Epoxy fillers for cheapskates

[thinwater]

West Marine sells Cabosil for $118/pound ($37 container). 10 pounds on Amazon is $14/pound.

I never weighed it carefully, but I think the most you typically use is about $0.05-0.10 per pound of epoxy. You really don't use much because the density is very low. Closer to $1-3 if you buy small amounts at the chandlery. Don't buy there.

 

[Ceirwan]

Well I guess most of us won't be buying our filler from the USA!

East Coat fibreglass does it for pretty cheap, I did manage to finish off a large tub of silica of theirs off once, but that took me 5 years and several kg of epoxy to get through. The good thing with the fillers is that you can use them with Poly or Vinyl resins as well, so lets say you're filling screw holes in the cockpit (pretty common on older boats that have had stuff added and then removed) then you can use gelcoat without worrying about bonding issues.
That Silica can be used to thicken gelcoat as well, useful stuff.

 

[ducked]

You would be surprised as to how often Isopon Filler was used in times gone by ...

I wouldnt be, since I used it quite often in times gone by.
Worked fine.
That was on a Mirror dinghy which wasnt continuously immersed, though

 

[Stemar]

I wouldnt be, since I used it quite often in times gone by.

Same. I wouldn't use it below the waterline, but no problem above, unless ultimate strength is needed

 

[thinwater]

Well I guess most of us won't be buying our filler from the USA!

East Coat fibreglass does it for pretty cheap, I did manage to finish off a large tub of silica of theirs off once, but that took me 5 years and several kg of epoxy to get through. The good thing with the fillers is that you can use them with Poly or Vinyl resins as well, so lets say you're filling screw holes in the cockpit (pretty common on older boats that have had stuff added and then removed) then you can use gelcoat without worrying about bonding issues.
That Silica can be used to thicken gelcoat as well, useful stuff.

No much different.

ECF sells 22 pounds of fumed silica for about $11/pound delivered and 3.3 pounds for $21/pound delivered. Basically the same as $14/pound delivered from Amazon.

It's the package size that is the big driver. And chandlery pricing.

--

And yes, fillers can be used with many resins. I'll use it with polyester, 5-minute epoxy, and Plexus if needed to get the characteristics I want.

 

[Refueler]

Same. I wouldn't use it below the waterline, but no problem above, unless ultimate strength is needed

Years ago - I bought a Snapdragon 23 that had been treated for osmosis by a well known south coast yard ....

When I bought it ... the coating looked like the dry flaky outside of an onion...... what was also noted - the coating used was Polyester based .. and I'm fairly sure the same manufacturer as Isopon.

We ground it all back - gave her a decent coat of Interguard and she was fine ...

 

[lustyd]

I have tried polystyrene/petrol without the cement but the resulting snot wont stick to anything

I thought the whole point was that that mixture does stick to things. Our American friends certainly seemed keen for a good few years in the ‘60’s

 

[ducked]

I thought the whole point was that that mixture does stick to things. Our American friends certainly seemed keen for a good few years in the ‘60’s

I think the stuff involved in a "nape scrape" probably had a higher ratio of petrol to polystyrene, whereas I was trying for a
ｔｈｉｃｋｅｒ　semi-solid　ｆｉｌｌｅｒ. Ｔｈｅｎ　ａｇａｉｎ　Ｉ　ｎｅｖｅｒ　ｔｒｉｅｄ　ａｐｐｌｙｉｎｇ　ｉｔ　
ｗｉｔｈ　ａ　Ｐｈａｎｔｏｍ　ｊｅｔ，ｎｏｔ　ｈａｖｉｎｇ　ｏｎｅ　ｈａｎｄｙ．

 

[The Q]

Iirc it was plastic padding that couldn't work out why boat users wouldn't use their product..
So they brought out a new version called plastic padding marine..

The difference?
The label...

 

[Ardenfour]

As the main rainbelt of Storm Goretti sweeps in off the Atlantic, and further north 'Jack Frost nipping at your nose', I hope no-one nearby is seriously girding-up for an epoxy mixing session. While 'doom-scrolling' to see what others are up to in other dark corners of the earth, I turned up this argument learned discussion on Sailing Anarchy and thought it worthy of sharing on here...



I'm not quite ready for another year of anchor arguments.so howzabout some outlandish suggestions for 'cheap' epoxy fillers that might just work..?

custard powder

 

[VicS]

If I ever needed a decent filler .... I used to revert to DEVCON.

Its not epoxy - its Polyester with chopped strand filler .... giving a) excellent filling .... b) strength.

But like Epoxy - a PITA to sand ..... so the best way to use - fill the area and then clear plastic sheet laid on and a smooth plate pressed onto the plastic .... let set and remove plastic with plate and you should have a reasonable surface finish to get you halfway to final

ITYWF that it is epoxy.

Your description is of Isopon P40. Body filler for holes.
.

 

[thinwater]

If I ever needed a decent filler .... I used to revert to DEVCON.

