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Paint chipped a little easier than I thought it should.

I am doing a frame off restomod on my 74 bronco. I painted the body back in March and put it on the frame in June, and dove it a couple of times since. Our driveway has rocks in it and the new BFG all terrains pick them up pretty good. I noticed the last time I ran around the block I chipped the paint in two different spots. Both on corners. They are rather small but it chipped all the way to the epoxy, a little to easily in my opinion. I used Spi epoxy, spi regular build primer, TCP Global base coat(don't judge me lol), and spi univesal clear coat. I didn't use any sealer.

Could I have done something wrong when painting that caused this or just bad luck with the rocks. I am not to mad about it as I am used to having stupid problems regularly. And it is a 4wd so big deal, but that was a lot of work just to have chips in it already.
Been rather busy lately so I am getting ready to paint the rest of the body panels. If I did something wrong I'd like to know so I won't make the same mistake twice. I will upload a picture if needed.
Did you activate the basecoat? I believe that is one of the key steps to help prevent rock chips. IIRC, using reduced epoxy as a sealer prior to base would have helped as well.
unless the epoxy was fresh, say 24hrs or less then you can base on it. over 24hrs then base wont be bonded like it should and chipping will occur easier. the longer you wait to put base one epoxy the worse the adhesion will be. beyond the 24hr mark you should always spray a reduced thin coat of epoxy down as a sealer before you base on it.
I didn't spray base over the epoxy at all. I first sprayed the epoxy with two coats over the bare steel. Let that sit until the next day and then sprayed two coats of spi regular build, sanded it with 300 then 500 sprayed 1 more coat of regular build. Waited until the next day and sanded that flat with 500 again. Sprayed base that morning and clear that evening.

The chips go straight through the clear, base, and regular build straight to the epoxy. So I don't think it was the base, but I'm no painter.

Jim C, Does that apply to the regular build too? I applied the regular build about the same time the next day. I was under the assumption I was fine within the 7 days.
not really. base i dont let go more than 24hrs in summer or 36-48 in winter months. 2k primers over the epoxy will bond much better. i have never had an issue at the 48-72hr mark. the 7 day window.....ehhh, i would never let it sit that long before i put 2k or base on it. only thing i would put over it at that point would be filler and it would need to be scuffed really well. epoxies just lock up way too tight to allow anything to bite into them and bond well.....except more epoxy. not saying you have a problem either. those rocks could have just really hit hard. anything will chip from rocks if its nailed hard enough. only time will tell if you have weak adhesion. if you end up having 100's of chips after 6mos, then i would say you have an problem.


Paint Fanatic
Staff member
Maybe more of a fluke than anything,
Frames are very had to spray and my best guess is the first coat of base in that area had some overspray on it and looked covered.
Frames over the years I have totally changed the way I spray them to avoid problems in isolated areas, only other advice is I would have sprayed a seal coat of epoxy over the 2K primer.
I don't mean to hijack this thread but it's funny I saw this thread because I was planning to start one myself for a similar issue. I recently repaired a 2016 camry that was damaged in the front and I used OEM parts from Toyota when repaired. I scuffed/sanded the hood and sprayed epoxy as a sealer directly to the sanded ecoat and used PPG base and universal clear. I did induce the epoxy and mixed 1:1:1 and waited approx. 45 minutes before applying base. It is my wife's car and it sat in my shop for maybe 2 weeks before she started driving it. She has been driving it for approx. 1 month, but I noticed this past weekend that she has several chips (maybe 5 or 6 chips already) in the hood down the the epoxy/sealer. I have not noticed chips in the OEM bumper yet, just the hood so far. I did not activate the base when it was sprayed. Would activator helped to avoid this? I have never activated the base before and never really had issues. I painted my personal truck 2 years ago with nason sealer, chromabase, dupont 7900S clear (do not hate on the nason sealer and dupont clear as this was before I discovered SPI) and I did not activate the base and I do not have a single chip in the front end. I was expecting the SPI epoxy and universal to help me more with front end chips and was surprised so I was wondering what might have went wrong.
Base is always the weakest link, it must be activated for flexible parts, and should be activated anywhere there is a risk of stone chips. Excessive urethane primer build will also make a finish more stone chip prone. The properties that make primer easier to sand can also make it easier for rocks to break it off the finish. The most rock chip resistant final vehicle finish is epoxy only with epoxy sealer, minimum amount of activated base, and a flexible clear like SPI.

OEMs put clear films over areas that are chip prone, we also advocate mud guards for daily drivers here because the roads are full of viciously sharp stones that are used in the chip-seal process used to protect our roads from freeze-thaw cycles and aid winter traction.
Yep, this camry had clear films on the hood and both fenders before the repair. Also, it is my wife driving and she is not as cautious as I am when driving. LOL. I have a habit of not tailgating vehicles because I can just envision my hard labor going down the drain by rock chips. She does not have this issue on her end. Haha
yup as both these guys said, always activate base and the paint wont be 100% for 90 days out in the summer heat. wintertime it takes much longer. also remember a camry is alot lower than your truck so that hood takes alot more abuse. its in more a direct line of fire compared to your truck.
I theorize this is one of the trade-offs with how easy the universal clear is to sand and buff. It seems to stay softer much longer than your average production clear. But avoid damaging it while it cures and it looks 10x nicer than production clear!


Paint Fanatic
Staff member
Not to hijack, but can using a heatlamp at, say, 120 degrees fully cure something much quicker? Or is it a strictly sunlight kind of deal?
A r heafriemdregul
Not to hijack, but can using a heatlamp at, say, 120 degrees fully cure something much quicker? Or is it a strictly sunlight kind of deal?
A heat lamp or heat gun can be your biggest nightmare.
The type of lamp that will be your best friend is a medium wave lamp ($175-200) or a portable shortwave ( $1000 give or take)
With a medium one at 100-120 degrees metal temp, 30 minutes should cur most clears to about 90%


Paint Fanatic
Staff member
Activator in the base is the best thing you can do period like said.
A month ago I had a batch test of epoxy on a 55-gallon drum that had been there for over two weeks setting in the breezeway.
Had to spray a batch of red spi base we were making, so all I did was blow with the gun and wipe with my hand and shot one wet coat looking for 95% coverage in one coat.

Did what I wanted and then in 10 minutes did a second wet coat. (no activator)
Next day had a brain fart to check adhesion with a razor blade, to my shock I had a 100%.
Just kinda confirmed what I have believed for years is most chipping problems are from dry spraying the first coat.