Im having a lot of the sheet metal on my 64 pick up blasted to see how much I need to replace. What’s a good coating that is paint & weld through friendly. I’m hoping something that is diy that I don’t have to grind off to paint.
Why not mask off any parts where welds will go and then shoot the rest with epoxy primer. Then remove the tape and use Gibbs or a spray can of weld through primer on the taped off areas.
I thought cleaning before welding was part of the game. I’d rather remove a little epoxy on a weld seam then fight rust from handling or humidity. But Gibbs oil is a nice product. After blasting a body, I’ll DA with 80 grit then clean followed by epoxy. Clean weld joints as needed. You can tape em up before epoxy but honestly a 3m stripping wheel is about as fast as taping
I'm sure we all have our way of doing, but I like working on things more when things are clean. I like this stuff or similar. Enough protection for my liking. If you've sand blasted, wash first with hot soapy water. Then mix in a spray bottle with hot water, spray and scrub. Rinse wipe with a spray bottle of hot water. Air dry blow off any excess in cracks or crevasses. Sometime however, you have to hold things together so they don't fall apart further in the attempts to get them clean. Some would weld those cracks and call it good. Me, I thought differently. Tack enough for handling, a blast or dip. Condition. Repair. Recondition. EP. It's my way anyways. One thing to mention, from a welding eye, taping prevents paint contamination in the joint that a disc can't reach to remove. That little bit of paint can cause welding issues. And as far as it goes, those weld thru primers...I'm shaking my head. And the Gibbs...if your going to paint it, ya might want to rethink that product but in the same breath, if your trying to protect it till then, why not? Gibbs on bare metal???? | The H.A.M.B. (jalopyjournal.com)
X2 on metal conditioners. Ive used the PPG products and like em. I doubted Gibbs until a painter friend of mine praised it. He’s painted 2 or 3 Riddler winners and uses the stuff to keep bare metal from flash rusting during a build. We used weld thru due to warranty demands in collision work. I was indifferent about it. Never had an problem with it causing welding issues but the vast majority of our welds were resistance spot welds. I removed a rear body panel we had replaced probably 3 years earlier (car wrecked again) the joints were spotless under the weld thru primer. We also used cavity waxes which I’m sure helped. There are multiple answers. Every person is correct with what worked for them. epoxy, etch, metal preps, preservatives, weld thrus ……. Every product used today is debated just like which oil to use. the fun part is finding what works for you But whatever product you decide on, read the tech sheet and use it correctly.
I had several parts sandblasted and they sprayed them with Duplicolor Self etching primer before I picked up pieces. Thought it was a good idea. Got in trouble with it and am using 2K primer sealer over it. Guess the duplicolor is difficult to work with.
I trust my sandblaster but I like to see so no primer at blasters (I also like to know exactly what primer is used not something in white tins) , immediate rust treatment like deoxidine or similar will hold it a while. Epoxy primer will hold up for a very long time. I wouldn’t leave a body shell naked for more than a few weeks . Don’t blast more than you can handle, consider doing underside to epoxy stage then topsides and interior to epoxy……outside last . Also depends on how much of a mess you have as to your plan.
I have been preaching Cavity waxes for 20 years, it was a revelation. All those SUVs I repaired in the 80s and 90s would still have wheelwells!
Thanks guys. A lot of these panels will sit for a while as I slowly work my way through each repair. All will be in a conditioned shop. I’m having the frame blasted and phosphated but the panels are only being blasted on the backside to preserve the 60 yr old paint that is in remarkable shape considering it was” used” as a truck. I’m only repairing the places that are rusted through.
