glues for cold moulding

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JimC
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glues for cold moulding

Post by JimC » Fri Aug 01, 2014 2:50 pm

Going to have to do the bottom of the moth cold moulded in strips - at least forward of the daggerboard. Making up about 30 separate separate batches of epoxy doesn't appeal. Would something like the foaming urethanes be suitable? Trouble is I can't vac bag, it will be staples to hold the bits down. Other ideas?
Ta jimc

Obscured by clouds
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Re: glues for cold moulding

Post by Obscured by clouds » Fri Aug 01, 2014 8:21 pm

I used the foamy stuff to glue down the decks on Sibrwd and wished i had'nt. no matter how well I stapled, clamped and weighed down the panels the foaming action pushed them up. I would'nt have that stuff anywhere near my workshop now. Bite the bullet and get mixing
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JimC
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Re: glues for cold moulding

Post by JimC » Fri Aug 01, 2014 9:03 pm

Andy (Bloodaxe) Paterson gave me a great tip. first put down every other strip in parallel sided strips, which is one batch of glue. Then make all the trimmed strips to fill in the gaps, and glue all them down in a second batch.

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Ed
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Re: glues for cold moulding

Post by Ed » Sun Aug 03, 2014 9:56 am

I can echo Tony's experience with the foaming glues for moulding....although it is much better if you get the slow-setting version rather than the fast, at least this was the case with Balcotan (Can you still get it).

You could try one of the PVA waterproof wood glues, like Titebond http://www.titebond.com/product.aspx?id ... 3970f736af I know some have tried it and found it easy to use.

Personally, I like epoxy, know how it works and feel happy with it....so would just think of ways of making the measuring and mixing easier.

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Re: glues for cold moulding

Post by phil58490 » Sun Aug 03, 2014 4:46 pm

I use the west system plunger measurers, and being a slow worker use the slow formula which I find gives plenty of time to make numerous joints and set them up before the epoxy has started to set. That way I find I have very little waste, can easily mix the correct ratios but it does add to the initial expense of the epoxy.
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Stephen Hawkins
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Re: glues for cold moulding

Post by Stephen Hawkins » Sun Aug 03, 2014 8:39 pm

I like the foamy stuff.but I understand that you have to be careful where and how you use it. I am about to embark on a redeck of my favourite National 12 and I will be using the balcotan equiv and g4 as the basis of the repair. However I will be using a nailed redeck method as a nod to the way it was done in the first place.
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roger
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Re: glues for cold moulding

Post by roger » Mon Aug 04, 2014 3:21 pm

A cheaper way to the west plunger system is veterinary syringes. You can get them in farm suppliers. I use out of date ones from our stores at work. They only get chucked away.
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Rupert
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Re: glues for cold moulding

Post by Rupert » Mon Aug 04, 2014 6:42 pm

I've used Cascophen for cold moulding a couple of times. It is a Resorcinol Formaldihyde (however you spell it) glue, I think, and is the most similar to the hot glues used by Fairey's.
Rupert

Ian Malcolm
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Re: glues for cold moulding

Post by Ian Malcolm » Tue Aug 05, 2014 10:53 am

If you are using Epoxy, it is simple enough to mix by weight. Get the resin and hardener densities from your epoxy suppliers and make a spreadsheet that tabulates the component weights and total weight for 5ml increments of total volume. Print it and laminate it! Put a digital scale that can read to 0.1g and has a tare function into a pop-seal plastic bag to protect it and you can now measure and mix small volumes direct in your mixing pot. Simply use the tare button to zero out the pot weight, and weigh out the resin and hardener.

Also, some brands (e.g BlueGee) have friendlier mix ratios for small volumes - if you can measure 5ml accurately, a 2:1mix ratio epoxy lets you do a 15ml
batch, but a 5:1 system like most WEST products means you cant mix less than 30ml.

If you aren't in an air conditioned workspace, and the weather is hot, keep your resin and hardener in a coolbag with an icepack at the bottom under a cloth or newspaper so that its cool but not cold. (its critically important that nothing is cooler than the dew point to avoid condensation) If your resin is hot to start with pot life is vastly reduced and it may even exotherm if you mix larger amounts. Try and keep your pot in the shade and note the time you started each mix. A helper to mix fresh epoxy and clean up the previous batch makes a massive difference if you are doing large or fiddly work in hot weather and can triple your productivity.
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