DIY thickened epoxy recipe

[GHA]

This pops up now and and again but nothing much from the search so once more - rather than first find some micro balloons then pay for too much - what from a B&Q type place could be used to thicken up some 2 part epoxy to fair a bit painting on a bit of steel deck? Any recipes?
Talc powder maybe?
TIA

 

[fredrussell]

Sawdust (finer the better), flour, cocaine. Pretty much any fine powder. If you have an orbital sander the dust from the collector bag is very good.

Edit: see no reason why talc wouldn’t work. It’s a very similar consistency to flour which I’ve used plenty of times to thicken epoxy.

 

[vyv_cox]

I suspect you could use almost any powder but the resulting solid might be very tough and hard. The beauty of micro-balloons is that the solid product is quite easy to sand if fairing is required.

 

[GHA]

Ta, might give talc a go then.

 

[AngusMcDoon]

Ta, might give talc a go then.

I use Microdol which is ground up dolomite. When cured it's beeping hard, and consequently very difficult to sand. Has to be ground with a Dremel to remove any thickness. I expect talc will be similar.

There are some reports that talc should not be used externally as it is slightly water soluble and will lead to an increased risk of osmosis. That's with polyester. Might not be a problem with epoxy.

 

[Javelin]

West Systems 406 Colloidal Silica is less than a tenner, hardly a bank breaker.
If anything else was any good we'd be using it.

 

[Deleted member 36384]

Dry tree bark blended in a food processor turns into a fine flour. My daughter makes a biscuit out of the bark. Google Pine Bark Bread and Birch Bark Shortbread. When she started I thought she was mad. A cautionary note, the blender now has a smear of bark stain around the base.

Can't get any lower cost than some Mediterranean (I assume that is where you are, somewhere sunny) pine tree bark, nice and dry, ground to a flour in a food processor.

 

[Hacker]

A very good fibreglass technician told me that mixing talc into Araldite gave a good thickened mix. I was using it to repair the base of a hockey stick and it worked well and was being used on a water based hockey pitch.

 

[[159032]]

The problem with micro balloons (if you are forming the paste into a joint or vertically is that it goes really slimy. If you are repairing something like frame joints in a wooden dinghy using wood flour (very fine wood dust, as already suggested) allows you to make it as thick as you like.
If you use the right coloured wood to produce the dust you can get a pretty good match as well.

If you don't have any wood dust it is cheap enough to buy Epoxy Fillers - Fyne Boat Kits

 

[pyrojames]

Another vote for wood dust. I use pine and find the hardened version sands well.