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POR15 or epoxy mastic paint??
Yazza54 - 24/2/16 at 07:43 AM

Hi guys

I'm currently refurbing a GTM libra, all the wishbones, brackets and engine frame is coming off the tub. I have access to a shotblaster big enough to get all the bits in including the engine cradle. But I'm not sure what the next step should be.

The last one I did was blasted then just sprayed with red lead and black top coat, nothing fancy, it didn't take long for it to deteriorate in places albeit not that badly.

I've heard POR15 is very good, and also heard some positive things about epoxy mastic paint. What do you think??

I was also toying with giving the bits a coat of cold galvanising spray before either of the above but I've heard the POR15 in particular prefers a rough finish to adhere to.

What say you???

[Edited on 24/2/16 by Yazza54]


hughpinder - 24/2/16 at 08:51 AM

POR 15 is good. You are supposed to acid etch the metal before applying it to roughen the surface.

I have recently used Tractol:
http://www.smithandallan.com/products/agricultural-farm-paint/1502-tractol-329-formerly-be27-single-pack-machinery-enamel-all-colours/

Which is much cheaper and you can have it in any colour you like. It seems to work very well, but I only started using it for outside stuff a couple of years ago so can't comment on long term durability. I know a few farmer who rate it highly.

Regards
Hugh


CosKev3 - 24/2/16 at 09:03 AM

Rust Bullet Automotive is by far the best paint I've used.

I've used Epoxy Mastic,which went off nice and hard,but was peelable if you broke the surface.

Not used POR15 but was put off it by a m8,as it does not stick to good metal aswell as it does to pitted metal,so if you go for POR15 make sure all surfaces are shot blasted,or it will peel off if gets chipped etc.


Yazza54 - 24/2/16 at 09:06 AM

Cool I'll have a look into the rust bullet paint

All the bits will be shotblasted and will leave a rough finish so I would hope the POR15 would be ok. But it sounds like the cold zinc base coat is a no no.


CosKev3 - 24/2/16 at 09:07 AM

Description
Description


That is Rust Bullet on the inner arch of my old Evo.

One thing with Rust Bullet is you must use two coats,so can take a bit more time.

They sell a acid etch/rust removal spray too to wipe over the metal,Metal Blast


Yazza54 - 24/2/16 at 09:28 AM

That looks good, how durable is the finish? I like the sound of the POR15 due to it's resistance to scratching etc. Also is the rust bullet intended to be used more as a primer? I see it only comes in one colour unless I'm looking at the wrong thing


CosKev3 - 24/2/16 at 09:35 AM

It is only available in silver yeah,you can use it on its own,if you want a sliver finish!

I used it on to bare metal,then seam sealed the shell,then top coated it on Evo.

If your painting over it it needs to be done within 48hrs iirc,if it's after its gone off totally you need to rough up the surface for the top coat to take.

It is unbelievably hard once it's gone off,and if it chips it won't peel or lift letting water under it.


CosKev3 - 24/2/16 at 09:37 AM

Description
Description


Used it on my sierra hubs for kit car,then finished them in satin black.


DJT - 24/2/16 at 11:52 AM

Just painted my bare metal front wishbones with epoxy mastic. It is hard to get a good finish with a brush, even if using the supplied thinners. It's not too bad though and at the end of the day I need durabiliity over esthetics. It won't look nice anyway if chipped!

I ruled out POR15 as it is not UV stable and needs some form of top coat.


Yazza54 - 24/2/16 at 11:59 AM

From what I've read the topcoat is optional?

Also in my case on a GTM libra it not being UV stable really isn't an issue but I can understand where you're coming from on an open wheeled car


ALLAN 14 - 24/2/16 at 12:48 PM

Hi,
The most important thing is to get setup ready to paint before you start blasting,for best results your work place needs to be dry and warm,
If that is not possible you can cheat a bit by pre warming the componants prior to blasting this prevents the moisture getting trapped under the paint finish.
Shotblast finish gives an exceptional grip to the paint and you get better results if you do not put the paint on too thick as that improves the
chance of it chipping off.
Happy painting

Allan


coozer - 24/2/16 at 03:12 PM

I used hempathane on my chassis. Reason being the blaster I took it too was in the process of painting off shore oil rig modules with the stuff and primed my chassis with it after blasting.

http://www.hempel.com/en/products/hempathane-topcoat-55210


Yazza54 - 24/2/16 at 03:42 PM

quote:
Originally posted by coozer
I used hempathane on my chassis. Reason being the blaster I took it too was in the process of painting off shore oil rig modules with the stuff and primed my chassis with it after blasting.

http://www.hempel.com/en/products/hempathane-topcoat-55210


So many options!!

Whats it's scratch resistance like when cured? Is it just like a paint or similar to por15, and enamel like?


rusty nuts - 24/2/16 at 07:31 PM

I did my chassis in POR 15 , top coated it with Hardnose from Frosts after stripping off the crap powder coating and shotblasting . It was done in a lock up garage with just a Calor gas heater to take the chill off so probably a bit humid . This was done about 7 years ago and has not chipped or peeled at all . I did follow the instructions on Frosts website and would happily use POR 15 again even though it's not particularly cheap . Use disposable brushes if you use it .


Bluemoon - 24/2/16 at 08:04 PM

Hotzinc spray would be great (as good as galvanisation) , but will need special primer if you want to paint it (acid etch).


Did consider getting the MK done this way but you can't weld it simply afterwards so didn't bother (had some mods in mind). Price was good, and it should last 20+years without issues including chips....

Dan.


JMW - 24/2/16 at 08:06 PM

I believe POR15 uses dampness (presumably in the atmosphere?) to cure.

If that's the case does it matter if the component isn't completely dry when you are using POR15?

Anyone know for sure?


jps - 17/8/16 at 01:15 PM

quote:
Originally posted by rusty nuts
I did my chassis in POR 15 , top coated it with Hardnose from Frosts after stripping off the crap powder coating and shotblasting . It was done in a lock up garage with just a Calor gas heater to take the chill off so probably a bit humid . This was done about 7 years ago and has not chipped or peeled at all . I did follow the instructions on Frosts website and would happily use POR 15 again even though it's not particularly cheap . Use disposable brushes if you use it .


I will be revisiting my chassis paint soon - I used POR15 and then topcoated with BlackCote (I think it was called) and although the coverage is good i'd like to improve the quality of the finish (it's a bit rough and bumpy in places...)

When I bought the stuff POR said you could do this - nowadays they say that there has to be an etching primer coat betwen the POR15 and the top coat layer - which seems like overkill to me...

Did you put the Hardnose straight on to the POR15?


Irony - 17/8/16 at 01:33 PM

I have used Jotamastic 87 undercoat and Jota Hardtop flexi for the top coat. They guarantee it won't rust for 10 years submerged in salt water!!!! It'll mark if you use a chisel on it but thats about it. Not easy to use though, You have to use their thinners or acetone to thin. Anything else won't touch it. Not tried spraying but I'd like to redo the whole chassis in it!


Benzine - 17/8/16 at 04:12 PM

I've used jotun on shotblasted parts, very tough stuff. Brushed on is okay, rollered is better but sprayed looks best and, i found, is better at resisting scratches/dings etc