Epoxy second layers - the solution

This has been a lot of hard work

but the solution is simple and easy and FAST and cheap

wash with dishwashing soap - sand - wipe with vinegar

WHY ??

first lesson - what is known as Denatured alcohol in other parts of the world we call Methelated spirits = purple - our homeless people filter it through bread and then drink it with coke - only available from pharmacies and expensive - will cause blindness

for some reason BOTH DONT WORK

i work with two types of epoxy a 2:1 mix and from another supplier a 5:1 mix, both work well but both give a blush

the 2:1 is nice and thick with a consistency of syrup or honey - slow curing and very nice to build / glue with and makes a great putty mixed with equal portions of cotton flocks and cab-o-sil

the 5:1 is very watery and is fantastic for wetting out glass and coating / painting large plywood surfaces - the first coat goes on nice and thin with a scraper - easy to sand down

"peelply' works well on large flat surafces - but when you want to "paint" in tight corners - or if you just havent got the time to go wet on wet - or if you have a small bit of epoxy left over - even repair work

YOU MUST BE ABLE TO SCRUB afterwards to ensure that subsequent layers of epoxy stick well

firstly i give a light wash with a pot scourer - cloth and dishwash soap and water
then my little sander came with a "scouring" pad that works like a bomb - scrubbing is easy now
then wash again with the soapy water and rinse well with a cloth dipped in CLEAN water 2 times

SAND WELL - 60 grit paper works well for me

now the easy part - WIPE DOWN WELL with a solution of 1part vinegar and two parts water (our household vinegar is only 5%) let it dry

when dry it leaves a very slight film of white powder (almost unnoticeable) on the surface - i am not sure if this is the vinegar or our crappy water - but i wiped it clean with toilet paper

WHY ??

soap is an alkaline
vinegar is acidic

it is important NOT to have a alkaline surface
believe me i have gone thru enough **** this week
and tried many many things
i am convinced that
THE SURFACE MUST BE ACIDIC

love to know what the experts have to say about this one

anyway you can see that i got so flippen mad that i even have separate gloves for specific usage

i read wikipeadia and the very good forum on bateau

http://forums.bateau2.com/viewforum.php?f=4&sid=efe7a525ae1b1f040bcf5e753bebb89e

all very good information

so here are the pics

my "shine" of 3 layers epoxy and 5 layers of varnish is actually achievable AND i know that when i build and work on my CAT my second layers have got GOOD ADHESION and i dont waste epoxy because i can paint it on my big boat in open spots

this has been a very valuable exercise

if at first you dont succeed - try agiain

 

oh i forgot

i rolled the epoxy out with a regular sponge roller
and then just "tipped" the air bubbles out with the paint brush

all very easy and fast

 

Hey Manie, I'm glad you could get your problem sorted out too.

 

Some more info as i remember them

during this weeks research there is a rather common thread that does come thru - it seems like in first world countries you can get very smart epoxies that have no blush, but are very toxic and emit heavy fumes

the stuff i get here are no/low fumes, easy to work with, and so far no skin irritations and/or side effects

BUT it does have blush, but it is easy and fast to clean off

this is the watery epoxy that i have no problems with

so the idea that comes to mind is that maybe too smart is not so clever at all - just thinking out loud

http://www.amtcomposites.co.za/data_sheets/SP_106_TDS.pdf

http://www.amtcomposites.co.za/index.html

 

I disagree. You can get in SA what you get in other countries. Other countries doesn't have this f plague we have here that is stupid and arrogant and fcuks everything up in their path. In other coutries the people that handle stuff have a tendency to treat the stuff you bought (other people's stuff) with respect. I cannot tell you how many times I have received goods that was ****** up before I could receive it. Other than that, SA could be a leading first class country.

 

i hear what you say
and i agree

but there is some smart stuff that we could only import
out markets are too small even to have a local agent
only problem is that the stuff is flippen expensive even by their standards

http://boatbuildercentral.com/proddetail.php?prod=S3_ST_3qt

http://boatbuildercentral.com/proddetail.php?prod=S3_kit_4.5gal

so far i am even battling to get metering pumps - only harveys has got the West pumps

 

I've never heard of the need for an acidic surface. I'm not discounting this, I've just never heard of this before now. The soap and water scrub is considered the best way to remove the amine carbonate salts that deposit on the surface as 'amine blush'; the alcohol wipe is just for final cleaning before bonding. But sanding is a good idea if the resin has cured fully, which in your climate it certainly will have in 24 hours.

I forgot that 'denatured alcohol' is banned in many places. Most people have the good sense not to drink the stuff since it's poisonous. Here they take cold and allergy medicine and turn it into a highly addictive drug, so now it's become regulated and hard to source where it used to be a non-regulated domestic medicine like aspirin.

Jimbo

 

West doesn't seem to blush here so only have to sand.
Must remember to try vinegar tho'.
We use it for 1st wash of brushes to save acetone.
Turns the acetone cloudy. Must be some kind of precipitation?
Good trick to know...thanks for the research Manie.

You must spread a little around before you...............geez, boring bit of dialog that.
Musta been a long time ago, 'cos I don't remember it.

Edit again I must be goin a bit senile.
West DOES blush from time to time ( or is hard to sand anyway)
When I need a bit more elasticity in th epoxy I don't use the full 1 part of hardner (5:1 mix) (Like 5.5:1)
and it is a whole lot less brittle. Used It on the engine beds where th laminate is thick hoping for a bit of extra damping.
Whatya think?

 

The reason why i refered to the acidic surface is because some folks on Beateau tried a pool acid solution and it worked

In one of my experiments i wiped a "vinegar surface" with alchohol / meths and back to square one = no adhesion

back to vinegar and bingo - all good

what struck me was the absolute simplicity of it all
dishwash soap wash - clean water rinse - sand - vinegar wipe - next coat of epoxy

clean brushes with undiluted vinegar and final wash with soap

my next experiments will be PU varnish and white enamel paint

one of my beeeeg problems initially was fear of the unknown - i had read so many horror stories on epoxy that i was loath to work with it in my garage at home, i dont want to create an image of over simplicity and /or carelessness but i do want to encourage people to build - its not that difficult.

 

Manie

Vinegar is good for cleaning epoxy, I only use it to clean epoxy of my skin but prefer acetone for equipment.
Water is all you need to wash off amine blush.
Vinegar being an acid will react with the amine (base) to form salts, this is the white powder left behind after drying. If all of the amine was washed off in the first place then you would not get any salts after vinegar wipe.
You say that if you follow up the vinegar wipe with metho the problem comes back, then I would suspect that it is the metho or rags used to wipe that is part of your problem.

Regards
Andrew