LureMaker1000

I have been making a few stick baits with an empty weight hole in the nose to be filled later on the water. I secure the weights with craftsmart plastilina clay from Michael's. I have a couple other baits that have had the clay in them for a couple seasons. This clay doesn't dry out and it secures disc-shaped lead pretty well. Saltwater doesn't seem to degrade it. The clay can be picked out of the hole with a hook and a new weight added then the clay repacked and made flush with the body of the bait. I think if I were looking to make something that had to suspend perfectly and had to make adjustments on the water I would do this. Then could finalize it later.

Now a year later I been fishing a spook made with this problematic alumifoam right after I got it vs. the ones I made about a year later. The ones made a year later have broken down a lot faster under the hook rash than the other ones. Interesting stuff.

I finally tried etex. Didn't solve the problem. Per AnglinArcher, and after discussing with Alumifoam, I'm going to order new bottles and start afresh with that. I've gone over the instructions pretty carefully but will definitely reread them carefully when I try these new bottles.

I am on luremaking hiatus currently. My last casting was of the 9" plug and I spray painted it but did not it epoxy it. It has been sitting in plug bag in car and is getting fished. Haven't caught on it. But no cracks. I flex it every once in a while. There is a quite a bit of flex. And no cracks showing. RideHPD: 1) the 36hrs cracked one was not subjected to car heating it went into car on the same day as I went fishing and it was a cool day to start with. 2) All the plugs have spent a number of days in car, some more than others. 3) I love your analysis ideas. I will refer to them should the etex thing and trying a new batch of the resin does not result in the problem being resolved. I'm ordering some more foam soon. Alumilite kindly offered me 25% coupon. Here's the picture Anglingarcher requested. The foam was purchased directly from Alumilite, not via Amazon.

I picked up the .5g mb/32g resin lure that developed the crack so soon after making it and tried flexing it at the hook hanger. Broke apart fairly easily--I think the weight of a big fish could lead to breakage there if pulled the fish by the lure up the bank. I then tried flexing it between the two existing cracks. Took a good deal more flexing before breaking. I'll have to find some other ones to break ha ha.

Thanks for your reply Ride and your thoughtful ideas. That one broke on day 5 or 6. I fished it on day 5 and discovered the crack on day 6. I waited two days to paint. Then waited another 72 hours to epoxy. Fished it throughout next day. Basically discovered the crack 36 hours after applying the epoxy but it could have happened while fishing. Didn't catch any fish on it. Yeah. All lures fished. But 2 and 4 I never caught a fish on them. OF course I probably dragged in some seaweed at some point on them. That big yellow lure #1 the crack on the left developed when I tried flexing it after the crack on the right had happened while catching fish. Other lures have multiple cracks in epoxy but not all of them seem to have developed to split stage. I made another version of the yellow one about five days ago. I spray painted it, but no epoxy. I was flexing it last night. Quite a bit of flex in this foam. I didn't try to break it but I flexed it a good bit. No cracks. I'll try some others. It's sort of a mix. I fished just about all of these. But a lot of them that cracked never had a fish on them and I don't think many of them got snagged either. They all did go through a fair amount of heating and cooling cycles while just sitting in my car for weeks. Great ideas. I will see if I can do the flex epoxy without a turner. I just heard back from alumilite and they gave my a 25% off coupon so I might order some new foam, try again with old pcess, and see what happens. I am about to run about of devcon 2-T and they don't sell in local stores anymore. Maybe now will be good time to swtich to etex for a while just to see if it easier to use, makes better end product anyways.

By the way, while I don't know if this qualifies as flexural testing, I tried bending the new 9" plug with the new crack and while there is definitely some flex in this thing I did not observe any cracking. I didn't try to break it but I did flex it pretty good. The yellow plug #1 in the photo above broke while catching a fish on it, just fyi.

RideHPD, So I just poured a new one and got a crack within 36 horus of epoxying and painting it. Crack is on one side of the plug and is propagating around to the other side as I fuss with it. Do you think the plug could be shrinking unevenly and putting one side under tension as the other side shrinks at faster rate? The crack is located at an area where I glued on some pancake weights to the wire harness.

Thanks for these posts, folks. I have not tried etex yet as my understanding is I will need a turner. I will get to that at some point. I tried 32g resin with .05 microballoons mixed in and poured a 9" 3/4" diameter plug. 48 hours later painted. 72 hours after paint epoxied. Fished the next day. Today is next day and I have my first crack it's on side of plug. I gave it a flex and the foam has separated inside. Crack looks same as the ones above--crossectional crack. I just poured another plug and will fish this one without sealing it with epoxy--for now. This will test if unepoxied plugs don't crack. Later I'll try the etex once I procure some and build myself a turner. Thanks again!

Alumilite emailed me the following thing to try: "One trick of the trade is to add 10% by volume of Microballoons to the Alumifoam. When it cures, it provides a much more consistent cure and porosity throughout the foam. It comes out tan like the RC-3 and all the bubbles inside the foam are very similar in size. It does continue to shrink as it fully cures even though 98% of the hardness and movement happen within the first 4 hours or so. " I have no idea what 10% volume of microballoons would weight and I do everything by weight. With Amazing Casting Resin I can do between 10-15% by weight.

I think I will be trying Etex. I wasn't aware of the decoupage vs. glue epoxy distinction. I just need to rig up a turner. But still interested in investigating the source of this foam cracking issue. Here are the requested pictures. I numbered the lures. Here are some notes on the process. Alumifoam cast in a silicone mold. Spray paint usually 3-7 days after casting. Epoxy some at least 1 day after painting but sometimes much longer. All the red circles indicate splits in the plug all the way through. On 1 the split on the right occured when catching a fish and that split was at the hook hanger. The split on the left was when I was testing the lure for other weak points by trying to bend it. On 2 and 4 I never caught a fish and hardly fished them. On 3, this is interesting, the paint and epoxy started flaking off almost immediately. I believe tried dipping that one in primer immediately after demolding. That split didn't happen though for several months.

Thanks Anglin. Are you epoxying your plugs with D2T? I've reviewed some of your other posts on alumifoam and if I recall correctly you use pretty stiff molds for this stuff. I wonder if you are packing the foam at allso it cures to a higher density which perhaps means smaller cell size and maybe greater cell strength and possibly less shrinkage or sufficient resistance to shrinkage to prevent this cracking stuff to happen.

I was googling about expanding foam cracking and I guess in the insulation spray foam world you get this sometimes. Cracks in foam or even wood framing being distorted when foam shrinks. Causes of the shrinkage were suggested as 1) a bad mix from the factory 2) applying too much foam at a time leading to improper curing conditions (too hot and fast). So maybe the epoxy or the wire harness or both in tandem are preventing the foam from shrinking and the plug basically tears(shrinks) itself apart. I am trying to get alumilite on the phone about this will report back with any news.

Hi All, I bought a batch of Alumifoam from Alumilite last season. I made a number of lures--4"-9" sized striper lures mostly all round basically e.g. spooks. I spraypainted most with Rustoleum 2X Ultracover rattle cans and then topcoated with Devcon 2 ton epoxy. Just about all of the painted and epoxied plugs have developed crossectional cracks (running around the circumference). Of these plugs, the ones that I used a lot ended having these cracks develop into a full split of the plug body. These are all throughwired plugs(308L TIG wire). I made a few that I neither painted or epoxied. No cracks on these. Some of the plugs I painted right away, some I waited a week. I would usually wait a week before epoxying them. I am curious if anyone else has had this problem with the cracking?