How to thicken epoxy

[qwertyu]

Thicken as in turn it into a really thick paste - so it can be applied with a spatula

I bought some 'aerosil' which can thicken it but its very difficult to mix in theres always clumps. Any other options?

Anyone tried using timbermate wood filler to thicken it? Doesnt need to be structural just want to fill some checks/gum veins

[dusteater]

Sawdust?

[qwertyu]

I tried sawdust, the sawdust stays in place and the epoxy flows down

[havabeer69]

Wait till it cures a bit then apply it?

Or mix some of the dye etc into builders bog and use that instead?

[riverbuilder]

Keep mixing the aerosil, all of a sudden it will merge with the resin, and then you can add more if desired. Just use a flat stick, an offcut of 3 mm ply is what we use, but it does take time, longer than you expect.

[AndrewPatrol]

I wouldn’t use Timbermate it’s a water based filler. Maybe try feeding in your filler more gradually rather than all at once. It’s one of the tedious things about epoxy , mixing in the fillers unfortunately. Sometimes while mixing if I think I’ve added to much I’ll blow off the excess before it becomes too stiff. Dont tell te OHAS rep I said that!

[NewLou]

Get some west system 413 microfibres that always works for me

Regards Lou

[woodPixel]

Fistfuls of clear fibreglass hairs?

[KeithP]

I understand that adding talc to epoxy will achieve what you are looking for. (preferably non scented talc). Mix to a paste.

Regards
Keith

[derekcohen]

Epoxy is thickened with micro balloons. You can purchase it at Bunnings. An alternative is bicarb (but this makes for a heavy solution). Flour is another alternative.

Regards from Perth

Derek

[qwertyu]

I read talc does it - Im a bit worried about baby powder as it has other stuff in it not sure if it will be bad for the epoxy?

Is there another name for micro balloons? I searched bunnings and nothing came up

[riverbuilder]

Don’t use anything but the correct micro hemispheres, they cost very little and are engineered to blend with the epoxy resin correctly.
Fillers | West System | Leaders in Marine Epoxy (https://www.westsystem.com.au/product-category/fillers/)

just keep mixing it, all of a sudden, it will just blend and merge and you’re away.

[derekcohen]

I cannot find the link to Bunnings. Probably old now. You can order these on line: SIG Micro-Balloons - Filler Material - HTA (https://www.hobbytools.com.au/sig-micro-balloons-filler-material/)

I used micro balloons thickening epoxy when repairing surfboards and windsurfers.

Regards from Perth

Derek

[Mr Brush]

West System needs fillers to thicken it up, but Techniglue is a lot more "gluggy"* in standard form.

*adhesive technical term

[riverbuilder]

West System needs fillers to thicken it up, but Techniglue is a lot more "gluggy"* in standard form.

*adhesive technical term

Techniglue already has fume silica thickening hemispheres in it, same as araldite and other epoxy glues.

[clear out]

Reading what you want use it for ie gum veins etc, l use Ebony dust I’ve collected plus some black pigment mixed in with the epoxy. Using this sort of filler you can just use cheap common two tube Araldite stuff not bother measuring and mixing West or Epidure.
The Ebony dust takes the shine off it so it looks more natural than just pigment.
Micro spheres would ok but to disguise or blend it add some appropriate coloured pigment.
Carbon black is another, also good for adding to shellac for a lacquer effect.
H.

[GraemeCook]

Having tried them all, I now use just two thickenners in epoxy:

Saw dust. Actually sander dust - I have jars of different types of wood dust - gives a good finish and matches best with the wood colour, but certainly not invisible.

Colloidal silica. Cheap, readily available, mixes easily and has the best anti-slump properties if using on a vertical surface. WEST product #406.
Additive of the month - Epoxycraft (https://epoxycraft.com/news/additive-of-the-month/)


The thickenners that I have used in the past include include:

Talc. You buy it in "cement bags" from plaster suppliers rather than in Johnsons tins. It no longer includes the free ashbestos, but there may be some suspicions with talc, itself. Works well, but only cheap if you buy 25 kg bags - #406 is better and more convenient.

Micro fibres. Works fine, but marginally rougher finish than #406. I only need 1 or 2 thickenners and #406 is anti-slump.

Micro balloons. I hate this product! It is like ultra light microscopic hollow ball bearings looking for an excuse to run everywhere. A hand tremour when spooning and they go everywhere, breathe on it and it runs everywhere. A little wind and ... When mixing it requires more stirring as it tends to float on the resin mixture. After that, it is easy to use and hardens a little lighter and a little softer than micro fibres, according to WEST brochures.

Saw dust - course. (from saw bench) Doesn't bond well to surfaces unless mixed fairly runny, and dried stuff looks like bakelite plastic, in my opinion.

Shavings. Most uncompliant, a disaster. Like chipboard gone wrong.

Metal dust/powder. Excellent in the right situations. But remember dried epoxy will melt with heat.

Sand. Hopeless. Initially looked good, but how do you sand sand?

Paper. Actually just A4 put through an office shredder twice to create 2 mm squares. Almost as hard to mix as micro spheres, and I just did not trust the outcome.

Others. Either forgotten or I am too embarassed to mention. Some crazy experiments or improvisations.