ,just don’t get it on the surface or it will show up yellow/brown.
Epoxy putty works but it’s to freggin’ expensive ! …and BTW… if you’re not using marine grade putty…it will allow infiltration and delam.Marine grade is the only waterproof epoxy putty.
As far as close tolerence FCS box holes go…it’s fine as long as you score under the surface of the glass around the box hole before install.
I 'll bet 90% of the posters here don’t even know what I’m talking about when I state," Scoring the box holes ". Let alone, even doing it.
If more installs, where the box holes are scored were done,there would be less of these questions about box failures.Herb
I 'll bet 90% of the posters here don't even know what I'm talking about when I state," Scoring the box holes ". Let alone, even doing it.
I have this little 4d finish nail. I bent the pointy end of it at a slight angle, maybe 1/4" from the end. I hold it tight and turn it in a circle. It makes a little groove.
In a close tolerence FCS hole,scoring the foam/glass just under the surface will actually be stronger than larger holes w/ gross amounts of resin.
It’s just better engineering that’s all.Herb
Benny,
Ya, that’ll work…I use a small/tiny file handle with a flat,broadhead screw set in it.I can vary the depth of the score by turning a screwdriver.(In cases where strength is absolute),I also score below the original scoring line, to give it a multi-ridge type scoring(more that one score).Herb
I’ve blown out a few proboxes both with poly, epoxy, and 5200 as the adhesive. But these installs were all missing a double patch. Box was flexing on a bottom turns, and the fin boxes were cracking at the top or bottom of the fin slot.
Now since getting into EPS I can afford to lay down a bit more cloth and not really get a weight issue. All board fin areas get a 6/6/4 treatment. Now I can honestly say “no more box blow outs”
The culprit was in the flex, you don’t want the fin box flexing and loading up. Leave the flex to the fin. I personally haven’t gone back to 5200 for the probox (too much of a puss), I feel it’s best left with FCS or plug type applications. But I guess if you really reinforced inside the cut out, and had plenty of cloth around the deck…it might be a good application. But it now seem to be too much work.
The whole idea was to make it be an easy application. Not so easy with Probox…in my opinion.
if you dont anchor the base (end closest to the deck) of the fcs plug,
the resin fillet Herb is referring to has to be made much bigger; cuz by not anchoring the base, you get a pivot point at the top (bottom skin).
I anchor my bases but I dont use an H pattern cuz I feel my foot can push the plug outward; iow, the H becomes a push rod. My base pattern resembles a bipod (tripod minus one?) and angles away from the plug (like the roots of a tree) and I use a more flexible epoxy putty (a bit of flex prevents cracking). If my foot starts to push down over that area, the angled resin anchors flex and dont push down on the plug like a push rod which is what the H pattern does in some cases . These angles are also better reinfs, like I said, roots of a tree splay out. I guess if you looked at it under xray it would look like a tooth but with the roots splayed.
