A bit of newbie confusion

[Gunner]

I've got my tank stripped, an extension welded on and smoothed. I'm a bit confused on the etching primer, primer, etc, that gets mentioned and where in the process it comes. This is my first job and I'll be using HOK solar gold as my BC.

Do I do body filler first, then sand, then prime. Or do use the etching primer first?

Scott's how-to is great and is what led me to this point, but it only talks about going over the factory paint.

Gunner

 

[rex]

OK,here comes a partial book again /ubbthreads/images/graemlins/haha.gifI haven't used HOK's system but here's my gig.(using PPG).It depends how I strip it for the etch primer.If I chemical strip and sand it I almost always use a wash or etch primer-the 1790 2 part,no rattle can crap-,but if it's been bead or sand blasted I just use PPG's DP40 epoxy primer(and it's what goes over the etch primer).This stuff is t!ts for corosion protection(and doubly so over the etch primer) and all mudwork or painting can be done over it but you have to realize it's drawback is a slow drying and shrinkage prone epoxy primer.If you use etch primer you can't mud (or bondo) over it,and vice versa.Mud or putty on a bare substrate like steel is not ideal but will last quite a while depending on the thickness and the severity of heat cycling.Doing the bodywork over DP will last much longer as long as you can deal with some waiting while the DP dries before continuing with any work.I believe HOK's system intends to be used as a primer surfacer which the users of it can elaborate on,but I have a problem with doing bodywork over bare steel and guarranteeing it.I've done tons of it in my life but I've also seen the drawbacks to it.You also need a primer surfacer to finish off your bodywork where I believe the HOK 'epoxy' will stick to steel great and double as a surfacer where DP isn't a surfacer primer. I figure if you're giving top $ or want to do it yourself just one time it's the best way,I don't want someone coming back in 5 years with a sweat (as in persperation) problem coming through a thin spot of repair and having to eat it.This is an unheard of warrantee for most paint paint and bodywork but if I charge you for top notch work,I'll stand behind it for at least 3 and 5 isn't out of hand depending on what you want for paint.I have 10 year old jobs floating around that look like the day I got done with them but the owner took care of them and listened to the care factors.These thicker custom jobs with multi layers throw a little kink in the equasion but the base bodywork should hold up if done properly.

 

[Gunner]

Thanks for the reponse, Rex, though I'm not sure I'm not more confused now. From your response and reading the tech sheets for the HOK stuff, I'm thinking the correct steps would be:
- Filler
- Epoxy primer surfacer (since it says it prevents plastic filler bleed through). What's the difference between the regular primer and the chromate free (other than the chromate, of course)?
- KO-SEAL II primer
- Base coat
- Clear

Any HOK users that can confirm this?

And can someone give me a crash course on the National Rule and SCAQMD stuff? How do the products that comply differ from the ones that don't (such as UFC-19 vs. UFC-35 or RU-300 vs. RU310) and how do I choose between them?

Thanks

 

[Gunner]

To add some more info:
The tank was chemically stripped before having the extension welded on.

I didn't include cleaning and sanding the tank before the body filler, since I figured those steps were a given.

 

[DaveK]

I saved and printed this info the last time Rex wrote it. But Rex, please.... do ya need to sand the epoxy out befoe doing your filler work?? I debated with my neighbor on this very subject. He has been painting autos for 30 years and insist on doing filler work on bare metal. I believe more of what Rex's reasons are. And I take etch primer out of the equation all together.

And Dennis.... you engineer.. you think too much!! LOL. Your finally gonna paint it. I know that the 19 is a Top top coat clear and the 35 is meant for a starter top coat clear. And the difference between 300 and 310 is probably California laws. Just get the 311 medium reducer. Its gonna stay warm here for another couple of months.

Give me a shout sometime Dennis!

DaveK

 

[rex]

What's up Dave?I know you know what I'm saying but I'll repeat it for the sake of newbies reading this.

