Instructions on making a lifeguard rescue can float buoy for spearfishing, foam filled with ballast and flag base.
Here's the cheapest source I found for the rescue cans $65 https://www.marine-rescue.com/…quipment/rescue-cans.html Shipping was reasonable. They first sent me one that had a little hole in the handle. I called to ask for another one and they told me that it does happen from time to time and to cut off the piece that had the hole (happened to be the handle) and send it to them to get a replacement float. They actually sent me the new float before I ever sent them the piece. I cut out as small a piece as I could, about 1" long and sent it to them. Then managed to repair the first float after with a piece of PVC and epoxy putty.
I was contemplating how much weight to use for ballast and which density foam available in 2,3,4,8 and 16lb. I went with a 2lb lead weight ballast and 4lb density foam from http://www.shopmaninc.com/foam.html I bought the 16lb/4 cubic feet kit and had quite a bit left over but maybe not enough to do another complete float.
Forget about pouring the foam through the little hole covered by the plastic cap. You will need a bigger hole to insert the lead weight anyways and a place for the flag base. I used a hole saw to cut a circular hole at the top of the rescue can. I kept the resulting round piece of plastic with a hole in the middle of it to use later to cap the whole thing off. The lead weight had to be chopped up into 3 sections to be able to insert it through the hole. Maybe a different round weight would have gone in complete but that's what I had at the time. I used a dab of sealant to keep the segmented weight where I wanted it while I poured the foam.
When it comes time to pour the foam do not mix large quantities of it. Have a large supply of disposable plastic cups and do about half a cup at a time. The two parts need to be mixed well and the foam starts expanding very fast. Once it starts expanding you can't pour it. So do well planned small increments to best fill all crannies of the rescue can. I started with filling the handles, directing the flow from the cup more or less in the direction of the handles and then tilting the float to make sure the liquid foam seeped well in there. You will see if you did a good job of this as the foam will expand out of both ends of the handle hole. Next I poured into each end of the float alternating.
When the float was filled from each end almost to the middle I poured straight down and covered the weight. The expanding foam secures the weight inside the float. At that point is when I put the fuel hose (flag base) all the way down against the bottom of the float. Actually it's resting on the top of the weight. Before doing so I poked some wire through the hose to secure it from coming out of the foam. I also shoved some epoxy putty into the bottom of the hose to not have water enter the float through it. Once the hose was in place I poured the foam in increments all the way to the top. Support the hose straight throughout this process by keeping the flag pole in it.
I suggest you pour carefully as you get to the top so as not to have the foam expand out of the float. It's very sticky and hard to clean up. I managed to do it almost flush and then did a little scraping to make the hole deeper. I then drilled the cap I saved earlier from the hole saw with a bigger diameter bit to accept the fuel hose. Then used epoxy putty to give the hole a final level, put the hose through the cap and set the cap into the epoxy. Had I calculated better the cap would've been completely flush with the top of the float but it's fine and looks clean like this too.
Conclusions; I do not use this float for almost two years. The total weight of it is 9lb. It has a lot of drag which I can feel especially when there's wave action. If I were to do it again I'd still use 2lb ballast but 2lb density foam instead of 4lb. I think if you know for sure you'll be using it in bluewater with fish that will take it down then you may want to use the higher density foam. For reef diving like we do here though it's really overkill and you will dread dragging it around. The ballast and flag base system work great. The hose is of perfect diameter for the flag post and it stays in there very tight with just suction. I would also consider how to fasten a line spooling system and a cleat to it.
EDIT - The new Rob Allen 12L Overblown Hard Float has similar characteristics to the lifeguard in a smaller lighter package. At $94 it costs less than the sum of the materials to build the lifeguard can float, and is already foam filled and has a ballast and detachable flag.
I will love to put the weigh inside so the weight wont hit anything and scratch it. I like the way it finished::). I definitly will try that.
I hope it helps.
