Panel prep before epoxy

M

Mtn.quail

New member here with a question regarding final panel prep before applying your first coat of epoxy over bare metal, and then procedure between primer coats after blocking, and before appling next coat.
What I am wondering is should I wash with soap and water / wash with wax and grease remover etc. I would appreciate any detail as far as how you apply and remove your wax and grease remover as not to smear contaminates into the bare metal. Wiping down vs. let evaporate etc.
Thanks in advance for the help and patience.

Mtn.quail
 
I'll tell you how I do it. Someone else can come on and tell you what I misses.

I spray the W&G remover on with a spray bottle, while others may just use a wrag that is saturated, to apply it. Immediately after applying it, wipe it off with another clean rag, constantly turning the rag over, to a clean side. After wiping the panel off, before spraying any paint or primer, I take the air hose and blow it off real good. This is to make sure that there is no W&G remover left on the panel.

Do not apply and let it evaporate, as that will simply leave the contaminates on the surface.

As far as the soap and water, I don't use it on clean metal unless there is some serious contamination on the metal. Just something about metal and water that don't go good as far as I am concerned. Others do it all the time, and that is fine for them. If it works for you, then do it.

Aaron
 
Thanks for the reply ADTKART. That makes sense. I have read about the dawn soap and water washdown, but being new to this sport it seamed to me that it would accelerate the rusting process.

Larry
 
Figured I would post in this thread rather than start a new one

I am going to spray SPI epoxy primer on my firewall and underside - both will be bare metal and cleaned with SPI W&G remover. Will be using a HF "silver-purple" gun with a 1.4 tip. I read the spec sheet (several times), so am familiar with suggested induction time, wait time after cleaning surfaces, and wait time in between coats.

I plan on spraying two coats, so will wait no more than 30 minutes in between coats.

1. What would be a good psi at the gun to start with? 30 psi and adjust?

2. How much overlap is suggested? 50%?

3. How long do I wait until I can apply body filler over the epoxy primer?

4. Any other tips you can suggest?

Thanks!
 
Your plan that you have seems to be right on, I would let epoxy dry overnight if spraying two coats. Most of time when I mix epoxy I'll mix it in a quart can or plastic mix cup and let it have some induction time in that.Then stir product throughly ,run through a strainer and put in gun to use. Joe
 
Novablue71;497 said:
Your plan that you have seems to be right on, I would let epoxy dry overnight if spraying two coats. Most of time when I mix epoxy I'll mix it in a quart can or plastic mix cup and let it have some induction time in that.Then stir product throughly ,run through a strainer and put in gun to use. Joe
Click to expand...

Thanks for the info. Why do you think it's a better idea to spray the 2nd coat the next day? Only reason I ask is because the spec sheet says something different, so curious if you have found better results with your prescribed method. I am a rookie, so I don't know :D From the SPI spec sheet:

Spray two wet coats for normal applications. For special projects such as restorations
spray one coat and let it flash about 10-30 minutes at 70° degrees or higher. Then spray second coat for maximum corrosion protection.
 
basscat;499 said:
There's a thread at the old forum where I posted my settings for spraying epoxy with the HF gun:

http://spi.forumup.org/about21-spi.html
Click to expand...

Thanks for the link. I posted in that thread just before the old forum was closed. So you mention reducing by 5% - was that because of certain temp conditions or just something you prefer to do in general? And to be clear, that means if you have a quart of mixed epoxy primer, you add ~1.6 oz of reducer (32 oz * 5%) to give you 33.6 oz total??

Your setup for anyone else looking:

Gun Maker - Harbor Freight
Gun Model - 43430-8VGA
Tip - 1.4
Inlet air pressure - 37 psi
Fluid adjustment (# of turns off of seat) - 2
Fan adjustment (# of turns off of seat) - wide open
Comments - This is to get you close, check your pattern and adjust accordingly. I reduce the epoxy by 5%.
 
One other question - how many quarts of epoxy primer mix do you think I would need for the firewall and underside of a 76 Camaro? Some others have said ~3 quarts would do it. Would rather mix a little too much than too little (I think).
 
The way I spray I would use approximately 2.5 quarts of unreduced epoxy 2 coats over the firewall and underside. Mix 1.5 quarts and apply your first coat noting how much material it took-now you know how much is needed for the second coat. Give it an hour or more to flash between coats.
 
76_TypeLT;500 said:
Thanks for the info. Why do you think it's a better idea to spray the 2nd coat the next day? Only reason I ask is because the spec sheet says something different, so curious if you have found better results with your prescribed method. I am a rookie, so I don't know :D From the SPI spec sheet:

Spray two wet coats for normal applications. For special projects such as restorations
spray one coat and let it flash about 10-30 minutes at 70° degrees or higher. Then spray second coat for maximum corrosion protection.
Click to expand...

Sorry I meant let two coats of epoxy dry overnight if planning on putting filler work over it. Joe
 
Ah, I understand now, thanks for clarifying Joe.

Appreciate the great info everyone.

So I have another - when is a reducer required or advised? Or is that a personal preference thing?
 
Use reducer when you want thinner coats, you can also use reducer to change the level of gloss if you're using the epoxy as the only coating on suspension and frame parts. The faster it flashes off the lower the gloss will be.

Example: I epoxy sealed a subrame last night that was detail sanded to perfection with 600 grit, I needed the epoxy to go on as thin and slick as possible for the best end result in paint, the epoxy was mixed an hour in advance and reduced with slow reducer, today I checked if over for any flaws and sprayed three slick coats of Sikkens Rally Black.
The epoxy sealer made a nice solvent barrier that offered excellent adhesion and also it highlights any flaws that you might need to take care of before paint. Very durable system.

For bare metal applications I always start with two coats of unreduced epoxy-this is the best foundation for fillers and all primers and paint. You will have cut throughs as you do your filler and primer surfacer work that will need to be spot primed, also keep in mind spi epoxy can be brushed which also comes in handy for small applications. Pot life can be extended by adding more mixed epoxy so for restoration work that involves priming day after day there is potential for no waste.
 
Nice info. Since the epoxy is going to be THE final coat on the firewall and underside, I might have some reducer on hand just in case. I will do some test runs on some panels w/o reducer and see how it looks. Then I can decide to reduce it by 5-10% if needed.
 
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