Its not epoxy - its Polyester with chopped strand filler .... giving a) excellent filling .... b) strength.

But like Epoxy - a PITA to sand ..... so the best way to use - fill the area and then clear plastic sheet laid on and a smooth plate pressed onto the plastic .... let set and remove plastic with plate and you should have a reasonable surface finish to get you halfway to final

Please be more specific. We're interested.

Devcon makes epoxies. They make polyester resins. They make polymethylmethacrylates (Plexus). I'm sure they make other cool stuff. Which specific product are you talking about?

BTW, if you are bonding plastics, like nylon, Plexus is going be much stronger than epoxies as a rule. Very good with epoxy and polyester and metals as well. Fast cure, pre-thickened. I don't use much of it, but it super in some applications.

 

[Refueler]

ITYWF that it is epoxy.

Your description is of Isopon P40. Body filler for holes.
.

Devcon is a brand they produce various different resin based products. Epoxy / Polyester etc.

Its been a while since I last bought it .. so giving exact label data would be difficult. But I'm sure that putting Devcon into search will bring up their products - then its up to you guys ..

 

[ducked]

We all have some really old rope-bits cluttering up lockers and sheds. Surely some of that stuff, cut into short lengths and shredded, could do some of the jobs?
Dyneema?
Polyester?
Polyprop?
Nylon?
Carbon fibre tows?

I've seen carbon fibre filler recommended for filling stress cracks in gelcoat. I dunno if small quantities of it can easily/economically be acquired, but this was a commercial boat repairer so they probably already had some

 

[ducked]

My standard rust treatment (mostly used on cars so far) involves abrading with aluminium, with a "drying" vegetable oil as a binder. If I dont bother to abrade off the existing rust and any old paint before applying the oil, then it acts as a filler, giving the covering a brown (if its mostly rust) rather than silvery grey appearance.

I dont know which approach is most effective.

Electrolytic cleaning of rust off steel using beercan as sacrificial anode produces a lot of aluminium oxide powder which MIGHT serve as a filler/abrasive, though I've never tried it.

Crumpled and compressed aluminium foil bound with a little vegetable oil can be used for filling and fairing, though I'd hesitate to use it on a boat.

I developed these techniques in Taiwan, where there is no DIY　ａｎｄ　ｎｏｔ　ｍｕｃｈ　ｒｕｓｔ　（ａｐａｒｔ　ｆｒｏｍ　ｏｎ　ｍｙ　ｃａｒｓ）so commercial materials were not available, but I would use them in the UK if the occaision arose.

 

[shanemax]

Rust proofing is best done with old oil from a diesel engine, it has to be full of carbon, spray it inside the chassis and the chassis will last for ever, literally for ever and once a year paint it on any outside metal, under the vehicle, with a brush, I was fed up with my Transits, all with good engines turning into tea strainers and once I rather sceptically tried this method I never looked back.

 

[thinwater]

I've seen carbon fibre filler recommended for filling stress cracks in gelcoat. I dunno if small quantities of it can easily/economically be acquired, but this was a commercial boat repairer so they probably already had some

Seeing as how carbon is very non-stretch (makes it bad for patching something that moves) and black, I'm thinking that was just a mistake. Carbon as a reinforcement to reduce movement is a different thing.

 

[ducked]

Rust proofing is best done with old oil from a diesel engine, it has to be full of carbon, spray it inside the chassis and the chassis will last for ever, literally for ever and once a year paint it on any outside metal, under the vehicle, with a brush, I was fed up with my Transits, all with good engines turning into tea strainers and once I rather sceptically tried this method I never looked back.

Not sure if that is a response to my post, but I suppose so.

If so, thats different, being a rust inhibiting spray, rather than a paint with "filler", a la thread title/topic.

I have used motor oil thinned with diesel or white spirit as a rust inhibiting spray on vehicles. Latterly i added vegetable oil to the mix.

I wouldnt use sump oil on road vehicles, since its teratogenic, carcinogenic, a skin irritant, and isnt necessary since a little fresh oil goes a long way. I have generally crawled under my vehicles and fiddled with them a lot.

I MIGHT use it on timber if I could avoid skin exposure (say in the bilges of a wooden boat, or on rubbing strakes) where its probable antimicrobial effect might be of value.

I CERTAINLY would not spray it.　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　

In particular your requirement to use diesel sump oil "full of carbon" doesnt make much sense to me since as I understand it carbon's electrochemical properties will tend to encourage corrosion, though the oil may still have a net positive effect on corrosion, as might the relatively high TBN of oil for diesel engines.

I suppose the carbon could perhaps keep a thicker layer of oil next to the steel

 

[ducked]

Seeing as how carbon is very non-stretch (makes it bad for patching something that moves) and black, I'm thinking that was just a mistake. Carbon as a reinforcement to reduce movement is a different thing.

I suppose/think the carbon reinforced a (probably epoxy) resin fill in the opened-up crack which was then covered with coloured gelcoat.

I'll probably never try this and dont have an opinion on whether its likely to be worthwhile.