Baffled by Epifanes

[richardabeattie]

I am about to paint my tiller with Epifanes two part poly-urethane. The instructions say the mix is two parts of big tin A to one part of little tin B - by weight. But tin A is 750gr and therefore three times heavier than the 250gr tin B. Why is this thus? Am I just supposed to throw away the extra 250gr that will be left in Tin A?

Grateful as ever for advice and yes I do want a shiny tiller and yes I will put the cover on it when not in use.

 

[Talulah]

Are you sure the 750g doesn't refer to the pack size?

 

[richardabeattie]

Yes you are quite right - how dumb of me not to have noticed the A + B = 750gr formula on the tin. But Tin A is the same diameter and much more than twice as tall as tin B. However upon opening it all is revealed - it is only two thirds full! A marketing ploy to make it stand out on the shelf? I will now make the heroic assumption that the 2:1 by weight instruction can be treated as 2:1 by volume which is a lot easier to work out. Or am I wrong again?

 

[Evadne]

I think you've got it. Pour the contents of tin B into tin A and it will fill up in the correct ratio; stir, and apply to the wood. Then go and buy another tin for the second coat. Or buy a graduated jug from a cheapie shop and mix as much as you need at a time by volume. Do NOT use the one from the kitchen, it will result iin a severe loss of Brownie points.

 

[Talulah]

Do NOT use the one from the kitchen, it will result iin a severe loss of Brownie points.

+1
(Kitchen electronic scales. )

 

[prv]

Tin A is the same diameter and much more than twice as tall as tin B. However upon opening it all is revealed - it is only two thirds full! A marketing ploy to make it stand out on the shelf?

No - it's so that if you're using whole-tin quantities you can simply tip the Comp B into the Comp A tin and stir, no messing about with other containers. Perfectly standard with two-part products.

Pete

 

[parbuckle]

To save using a graduated jug use a thin batten marked with a 2 : 1 ratio and stand it in whatever straight sided receptacle you have. Use the batten to stir with.

 

[richardabeattie]

Thanks everybody - even stupid questions get good answers here!

 

[Lakesailor]

use a thin batten marked with a 2 : 1 ratio and stand it in whatever straight sided receptacle you have. Use the batten to stir with.

I do that with epoxy resin. It works well, even for very small amounts.

 

[Amulet]

Syringes are dirt cheap and can be reused a few times for measuring small quantities. NB don't buy from chandlers or epoxy suppliers - pretend to be a doctor and buy a hundred. The sterile medical ones are much cheaper than the boaty ones.

 

[alahol2]

I've found digital scales are the simplest way of measuring, even for quite small quantities.

 

[PabloPicasso]

Syringes are dirt cheap and can be reused a few times for measuring small quantities. NB don't buy from chandlers or epoxy suppliers - pretend to be a doctor and buy a hundred. The sterile medical ones are much cheaper than the boaty ones.

+1. Why I don't know

 

[prv]

For small quantities (6ml of polyester catalyst / 3ml of wax in styrene / 12ml of... etc) I use disposable plastic pipettes. Even cheaper than syringes, and also great for filling holes because the nozzle gets right down inside them and you can withdraw it while squeezing to fully fill the hole without an air pocket.

I will reuse a catalyst pipette several times in one fibreglassing session, but start the next with a fresh one.

Pete

 

[cliff]

also great for filling holes because the nozzle gets right down inside them and you can withdraw it while squeezing to fully fill the hole without an air pocket.

Oh, er, easy there - might get the mods worked up.