Just about to dive into my first EPS shapes and I’m intending to put HD inserts into 'em for around the fins and leash plugs. I’m getting the majority of my materials from FiberglassSupply.com, and I’ve found these things to be a bit difficult to track down. It seems they only stock up to 1" d cell and I am thinking, with some advice from another swaylocker, that I will need around 1 1/2" to comfortably contain the proboxes I will be installing.
They DO stock 1 1/2" ‘Last-A-Foam’, a closed-cell rigid PU foam… is this interchangeable with Divinycell?
…or is all this a moot point and do people think that 1" of d cell will be enough to nest the proboxes in enough foam to make the HD insert worth having?
Bill, I was thinking about layering… is there a best way to glue it together? I wasn’t sure if a layer of resin holding two sheets together might catch on the router bit and rip out little chunks of foam around the edge of the routered fin box hole.
Oneula, thanks for the heads-up on the UV sensitivity of the last-a-foam… good to know. maybe some pigment in the tail if I use it.
you know you can go down to the local hobby/crafts store and buy a cheap 4"x 36" long panel of 1/4" balsa or basswood and build your own layered fin box inserts from that as well. Bass and Balsa wood works as good if not better than Dcell for fin box inserts.
"Just about to dive into my first EPS shapes and I'm intending to put HD inserts into 'em for around the fins and leash plugs."
1) What type of construction. Maybe you don't need inserts......(yes...I've had melt downs...)
2) See Lavarat's post
3) I like the balsa idea....rumor in San Diego is..... When they ship those nice big beams of balsa up here to the US they use balsa scraps as packaging material........I did not pay for my three home made balsa stringers....
One of the great things about inserts is they can be made tougher than PU. PU will insulate your EPS from box-to-foam bond cracks, but why not go bullet-proof?
BC...If you are doing a straight shape in EPS (I.e- not composite skins...) you can either rout your insert depth exactly flush with the shape, or put them in through the glass, then shape them back and patch.
Attempting to shape inserts down flush next to raw EPS is very difficult, worse than where triple-stringers come out in the rail of a longboard shape.
I'm interested to hear of "last-a-foam"...it is'nt available in Aust. as far as I know, but if it is tough, I'd use that over PU.
Speedneedle: that was one of my concerns. I’m trying to figure out if I can manage to route the depth exactly, go deep enough to provide enough material to secure the box. That would be the best way I think, but of course not always possible in the case of any kind of concave etc. You’re right I am hoping to go as bulletproof as possible: I want to take as many precautions as possible against the dreaded unnoticed mystery leak. “Why is my board so heavy now?”… lol. One of the boards I am making WILL get bashed around considerably; the break it’s intended for always bashes boards up. Every precaution is good.
Lavarat & Oneula: Thanks for the input in alternate systems: I like the idea of balsa particularly although are there leaking issues? I’m just curious how you go about making a balsa insert like you mention; is it a laminated chunk of balsa? Or the balsa cross-bar reinforcement kind of thing? Maybe I’ll try it in one of my other boards.
The recycled PU makes a TON of sense, financially and environmentally…! …I am exceptionally paranoid about this one board though and want to make it as bombproof as possible.
"I'm just curious how you go about making a balsa insert like you mention; is it a laminated chunk of balsa?"
... laminated with Tri-bond 3 wood glue four layers to the inch If you glass in the insert like you'll do the box after you route the plug you shouldn't get any water intrusion into the foam due to a leak around the edge of the box and wood.
Q.
"I am exceptionally paranoid about this one board though and want to make it as bombproof as possible."
... Then do what every pro does..
Use glass-on fiberglass fins
can't get anymore bullet proof than that
Flimsy plastic replaceables are over rated (Griffin taught me that)
You need some "Last a Foam" (Actually I have something called Precision Foam its replacement) ?
For what kind of boxes?
I bought a 4'x8'x1" sheet a while back and cut it all into insert sized blocks with my band saw and put them away for future use...
chris p...it can be done, shaping inserts down against EPS...
If you were to insist on going down that route, here's the trick:- brush a little extra resin onto the EPS area surrounding the insert, say a couple inches bigger each way.
Allow that to cure before attempting to cut the top of the insert down to flush with your shape.This sealed foam is protected a little. Then the best thing to use is a super-sharp stringer plane, to shave down the insert material but only scrape against the cured resin surface of the adjacent EPS. This cured resin however will then require scuffing before lamination:- scratch it up for a bond.
My recommendation would be to laminate, then rout the holes, then insert, then shape down, then patch, just as if you were putting fin-area reinforcement down anyway. Guaranteed cleaner job in the end. That need not be difficult.
Or, as Oneula suggests , ol' fashioned stylee glass-ons, in which case I give a double layer base patch just as if it were for FCS.
thanks for the clarification! I agree on glass-ons for bombproofness; I guess I meant ‘as bombproof as a removable fin system can be’, lol. I don’t trust my placement enough to not want the movement and cant offered by probox, I guess I figure that gives me more than one shot at getting it right in a way. At least without grinding off fins and shifting 'em. …maybe I’ll try out the balsa on one. I didn’t pick up any divinycell, in the end.
I am, indeed from British Columbia! …Just got back to vancouver island from a run through washington for fiberglasssupply, and I’m stoked! Are you from around here also?
Greg, you find that 1.5# and up eps blanks are strong enough without inserts? I’ve got some 2#, and a couple others, I think the lightest is 1.7#. All US Blanks, in the end they were low on Marko stock and so I just went with all US Blanks. I’m going to glass a bit heavier than ‘normal’, meaning more than 4 oz on the bottom with tail patches and also additional football patches I’m thinking. I just really want to avoid the sudden realization that my board’s been soaking water through some silly little microcrack by a fin box for the last five sessions… If you feel they’re solid enough to avoid unnecessary repairs without inserts that would be reassuring.
My EPS surfboards are all home made blanks using industrial grade 2# EPS foam. Recent discussions with other Swaylock's members tells me that 1.5 and 1.7 from good blank makers like Swegway gives you foam that is the same or better than what I have....
All of my fin install meltdowns / problems were caused by me using fast hardener...rushing the job.....
For bombproof....cap the boxes with one layer of 4oz after the install......that's when I do my "tail patch".....slow and steady...not a pro...just a Bro....
stingray, I picked up a smallish amount of slow hardener to go with the fast also. made sure I had enough to do all the leash plugs and fin boxes. Thanks for the lead on that thread, looks to be useful!
Thanks for the lead on that thread, looks to be useful!