Epoxy primer after chassis repairs

[badabec]

Hello, I'm now convinced epoxy primer is the way to go. I am restoring a Citroen DS, three years in and about another three years to go.
Is there any problem with painting each area as I finish the repairs. Or do I have to spray the whole 'chassis' in one go?
I'm cleaning the engine bay and front suspension mount areas at the moment. OK to epoxy prime those areas when complete then move onto the next area?
Is any epoxy primer better than the rest? Jotun 87? This one?

Pardon our interruption...

I have a decent compressor. For the small areas involved, around three square feet, what would be a suitable spray gun, needle etc?

Thanks

 

[Dcal]

No problem doing it in sections, in fact it's a better way to go if it's normal diy restoration that goes on for years.
Only thing to watch, is to be sure to clean and sand the epoxy before you overcoat it. (As you would with any primer or paint)
I think it's the best primer for the job because it sticks well to most substrates, isn't porous and can be overcoated with pretty much anything.

It can be brushed or rolled, however a cheap gravity gun and 2.5mm fluid tip works well.

 

[badabec]

Perfect thanks.
Some of the guns on ebay say solvent paint only. Any reason or no good for this purpose?

 

[Dcal]

Epoxy is solvent based so any should do.
For water based paint you need a stainless needle and fluid tip.

 

[badabec]

Thank you, I was over thinking it.

 

[fizzy]

The best epoxys are made by Leighs paints in the NE. Now taken over by Sherwin Williams but still made in Britain.
Not cheap though mainly used in industry.
Jotun is similar but cheaper for home users.

 

[ronan]

I found you do need a large fluid tip for epoxy primer. No matter how much i thinned it, it was still like trying to spray quick setting concrete.

 

[fizzy]

I found you do need a large fluid tip for epoxy primer. No matter how much i thinned it, it was still like trying to spray quick setting concrete.

They are designed to be sprayed with an industrial airless sprayer at 3000psi - a bit like a pressure washer.
Some people on here have had good results with conventional spray but brush or roller if appearance not critical.

 

[ronan]

They are designed to be sprayed with an industrial airless sprayer at 3000psi - a bit like a pressure washer.
Some people on here have had good results with conventional spray but brush or roller if appearance not critical.

I brushed it once and it came out full of brush marks and about 1/4 inch thick .

 

[Prawnabie]

I wouldn't worry about spending a lot on a gun to spray Jotun. I have used quite a lot of this recently and its that thick that you don't really get a decent fan. I have had good results with the following gun in the 2.5mm setup though..

https://www.spraygunsdirect.co.uk/i...et-gravity-spraygun.html#sthash.y3UfvQJj.dpbs

You can actually get a really smooth finish with this gun and Jotun if you get the technique right. I then use a Devilbiss FLG5 in 1.8 and 1.3 for normal epoxy primer and cellulose.

Just remember whatever you use, clean it out as soon as you have finished as epoxy will set like.....epoxy if left in the gun!

 

[badabec]

I put one of those guns in my basket after @Dcal replied, glad to hear it is suitable.

 

[badabec]

Is there any point in removing the original 50 year old paint if it is in sound condition? Scotchbrite or something coarser to key?

 

[Dcal]

If the existing paint is well adhered and sound, I'd just sand it well with 240 or 320 sandpaper and crack on.
Make sure it squeaky clean and panel wipe it before sanding.
Jotun is thick so it will cover any sanding scratches.

 

[fizzy]

I brushed it once and it came out full of brush marks and about 1/4 inch thick .

It does indeed but then I follow up with a roller. Getting it on thick is important.
Just wish I could afford one of the airless sprayers. They are awesome but even used ones go for silly money.

 

[Shedendman]

Only thing to watch, is to be sure to clean and sand the epoxy before you overcoat it. (As you would with any primer or paint).

Just a little question on that,are we talking sand as to give a key for the next coat,if so light rub with scotchbrite or a grit etc?

 

[Dcal]

As with spraying, heating the paint and / or adding a dash of thinners, greatly improves the brushing and rollering experience. (and finish)

 

[Dcal]

Just a little question on that,are we talking sand as to give a key for the next coat,if so light rub with scotchbrite or a grit etc?

A clean with panel wipe and a sand with 320 would be my choice.
You are trying to provide a mechanical key as well as provide a clean surface for the new paint.
The deeper the sanding scratches the better the mechanical key, but there is no point in overdoing it.
I think a scotchbrite is not aggressive enough but they certainly have their place.

 

[bricol]

As I always rattle on about - wherever you use the epoxy, follow the surface prep instructions - it goes on lovely on an anything - but doesn't stick as well as it should if the surface prep isn't right. And if you intend the restoration to be a one off occurrance and out live you . . .

 

[Dcal]

As I always rattle on about - wherever you use the epoxy, follow the surface prep instructions - it goes on lovely on an anything - but doesn't stick as well as it should if the surface prep isn't right. And if you intend the restoration to be a one off occurrance and out live you . . .

Nothing sticks as it should if the surface prep isn't right.

Jotun 87 is surface tolerant so is more forgiving than most primers.
Not everything need to be blasted back to white metal however any decent coating will preform better if it is applied to a blasted surface

 

[bricol]

Its just so easy to keep applying it as it looks so neat tidy and protected . . .

Having had to redo repairs, or repair areas that weren't actually rusty the first time around, ten years after I simply power wire brushed areas, and areas with a good key (blasted) were still pretty much as good as I left them, its annoying to to know a little more time would have saved more later. Don't skip the keying!