SPI Black Epoxy Primer

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Ltank

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I bought SPI Black Epoxy Primer. I'm planning to Spray SPI Black Single Stage on it after it cures. I saw a video that says Epoxy Primer needs a 2k Primer sprayed on it before you can apply the Base coat.
I'm confused and frustrated! I don't have money to spend another couple hundred on a 2k primer. Was their info wrong?
Can I sand the SPI epoxy primer without leaving deep scratches because the sand paper gums up?
They also say Epoxy Primer is very thin and needs other Primer so it won't get sanded through easily.
Any pointers is appreciated! Thanks
 

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rock is totally right. i will just add that as a general rule epoxy isnt really a high build primer so if you have some bad irregularities then you will need about double the coats of epoxy as you would a regular 2k primer. witht hat said, epoxy only will give you way less shrinkage and better longevity of your finish. with ss you have a much wider recoat window than with basecoat. i would say this time of year you will have 5-7 days to get your ss on. if you get way out of window then just reduce some more epoxy down and spray a sealer coat 30-60 min before you spray the ss.
 
Not to mention the greatly increased resistance to chipping due to the permanent flexibility of epoxy.

Couple of tips for spraying SPI Epoxy. To increase the amount of build per coat, mix your epoxy then let it set (induce) 4-8 hours before spraying, I think Barry used to say you could let it sit overnight IDK. The longest I've let it induce is around 8 hours. Unlike normal 2K urethane primers you can spray several coats and come back and spray several more the next day without sanding and without any worries about adhesion. It builds nicely and it sands very well. It's a terrific product and the best epoxy on the market. Hands down.
 
Lizer said:
You don’t even need to sand it before your single stage. I do with 400 wet just to remove imperfections and any peel.
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Exactly but, any peal or texture in your epoxy will show in your SS. 2 or 3 coats of epoxy, 400 and spray your paint.
 
Ok thanks. I don't mind sanding but by reducing the Hardener make it less able to bond to steel or the fiberglass saddlebags?
 
No mix the epoxy 1 to 1 as normal then 10% of that amount is what Lizeris saying. I play with the reduction from 10 up to 50 % as a sealer and type of job I am using the epoxy on.
 
Ltank said:
Ok thanks. I don't mind sanding but by reducing the Hardener make it less able to bond to steel or the fiberglass saddlebags?
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OP, anytime epoxy is reduced, it's meant to be used as a sealer 99.9% of the time. It's not meant to be sprayed over bare metal of raw fiberglass. There are exceptions to that rule. Such as a small break thru to metal after block sanding before final paint. or to be used as an adhesion promoter if the unreduced epoxy has gone past the open window for recoating.

To keep things simple, and as not to confuse you..........here is two ways to prep for spraying single stage in your situation.

1. Prep surface to be primed with 80 grit on a dual action sander. Hard to reach area's can be sanded by hand with either 80 or 180 grit. Spray unreduced epoxy mixed 1:1. Sand epoxy with 400 grit and if there are no break thrus to bare metal or fiberglass, go a head and spray Single Stage paint if you're still in the re-coat epoxy window.

2. If you have gone past the unreduced 1:1 epoxy re-coat window or there are small break thurs to bare metal after sanding, spray a reduce coat of epoxy before final single stage paint.
 
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MJM said:
OP, anytime epoxy is reduced, it's meant to be used as a sealer 99.9% of the time. It's not meant to be sprayed over bare metal of raw fiberglass. There are exceptions to that rule. Such as a small break thru to metal after block sanding before final paint. or to be used as an adhesion promoter if the unreduced epoxy has gone past the open window for recoating.

To keep things simple, and as not to confuse you..........here is two ways to prep for spraying single stage in your situation.

1. Prep surface to be primed with 80 grit on a dual action sander. Hard to reach area's can be sanded by hand with either 80 or 180 grit. Spray unreduced epoxy mixed 1:1. Sand epoxy with 400 grit and if there are no break thrus to bare metal or fiberglass, go a head and spray Single Stage paint if you're still in the re-coat epoxy window.

2. If you have gone past the unreduced 1:1 epoxy re-coat window or there are small break thurs to bare metal after sanding, spray a reduce coat of epoxy before final single stage paint.
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When you say the “re-coat window “ you’re talking about the 7 day window ? I’m prepping for SPI Epoxy Primer on my 77 Vette , also shooting single stage and just want to make sure when I start painting in about a moth .. thanks
 
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Race x190 said:
When you say the “re-coat window “ you’re talking about the 7 day window ? I’m prepping for SPI Epoxy Primer on my 77 Vette , also shooting single stage and just want to make sure when I start painting in about a moth .. thanks
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Yes recoat window is the 7 day window. Try not to stretch it to the limit since it varies depending on temperature etc.
 
I know there is some mild debate here about this but whenever I spoke to Barry about this, he was pretty adamant that the 7 day window was very solid provided no UV light on the car, irregardless of temperature. This was in regards to re-applying epoxy over epoxy. Now if you are applying a topcoat over the epoxy it may shorten some. I know Jim C has mentioned that.
 
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