Epoxy Filler

[yachtorion]

I got sick of buying ludicrously expensive small pots of mixed filler for doing GRP work, so decided to try making my own.

I've got MAS non-blush epoxy resin with fast hardener, mixing pots, lollipop sticks, colloidial silica, microbeads (above W/L), glass bubbles (below) and epoxy pigment. The up-front cost is quite high, a few tubes of plastic padding, but what I've discovered is that a little of each goes a really long way - lots of tubes of plastic padding.

You get a lot of glass bubbles for not a lot of money, they are mostly air after all... and once you add them to a little bit of resin it seems to at least double the volume of the original resin (I mix the resin and hardener first as i've got a good pot life).

Resin, add beads.... Stir a lot... add silica... stir more.. add silica... until you get the consistency you want for the job at hand (do that with pre-mix filler)... then add some pigment and stir well again.

The resulting filler is just brilliant. Sands easily. Spreads easily. And you don't run out because there is a load of the raw material and you just mix some more.

The manufacturers give weights of how much of X to add too how much Y resin, but to be honest it's pretty easy to judge by hand.

For many on here I'm sure this is all really old news.... but if you are sick of little tubs of plastic padding etc hanging around and costing a fortune... it's really worth giving this a try! It's so easy and the results are actually better than the pre-mix fillers because you can vary the consistency.

Do wear a mask though. Until well mixed in those microbeads fly everywhere.

 

[MagicalArmchair]

I do the same, but I swear by the West System stuff (to be fair, its the only stuff I have experience with), again, high up front costs, but lasts forever. http://www.ecfibreglasssupplies.co.uk/ are very helpful, reasonably priced, and have answered all my daft GRP repair questions, fibreglass and epoxy questions in short order.

West System provide some great documents too.

• This one I used to patch a skin fitting up: http://www.westsystem.com/ss/assets/HowTo-Publications/Fiberglass-Boat-Repair-and-Maintenance.pdf
• Wooden boat repair: http://www.westsystem.com/ss/assets/howto-pub2/Wooden Boat Restoration and Repair.pdf
• Finishing and fairing: http://www.westsystem.com/ss/assets/HowTo-Publications/Final-Fairing-and-Finishing.pdf

Important to note, I have no affiliation to EC Fibreglass or West System, just love em both.

 

[yachtorion]

EC Fibreglass

West's a bit dear for me - though I do wonder if I might one day decide it's a false economy. I've also had great experiences of EC Fibreglass.

Are the West resins non blushing?

 

[MagicalArmchair]

They do produce amine blush, but its pretty simple to remove as its water soluble:

Amine blush may be formed when epoxy
cures. Amine blush is water soluble. Many organic
solvents are completely ineffective for
removing it. That is why we suggest washing
an epoxy surface with water (water clean
enough to drink) using a Scotch Brite™ pad
(or wet sanding with waterproof wet/dry
sandpaper) and drying it with paper towels
before continuing with another operation.
Soapy water, or water with ammonia or
bleach, is not necessary and may leave a residue—another
possible surface contamination

http://www.westsystem.com/ss/assets/Uploads/Ew20Contamination.pdf

 

[Tranona]

Amine blush is less of an issue when using the epoxy as a base for fillers. You might also look at Blue Gee epoxies which i find equally as useful as West, but cheaper.

 

[yachtorion]

Agreed blush isn't world ending but if I need to add another layer of filler on top of a set one it's nice not having to wait for it to dry after a wash

I've looked up the Blue Gee, West and MAS prices... they aren't as different as I thought really. The MAS and Blue Gee are a bit cheaper.

Does anyone know of any comparison tests that have been done on epoxies?

 

[MagicalArmchair]

West say: http://www.westsystem.com/ss/why-west-system-brand-epoxy/

There is an element of "Well they WOULD say that wouldn't they"...

 

[laika]

I suspect that people who buy the filler stuff are generally using it for small jobs and I'd argue that in those cases it makes sense. Yes microballoons, silica etc. go a long long way but epoxy and hardner is still expensive. I've tended to use Blue Gee simply because it's what's readily available in my local chandlers at the time and I splashed out on the pumps for them. The downside is that you've got to store all that kit (the right way up so you don't get a gunky epoxy mess in the locker: DAMHIKT). I've got half a good-sized locker of precious space taken up with epoxy, polyester and gelcoat stuff. Much simpler to buy a tube of gunk, use it for what you need it for then fill your lockers with something useful like gin. Also any process which encourages one to consume pot noodles and walls magnums has got to be questionable.

 

[actionoptics]

We had to renew the epoxy coating after grit blasting the hull and finding quite an irregular surface on our 31 ft twin keel boat during this last winter so we bought a "Field Kit" from Sicomin / MapYachting which could be applied as the name suggests in a field and down to temperatures of 8 to 10 degrees C. Two coats of undercoat EP215 and one coat SD5550 with enough colloidal balls to stop it slipping off, plus box of gloves, a box of mixing sticks, bottle of thinners ( not used except for cleaning spills), 20 measuring / mixing pots and half a dozen face masks all for just over £150. I was advised to wash down each coat with water even if a bloom could not be seen.
We applied the three layers of epoxy plus undercoat and anti fouling during early March but we did build a tent over the whole boat to stop ourselves getting too cold. The result was just great and took a lot less time and effort than we expected.