Hello all,

After intex has failed to restock this kayak skeg
for several months, I've decided to take it into my own hands to obtain a kayak skeg for my inflatable kayak. I bought this piece of plastic board and cut it in the shape of a fin. Now I have to glue that piece onto a perpendicular piece which will slide into the holder for the (removable) skeg, and perhaps also alter the fin/skeg to improve its rigidity. I wanted to ask what adhesive you all would recommend I use - considering how difficult plastic is to bond/adhere to, and also that it will be exposed to long periods of immersion in water (including salty) with possibly somewhat strong currents.I actually made and used a prototype skeg, for which I used hot glue. After the use, I found there were some pieces of the glue that had come off with the use (some force), although I'm inclined to think this might still be the best avenue although with some better glueing technique so I can get the plastic board to actually melt a bit and bond better with the hot glue. Perhaps I could heat up the plastic board before glueing (I am roughly aware there are dangers with heating plastic at levels too hot, i.e. burning it to create toxic fumes). As for rigidity, the board has a structure somewhat like how cardboard is made, such that there are fine holes/tunnels inside the board that I figure I could fit a rigid couple sticks. I was able to quite snuggly fit chopsticks inside these channels, although I figure wood is probably not my best choice for something that will be constantly immersed in water. Thoughts?

Note: I'm not trying to make this skeg absolutely foolproof. If I can have it work for 30 uses, I'll be satisfied. At that point I could make another of the same, eventually Intex will restock the item, and I will likely get another inflatable kayak from another manufacturer soon.
Note(2): Let me know if there is a better subforum/category to post in.

 

I don't think your plan will work. Gluing plastic is marginal at best and the base of the skeg/fin is a high stress area. Instead I would measure the mount for your fin and look for another one, possibly for a surf board or windsurf board.

 

Well I actually did look into obtaining a similar replacement skeg from a manufacturer other than intex - the only one I found that I thought looked like it would work, was on ebay and despite shipping from china for 3 weeks or possibly more with current conditions and, with shipping, costing over $20 which was roughly 1/4 of the price of the kayak, I was all for ordering it. Before I did though, I messaged the seller asking if it would fit the specific model kayak, who told me that it would not fit, so I just scrapped it. Perhaps there are other sites you could recommend me to search through, I only looked at ebay and I think Alibaba haha which didn't have any but even if it did I wouldn't want 10

 

I agree,,,,,,you likely can not glut that type of plastic.
PVC and ABS plastic pipes may be similar but the glue used for those is specifically formulated to bond only each type.
Also. when you glue plastic pipes the joint gets mechanical strength from inserting into a fitting and they will not bond when trying to glue them without the support of a fitting.
Many types of plastic like what you have could be plastic welded by knowing the type and using the correct welding rod or plastic salvaged from more of the material you have.

If you show pics of the attachment to the kayak we might have a better idea about what you are trying to do.
Maybe you could fashion a wood or metal attachment piece and bolt the plastic fin to it..

 

First, most manufacturers don't keep track of what will fit what unless they are marketing it to do so. They can provide you with the base mounting dimensions. Then it's up to you to see if it will work. If you can't find a fin that uses the same mounting it would be easiest to make an adapter so you can use a fin that you can buy.

 

I will take another look into the replacement skeg, see if the base dimensions would fit, even if perhaps with some sanding/razing down. Even then... I'm hesitant to go that route; Delivery would take at minimum 3 weeks and I'm eager to keep using the kayak this summer. I already made and used a more simple prototype makeshift skeg, only it lacked rigidity. I'm already more than 50% of the way to the improved makeshift skeg. Here's more specifically what I intend to do:

I did a little more reading and it sounds like I could soften the plastic, and perhaps that will help it bond. I found this data sheet which sounds like the material I have, which says it will soften around 300 Deg. Fahrenheit. (converted from C). So I figure I heat that up in the oven at 300 F, perhaps also the fiberglass chopsticks I just ordered which should soften around a similar temperature. The main hazard and complication I see here is proper safety working with heated plastic. Also what tray I put the plastic / fiberglass on so it doesn't bond to it - and also how to ensure that the plastic board doesn't lose its corrugated biplex shape when softened. I figure I keep all the windows open when heating, take it out immediately after 10 mins, wearing a regular mask (don't have one that filters oxygen or is airtight - should that be a concern?) and then once outside I lightly coat the fiberglass in whatever adhesive before inserting it into the board, and similarly bond the fin to the base. I'm guessing I'll use the hot glue. as for the board keeping its biplex shape, I could temporarily insert wooden chopsticks, although getting them out might complicate things when the plastic is softened. alternatively I have a regular soldering tool, similar to the one GregH linked - I could use that, difference being that ofc the sodding tool doesn't have a fan - I'm guessing this has to do with the toxic fumes issue presented with heated plastic? Should I take additional precautions like perhaps keeping a strong fan next to me on the patio when working with the softened plastic? I'm trying to keep this low cost so I don't think I would get a whole other plastic sodding tool just for this project. Any recommendations for adhesive? or for the tray on which to put the plastic on in the oven dilemma? My guess is a wooden tray sort of like a cutting board would work.

 

Look at replacement fins for inflatable stand up paddle boards. I found this one on Amazon that looks to have a similar mounting.

I think you are going the wrong route trying to make a fin. I assume you have some corrugated plastic used for making signs. First, corrugated plastic is not good for this application. It really doesn't have the strength of solid. Then the whole heating thing is just going to make it worse trying to glue especially when you throw fiberglass (polyester or epoxy) into the mix. If you want to fabricate a fin I would either 3D print it or make it out of aluminum which can be brazed/soldered to a aluminum base plate with decent strength.

 

OK, well I will refrain from trying to make the skeg myself. Actually a family member ordered one of the detachable skegs from amazon. now my question is: how to make sure the base stays put when glued / attached to the kayak. the kayak itself (intex explorer) is some sort of plastic/rubber material so again I'm concerned with the adhesion of plastic to plastic. Will any old super glue do? any tips?

 

Ok.
We have told you multiple times that glue will not work.
I don't mean to sound rude but are you not paying attention to the advice we are giving you?.
The folks who spend time trying to help have varying amounts of experience with what you are trying to do.

I would suggest you carefully read the advice offered, give up on the glue idea and just order and wait for the right part if it's available.

 

How was your original fin/skeg held to the board? It was not glued in place so why do you want to glue it now? You need to mechanically fasten it somehow. If the new fin's base is a bit too big... sand, file or grind off what's in the way. If you need a way to hold it in place look for a way to use a screw or bolt.

If the new fin's base is too small then you can start thinking glue (I know you're getting excited). You'd still want to mechanically (screw, bolt...) attach the fin but the extra space in the socket can be filled with epoxy to help hold things in place and not give the fin anywhere to wiggle. The key is glue would be used as a space filler and not structurally attaching the fin.