your procedure for painting rust areas, welding, seam seal

[xpress]

hi there. i was just wondering what your procedures are for painting inner arch areas and seam sealing, and also box sections.

i have flattened back the inner arches, then a coat of rustoleum colour matched paint, then i am going to seam sealer on top of that in the inner arch areas, do i need another coat of paint on top of the seam sealer?

i know rustoleum needs about a month to fully cure but is it ok to brush seam sealer on after a few days after it's skinned over? then it can all cure off for about a month or does it need to breathe?

what is your procedure for box sections?

what's your rationale for welding bits on and getting rid of box sections?

on the original arch, in the factory, it looks like they paint then seam seal, is that right?

[jamesc76]

I used a high zinc primer on mine then lathered brushable seam sealer on left it a good few days then waxoiled it!

[xpress]

oh well, i was thinking of zinc phosphate primer first but i etched, then i used rustoleum on the inside and outside sections, going to lamp on the seam sealer after it goes on, will tell you if it holds up! what seam sealer did you use?

[boatbuilder]

It depends whether the surface is 100% rust free to begin with.
Under my arches, I used vactan on the old metal, acid etch primer on the new metal, then seam sealer (dinitrol brushseal), then gravitex stonechip primer, then a topcoat of gray tractor paint.

For future work, I'm planning to substitute epoxy primer for the acid etch primer and also use phosphoric acid instead of vactan to treat metal before applying the epoxy. I'm not 100% happy with vactan's adhesion to the metal or where you accidentally put vactan on top of an old adjoining painted surface.

[xpress]

for the new panels going on, i am putting a lot of trust in rustoleum, i didn't prime, just hand sanded the black panels and then painted rustoleum on top, will seam seal on top of this all the underside which is around the arch area, to protect from the elements and stonechips. the etch primer, a high zinc phosphate one however, seems like a good idea. i might add this on top of the inside bits where it's in contact with the elements as a further sort of underseal once the rustoleum has fully cured, then a zinc phosphate primer, then seam sealer. seems like a back to front thing to do but i figure it can't hurt it.

[Nicola&Tony]

Isn't primer designed to be used on bare metal, what would be the point of painting over rustoleum with etching primer, or have I misunderstood what you're thinking about doing?

Tony

[boatbuilder]

Normal etch primer is becoming a thing of the past I reckon. Epoxy primer is a superior solution, will stick to almost any surface, is fully waterproof and tougher than almost all paints available and some brands have zinc phosphate in the epoxy, so you get the best of both worlds. (Lechler 29107 for example)

After discovering this stuf, I'll never buy etch primer again. Why buy etch when you can get epoxy for the same cost?

[Nicola&Tony]

Thanks for the info. So is epoxy primer designed to be used on bare metal in order to give the following coats of paint a good foundation to stick to? (That's my understanding of how and when to use primer).

I'm still confused about what is to be gained from painting over rustoleum with a primer?

Tony

[boatbuilder]

I'm still confused about what is to be gained from painting over rustoleum with a primer?

Tony

Nothing to gain as far as I can see.

by the way, www.metalflake.com sell Lechler Epoxy primer at a good price.

[xpress]

you don't want to get that epoxy primer off any time in the future, it's hard stuff to get off! when i said etch before, i just meant manually scratching up the surface with some fine grade sandpaper for the paint to key onto it. i would think all modern paints would have some sort of etching component as part of their formulation. i would recommend a high zinc primer/zinc phosphate. i was talking about priming only thinking about going over the inside of the arch then overpainting to strengthen the protection under there as an option. i would think any primer is ok as long as you topcoat it.

[boatbuilder]

you don't want to get that epoxy primer off any time in the future, it's hard stuff to get off!

I suppose that's the main benefit of epoxy primer, its tough stuff and even if the topcoat fails, it still provides a tough waterproof surface to protect the metal, unlike other primers that supposedly absorb moisture.

[Plasticman]

Dont forget to do a risk assesment first, ie;if I do this will I be opening a money pit
mike

[xpress]

risk assessment, what's that? if we all did that then we wouldn't have started loll.

fair comment about the epoxy primer. i think jenoseel might have some sort of thing like that in there stiffening it up, it seems a bit more durable than most paints. i have put my money on rustoleum, and jenoseel. bear in mind i have seen jenoseel sit on bare metal for over a year and all it's done is changed colour, no cracks or any sort of discernable change to the surface. that's good enough for me.

anyone have a good idea for waterproof panel adhesive, similar to seam sealer to finish up the seams, and preferably sandable, similar to filler?