TREATING SANDBLASTED PANELS I guess I am old-fashioned but I generally start with a good restaurant meal then maybe take in a movie or go see a band. If things go exceptionally well, I just might end up making her breakfast
If you sandblast steel panels you remove the phosphate coating, which is the first step to protect steel from rusting. There are 2 basic ways to replace the phosphate coating: metal prep/acid wash--and--self etching primer. Epoxy primers do not convert or stop rust chemically, and most of the popular epoxy primers have little film build, long cure times and can absorb moisture and solvent--PLUS--most epoxy primer tech sheets recommend treating the metal with metal prep/acid wash for the best corrosion protection. Over the last 50 years, lead, zinc and chromate have been removed by law from paints. These are heavy molecules added to paints to protect from Ultra Violet, chemicals and moisture. The acid in metal prep (phosphoric acid) can affect the hardner part of epoxy primers causing them to air dry but not cure partially or completely. This is why most epoxy primer tech sheets recommend completely neutralizing the acid/metal prep before applying epoxy primer. Epoxy primers have been "sales promoted" pretty heavily in the last 50 years. I remember PPG/Ditzler promoting their DP40 primers with "Just DP it and Forget it", but that was back when DP epoxy primer actually had lead in it and they kept on promoting it because they knew regulations were already removing lead from paint products. Now they are selling DPLF (lead free) epoxy primer. Back then, if I needed to use epoxy (on restorations) I used DPU 35 epoxy (from their aircraft and industrial line) which had 3 times the film build and cured at least 3 times faster-and contained lead. We used metal prep on rusty steel first, and then the DPU35-per PPG tech sheets. Today, I see PPG has some really nice high build epoxy primers (again from their industrial products) that are becoming popular for high end restorations--VP2050 and CRE-X21--of course lead and chromate free. These are quite expensive and still are recommended over properly treated steel (metal conditioner). watch the video
Why do you feel sandblasted metal needs to be DA'd before painting? I'm preparing to put some etching primer on a new sheetmetal body. First up is getting it mounted on the rotissere. Found I need to fix something on the rotissere and am waiting for a part to arrive before I finish mounting it. The first thing will be to flip the body upside down and get a good covering on the bottom of the body and a lot of the interior surfaces .......like under the dash and inside the doors, as well as the bottom of the roof. Figured I'd wipe everything well with some lacquer thinner and put a fan blowing on it for a while. Then once the thinner has evaporated, spray the etching epoxy primer and maybe follow up with some black urethane on the bottom of the body. Not going to sand blast but am dealing with virgin metal. My son is waiting on a guy to blast his 56 Chevy pickup body though. We planned to wipe it with the thinner and again follow up with epoxy primer. There are lots of places where you can't DA stuff, so I'm wondering why you feel the "etching" from the blasting isn't ready for paint.
I’m a little goofy. Heavy stuff like a chassis we’ll blast and shoot. For sheet metal I like the smooth surface from the DA. If you read the tech sheets for some cleaners it may have a line something like this “not for sandblasted surfaces”. A paint rep I asked said that was due to the rough surface from blasting slowing the evaporation rate and the inability for the cleaner to do its job well. For a product like metal prep the texture can affect how it works. So I’ll DA the exterior side smooth and treat the panel like a normal bare metal surface. The rags don’t snag and leave lint stuck to the panel either. But that’s just how I was taught. This subject has many correct answers.
In my above post, I explained probably the best procedures for treating metal for storage--but some of these products are very expensive. For the "informed" hobbyist, I recommend the following on sandblasted steel: 1)Sandblast- carefully to avoid warping. 2)DA sand the sandblasted steel with 80 grit to soften the blast profile/texture. This helps keep the acid in self etching primer from being trapped in the texture--watch out not to apply too heavy of a coat. 3)prime the steel with a "mild" self etching primer (chemical adhesion) followed by at least 2 coats of hi-build 2K urethane primer. This (self etch) will neutralize rust in the pores of the sandblasted steel and the (2K) will add a moisture proof layer to protect during storage. 