How much epoxy primer to mix at a time?

[JimC]

When working alone (i.e. mixing and painting) in typical UK Summer temperatures.

 

[jwfrary]

Are we talking hempel light primer?

If so then half a 3.75 litre (5 litre mixed) is doable

A paint mixer for a drill is helpful!

 

[dankilb]

We went to opposite route with our epoxy barrier (9 coats - 41’ - UK Aug-Oct temps) and always mixed small batches, typically around half a litre. I found the tin only needed a big power mix upon first opening. Then a quick stir and decant, before adding hardener, worked for us. The two part mix was always done by hand.

I was typically working alone, so last thing I wanted was more pressure of getting through a ‘hot mix’ if the weather, or my energy levels, took a sudden turn.

Half a litre of Jotun does about 5m, which doesn’t sound much, but is about the right time between brews!

 

[JimC]

We went to opposite route with our epoxy barrier (9 coats - 41’ - UK Aug-Oct temps) and always mixed small batches, typically around half a litre. I found the tin only needed a big power mix upon first opening. Then a quick stir and decant, before adding hardener, worked for us. The two part mix was always done by hand.

I was typically working alone, so last thing I wanted was more pressure of getting through a ‘hot mix’ if the weather, or my energy levels, took a sudden turn.

Half a litre of Jotun does about 5m, which doesn’t sound much, but is about the right time between brews!

Thanks for that, can you keep using the same roller and tray throughout the succession of small mixes? I had a notion that the presence on these of traces of earlier batches which were starting to go off could affect the later batches.

 

[dankilb]

Thanks for that, can you keep using the same roller and tray throughout the succession of small mixes? I had a notion that the presence on these of traces of earlier batches which were starting to go off could affect the later batches.

Good question. I can’t directly speak to the risk of ‘contamination’ between batches. There were definitely times when I hastily stopped various helpers rolling on decidedly gloopy looking paint and furnished them with a new roller/mix!

I never found a satisfactory way to stop going through trays. In the end, I favoured ‘pull liner’ type kettles (although a plastic bag in a normal tray or kettle achieves the same).

I used Rota solvent resistant rollers and changed them every couple of mixes. If they’re not left in the sun to cure or too loaded in old gloop they last ‘long enough’ (say, between proper meal/tea breaks… you can see how I structure my work days!).

In short, I treated tray liners, rollers and (paper, takeaway style) mixing pots as disposable sundries. In the end the cost of the paint and expended effort justified any wastage for me.

I noticed Project Brupeg on YouTube mixed entire 5L pots and even left them overnight (in Queensland!) so it’s definitely possible to go the other way!

 

[Keith-i]

I used Hempel 2 part polyurethane last year and found it lasted longer in the pot than painted on the boat before hardening. I had no problem reusing the roller and tray between mixes.