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Gelcoat repair
Posted: Mon Jan 04, 2016 3:34 pm
by Eliot
With a big thanks to Gelmonkey who very kindly provided me with some yellow gelcoat and fixer - I had a go over Christmas fixing the void in the side and the damaged lip near the windscreen.
I'm sure Paul is probably rolling his eyes at my poor workmanship - but i'm over the moon compared to what it was like before!
Few questions:
How long will the gelcoat stay workable in the tub, as I've got tons of it and only used a tiny amount so far.
And I totally guessed the amount of fixer which I randomly seemed to get right, I could do with a more scientific way to make up small batches like this so I can fix the rear arch next.
Paul - hopefully I'll see you this year at the pod with a drink for you!
Posted: Tue Jan 05, 2016 4:59 am
by unstable load
Thorough mixing of catalyst into resins and gelcoat is very important. Also the correct additions should be observed to maintain good results. Dispensers are advised for accuracy. The table below gives the correct ratios of catalyst to resin and gelcoat by weight. 1% is considered a slow mix, 2% is ideal, 3% is a fast mix. Additions outside these bands in not advisable for proper curing, in fact adding more than 4% may result in a failure to cure. The pot life of these mixes is also determined by temperature. The higher the temperature the faster the cure. As a general guide 2% addition at 20ºC gives 15-20 minutes pot life. The resin will always cure quicker if left in a mass such as the mixing bucket or in castings.
For measuring we supply a 10 ml syringe or 15ml & 80ml dispenser bottles.
For measuring tiny amounts, a medical eye-dropper may be used. A plastic teaspoon, not metal, can also be used. 1 tsp. = 5ml
http://www.cfsnet.co.uk/acatalog/method ... alyst.html
Posted: Tue Jan 05, 2016 9:40 am
by Darkspeed
I am assuming that Eliot was referring to un-catalysed shelf life rather than its catalysed pot life which I would imagine he would have already discovered if he catalised the whole pot
I have had resin on the shelf for a couple of years that I have used for non critical applications and its was still good but it really depends on temperature and exposure. A lot like paint in fact - some you can leave on the shelf for a decade and find its still good and others 2 months later and its solid.
Andrew
Posted: Tue Jan 05, 2016 9:55 am
by Eliot
Darkspeed wrote:I am assuming that Eliot was referring to un-catalysed shelf life rather than its catalysed pot life which I would imagine he would have already discovered if he catalised the whole pot
Andrew
Indeed - although the notes above are useful too.
It's in about a 1L pot, but about 1/2 empty - I wonder if I should decant it into something smaller with less air space?
Posted: Tue Jan 05, 2016 3:43 pm
by gelmonkey
Wanna job?
will phone you tonight mate
P