Brushing epoxy

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Dominic
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Brushing epoxy

Post by Dominic » Sun Sep 23, 2012 1:15 pm

Hey, I have usually used a old credit card to spread epoxy and then sand it back to wood. But I end up with some sinking of the finish into grain lines after about 6 months. So reading the Gore/Gilet book Trevor suggests brushing the epoxy and leveling it so I thought I'd give this a try. My first observation on this is that the brush sucks up as much epoxy as ends up on the guitar. But I got a very flat finish. And then there is the issue of cleaning the brush.
Anyone else brush epoxy, what sort of brush and how should it be cleaned. Metho?
Cheers
Dom
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kiwigeo
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Re: Brushing epoxy

Post by kiwigeo » Sun Sep 23, 2012 1:23 pm

Dominic wrote:Hey, I have usually used a old credit card to spread epoxy and then sand it back to wood. But I end up with some sinking of the finish into grain lines after about 6 months. So reading the Gore/Gilet book Trevor suggests brushing the epoxy and leveling it so I thought I'd give this a try. My first observation on this is that the brush sucks up as much epoxy as ends up on the guitar. But I got a very flat finish. And then there is the issue of cleaning the brush.
Anyone else brush epoxy, what sort of brush and how should it be cleaned. Metho?
Cheers
Dom
I used acetone for cleaning brushes I used for laying CF Tow on falcate braces. In the end I gave up trying to rejuveate brushes after an epoxy session and I just chuck them away. Im about to do an epoxy pore fill on my current build and dont plan on re-using the brush
Martin

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Trevor Gore
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Re: Brushing epoxy

Post by Trevor Gore » Sun Sep 23, 2012 1:46 pm

Provided you don't leave it too long, squeeze out the excess between sheets of paper (newsprint, anything) a quick rinse in acetone, wash in bar soap and water. Takes me about 2 minutes. Current brush has probably been rinsed and re-used ~50 times. The longer you leave it, the exponentially more time consuming and solvent intensive the washing is.

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Trevor Gore
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Re: Brushing epoxy

Post by Trevor Gore » Sun Sep 23, 2012 1:49 pm

Another tip:

Leave the epoxy to harden at least 24 hours and preferably 48 before hitting it with nitro. Hit it too early and you seem to get more sink-back. After 48 hours, I get none.

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Allen
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Re: Brushing epoxy

Post by Allen » Sun Sep 23, 2012 5:10 pm

I don't use a brush, but I've seen Rick Turner comment that he uses disposable foam brushes. Especially on necks
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Re: Brushing epoxy

Post by jeffhigh » Sun Sep 23, 2012 6:29 pm

I used a rubber tile grouting squeegee on my last. seemed to work better than the credit card.

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Re: Brushing epoxy

Post by Paul B » Tue Sep 25, 2012 7:41 pm

During my kayak building days the word from the wise was to buy a bunch of cheap brushes and use them once. But cheap brushes shed bristles, mine did anyway. So foam was the go. But that was when we wanted to lay a fair bit of epoxy down to fill the weave of the fibre glass. Not sure I'd want to do that on a guitar where you're just going to sand most of it off again. The squeegee works better in as far as laying down just the right amount. At least for me. A few thin coats.

simso
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Re: Brushing epoxy

Post by simso » Tue Sep 25, 2012 10:13 pm

Dominic wrote:I end up with some sinking of the finish into grain lines after about 6 months. So reading the Gore/Gilet book Trevor suggests brushing the epoxy and leveling it so I thought I'd give this a try.

Dom, what type of epoxy are you using. And on what type of wood are you getting the sink back happening
Steve
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Do your own repairs - http://www.mirwa.com.au/How_to_Series.html

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Dominic
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Re: Brushing epoxy

Post by Dominic » Wed Sep 26, 2012 9:06 am

Hey, I've used mostly Zpoxy but have tried west systems. I prefer Zpoxy. Sands easier than WS. My problem was when sanding back to wood and opening up small pores. I notice it most on the headstock where lots of prep and pore filling I still get a bit of sink back it I sand back to wood.
I tried a brush but had better results using a soft rubber spreader/squeegy. A light hand can leave a nice flat finish with care. A bit more practice and I'll be able to get a good even coverage with 2 coats.
Cheers
Dom
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ernie
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Re: Brushing epoxy

Post by ernie » Sat Oct 06, 2012 5:05 am

I use acid swab brushes their cheap 25 cents a piece with metal handle , and thrown away after using epoxy.Costs more $ in acetone than its worth. Don/tknow if you can get them in OZ. woodworking suppliers here carry them .Think plumbers use them as well

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kiwigeo
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Re: Brushing epoxy

Post by kiwigeo » Sat Oct 06, 2012 9:01 am

A problem I find with alot of the cheaper brushes is the acetone actually melts the glue that holds the bristles in. I just use the brush once and then biff it...wasteful yes but acetone is cr*p stuff to deal with and after youve washed your brushes you've got a pot of acetone to get rid of.
Martin

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Dominic
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Re: Brushing epoxy

Post by Dominic » Sat Oct 06, 2012 2:40 pm

Keep the used actetone for the initial wash of the brush, then use a little bit of clean stuff to wash the brush. Keep a lip on the old stuff and I found the old glue or resin sinks. The clean acetone keeps your old stuff from getting too crappy.
I found a really nice squeegy that leaves a very flat finish so I won't use a brush, but I clean it as described above.
Dom
You can bomb the world to pieces,
but you can't bomb the world to peace!

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