epoxy shinking

[Daren]

I ended up using system three's general epoxy from my local woodcraft; 750ml when mixed A and B kit was 38$; mix is 2:1. (I did not feel comfortable with "EpoxAcast 650"'s 100:14 mix ratio, I don't have tools to be that accurate). To fill the coil I used 150m. #2 medium hardener was used that gave me plenty of time. Null of the coil readjusted after pour and when epoxy was in jelly consistency. Current null is 8mV, there is no detectable detection range loss from 2mV null. I did not detect a noticeable null change when epoxy cured (its aout 80% cured). The epoxy dries clear (you can get black pigment). This was my first IB DD coil, I did not appreciate how much work goes into making one, but the results are quiet satisfying. Quality ID DD coils can definitely be build at home.
BTW: I also looked at west system's 105 resin with medium hardener; It probably would work fine too; The price is ~75$ for a quart of resin + epoxy at your local west marine.

here is a free book about epoxy work:
http://www.systemthree.com/reslibrar...Epoxy_Book.pdf

[SVEN1]

System 3 is an excellent epoxy, one of my favorites for wooden boat restoration and kayak canoe boat building.
I would stay away from West System, I don't like it at all. Brittle when cured, does not take impacts very well, will craze and crack. besides the sun UV attacks it unless coated with UV resistant paint. It will turn a funky yellow.
Also an moisture in the air during curing will cause it to blush. After curing it does have an oily surface coating, its Amine blush. Can be washed off with soap and water. Must be washed off and sanded before applying a second coat
if allowed to cure. Folks who build boats with it swear by it, not me.

[Daren]

The coil I worked on works great. System 3's general epoxy with #2 hardener is a nice combination. Shrinking of the epoxy does not seem to be an issue. If needed coil can be renulled after epoxy dries with small ferrite (3x3x7mm is was sufficient to alter null very significantly). Just find the ferrite position on the top coil where it brings coil to null and glue it. I did not have to use ferrite.

[Gwil]

Hi Koala

Re post #11: The link you gave goes to a page showing a number of different products. Could you confirm which one you use? Thanks.

Gwil

[Koala]

Hi Koala

Re post #11: The link you gave goes to a page showing a number of different products. Could you confirm which one you use? Thanks.

Gwil

Sorry did not see your request

this is what I use

General purpose laminating epoxy resin Suitable for use with fibreglass, kevlar, carbon fibre etc, Also to produce lightweight fairing putties and mineral based gap filler & adhesives.
750g Resin/hardener kit @£15.34
1.5 kg Resin/hardener kit @£29.04
3 kg Resin/hardener kit @£42.08
7.5 kg Resin/hardener kit @£93.06
37.5 kg Resin/hardener kit @£350.96

Its a two to one mix. I use some some cheap eBay scales. Those silicon cake molds are perfect to mix in. After it hardens (i normally speed it up in the oven at 50C )you just peel it out and you are ready to mix some more.

Light will ruin the hardener over time and its in a clear bottle so I keep mine in the fridge. Makes it a bit thick to pour but no big deal.

[Koala]

Watching "how its made" last night and they were making surfboards.

They used fiberglass and resin over a foam former. The resin that they were using was set by ultraviolet light. Look interesting.

[Gwil]

Thanks Koala