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Author Topic: Epoxy for consolidating ballast shot query  (Read 464 times)

mrlownotes

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Epoxy for consolidating ballast shot query
« on: August 19, 2021, 09:40:17 pm »

I am about to ballast a deepish keel, in a fibreglass hull, with lead shot and am considering consolidating it with Z-Poxy 'Finishing Resin'.
I have plenty left over from a previous wooden model.
My reckoning is that it is quite 'runny' and quite likely to find all the nooks and crannies.
I'm no stranger to lead shot and epoxy ballasting.
However, I wondered if anyone can foresee any short-comings of using 'Finishing Resin' in this way ?





 
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Bintur Ellenbach

Taranis

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Re: Epoxy for consolidating ballast shot query
« Reply #1 on: August 19, 2021, 10:01:50 pm »

It is all I use






« Last Edit: August 19, 2021, 10:07:47 pm by Taranis »
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ANDY
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JimG

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Re: Epoxy for consolidating ballast shot query
« Reply #2 on: August 19, 2021, 10:07:19 pm »

Epoxy hardening is an exothermic reaction, it produces heat.Larger quantities in an enclosed space such as a keel can get very hot. It might help to sit the hull in water while the epoxy is setting to help keep the temperature down.
Jim
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Taranis

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Re: Epoxy for consolidating ballast shot query
« Reply #3 on: August 19, 2021, 10:28:12 pm »

I cannot say that I've experienced heat as a problem with Z poxy finishing resin in particular and my earlier builds were done out of the water.


However its a good idea to do it in the bath a little at a time and keep an even keel. Most important is to leave some spare displacement to make up with adjustable ballast .


My current build during the process.
https://www.modelboatmayhem.co.uk/forum/index.php/topic,66723.msg723430.html#msg723430
« Last Edit: August 19, 2021, 10:33:45 pm by Taranis »
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ANDY
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Klunk

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Re: Epoxy for consolidating ballast shot query
« Reply #4 on: August 20, 2021, 08:48:16 am »

Use pva 75/25 water. Any orobkems in the future and you can dig it out
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Re: Epoxy for consolidating ballast shot query
« Reply #5 on: August 20, 2021, 09:17:28 am »

I have used varnish. It takes time to dry out but the benefit is that you have time to realize that you got it wrong & still do something about it.
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tsenecal

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Re: Epoxy for consolidating ballast shot query
« Reply #6 on: August 20, 2021, 06:42:30 pm »

i have used lead shot and epoxy in zip lock sandwich bags.  the end result gives me a properly shaped heavy block that is still removable.
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Colin Bishop

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Re: Epoxy for consolidating ballast shot query
« Reply #7 on: August 20, 2021, 07:04:53 pm »

Good rule of thumb. Never put anything inside a hull that you cannot subsequently remove whether batteries, motors or ballast etc.

Colin
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Mark T

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Re: Epoxy for consolidating ballast shot query
« Reply #8 on: August 20, 2021, 07:37:57 pm »

I did exactly the same as Andy except I wrapped my shot in cling film first.  I then poured the epoxy into the cling film bag and let it set hard.


The upside is that I can now remove my shot when ever I want as it did not stick to the hull and set as a solid block.  However I only used enough epoxy to cover all the shot and a little more.  I have experienced the heat issue that Jim has explained and it actually boiled the varnish on the outside of the hull.  It took a lot of repairing to put right. 


So only use enough epoxy to set your shot into a solid lump.

andrewh

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Re: Epoxy for consolidating ballast shot query
« Reply #9 on: August 21, 2021, 07:31:16 am »

As people have said,  the setting of epoxy resin is very exothermic, and can get seriously hot   


The reason that this is not noticed when using it normally is that finishing resin is put on in relatively thin layers, and the heat produced is not very noticeable
If you mix it in a deep container and leave it there until it starts setting it can get very hot and may melt or split a plastic container


Me, I like the idea of a plastic bag and pva glue so that the bag can be removed (PVA glue is soluble (eventually) in Iso-propyl alcohol)
So if necessary the shot could be reclaimed and cleaned up


Having said all that I normally use strips of roofing lead and hold them in place with dabs of silicone glue (bathtub sealant)


andrew
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roycv

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Re: Epoxy for consolidating ballast shot query
« Reply #10 on: August 21, 2021, 09:48:03 am »

Hi all I agree with previous posts that putting the lead shot into plastic bags is a good method.  It all finds its own spaces to fill up and can be held in place with bathroom sealant which will unpeal if necessary.
I think some time ago on this forum there was a comment on using lead shot to the effect that with the airgaps the density of lead is reduced and the overall volume taken up by lead and air is the same as having iron or steel as a solid piece.  Lead is still dearer than steel or iron and if you mix the two you might save some money.

My choice is lead flashing and mine comes from the old lead replaced by new.  I clean it up and cut it with sturdy sissors to shape or outline making several, a few dabs of sealant will hold them together and then beat them into submission or shape and fit in place.
The lead is quite malleable and again I use bathroom sealant to seal the space.  One reason for this is to stop possible pond water getting into the space and maybe starting to smell.
The sealant is very strong when dry and anyway all my yachts (with the masts removed) have to pass the upside down test, when all the bits and pieces and battery inside have to remain securely in place.
Regards
Roy
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mrlownotes

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Re: Epoxy for consolidating ballast shot query
« Reply #11 on: August 23, 2021, 04:10:33 pm »

Many thanks to everyone for their suggestions and preferred methods for securing ballast. 
All options are meritable so it is decision time.
Thankyou all.
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Bintur Ellenbach
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