SPI epoxy questions

M

Mike240

Promoted Users
The underside of my car has been blasted and has SPI red epoxy on it. It is on a rotisserie still and figured red over bare metal would allow me to see if I missed spots.

Can I put black epoxy over the red after seam sealing and leave it at that? Will be a fair weather car in desert Az. Does the epoxy need a sealer or clear over it as a final coat?

Suspension parts. Can I blast and give it two coats of epoxy and leave it? Clear it?

One more thing. Would like to continue work but it is now over 115F daily here in the shade. Is there anything I need to do to continue to spray SPI epoxy? Add to the 1:1 mix…
Thank you.
 
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You can seam seal and switch to black epoxy with no issues. I have left many undersides in black epoxy with great results.

On the suspension parts, if you like the look, leave it, it's more chemical resistant and more durable than the other options

115 degrees, I am not 100% positive on as I don't see that environment to often. Pretty sure you should just mix and spray as normal but better wait for the others to chime in.
 
I have had 2 coats for epoxy outlast powdercoat....was it the powdercoat prep job? Maybe. But I'll put spi epoxy against any powdercoat any day....that being said, it's simply bullet proof on floor pans and suspension
 
If your red epoxy is more than seven days old it will need to be sanded before you should add more epoxy.
 
RenewAP said:
adding 10% slow reducer # 885 or very slow # 895 will help.
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Be aware if you do this, it will also shorten the open window of the epoxy to around 24 hours.

Barry has always said, epoxy likes heat. It will spray (unreduced) in those conditions. It doesn't significantly change like a urethane based product would in that type of heat. Mix it and spray immediately. Would help if you could keep your epoxy and activator in cooler temps prior to mixing. Pour it back into the cup and clean your gun between coats. Mix the epoxy before every coat.
 
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Yotabldr said:
Does this apply to seam sealer as well?
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If your job hasn't seen the sun (UV light) you should be OK with applying seam sealer over epoxy for up to 14 days. Assuming you are using a 2 part epoxy based seam sealer. If you are re-coating epoxy with more epoxy, 7 days should be considered the limit.
 
Chris_Hamilton said:
If your job hasn't seen the sun (UV light) you should be OK with applying seam sealer over epoxy for up to 14 days. Assuming you are using a 2 part epoxy based seam sealer. If you are re-coating epoxy with more epoxy, 7 days should be considered the limit.
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So I take it anything over 14 days should be scuffed (for seam sealer)?
And if so, what grit?
 
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Yotabldr said:
So I take it anything over 14 days should be scuffed?
And if so, what grit?
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IDK exactly as I have always seamed in the window since I started using epoxy. I would think you could use a maroon 3M scuff pad on the seam areas. Check with Barry on the Tech Line for further guidance. He may say something different.
 
Chris_Hamilton said:
IDK exactly as I have always seamed in the window since I started using epoxy. I would think you could use a maroon 3M scuff pad on the seam areas. Check with Barry on the Tech Line for further guidance. He may say something different.
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For filler he has no preference between in the window or scuff it up and apply filler at some later date. He said my choice.
 
Does adding reducer really close the recoat window sooner? Heat might, but I don't see any record of reduction doing so.
I'm wrong, see below.
 
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crashtech said:
Does adding reducer really close the recoat window sooner? Heat might, but I don't see any record of reduction doing so.
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Barry says it does. Our resident Chemist Lizer says the same thing. Adding reducer changes things/speed things up. Maybe @Barry can weigh in on the particulars.
 
From one of the SPI Tech Manual's (2020 I think)

"Remember, reducing epoxy speeds up the cure time, so when mixed as a sealer the best application of base is within 2-18 hours (no sanding is needed within this time frame)."
 
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