Almost done with my patch panels! Epoxy/filler question.

C

CMS829

So I have finally begun attacking my replacement bed. Looking back - I should have just spent the extra money on two new bed sides or just put an aluminum flat bed on her. But I am enjoying the learning process. I sprayed two coats of epoxy on the backs of these patch panels. The inner wheelhouses were rather rusty and without a blaster I took off as much rust as possible and put on two good coats of zero rust. Didn't want to risk adhesion issues after treating with ospho and spraying epoxy. Hopefully they last. I cut access inside the bed itself to planish the welds. I believe I am going to weld these panels back in then drill a few 1/2" holes so that every so often I can spray some cavity wax or something in there to prevent rust.

Anyway - The welding is going well given the thin thin sheet dodge uses. This is off a 2004 dodge ram. I have the other side done I just need to do some more hammer/dolly work (learning that as well) before I put down my epoxy. I am doing better on this second side and keeping the warping to a minimum. This is not a show truck by any means. I am perfectly fine using filler (Rage gold) to straighten out these panels after i do my best with the hammer and dolly. Given this is my first time, I will be extremely happy if it at least looks "ok".

So thats where I am at. A few other spots to use a puller to work out a few smaller dents and I'll be able to shoot my two coats of epoxy. My question relates to after I do my filler..... Given they will need a lot of work I will be sanding through the epoxy to metal, and then have to add more filler to touch up spots. Is the right thing to do would be to apply first coat of filler....sand....spot prime the spots I went through with 2 coats of epoxy....then do my filler again.... and if i go through again then spot it again? and then go with my 3-4 coats of 2k?

Also - I am using black epoxy. What is SAFE and COMPATIBLE to use as a guide coat on the epoxy? Is there some type of aerosol I can use as a guide coat? The only thing labeled as "guide coat" I can find is black. And obviously that wont work.

Thanks in advance guys!
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If you want a aerosol can of guide coat in gray you can buy a can of primer
at Wal-Mart that works real good.
Just make sure it says "sandable" on the can.
 
Once I switched to dry guide coat I never wanted to go back to using a aerosol can. So much better. Drawback is the cost. You can find it on Ebay for around 20 bucks. You can get 3M for around $30. Shine makes his own. Google "pounce powder". You can get it at an Arts and crafts or quiting supply store. Use that with an old sock or microfiber cloth. It's so much more convenient than an aerosol. No worries about overspray and you can reapply it and sand immediately after doing so.
 
Agree with the epoxy primer is a great guide coat. Since it goes on with a shine when you block it the shine goes away on the high spots. I bought the 3M guide coat kit and used it once. Not even sure where it is right now.
 
Chris_Hamilton said:
Once I switched to dry guide coat I never wanted to go back to using a aerosol can. So much better. Drawback is the cost. You can find it on Ebay for around 20 bucks. You can get 3M for around $30. Shine makes his own. Google "pounce powder". You can get it at an Arts and crafts or quiting supply store. Use that with an old sock or microfiber cloth. It's so much more convenient than an aerosol. No worries about overspray and you can reapply it and sand immediately after doing so.
Click to expand...

Same here it works so much better than the spray cans IMHO but I don't use it on the epoxy. Everything after that though. I find the 3M powder goes a long way (at least two completes) so really not that expensive.
 
Guess I'll just see how the epoxy works as a guide coat by itself at first. Can always pick up dry white powder at the local shop. I found out they have it.

Anyway - 1 side 100% welded up. The other side is 98% done. They definitely are not perfect and I will need filler (I think 1/16 in most spots maybe the max 1/8") Im fine with that as this is my first time ever welding sheet metal...and these were BIG panels to attack for my first time. I was able to get 1/4" gaps down to 1/16 or no gap with the hammer and dolly in most of the spots. There are still some highs and lows though.

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Also used nails tacked onto the sheet metal and my slide hammer to pull a dent on the rear corner. Im pretty darn pleased with how it came out! Again, first time doing it.

Before:
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After:
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So I do have a question pertaining to the backs of the welds. I dont have a sand blaster, so I am thinking just hit it good with a wire wheel on my die grinder, scuff it up with some 80 grit rolocs....and do like 3-4 coats of epoxy primer with a brush or little foam roller?
Can anyone think of any better options? I cant really get in there to really grind the backs of the welds flat safely enough. Visibility is a problem and I really dont feel like thinning out the sheet metal any more.
 
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When I cannot blast the back side of my weld, I wire brush (or what ever is possible) then brush on 3 coats of epoxy, then wait a 5-6 days and apply seam sealer. I have read the seam sealer will add a layer of protection to prevent moisture from getting to weld. Actually, I have put seam sealer on most of my welds whether I can blast them or not (back sides) just for the added protection.

