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POR-15 help - how to (or not too)
MikeR - 24/8/08 at 11:54 AM

Folks,

I keep hearing how people have had great success with POR-15 or have had a disaster.

I'm going to be painting my chassis soon and i'd like to know how to do it properly. So could people who've had success post what they did and people who've not had success also post.

Hopefully at the end of it we'll be able to spot common themes so that we can all use the stuff and get good results.

Currently i've got 10 year old metal, light coating of rust in some places, clean in others, some of it has had wd-40 on it. I don't want to powder coat as i'm sure i'll want to change bits later + have no idea of a good place to go to nearby. (and i like making things hard for myself).


GaryM - 24/8/08 at 12:47 PM

Mike

I just followed the instructions on the tin (and website).

I degreased my chassis very carefully using white spirit and then used the recommended rust remover/pre primer (Metal Ready).

I applied the POR15 using a brush.

Seemed to worked very well and is as tough as nails. Much tougher than the top coat I used.

Cheers
Gary


AdamR - 24/8/08 at 01:11 PM

I had good results with my recently POR-15’d chassis, though I can’t yet comment on it’s longevity. My process was as follows:

1) Degrease chassis with Marine Clean. Use big rubber gloves for this as it is seriously toxic stuff. Hose off with water.
2) Etch steel with Metal Ready and hose off. The chassis is left covered with a zinc residue. Make sure there’s no lingering water in your chassis tubes from all the hosing – I had to drill and re-weld a couple of holes to empty my roll over hoops!
3) Brush paint on 1st coat of POR-15. I initially planned to spray it on, but this is not recommended unless you have a proper air-fed mask setup. Luckily the first coat brushes on beautifully – nice and thick; doesn’t easily run; dries perfectly smooth with no brush marks.
4) After the first coat is touch dry, brush paint the second coat of POR-15. This is where things went a bit wrong for me. The second coat runs very easily as it’s going onto a smooth surface – and black POR-15 is very glossy so and imperfections really show up. I was pretty gutted when I saw the results and spent the best part of a day rubbing down the worst of the runs. So definitely go easy on the second coat!
5) I didn’t get round to top coating the chassis until a couple of months after the POR-15 had gone on, so I decided to use some POR-15 Etch Primer first. This was probably not really necessary, but by this point I didn't want to cock it up by taking any shortcuts. Went on quickly with a spray gun.
6) Top coat with Chassis Black. This sprays nicely, though needs thinning with POR-15 thinners. As soon as the glossy POR-15 was covered up the chassis looked much nicer, and any remaining runs/imperfections underneath are soon forgotten.

The end results are great, but the caveat in all this is that it’s quite a lot of effort and it’s certainly not much cheaper than powder coating. I’d reckon on £200 for all the different coatings, thinners, brushes etc.

Good luck!

[Edited on 24/8/08 by AdamR]


MikeR - 24/8/08 at 01:35 PM

now i'm curious what hte people who've had trouble with por-15 have done differently to the people with success.

Did you use a wire brush in the angry grinder before doing the metal ready / de grease ?


GeoffT - 24/8/08 at 02:06 PM

After washing off the Metal Ready I was left with a powdery white coating on the chassis. This seemed like a poor foundation for the topcoat, so in my "wisdom" wiped it off with a rag wetted with POR15 thinners.

This was my BIG mistake, and resulted in an almost complete lack of adhesion of the paint. My punishment was to spend the following day getting it all off.......


r1_pete - 24/8/08 at 04:44 PM

I applied it to newly shot blasted steel, figuring no additional key was needed, as per instructions, metal ready on smooth new steel, the steel was absolutely spotless and dry - no hint of grease etc, it peeled off almost in one sheet, no adhesion whatsoever. Only deviation was not using the marine clean, I would have thought the rough blasted finish was ideal for their so called hook adhesion properties, but it totally failed.


smart51 - 24/8/08 at 05:10 PM

Metal ready is great. A sort of mini galvanising. I probably didn't gegrease my chassis well enough because the POR-15 peeled in lots of placed. It has to be insanely clean. The instructions say that even a drop of sweat can ruin the adhesion.