Filler Onto Bare Metal Or Epoxy Primer

[JonnyAlpha]

Hi;

Just after some confirmation please, should I fill onto bare metal or should I apply a coat of Epoxy Primer onto the metal first.

My understanding is that Epoxy Primer works best apply onto bare metal however according to other information on filler, it is best to apply filler to bare metal, so when using Epoxy Primer and Filler which way around should they be applied? Hence my question.

I am using Jotun Jotamastic 87 Primer and U-POL Fantastic Filler.

Many thanks

 

[piman]

Hello Jonny,

I have always applied filler to bare metal, then prime over the top.

Alec

 

[BrokenBiker]

fill first, prime later. Key the bare metal allow the filler to get a good hold, then key the filler to allow the primer to get a good hold

 

[keithski122]

I epoxy first,then filler,then epoxy, then normal primers.

 

[eil]

I do both dependant on the time I have, the important thing is to make sure that your panel is moisture free in both cases as that is what will let the job down in time. The instructions with the old fillers used to be apply to bare metal but filler technology has since moved on

 

[Flapdisk]

Hi Jonny, errr well I understood that with epoxy primer you fill after you have primed because filler is porous to water and can hold quite a bit to the metal, to be certain the bare metal is protected prime first with epoxy and you know it's sealed and waterproof, the bond is better than the filler so filling on it is not a problem.

 

[anjum]

Prime first (epoxy) and then fill and sand. Prime again where you go through the primer.

 

[JonnyAlpha]

Mixed responses but the reason I bought the expensive Epoxy Mastic Primer was to protect the metal so I'll go with the Epoxy First Fill After.

Couple of follow on question in relation to Epoxy and FIller:

1. When keying the metal for the Epoxy I was told 320 Wet n Dry would be fine?
2. What about keying the Epoxy for the Filler?
3. I have heard talk of 'time windows' for applying the Filler / Second Coat of Epoxy, the TDS for Jotun 87 gives drying times of 'Through Dry 10 Hours @ 23 Degrees and Cured 7 Days @ 23 Degrees. So I have to leave between 10 Hours and 7 Days before applying second coat of Primer / Seam Sealer or Filler - Agreed?

Thanks

 

[langy]

A lot of the replys you will get are based on old tech, I've epoxied onto bare metal then filled for years and all the painters I know do the same, things have moved on these days.
Epoxy is an excellent sealer/isolator, steel is a magnet for moisture. Makes sense to keep them apart.
Key bare metal with 120 then epoxy then key the epoxy with 120-150, if no filler is needed you can save time by going wet on wet with the hi build primer.
I use the Lechlar epoxy which is much better to use than any other I've tried, time between coats is 10mins and after 3hrs can be flatted for filler.
I see people having trouble getting Lechlar epoxy so I have setup a deal with a supplier and can supply it tinted to your colour of choice.
Prices are £15 per litre for primer, hardener in 2 speeds is £15 per litre, epoxy thinner the same.

 

[ajlelectronics]

That is of interest to me Langy. 4 Litres of white with hardener to suit, would cost how much with carriage to Gloucester?

 

[langy]

That is of interest to me Langy. 4 Litres of white with hardener to suit, would cost how much with carriage to Gloucester?

I will have to check the couriers out as some won't take paint but cost for 4 litres primer and 2 litres hardener is £90