Epoxy substitute?

[R055]

Hey guys, I'm getting ready to install a wakeboard tower soon and going to do the backing plates first. The area I want to install the tower on is curved and I bought 1/4" x 5" x10" aluminum backing plates. I need to fill in the hole that the curve creates with something like epoxy but was wondering if you guys know of cheaper alternatives?
Thanks

 

[gm280]

RO55, a lot of iboaters use polyester resins. And it cost less then epoxy and does a very good job as well. heck it out and see what you think. JMHO

 

[robert graham]

I use clear silicone rubber in a caulking gun tube for stuff like that and many other things....Dollar General sells a tube of silicone for about $3.50....

 

[R055]

I use clear silicone rubber in a caulking gun tube for stuff like that and many other things....Dollar General sells a tube of silicone for about $3.50....

No silicone is soft, I'm thinking something hard so it doesn't flex easily.

 

[R055]

RO55, a lot of iboaters use polyester resins. And it cost less then epoxy and does a very good job as well. heck it out and see what you think. JMHO

Hmm going to Google and see that application process and how it works. Would be nice to Apple all of it at once.

Any experience with bondo all purpose fiberglass resin? Is a liquid and drips or can I apple a nice thick coat on a verticle surface and it'll stay?

 

[gm280]

Hmm going to Google and see that application process and how it works. Would be nice to Apple all of it at once.

Any experience with bondo all purpose fiberglass resin? Is a liquid and drips or can I apple a nice thick coat on a verticle surface and it'll stay?

Sounds like you are needing a polyester resin thickener. And they do have such things. You can mix in some Cabosil and mix your poly to whatever thickness you like. You can even make it a putty if you like. So when researching the poly resin, also look for some Cabosil. Most places sell both . JMHO

Oh, Bondo is polyester resins. But since you have no idea how long that Bondo was sitting on their shelf, I would look to other places that have a huge turnover of such materials so you get fresh poly. If it sets for too long on a shelf, it won't cure or harden up.

Usually places that sell lots of the polyester resin give a max of 3 month guarantee with theirs to be good for that long. After that time, you are on your own. Just a thought.

 

[jbcurt00]

Ya need hairy PB mixed polyester resin. For a wake tower the mounts need to be extremely well anchored thru solid material.

Cabosil and milled fibers and if you happen to jave or buy some CSM/1708 roughly cut into loose pieces/strands of glass.

Bondo polyester resin, and its cat hair filler would suffice, but isnt ideal in a marine environment.

Bondo resin alone is of no value. Runny mess and as its brittle w out fillers or fiberglass mat/cloth, itd would not be a good choice to use alone. May be 2nd worst choice, right above anything flexible /compressable.

Make sure the square edges and esp corners of the backing plates arent creating a hard point against the inside of the curved hull.

 

[R055]

Ya need hairy PB mixed polyester resin. For a wake tower the mounts need to be extremely well anchored thru solid material.

Cabosil and milled fibers and if you happen to jave or buy some CSM/1708 roughly cut into loose pieces/strands of glass.

Bondo polyester resin, and its cat hair filler would suffice, but isnt ideal in a marine environment.

Bondo resin alone is of no value. Runny mess and as its brittle w out fillers or fiberglass mat/cloth, itd would not be a good choice to use alone. May be 2nd worst choice, right above anything flexible /compressable.

Make sure the square edges and esp corners of the backing plates arent creating a hard point against the inside of the curved hull.

Thanks, I'm going to use a piece of thick cardboard same size as backing plates or a little larger originally to put the resin/putty on and then once it's dry I'll bevel the edges on the aluminum and put the aluminum on top.

Going to go research the fibers or hairs I can mix with the resin to make it harder.

 

[gm280]

Thanks, I'm going to use a piece of thick cardboard same size as backing plates or a little larger originally to put the resin/putty on and then once it's dry I'll bevel the edges on the aluminum and put the aluminum on top.

Going to go research the fibers or hairs I can mix with the resin to make it harder.

They also sell 1/4" and 1/2" chopped fiberglass strands to mix into the poly. But you can get some fiberglass material and cut up some yourself for that effort if you like.

 

[R055]

Also anyone know any premixed things that would work? I'm scared to screw up mixing the polyester resin. Will epoxy work good for this purpose?

 

[JASinIL2006]

What about PC-11? It's a thick two-part epoxy similar to Marine-Tex, but way cheaper. Best of all, you can find it at Ace Hardware stores.

 

[R055]

What about PC-11? It's a thick two-part epoxy similar to Marine-Tex, but way cheaper. Best of all, you can find it at Ace Hardware stores.

Hmm took a look at it and it looks like it may be exacly what I'm looking for, anyone else suggest pc-11 or discourages using it for any reason?

Edit: turns out I auctally have some pc-11 i used for gel coat repair last year. Going to mix some and make a 1/4 layer to see how it is after it dries.

 

[Scott Danforth]

2 parts bondo fiberglass reinforced bondo, 1 part waxed resin, add bondo cream hardener. mix well.

cheap and fast hairy PB that most people cant get wrong.

 

[R055]

2 parts bondo fiberglass reinforced bondo, 1 part waxed resin, add bondo cream hardener. mix well.

cheap and fast hairy PB that most people cant get wrong.

Is the waxed resin required? Doesn't that just make it not tacky? Won't be visible so don't need it to look good.

 

[jbcurt00]

Wax allows it to cure hard, w out wax, it stays tacky

 

[Scott Danforth]

If you are going to lay glass and resin over it, then you dont use wax

 

[ondarvr]

Forget wax, it's of no value in anything you'll be doing.

 

[fhhuber]

The fill doesn't need to be 100% epoxy... Use microballoons or shredded fiberglass or even sawdust to add volume. You are essentially making a formed block to fill space between the plate and the fiberglass.

You could spend time and carve a wood block to fit then soak it in a mix of linseed oil, spar varnish and mineral spirits. Result is extremely resistant to rot and being where it will be, should survive just about the life of the boat.

If going to poly resin, anything that excludes air from the surface allows it to cure. Actually only a thin layer at the surface stays tacky when you don't exclude the air. The tacky layer excludes the air from the rest.

Probably the blue lightweight bondo would be fine. I have used that to cast engine mounts for RC models holding 2.5 hp engines in place. The compression load of your desired filling of space between fiberglass and backing plate shouldn't be a problem....

Or you could fill most of the space with wood and then the rest with the epoxy mix or bondo or whatever, encapsulating the wood in the filler.

Many ways to do it...

 

[R055]

Thanks for the suggestions guys, I decided to use pc-11 to flatten the areas where the mounts go. I spread a layer on a piece if paper and it's rock solid after 3 days. And has a tensile strength of 1710psi which seems like more than enough when the load is getting distributed on a 5"x10" area.

 

[ondarvr]

Should work fine.