4) When you are ready to do rust repair or filler, you can cut out the replacement areas and repair/weld and do body filler either by grinding off the primer before filler or sanding the(good quality) 2K and applying filler on it (mechanical adhesion). I prefer filler on bare steel, but good fillers will adhere to good cured 2K. If you do either way, remember to sand far enough out on the areas to reprime (over filler) so you have good adhesion. Also if you apply the reprime 2K too heavy, the solvents can lift/wrinkle your filler edge. Etch primer There are 2 basic etch primers- VINYL WASH primer-has more etching capability but no film thickness or build. It needs to be topcoated with a fill primer or sealer and then paint. This type of etch primer should NOT be put over Bondo. It is for bare metal only. MILD ETCH PRIMER WITH SOLIDS-has a milder etch and some fill. It CAN be applied over Bondo. Vari-prime (DUPONT),Wash primer EM (SIKKENS AKSO/NOBEL) are a couple of names that come to mind. This can also be topcoated with a filler primer or primer sealer or directly with paint (industrial application.) You have to check and see what system/brand you are going to use and then get the technical info on the application requirements and read and follow the manufacturers instructions. DO NOT use metal prep before applying etch primer-it needs just a microscopic amount of oxidation to bond with. The phosphoric acid in the etch primer is usually less than 1% but that bonds with Iron oxide (rust) to form Iron phosphate which is the etching/phosphatiing process. Removing all the rust with metal prep/conditioner (phosphoric acid) will leave nothing for the primer to bond to and can lead to peeling. These systems usually go as follows: Vinyl wash primer-1 medium wet coat (.5 mil) over clean, dry, sanded/sandblasted bare metal. You can see through this coat-its very transparent (vinyl resin). This followed-probably within 30 minutes (wet on wet-no sanding) by a good catalyzed 2 part filler primer for filling and sanding (5-20 mils). Or in straight refinish (trailers/industrial) applications-vinyl wash primer followed wet on wet by a non-sanding primer sealer(1.5-3 mils)-followed by paint. With the milder etch primer you prepare the metal the same-do your bondo work then clean and apply the milder etchprimer (1-2 mils) followed wet on wet/no sanding (probably within 30 minutes- read the tech sheet for the product) by a good catalyzed 2 part filler primer for sanding and blocking. For project cars I usually rough out the metal-do my filler work on the large areas then use the mild etch primer followed by 2 part filler primer. Then for smaller areas I can use the spot filler/ catalyzed glazing putty over the sanded filler primer to smooth out small imperfections. I will probably reprime areas that need more fill and block sanding-then on to paint. If it is going to sit for as while, I prep the steel-then etch prime (either one) followed by good 2 part filler primer. Then when I'm ready for bondo work, I just hit the repair area with a grinder to bare metal and do my bondo work followed by the filler primer. Epoxy primers DO NOT etch the metal. They bond by mechanical adhesion. There are many different epoxies for specific applications. You need to research what will do the job for your intended purpose for which ever primer/paint system you are going to use. The acid in etching primers can cause the epoxy primer catalyst/hardner to change chemically and not cure or possibly fail/peel. The acid in etch primers slows down the catalytic reaction of the hardner in Bondo/body filler (polyester resin-catalyst MEK peroxide). If you put bondo over etch primer and there is still a minute amount of residual acid-you could have a failure/loss of adhesion etc. The amount of acid is very minimal in these primers. It is mixed with a solvent to reduce/thin the primer. If the etch primer is not fully dry and cured there COULD BE be residual acid/solvent in the primer film which could cause the reactions described above. Self etching primers/wash primers, typically have about 5% phosphoric acid (the etch part) in the hardner/reducer that is mixed 1 to 1 with the primer. This makes the acid content of the mixed primer around 2.5%. Acid is always converting with other substances/compounds like the iron oxide in the steel and the solids part of the etch primer or even the compounds in the 2K primer applied over the etch primer. Eventually all the acid will convert and become non-acid compounds. If your etch primer is applied too heavy it can trap solvents in the film which contain a small amount of acid. There is no real accurate way to know the acid content remaining in a heavy application, so it is best to manage your application to avoid this--don't pound it on! Self etch primer followed by a good 2K primer is an excellent system/foundation for restoration and custom work and you can shop for products that have good quality and price. It also makes an excellent storage coating for projects that won't be completed soon and is still compatible with almost all of the paint systems available for automotive refinish.
My question is about a newly manufactured virgin steel body. I don't want to scuff it until I know I have removed any oil or other possible manufacturing contamination. So I feel that there must be something done to prepare the raw metal before I spray the epoxy etch primer on it. Just don't know what, but its getting close to having to decide and buy some paint. So here is the bottom of the body, the thing I want to do first. I don't think I want to acid wash it, because I'm sure I'll end up with either some chemicals or the water from rinsing trapped inbetween some panels and the little holes for the rockers. Also the water will run inside the inverted cab and I'll have a rust problem in there when I do that. So rinsing anything with water doesn't seem to be an option for me. I watched the video a couple of times. Is there anything (lacquer thinner or ???) that I can just wipe the surfaces with and then apply the epoxy etching primer? I'd like to come back over the etching primer on the bottom of the car with a coating of Lizard Skin for some final protection. At the very least, I'd like to spray some black finish paint over the primer. What to do???
