Rhylsailer99
Well-Known Member
I've been mixing the mixro fibres but the co mpound tends to run . Should I wait a bit before I use it so it thickens or do I need to add more mixro fibres.
West epoxy mixro fibres
- Thread starter Rhylsailer99
- Start date
De.windhoos
Well-Known Member
add more fibres. Stir really well.
sarabande
Well-Known Member
What sort pf temperatures are you mixing in ? You need to get the ratio and temp right, otherwise when the mix starts to thicken it will harden quite quickly (see 'endothermic reaction').
Rappey
Well-Known Member
Chuck some cement powder in it. That will thicken it up 
Dont wait for it to thicken as it will be hardening/setting..
you do have to put quite a lot of additives in epoxy to stop it slumping.
Dont wait for it to thicken as it will be hardening/setting..
you do have to put quite a lot of additives in epoxy to stop it slumping.
VicS
Well-Known Member
Mix 4 to 6 % by weight depending on the consistency you require Syrup, ketchup, mayonnaise or peanut butter like
West System website WEST SYSTEM Epoxy - Marine Grade Resins & Hardeners
User manual and product guide at https://www.westsystem.com/wp-content/uploads/British.pdf
Basics : Epoxy Basics: Bonding, coating & applying fiberglass with WEST SYSTEM
Fillers and additives: Modifying with fillers makes WEST SYSTEM Epoxy extremly versatile
Videos: https://www.youtube.com/playlist?list=PLKrXmm9fNk0b_btfL4THlghAT6ciaY3hB
PlankWalker
Well-Known Member
Colloidal silica is best for thickening, microfibers give strength , I add a little of both.
You don't need to wait for it to thicken.
You don't need to wait for it to thicken.
VicS
Well-Known Member
Depends on the intended use
Selection guide: Epoxy Selection Guide - WEST SYSTEM marine grade epoxies
Rhylsailer99
Well-Known Member
I been fixing up a rudder but I hope to.smooth some into gouges in my bilge keels and worried it might run out . I think I will try the colloidal silica and fibres mixes.as I bought both thickness.
Rhylsailer99
Well-Known Member
But will wait till it warms up a bit as I think its too cold now
VicS
Well-Known Member
205 Fast hardener can be used down to 4C otherwise 16C is the minimum for 206 hardener
Use a low density filler, which is easily sanded, for surface fairing
Caraway
Well-Known Member
Wood flour thickens epoxy nicely. You can buy it or make your own with a power sander.
Lucy52
Well-Known Member
Pedant mode. It is exothermic not endothermic. Exothermic reactions get hotter, they give out heat, and the epoxy will set more quickly, endothermic ones get colder and take in heat from the surroundings, not so epoxy.
Epoxy mixed n a deep pot will have a shorter pot life than if it were spread out in a shallow tray as the heat will build up more slowly in the tray. Spread out on the work piece it will stay workable after the pot has gone off as it will be cooler.
Epoxy mixed n a deep pot will have a shorter pot life than if it were spread out in a shallow tray as the heat will build up more slowly in the tray. Spread out on the work piece it will stay workable after the pot has gone off as it will be cooler.
PCUK
Well-Known Member
I use chopped strands and thicken with filler powder to a putty consistency. Easy to apple, stays in place and is massively hard and strong.
dankilb
Well-Known Member
As above - milled/micro fibres not the right thing to ‘thicken’ (so it doesn’t sag).
As for chucking wood/cement powder in there, seeing as even ‘cheap’ epoxy isn’t cheap, I wouldn’t bother. Especially as colloidal silica is cheap! (And the right thing to use - unless you want low density, in which case microbaloons or similar).
As for chucking wood/cement powder in there, seeing as even ‘cheap’ epoxy isn’t cheap, I wouldn’t bother. Especially as colloidal silica is cheap! (And the right thing to use - unless you want low density, in which case microbaloons or similar).
Jim@sea
Well-Known Member
When fibreglass filler paste first came out for body shops it was Talcum Powder mixed with Resin. In those days Talcum Powder contained a lot of lead (Siberian Lead Mines) and there was no warning on the tin to wear masks. Since then they dont allow Lead in Talcum Powder. Silica Sand would be good (or is that what Colloidal Silica is ?)
PlankWalker
Well-Known Member
Don't know what colloidal silica is ,
but it's very light, and nothing like silica sand.
but it's very light, and nothing like silica sand.
Caraway
Well-Known Member
Using wood powder you can pre-colour your epoxy to match wood, if that is what you are repairing. It can be mixed as stiff or loose as you need and makes a bloody good repair. Stronger than the wood you are using it on.
The OP seems to be using it for fairing repairs to rudder and bilge keels. I'd go for better consistency and consequentially less rubbing down. (edited)
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dankilb
Well-Known Member
Yeah fair point about the colour - although given the UV instability of most epoxy, I might go for ‘regular’ thickened epoxy for the repair and then a matched wood filler to fair it off anyway. You could get a great initial match otherwise, but the epoxy will be determined to turn yellow (and brittle) over time.
I think the OP is indeed repairing a rudder and other (semi)-structural GRP, based on previous threads.
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Rhylsailer99
Well-Known Member
Did that today I was surprised how much more I can put in and it stayed in its shape and never ran.
Boathook
Well-Known Member
Depending on what I'm repairing I mix a variety of fillers into the expoxy. It does take a lot of fillers to thicken the epoxy, so best of mixing only smalls amounts of epoxy to start with until you get used to it.