You CAN mud over bare steel,the prob being with heat cycling the steel will sweat and all fillers(whether they say they're waterproof or not) will soak up any minute sweat and break down and bubble over time.Some take a long time and some take a short time.I've proved it and seen it multiple times over 20+ years of straightening previously repaired panels.Some with thin skimcoats of mud are showing mud blisters and the thicker ones aren't showing yet.The point is when you grind the stuff out you'll see small spots of rust on the steel under the filler caused by sweat.Don't ask me the physics because I don't know but if you DP the steel first this sweat prob is eliminated.Fillers stick very well to bare steel but sometimes they don't want to feather on heavily galvinized panels (even though they say they do and were given plenty of dry time) and tend to 'square off' on the edge,DP will eliminate that and any consequential shrinking of primer down the road trying to level it out.You have to remember DP is a true epoxy which means it stays pliable,meaning pushing it will cause shrinkage.My way is to put one straight coat over bare steel and let it set a day or 2-you have up to a week I believe at 70 degrees to do whatever without sanding it.I prefer to take a red Scotchbrite to the filler areas after sitting and do my bodywork.To speed it up you can reduce it 1/2 part on the 2-1 ratio (2-1-1/2) but you're protection is minimized,hence one reason to use the wash primer(this is also not PPG recommended).I scuff it for peace of mind only,it's not necessary.The wash or etch primer does provide added corrosion protection beyond what the DP does but it can also be a pain in the butt.If you blast or sand the steel with anything under 400 dry paper DP is fine,I just prefer to use something like 150-240 (150 or so if it's blasted to mellow out the pitting,180-240 if I chemical stripped it and have smooth steel).This is just my way and it has never bit me in the ass.HOK's epoxy works different and I've never used it but from what I've gathered it's not a true epoxy,more of a cross between epoxy and urethane primer.It sticks to steel great unlike most urethane primers but also sands and dries more like a urethane primer so you have some speed and minimal shrinkage compared to DP.

 

[kxmotox247]

Hey guys...
Still a newbie here too. Thanks for the enjoyable reading.

I'm a little scared reading about the sweatspots poking through the filler in a few years. My father is slowly teaching me what he knows about painting but we're not as experienced as the members here on this forum. We've done a few street rods (1- with Kandy Magenta, 1- with Kandy Apple Red) and my last Harley (Kandy Kobalt). I have a set of sheetmetal on the way for my new project which is why I'm chiming in right now after reading this.
So, when I recieve my new tank and fenders, I should use a etching primer first? Then filler. Then sealer. Then my bases. Then Kandy and clear?
I would like to stick with all HoK products. What primer should I use first? Any recomendations on type of filler (I know nothing about fillers and don't want to be cheapand pay for it later).
I don't want to hijack anyone's thread but it seemed like a real similar situation so maybe you guys can help us both out.
Thanks!

 

[DaveK]

Thanks Rex!! /ubbthreads/images/graemlins/cheers.gif

I'm new as well but, what I think he is saying is this. I know I'll get it wrong Rex but here goes....

Expoxy over steel - No etch primer at all
Body work
Filler primer
Surface prime - I guess?
sealer
Base and Clear

Got it??? Now go paint something...LOL

Thanks again Rex and I'm sure you'll correct me on something.

DaveK

 

[rex]

Yeah man,you got it Dave.The only thing out of place in that list is the filler primer and surfacer primer are one and the same product,filler is more of a slang term like mud for bondn the Epoxy,I don't know if anyone elses besides PPG's DP40 (40 is just the best of them because it has the highest zinc content) will accept having bodywork done over it,that's the reason I only use DP and put up with it's downfalls.I don't even know if you can bondo over HOK's epoxy and wouldn't be surprised if you can't.

Welcome KX ( my last real dirtbike was a 79 KX250 worked to the max).I have to say like above DP is the only epoxy I know of that you can bondo or 2part putty over safely.Don't totally freak over the bondo on steel because it will last a long time,and I did kind of forget that it's not near as bad now with the galvanized steels today and the fact that lacquer primers are for the most part gone.These are 2 big factors in that rusting but it does still happen on a lesser scale.

Don't bondo on etch primer,no good at all.I take it you're getting aftermarket steel that'll probably be oiled down steel (Harley steel comes in E coat primer).The HOK guys will have to help you out on this but guessing I'm going to have to say after you degrease the parts,and do it very well,you'll need to etch the steel with like 80grit on a DA or a 50grit gringing disc (and don't try to level out the welds!),bondo or putty it to smooth it out and then prime it,HOK's primer is great from what I've heard.Block it out and reprime for final sanding.After sanding with 5 or 600 seal it color it and clear it.A few good bondos are Basecoat/clearcoat,Rage,Tackfree?,and a cheaper one is Dyna-Plus.Dyna-Lite isn't bad for a cheaper bondo but that's the cheapest I'll go.Some good puttys are Icing and anything similar,just like bondo but much finer and smoother.Try to use the ones in the tubes,not the cans-they dry out too fast.If you're really not filling and are just using a thin skimcoat the puttys are nicer but they usually sand a touch harder than bondo,they aren't near as porous as bondo though so your first coat of primer doesn't get sucked into it as bad.It's best not to get thicker than say 1/8"finished thickness with the puttys though.Hope this helps.

Edited for spelling,it's starting to get bad.

 

[G0rdyb1ker]

Hi Rex

been reading your post I have been painting brand new sheet metal work, I've washed and degreased, then used a pad to give the bare steel a key then I've gone straight to primer, paint, clear.