First of all, there is NO epoxy etch primer-and acid washing/metal prepping steel is messy and a lot of work. There are epoxy primers and self etching primers. They are different types. If your new body is a Brookville, they are made of cold rolled steel and the steel is NOT phosphated. I called Brookville and talked to the shop manager to ask about the steel and the primer, as you can/could order them bare or primered. I was told the bodies were cold rolled steel and not phosphated and the primer was a very inexpensive lacquer primer used as a transport primer. A friend of mine ordered a Brookville 32 roadster and asked me for primer and paint suggestions. I suggested ordering the body bare (not primered), then he could clean the steel with solvent and scuff with red scotchbrite pads followed by a mild self etching primer. He was planning on a urethane or base/clear paint system and the lacquer primer was not compatible and would need to be removed. Most self etch primers can be coated wet on wet (without sanding) from 30 minutes to 72 hours with a 2K urethane Hi-build primer (check the product tech sheets for times). If you have visible surface rust spots showing, you should sand or wire brush those areas to remove the rust showing before using the self etching primer. The small amount of acid in self etching primers converts the surface of the steel to an iron phosphate coating including small amounts of rust left after cleaning, sanding and wire brushing. For inside body panels that are difficult or impossible to spray, you could brush on self etch primer or another rust treatment coating on the bare steel followed with a compatible paint that would create a moisture barrier or something like 3M cavity spray to repel moisture. If you would prefer an epoxy primer, you would get the best protection by using metal prep/conditioner (to phosphate the steel) before applying the epoxy primer (watch the video from Sylvester customs in my previous post.) Also you need to find a good epoxy primer that has good film build, fast through cure time, and does not absorb moisture or solvent. There are good epoxy primers available with these properties. I did not know anything about Lizard Skin, so I had to read the tech sheet (which did not have any good information on priming steel before applying Lizard Skin) and the FAQ (which did not answer my primer question(s). I have emailed them for answers. Lizard Skin is a water based product. I hope I covered most of your concerns/questions. If anyone has self etching primer suggestions, post them up. I am familiar with Dupont, Transtar, Sherwin Williams, Sikkens/Akso Nobel and several others.
Please call Bob Barney @ Tamco or Tammy Miller (his Daughter) at Orion Paints for all the info you will ever need! They both sell a DTA/DTM/DTR epoxy primer that is 2nd to NONE & will not break your bank! I trust both of them on all my builds whether it is one of mine or a customers. God Bless Bill https://www.jalopyjournal.com/forum...ar-transport-hauling-open-or-enclosed.614419/
I don't mind removing primer for a weld repair. I know the panel is protected. I work slow and have to walk away for extended periods of time. If you can get after it non stop - or you have a shop - opinion on panel prep may be different. New raw panels - DA, wipe with thinner. Epoxy New "e coat" panels. (I don't trust much of what's called e coat to be actual e coat) DA or strip, wipe with thinner. Epoxy Blasted panels, DA - maybe, depending on surface finish, wipe with thinner. Epoxy. Rusted / wire wheeled panels. Etch with phosphoric acid, neutralize, DA, wipe with thinner. Epoxy.
Confusing subjects. More than one correct answer. But if using an etch, I’d recommend a 2k version. Followed by a 2k urethane primer of choice. The couple of brookville bodies I touched was cleaned with metal prep and epoxied. Ive used a DTM polyester from Clausen with good results. My next body will probably have either PPG defleet F4921 epoxy or VP 2050 epoxy. I plan to sandwich any filler between the epoxy. I have seen VP used as the only primer in the process. No urethane or Polly used. But follow the tech sheet whatever you use. Sometimes DTM is misrepresented. So read the instructions carefully. Talking with ppg and looking at the tech sheet for VP2050. No mention of metal prep/cleaner listed.
I recieved the answer to my questions on the Lizard Skin over etch primer. Good afternoon Reed, We are a water-based coating, so a primer is necessary for bare steel surfaces to prevent flash rusting. Self-etching primers are perfect for use under our materials and should be applied to the manufacturer's recommendations (likely 4-6 mils). The typical recoat window for applying our product over a fresh primer is 24-36 hours. Primers outside of this window may need a slight scuffing to give us a bite since the surface becomes a little slicker after drying. I like to recommend starting with a light coat of our material to start and set up the bond strength. The coating should be applied no more than 24 mils wet per coat (40 mils; 1.00 mm total with two coats), but lighter coats tend to dry and lay down better. Cody Watson | Technical Specialist
I like lizard skin. But (just my worthless opinion) applying it underneath a fresh new body would be like asking Marlyn Monroe to wear a moo moo to bed
I’ve used Picklex 20 in the past and it works great…. Spray on and wipe off. The panels stay rust free if stored indoors. You cam weld, bodywork, and prime when ready, no need to clean or wipe down with any additional products, just blow the dust off and start working. Do not shoot etching primer on the Picklex prepped panels though. https://picklex20.com/
I am confused by some of the seemingly contradictory advice I have reviewed about treating vintage sheet metal bodies after media blasting (probably soda). What is the recommended procedure after blowing off carefully and wiping down with denatured alcohol? In particular, what primer does experience suggest as desirable? I probably will have to do some body work after priming but this will be some considerable time after priming. Also with whatever primer is recommended, can one wait several (3-6 months) before painting? Thanks in advance to any of you HAMBers for any assistance you choose to share, Michael.
Everything I’ve ever messed with that was soda blasted needed sanding in my worthless opinion I sand sand blasted sheet metal anyway. Some guys prefer etch Some epoxy Some epoxy over metal conditioners Some use DTM polly Whatever you use, use it correctly
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