Escaping the Dreaded Doom Loop

Kawickrice said:
Another question.
It is suggested to use 600 for metallic, 400 for solid color, has anyone shot a metallic with courser than 600 with success as far as seeing scratches?
Click to expand...
It depends on the metallic particle size. Coarse metallics have little issue, finer ones can show scratches if you're not careful.
 
ive got caugt in the epoxy doom loop a few times alot of times ill do my final prime with a couple coats of epoxy ive missed it before blocked it with 180 applied a couple more coats and sanded to finished grit applied epoxy sealer and never had issues that way but can definitley be hard. alot of it has to do with how old it is and if its been baking outside as well from what ive been told
 
Please take my replies for what they are. I am not in anyway suggesting people use any of my methods in any way on their own work. I will just say that I have sanded months old epoxy down to 400-600, sealed with reduced epoxy and painted parts. Most of the time there is a ton of taping on the base with stripes and what not and I have never had something lift on me. I guess I always figured a scratch is a scratch. I have never based directly on top of sanded epoxy without sealing it, so maybe that's why.-------(knocking on every piece of wood imaginable right now)

If this 7 or 14 day deal is real, then I would suggest final priming your parts with something else because most DIY guys aren't able to knock out everything in a week. I haven't read the tech manual in years and I guess maybe I missed that part at the end.
 
Last edited:
The thing that creates the "doom loop" is the stated requirement for 180. I've always chosen to ignore that particular recommendation, and hence have never had the doom loop problem, but like OJ I can't recommend it to anyone unless they want to do their own testing.

EDIT: I now believe this is a bad idea, and won't be recommending it ever again.
 
Last edited:
From what I’ve been told if has stayed inside and in final prime your good for 3-4 weeks to seal and go anywhere from 400-600 grit but take it with a grain of salt I would say. Don’t want anyone having issues I’ve done it this way with no issues but if it goes past that I would do the 180 and reprime or use another method if it’s going to take longer I’ve finished polyester out to 400 and sealed many times and never had issues
 
My plan was to seal with epoxy at 25%.
I totally understand why the tech sheet says what it says.
I also understand real world results from the professionals.
I now have some information to make decisions, and that is why I posted the question.
 
Based on some further research, I will no longer be sanding cured epoxy with 320, nor will I recommend anyone else do it from here on out. Fully cured epoxy is too insoluble to be playing around with fine grits. To escape the doom loop, paint smaller batches, or take a vacation to get the job finished.
 
crashtech said:
Based on some further research, I will no longer be sanding cured epoxy with 320, nor will I recommend anyone else do it from here on out. Fully cured epoxy is too insoluble to be playing around with fine grits. To escape the doom loop, paint smaller batches, or take a vacation to get the job finished.
Click to expand...
This is why I never leave anything in epoxy long term. I cover it with poly or 2k urethane in the recoat window. I make absolutely sure the parts are stored in a clean environment and store them unsanded.
 
Last edited:
The way I always read it was that epoxy long term was the best way to insure the safety of your parts if they were going to sit for a long time. Guess that's the problem with the internet sometimes. I do personally dislike the way epoxy sands after its fully cured so who knows maybe on this next bike Ill move back to final priming with 2K.

Maybe I have just gotten lucky? I have no idea. I will also add when I seal with epoxy I don't reduce more than 20%. So I am "ass"uming my seal coat is pretty strong.

Also I don't paint daily drivers. I am always open to opinions on these matters, I just like to see real world results.
 
If i smell heavy solvents when sanding does that mean epoxy has not fully cured?
The car is in a dark place with very little natural light. Just thinking out loud.
 
Kawickrice said:
If i smell heavy solvents when sanding does that mean epoxy has not fully cured?
The car is in a dark place with very little natural light. Just thinking out loud.
Click to expand...
You shouldn't be smelling "heavy solvents" with epoxy ever as it doesn't use conventional solvents really. Is it sanding well? How old is the epoxy? Did you reduce the epoxy or straight 1:1?
 
The epoxy is fine. Maybe I should have worded heavy solvents better.
When sanding fresh epoxy, as soon as the initial layer is sanded I can smell "that epoxy smell", weather those are solvent smells I don't know.
I had a fender that sat for a few weeks and when I sanded it I could still smell "that epoxy smell". Would that mean it isn't fully cured? Or does cured epoxy still have "that epoxy smell" forever if sanded, that's all I was wondering.
 
Does fully cured epoxy have the odor when sanded? Would this be a possible method of knowing if the window is closed?
 
Kawickrice said:
Would this be a possible method of knowing if the window is closed?
Click to expand...
No. The window for recoating or applying filler without sanding is 7 days if not exposed to UV light (sunlight outdoors). After 7 days and up to 14 days, you can sand and apply coating or filler. After 14 days consider it mostly cured. Anything past 14 days you need to treat as Tech Manual states for optimal adhesion. What I'm stating are the "safe" guidelines. And for optimal/max adhesion. Like has been said many don't follow this, some do. All I know to tell you really.
 
You must log in or register to reply here.
Back
Top