COIL RESIN PROBLEM

[daverave]

im about to make a coil for the surf pi and i want to use resin as filler...will the resin as it cures warp the coil housing plastic and also how do i mix the resin with hardner...whats the amount of hardner to resin..pls can anyone advise as i dont want to ruin my coil.

[WM6]

Not all resin are the same. For resin/hardener mixture you need to follow producer instructions.

[SVEN1]

All depends upon the hardrner you use, slow, medium, fast cure. Fast cure creates too much heat, could melt the coil shell, depending what its made of.
I use a slow cure, very little heat build up as it cures. You need to check manufacturers specs.

[Dixix]

Epoxy resin is more expensive, but it does not smell as unpleasant as polyester resin. I use polyester resin (inexpensive), however, I use it outdoors (but it may not be cold outside). I mix it with "micro-balloons". This makes the coil lighter.

But epoxy should be better, as some write here in the forum. (But is also more expensive).

It is really important to follow the manufacturer's instructions!

Mix ratio/ processing temperature, etc.
Dirk

[WM6]

It is really important to follow the manufacturer's instructions!

Dirk

You can experimet with mixture by yourself too.

Par example: if you wish more flexible (less crude) final epoxy mass, you need to add less hardener as per specifications - this will prolonge epoxy hardening time and produce less temperature.

[daverave]

the resin that ive ordered is a slow type and the mixture is supposed to be 5:1...is that 5 parts resin to 1 part hardner ??? im really not looking forward to doing this job as i live in a flat and i will have to do the coil in a friend's garden out building cause of the heavy smell of the resin

[Ferric Toes]

the resin that ive ordered is a slow type and the mixture is supposed to be 5:1...is that 5 parts resin to 1 part hardner ??? im really not looking forward to doing this job as i live in a flat and i will have to do the coil in a friend's garden out building cause of the heavy smell of the resin

The resin I use is a two part pack, mix in the bag type. No mess, no smell, and hardener in the exact quantity you need. It is jet black and hard wearing - just the job for a surf PI coil. The coil will end up a bit heavier than you would use for just land searching, but a bit of extra weight is useful in the water. I buy 500gm bags but you can also get 250gm. RS Components part number is 199-1430 for the 500gm bag. Go online to RS Components to find alternative quantities. Best cure is 20deg C and 24 hours. For light coils I use a microsphere filled resin for 2/3 of the pot and then finish with the RS resin. I have the lightweight resin specially made so can't give a RS part no. Thorough mixing is the secret for getting a good finish, and to pop any bubbles with a bit of thin wire. Alternatively use anti-bubble spray.

Send me a PM if you want to know more.

Eric.

[daverave]

i really need to know what it means when it says 5:1...is that like saying for example 500ml resin to 100ml hardner ???? pls advise

[WM6]

Yes, or per weight (par example) 500g resin and 100g hardner. For practical needs it is the same. Or in Jamie Oliver style: 5 spoons resin to 1 spoon hardner.

[daverave]

im thinking of adding the bubbles to the resin to make the coil extra light...ive already glued some balsa wood pieces in the coil to take up the volume...just hope i make a good job of it.

[WM6]

Buy vermiculite in your gardening or buildig store and mix it with your epoxy to get lightweight coil.

http://www.aliexpress.com/wholesale/...rmiculite.html

Once hardened ground epoxy surface using sand paper and then varnish once again with (pure) epoxy.

[Dixix]

Vermiculite is a great idea! Therefore less resin. Save money.
But the pieces of Vermiculite are not too big? How to connect the "garden stuff" with the resin?
However, a good tip - I'll try it.

One more question: Is better epoxy resin than polyester resin? keyword: Permeability?
Dirk

[WM6]

Vermiculite is available in different granulation. It is made out of mica stone (mica is widely used in electronic as an insulator) and is not used in gardening only.

Generally epoxy sticks better to plastic coil housing than polyester (if epoxy is not too crudely made, which depend on your mixture - less hardner is better).

[daverave]

i appreciate all your help guys....many thanks....david

[WM6]

If you do not use epoxy in form of so called "liquid metal" (epoxy filled with different metallc powder) there is no problem with its permeability.