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davidpbo
25-07-12, 06:38
I am doing a repair (http://i1205.photobucket.com/albums/bb425/17234/Boat/Shroud%20Fixings/Overlap.jpg) and may want to make either a dam, mold or use a flat surface applied to the top to give as flat a surface as possible.

I don't have any releasing agent, is there anything else I can use that will not discolour the gel coat, assuming I use some rather than a paint applied afterwards.

bert49uk
25-07-12, 06:51
i always use this it gives a great shine as a bonus

http://www.ebay.co.uk/itm/Honey-Wax-Release-Agent-Mould-Release-Compound-/230797248415?pt=UK_CarsParts_Vehicles_BoatEquipmen t_Accessories_SM&hash=item35bc96879f

srp
25-07-12, 06:51
A wax such as beeswax or caunuba (sp?), as long as it doesn't contain silicone. You could also brush on a dilute pva solution as well. Cling film might work as long as you can stretch a wrinkle-free piece over the area.

macd
25-07-12, 07:38
A wax such as beeswax or caunuba (sp?), as long as it doesn't contain silicone. You could also brush on a dilute pva solution as well. Cling film might work as long as you can stretch a wrinkle-free piece over the area.

Cling film (and polythene) not a good idea: however tight it's stretched, styrene will expand it, causing wrinkles.

GrahamM376
25-07-12, 08:19
For smaller areas laid up on a flat surface such as glass or Contiboard, I use beeswax. For larger things like dinghy layup, dilute PVA which is water soluble.

bigwow
25-07-12, 08:44
I don't use anything on glass or formica covered chipboard, just laminate straight on to it.

davidpbo
25-07-12, 10:41
Does the wax have to free of colourants in rder not to stain any gel coat?

Can I use plain white wax from candles?

If I use PVA which I have, what ratio PVA to water. Again if I am not painting whil it colour top surface?

As an aside. Can I add gel coat as a finish to epoxy? Once it has cured?

oldsaltoz
25-07-12, 13:07
Does the wax have to free of colourants in rder not to stain any gel coat?

Can I use plain white wax from candles?
NO

If I use PVA which I have, what ratio PVA to water. Again if I am not painting whil it colour top surface?

As an aside. Can I add gel coat as a finish to epoxy? Once it has cured?



You can even use Mums hair spray on small jobs as a release agent.


Good luck and fair winds. :)

nigelmercier
25-07-12, 13:26
Dilute PVA 4:1

To finish a surface you need Topcoat, not Gelcoat. Sand epoxy first, then clean with Acetone.

davidpbo
25-07-12, 18:26
Dilute PVA 4:1

To finish a surface you need Topcoat, not Gelcoat. Sand epoxy first, then clean with Acetone.

Presumably painted on the inside of the mould as smoothly as possible?

Is Topcoat Gelcoat with wax to make it go off or a different product?

rakaaw
25-07-12, 18:34
In case we are not all aware PVA as a release agent is Polyvinyl alcohol not Polyvinyl acetate which is an adhesive.

srp
25-07-12, 19:04
http://www.ecfibreglasssupplies.co.uk/c-819-release-agents.aspx do a good mail order service and it's worth getting the right stuff before you start, rather than trying to make do with stuff in the shed that might or might not work. Their PVA release agent for example is very cheap for a small quantity.
There are also a few useful videos on the site.

Amulet
25-07-12, 20:58
http://www.ecfibreglasssupplies.co.uk/c-819-release-agents.aspx do a good mail order service and it's worth getting the right stuff before you start, rather than trying to make do with stuff in the shed that might or might not work. Their PVA release agent for example is very cheap for a small quantity.
There are also a few useful videos on the site.
Agreed - given that 2.45 will buy you 100 ml of release agent, it seems a bit daft to bodge.
(And I agree about the supplier - call them up and you'll get someone who can understand the job you are doing and tell you how to do it best.)

davidpbo
25-07-12, 23:53
In case we are not all aware PVA as a release agent is Polyvinyl alcohol not Polyvinyl acetate which is an adhesive.

Thank you for that. It is indeed PVA adhesive I have. I had assumed because it forms a "skin" that it could be used as release agent.

nigelmercier
26-07-12, 10:15
It is indeed PVA adhesive I have...

Ah, right. I was thinking of PVA solder mask, which is the same as PVA release agent.