So thats where I am at. A few other spots to use a puller to work out a few smaller dents and I'll be able to shoot my two coats of epoxy. My question relates to after I do my filler..... Given they will need a lot of work I will be sanding through the epoxy to metal, and then have to add more filler to touch up spots. Is the right thing to do would be to apply first coat of filler....sand....spot prime the spots I went through with 2 coats of epoxy....then do my filler again.... and if i go through again then spot it again? and then go with my 3-4 coats of 2k?


Yes good plan- always recoat bare spots with epoxy. Always seal filler with epoxy before 2K. Always scuff epoxy if over 7 days. wait 24 hrs if u use wax and grease remover on filler. to make sure it is fully dry.
Good Luck.
 
Sounds good!

So I am going to do two coats of epoxy....then do my filler.... then spray a sealer coat of epoxy? Then 2k? Then another sealer coat before base?

I didnt know I should do a sealer coat of epoxy before the 2k. Absolutely necessary? Just asking because I dont know...not doubting you.

How long of a window do I have between the 2K and sealer coat? In other words can I do my filler over 2 coats of straight epoxy....then do my bodywork and spray the 2-3 coats of 2K within 7 days. Then how long of a window do I have to move on to my sealing coat and base?
 
I always like to seal any of the areas I’ve used filler on , just seems like a cheap insurance policy!
 
Wow, ok. Didnt know that. Thats a lot of coats! lol.

2 coats straight epoxy, filler, sealer coat, 2-3 coats of 2k, another sealer coat, then base and color?

Seems excessive to me, no? Doesnt the sealer coat prior to base seal off the entire underlying 2k and filler?
 
I am not an expert and agree when I first started it seemed like alot of coats, but now (few years later) all the steps make sense to me. You dont need to recoat the areas of expoxy that required no body work, just where filler is and where potential sand thru to bare occurred.

Read the "perfect paint job" (on this site somewhere): "It’s not necessary to sand the epoxy before applying the fillers (within the first 7 days of spraying epoxy) as they will bite into the epoxy and feather great. When you have finished sanding all of the bodywork you are likely to have some bare metal spots from sanding. Spray one wet coat of epoxy over all filler spots and over any bare metal spots. Now let the vehicle set overnight."
 
Its like the night before christmas. I have 4 spot welds to do that I forgot to do, but aside from that she is all ready for epoxy finally! Im excited and nervous as hell. LOL. Vacuumed the garage really well last night. Still think I may mist the floor with a small amount of water before I spray.

Anyone see anything wrong here?

Wiped down 2 times with W&G Remover last night. Tack ragged it once.

Plan to do my 4 welds, tack it again...and start spraying. I will mix my epoxy before I do my welds and set up my fans so I can let it induce for around 1 hour (should I induce it more? If it is worth the wait, I have no problem spraying at midnight).

Im using a LPH400 1.4 with Orange cap. 18 PSI at inlet with trigger pulled. Air fully open, Fluid out 2.5 turns, and starting with my fan fully open and will adjust on paper until i have a good fan.

Only other thing I am struggling with is how much epoxy to mix. Its a short bed and I am doing the bed sides, the top rail by the cab, the bottom rear (kinda roll pan section), and a rear bumper. Any tips on that? 30 minutes flash between coats ok? 45? an hour? whats best?
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I've seen people say as high as 26 for clears, and lower for base. Should I see how it is at 20?

Temp inside the garage should be low 70's when spraying. After the smoke clears I'll close it up and run a little space heater over night to keep it closer to 80
 
Temperature is the most important consideration with epoxy. If temperature is at all in question, you will want to overkill the induction and flash times. If temperatures are good, no sense staying up all night!

Yes, I would up the psi. Under-atomizing and solvent trapping is not a problem you want to have to worry about.
 
As for how much epoxy to mix, I’d mix 28oz (14+14) and see how much you use on your first coat. 28oz should be plenty for one coat, but I would guess not 2 coats. As soon as your first coat is on, see how much is left and add what you need to for additional coats. Let it induce between your coats.

Are you up to speed on the “cratering” problem that occurs if you spray too heavy? I learned that the hard way.
 
Write down what you use on every coat so that later on if you have to redo something you will have a guide to go by. Memory does fade over time. It has helped me a lot to do that. Looking good by the way. Lots and lots of work done there.
 
Thanks guys. Well- addicted. I just learned it the hard way too. I only sprayed the one coat tonight because I figured I’ll have to fix these areas before the second coat. Any tips on fixing it? I was stupid and didn’t move my welder far enough away. My foot got caught on it and my momentum pushed the gun about a centimeter away. Most areas came out great. I got too heavy in a couple other little spots. Thoughts
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Sorry for the double pics. And I guess this is why shops have nice big open booths. There’s just not enough room in my tiny garage.
 
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