Epoxy Primer

[Little Jerry]

A few members answered a lot of my questions around setting up to spray 2K in the sticky thread at the top of this forum.

 

[rcx132]

There are countires where charcoal filters are approved (or were) for isocyanate, but you need the right one, I think it's APEK1, but please check, also I believe they need to be changed regularly as the isocyanate damages the filters.

I remember reading that sticky 2k warning thread and something in there doesn't add up.

 

[Furiokid]

A few members answered a lot of my questions around setting up to spray 2K in the sticky thread at the top of this forum.

I’d read the sticky at the top of the page regarding 2k which is what had made me not think about doing it

There are countires where charcoal filters are approved (or were) for isocyanate, but you need the right one, I think it's APEK1, but please check, also I believe they need to be changed regularly as the isocyanate damages the filters.

I remember reading that sticky 2k warning thread and something in there doesn't add up.

Our smart repair guy said you have to change the masks every few uses if the filters are looking blocked, but he’s only using the 3M filtered ones, same as I used with my Epoxy

 

[vw1]

Change them if looking blocked ???utter nonsense. I'm no expert but how the hell can you tell if is looking blocked ..

 

[rcx132]

I am very weary of giving any health and safety advice, so please check for yourself. There is a PDF on this forum, was issued by a Euoropean health and safety department that gives info on using filters for isocyanate, please find it and read for yourself and bear in mind it may not even be up to date, as research and advice may have changed, and it gives different advice to what 3M themselves give and what the UK H&S exec gives.

 

[MG David]

The purpose of the air fed mask is to ensure that any leak is outwards not inwards. This is through the air pressure inside the mask being higher than outside.
There is no dispute that it is possible to have a filter that removes isocyanate. But if you wrinkle your face differently as you breath in air might bypass the filter and come around the edge. I know this risk is real as it happens very occasionally when I am spraying other paint.

 

[rcx132]

The purpose of the air fed mask is to ensure that any leak is outwards not inwards. This is through the air pressure inside the mask being higher than outside.
There is no dispute that it is possible to have a filter that removes isocyanate. But if you wrinkle your face differently as you breath in air might bypass the filter and come around the edge. I know this risk is real as it happens very occasionally when I am spraying other paint.

That was always my theory that a charcoal mask may not seal properly. Also trusting employers to regularly change charcoal filters is a risk. However air feed is also a risk if someone connects to wrong outlet and breathes in unfiltered oil mist from there compressor... it's happened before.

 

[Furiokid]

You can use weld through primer initially, then make good with epoxy.

Does anyone recommend a decent weld through primer to put on the inside of panels before I weld them in?

 

[Dcal]

How are you welding them?

If plug welds I use a zinc rich epoxy primer, the reasoning being some of the zinc might hang about and do some good.
If using a spot welder, then nothing at the site of the welds and epoxy zinc or epoxy mastic where it won’t be affected by the weld.
Spot welds need really clean metal.

 

[Furiokid]

How are you welding them?

If plug welds I use a zinc rich epoxy primer, the reasoning being some of the zinc might hang about and do some good.
If using a spot welder, then nothing at the site of the welds and epoxy zinc or epoxy mastic where it won’t be affected by the weld.
Spot welds need really clean metal.

I’ve got to stitch weld in some repair panels where I’ve got some rust/rot to cut out around window frames etc.
I was looking at the Upol Zinc Weld primer? Once welded in, I’ll try to spray some wax treatment behind the panels/repairs where I can as well

 

[Dcal]

"If" you can get to the back after welding, I'd keep the steel clean and apply paint or wax (or both) after.
Any paint or coating will be burnt off by the weld and the zinc will be vapourised, but outside the HAZ it will provide protection.
I was talking about flange welds, like where a sill meets the floor pan.

 

[rcx132]

Use wax or that ACF50 stuff. Weld thru stuff is rubbish.

 

[marlinspike]

Does anyone recommend a decent weld through primer to put on the inside of panels before I weld them in?

I use BH Electrox - high zinc primer - on the back of patches. Seems to work OK. I have used the Upol weld thru primer but I don't think it's as good as the Electrox as an actual rust preventing primer. If I was buying stuff from scratch now I'd buy the BH Etchweld too as it's their proper weld thru primer. Not cheap though and for me there came a point where I needed to make do with what I had rather than spending more cash.

 

[Kram]

Im about to epoxy prime my bike tank with hb body 989. The TDS has two sections, one normal spray 2 coats, other for "wet on wet"

The underside sounds ideal for wet on wet as I dont intend to do any sanding and can go straight on with black - it says after 3 hours, max 8 hours.
The wet on wet gives 50% reducer ratio!? Does it really need that much? Its a lot more to evaporate off, which will have additional layers of colour ontop, so I think Im reading it wrong.
Normal ratio is 100 parts epoxy, 25 hardener, 25 reducer.

So whats the reason? If I spray the underside as normal then wait 3 hours before the black will it have problems? Is it just to get a better finish?

 

[richie00boy]

The higher thinners content is to get a flatter finish because you won't sand it. If it's a hidden area you can just use the normal ratio.

I've used HB 989 before and it lays down fine, in your situation I'd go with the normal ratio.

 

[MG David]

The higher thinners content is to get a flatter finish because you won't sand it.

That is interesting and makes sense in relation to some other coatings I have used. The epoxy primer I use does not have different mixing ratios for wet on wet. It may be interesting to give it a try with a bit more thinner. Currently, the only time I use more thinner is for very small mixes that are going to be applied using an air brush.

 

[badabec]

And now a question I should have asked before. After applying epoxy primer with a roller, what preparation do I need to carry out before applying the second primer coat, again with a roller?

 

[richie00boy]

Look at the datasheet for the recoat window. If within that time can just go straight over, any longer and again the datasheet should suggest keying grit.
As a general rule any longer than next day I would key it up. Had you sprayed it a maroon scotchbrite works well, but with the texture a roller leaves you might be best flatting with sandpaper.

 

[Furiokid]

How long do people think Epoxy is ok on a body as I’ve considering recently building all the car up as it’s going to need tweaks possibly and brackets with it being a conversion project? Then once built and tested I can strip it back down and sort out painting it (less risk of it getting scratched as well whilst building)?

What are peoples thoughts? Right way to go?

 

[ajlelectronics]

You can take all the time you like, even store it outside if you wish. Just flat it back when you are ready to further coat it. That is one of the benefits of epoxy primer.