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[anmo]

Right you assorted modelling brains, anyone got an idea for solving this problem? I've just offered to do a bit of remedial work on a friend's model, a half-finished racing yacht, built on a highly polished pigmented polyester fibreglass moulding which isn't going to be painted. In sticking spruce inwales to the hull with 30 minute epoxy, friend has got a few blobs of adhesive on the outer hull surface. any ideas on removing these? I've tried my usual thumbnail method with some success, but a few of the blobs just won't shift. I don't want to damage the lightweight hull, so any ideas? Re-polishing the hull to restore the shine would be no problem, but wet & dry wouldn't work as the epoxy will be harder than the polyester. I don't think there's really an answer to this, but I'd be very pleased if one of you could prove me wrong, so any bright ideas?

[mike javelin]

It depends on which epoxy was used.
When this has happened to me using West or SP epoxy I find that if I get it thin enough it will peel off quite easily.

The blobs should be standing proud so what I would do is surround the blob with thin tape like gaffa tape and used 600 wet & dry on a flat block and sand it around 80% off and then straight away, use your fingernail to lift the rest.


 

[cbr900]

Or if your hands are steady enough tape as prescribed in the previous post, then with your dremel and a disk lightly touch the blob several times and it will pop off, but be very careful..


Roy

[anmo]

Thanks for the suggestions both of you, but most of the epoxy on the hull is the kind of thing left by a sticky finger, not really prominent enough for the Dremel treatment, and using wet & dry would be a bit risky as well. I haven't been able to think of any removal method that wouldn't be likely to cause damage to the hull underneath.

[HS93 (RIP)]

If some came of with your nail have you thought of trying a piece of plasticcard nice square cutand see if that will move it , the other is , in the motor trade they use  a small round block about 3/4" or 18 mm  "about"  this mas small discs of wet and dry that stick on they also have a tool that looks like a piece of very course file they use them for de nibbing paint in dealears Peter

[Colin Bishop]

Anmo, have you considered using fibreglass rubbing compound or car polish scratch remover? This might have the same problem as with using wet and dry in that the epoxy is harder than the polyester though. Another possibility might be to use a very sharp scalpel blade to level it off and then polish the marks away. It should come off as I don't think epoxy makes a very good chemical bond with polyester.

[cbr900]

Yes as Colin has said use a very sharp knife and pare it away slowly, it  may get thin enough to pop off, but take your time ....



Roy

[MikeK]

I've had some success using the brand new scalpel blade Colin mentioned, pressing it flat against the hull next to the epoxy and gently moving in, helped by a bit of good old spit on the area to lubricate things.


MikeK

[green-boat]

Epoxy can be softened/ removed by nail polish remover or acetone.

[splodger]

Epoxy can be softened/ removed by nail polish remover or acetone.

Bad advice. If you go back and read the first post carefully, the unwanted epoxy is on a polyester fibreglass hull. Acetone will soften most types of epoxy eventually as you say, the only problem is that it will soften the GRP moulding underneath at least twice as fast, damaging it beyond repair. Nail varnish remover is acetone mixed with something else, so it's really diluted acetone. It acts more slowly than the real thing, but it smells nicer as it dissolves your hull.

[martno1fan]

try mr muscle kitchen cleaner it cleaned all the polyester resin from my brushes when i tried it after a ran out of acetone and it also smells nicer than acetone and it wont dislove your hull .

[Colin Bishop]

it wont dislove your hull .

If it won't dissolve the hull then why should it dissolve the epoxy sticking to it which is harder? Don't quite see the logic there!  ???

[anmo]

try mr muscle kitchen cleaner it cleaned all the polyester resin from my brushes when i tried it after a ran out of acetone and it also smells nicer than acetone and it wont dislove your hull .

But surely you were just cleaning unhardened resin from your brushes, what help is that in answering the original question, removing cured epoxy from cured polyester?. The only reasonably safe solvent I know of that will work fairly quickly on cured resin is methylene chloride, and I doubt if that's a constituent of any household cleaner that the likes of Tesco would sell to unsuspecting housewives.

[andywright]

I usually use 'T' cut, or brasso is also good, possibly not as severe, finish off with a good wax.

[martno1fan]

try mr muscle kitchen cleaner it cleaned all the polyester resin from my brushes when i tried it after a ran out of acetone and it also smells nicer than acetone and it wont dislove your hull .

But surely you were just cleaning unhardened resin from your brushes, what help is that in answering the original question, removing cured epoxy from cured polyester?. The only reasonably safe solvent I know of that will work fairly quickly on cured resin is methylene chloride, and I doubt if that's a constituent of any household cleaner that the likes of Tesco would sell to unsuspecting housewives.

who cares what its made of if it works? i merely said try it, it cant hurt and it might just work anything is worth a try.if your methylene chloride whatever that is ::) works why didnt you try that instead of making sarcastic remarks?if its  as safe as you say whats the problem??by the way the mr muscle worked wonders on my cooker also .anyway why dont you sand the hull and give it another coat of pigmented gelcoat its not expensive?.

[Colin Bishop]

Anmo wasn't making sarcastic remarks Martno1fan. He was simply pointing out the difference between uncured and cured resin. If you use oil paint you can clean your brushes with white spirit immediately after painting. If you let the paint go hard on the brush then white spirit won't be any good and you'll have to use something else such as brush restorer which is an entirely different product. The principle is the same here, your kitchen cleaner may have worked on uncured resin but it won't work on the cured variety - you said as much on your earlier post by stating that it won't dissolve your hull! :) Also, I don't think I'd go down the route that "anything is worth a try" - you could inadvertently do a lot of damage that way. Reactions between different products can be very complex as all the stuff on this Forum about using different paints together all too clearly demonstrates. As far as methylene chloride is concerned, Anmo was simply making the point that it's not the sort of stuff the general public can easily get their hands on.

[martno1fan]

point taken colin ,maybe i took his remarks the wrong way also so i appologise if thats the case ::) ,i never said anything is worth a try only the cleaner lol.but like i also said maybe he should just bite the bullet and sand it and apply more top coat with a pigment!!.its only arround£8 to£10 plus pigment say £4 .heres a link to a very good site ,they deliver next day most of the time and the prices are exellent they also have some helpfull tips on the site on how to apply the stuff etc.http://http://www.ecfibreglasssupplies.co.uk/store/-c-58.html