Epoxy and fibreglass

[Simon]

Looking for epoxy here on France. There are a couple of suppliers near me (3hrs away). I need some epoxy now for the stems and intend to get the glass cloth at the same time. The book states that six ounce sheathing will be best. How does this translate into metric or is it sold here using imperial measures ?. Thanks in advance.

[Cruiser]

The equivalent metric cloth should be around 180 grams per square meter. What ever is close to that should work fine.


Brian

[Simon]

Thank you cruiser,most helpful. To tackle a similar issue the book suggest 2 to 2 and a half gallons per canoe. Problem is it is sold by weight and a U.S. Gallon is different to a U.K gallon. I am thinking that ten litres is sufficient and if so what does that weigh?.
Again thank you in advance.

[Cruiser]

I did a little digging, as my epoxy can doesn't list weights ... I think most resins will weight about the same, so this should give you an idea of quantity.

The recommended quantity for a canoe is 2 gallons (Canadian) which is 3.7 liters/gallon, so ~ 7-8 liters. Nominal weight of resin is 9.5 pounds per gallon (Canadian), which is 4.27 Kilograms, so 2 gallons is ~8.5 Kg ...so purchase whatever is close to that weight, with sufficient hardener (normally sold as a companion quantity).

Those weights are for West System epoxy specifically, but I believe all the resins are pretty similar in density, so it should put you pretty close to an answer you can work with.


Brian

[Simon]

Thanks for a very comprehensive response. Really helpful. I have found a supplier nearer to home too.
Has anyone had any issues with epoxy incompatabilty? To move things on I need to bond the stems with epoxy. I have epoxy in my workshop but it isn't wests. If I bond the stems with this will I create a problem when I come to epoxy over the stems with west systems epoxy?.
Once again thanks for any advice.

[Cruiser]

There is nothing magical about Wests, it is good, but most epoxies are going to work. as far as I know most epoxies are compatible.

You know to the routine to use epoxy in joints ... saturate surfaces with unthickened epoxy, then add thickened epoxy and clamp (no too tight)




Brian

[Simon]

Is this what I need,? wide enough at 1.3 metres. Thickness 0.15mm.

In the spec sheet it gives number of strands per cm on the warp 8.9 and the weft 6. Doesn't seem many? I can't get that page to open on this device.

If you could have a look please and let me know what you think. Thanks in advance.


https://www.boutique-resine-epoxy.fr/fr ... ge.amphtml

[Cruiser]

I haven't got time right now, but I will look up the conversions and comment in a few hours.

[Cruiser]

That certainly looks more coarse than I use, you can see that here : http://www.noahsmarine.com/fiberglass_f ... th_md.html

For width, that may be a bit narrow, I usually use 60", which is ~ 1.5 m

Brian

[sedges]

After a bit of conversion. The 202gm/m2 is 5.96 oz/yd2, so equivalent to 6 ounce cloth here in the US. The 8.9x6 threads per cm would be 22x15 threads per inch. The typical 6 ounce "boat cloth" here is 18x18 threads/ inch, so yours is pretty close. 1.3 M width would be like our 50 inch. Measure the hull at the widest and see if 1.3 M will cover. There might be wider cloth available in that same weight if you need it, or you will have to use two pieces to cover. You can over lap them at the keel. That is certainly an extra expense to buy twice the cloth.

you could also look for a lighter cloth. It would probably be around 135 gm/m2, equivalent to 4 oz cloth in the US. I use that on my canoes and overlap it over the whole area below the waterline.

[Phildub]

Not sure where you're up to with this, but thought I'd add by 2 cents worth. I'm in New Zealand so had similar problems converting to metric.
200g/m2 is the equivalent weight to 6oz. I couldn't find anyone in the country that could supply 60" (1500mm) wide cloth. So I had to go with 1000mm wide and have an overlapping join down the middle. It was looking possible to get 1300mm for a while, but my rough measurements suggested i needed 1400mm. I have met a guy who did his boat with 1300 wide cloth as he figured there will only be a small area at the middle uncovered and he made sure the gunwales hid it. I was too scared to try this!
In hindsight, if I'd had the time and money I would've tried to import some wider cloth. The 1m wide meant there was less difficulty with getting the cloth to sit right (especially on the inside), but it's really hard to make the join invisible (actually impossible). However, with a bit of care, it doesn't look terrible either. On the plus side, it's got a double thickness cloth down the middle of the boat for extra strength!
Regarding the resin - I've used about the recommended 2 gallons (~9 litres) of Wests epoxy. It's good stuff.

I didn't use epoxy on the stems because I didn't have it at the time. I used Gorrilla glue (http://www.holdfast.co.nz/pages/product ... psid=01494) , which is a solvent based waterproof glue that my cabinetmaker mate swears by. An advantage of this stuff is that it foams and expands a little, so it fills the gaps if your stem shaping isn't perfect like mine isn't!

Have fun!

[Cruiser]

Phildub, the gorilla does foam to fill gaps, but it is not gap filling. When it foams up, the foam has little to no strength, so any gap areas will be weak. Main reason I don't use it where gap filling may be an issue ...such as the stems. I just finished the stems for my current build and can't bring myself to use anything other than epoxy.

Having said this, in reality, most glues today will be strong enough for purpose, so we are really only discussing details ... just if you have a gap filling issue, don't depend on the foaming gorilla glue.

Brian

[Phildub]

Ahhh. Thanks for the heads up Brian. Hopefully I don't have to do a post someday on how to replace a stem where the glue has failed!!!