Havent used bondo or putty and have had good results(good smooth finish)will I get problems in the future by missing this step. /ubbthreads/images/graemlins/confused.gif

 

[robert.tallon]

Hey Guys,

I've been doing this for years and one thing I've consistently noticed on this website when referring to bondo use is putting the stuff over etch primer or other primers. Bondo adheres and fills best directly on metal. That is what it was designed to do. I've often been curious as to why I keep seeing people say that you put it over a primer first. Maybe all the certified people who I know in this business have been misinformed all these years.
Just curious.

 

[Gunner]

Yikes....now I'm just as confused as I was before.

Rex is saying:

epoxy primer
bondo
surface prime
basecoat
kandy
clear

But you're saying:
bondo
epoxy (?)
surface prime
basecoat
kandy
clear

Am I right here?

 

[rex]

Gordy,you're doing it right.Using the bondo or putty fillers is only for removing dents or straightening out wavy parts like most of the aftermarket steel.

Robert,you are correct about the bondo but... It's my fault about the confusion because I don't always specifically say PPG's DP40 epoxy,just about all primers are not supposed to have fillers put over them.This comes from back in my resto days and for the best possible job always use filler over dp40,it eliminates the sweat problem and the filler sticks to dp much better than newer galvanized steels.You can of course grind off the galvanizing to work on bare steel but then you're getting back to no protection is it does decide to sweat.I've used many brands of bondo and even though they say they stick to galvanizing,they don't stick as well as to bare steel.It's not a matter of losing adhesion and falling off but I don't like to rely on primer to do the work and many times I've seen the edge of the bondo when the first coat of primer goes on where it just won't completely feather in all the way.Honestly I get anal about things and this is the way I do it.At work,no-I grind where I need to pull a dent and then run the mudhog over the rest with 80grit and DA80 all the low spots before mudding (if the paint is good and sound).Bondo also sticks to sanded paint since it's been refined years ago and sticks extremely good,I do this because now I have the original corrosion protection under the mud to eliminate problems.I'm sure you know this but bondo is porous,and dont believe the label on Kitty Hair ,Duraglass,etc-they are too and it all sucks up moisture.I didn't notice your local but down here in S Florida the humidity is aweful,hence the reason for my practices.I'm not saying your way is wrong though because it isn't and 99.9% of the people I know do it your way,I just like the extra insurance if I'm personally warranteeing the job because if someone comes up in 5years and says it's blistering,if it is sweat bubbleing a skimcoat of filler I'll redo it free of charge.

Gunner,I hate to see you pulling your hair out in confusion so did this help any more?Also guys,I hear this and have been asked before this thread started-NEVER PUT ANYTHING BUT A COMPATIBE PRIMER OVER ETCH (OR WASH) PRIMER! Anything else is asking for a delamination problem.

 

[G0rdyb1ker]

Thanks for that Rex I was beginning to worry there /ubbthreads/images/graemlins/haha.gif

 

[DaveK]

Your right Dennis, Tallon is saying put it on metal first. And so does my neighbor who has painted forever. I remeber when Rex posted this a long time ago and have always wondered why or which way. The neighbor says "I'd rather have bondo stick to a grinder scratch". Rex says otherwise. Nothing against Tallon but, I believe Rex's theory on this. It just makes more sense to me. Bondo is epoxy and putting it over epoxy primer kinda seems to make sense. If the things move with temp variations then, the epoxy primer should move as well but, keep in contact with both surfaces and eliminate delamination. Rex is funny. Reminds me of a guy named Rex I used to work with. I called him the walking EPROM. He knew too much about everything. From farming to progamming logic that doesn't make sense. Interesting guy!

DaveK

 

[rex]

OK Dave now we're Buds,my wife calls me "You Mother F'er" so I love you more /ubbthreads/images/graemlins/haha.gifEveryone else just calls me 'A Hole' but I must say she's earned the right.

 

[rex]

I did forget,you're wanting to use HOK.Double check but you should only need one primer,their epoxy also doubles as a surfacer.I don't really know the system well enough to say. I heard they came out with a new primer that's supposed to be better than before.

 

[ezrider]

HOK KD 2000 is a newer primer, just released in March 2003, it ie an epoxy primer and primer surfacer all in 1 it can be applied directly over bare metal, body work, fiberglass and so on. dosent sand the easiest but with a little effort it ends up nice and i havent experianced any shrinkage with it. the price on a gall on set up was about $110.

 

[Gunner]

Good info, but would that mean my steps would go back to being: bondo, KD 2000, sealer, base coat, etc?

I'm getting great info and I'm still confused!

Gunner

 

[rex]

Yes,do your bondowork first,prime with the KD,sand it and continue.Don't forget to sand the metal well for the bondo and primer to stick,80 grit on a da will prep it real quick but anything up to 150 works well.See if the KD will work as a sealer too,then you'll only need one primer.