What are guys doing to protect the inside steel of their Model A frames after welding on their boxing plates. I want to get it blasted but then what do I coat it with that won't give off toxic fumes while welding the plates on? Is a weldable primer going to offer enough protection against rust? Or, do I just leave the inside and get the whole thing blasted once they're welded on? I'm not really worried about the frame rusting away from the inside...i'm sure it's going to be around long after I'm gone. I just kind of want to know what other guys in the same situation have done.
use the weldable primer and after you get done with the frame you should still have a few mounting holes that you can spray undercoating in..... Eastwood sells a product and it has some long tubing just for doing this...
I paint mine first. Then weld it outdoors to disipate the fumes. Then trickle more paint down into the seams and kind of ******* it around with a brush / sponge. Be sure to place weld nuts on the backside of the plates before welding to hold things like motor mounts / crossmembers / fuel pumps / battery tray / etc.
I'm just worried that with the very minimal number of holes that I'll have in the frame, I won't get proper coverage.
NO!!!! weld thru should only be used at the weld site on bare metal mating surfaces. It has very poor adhesion. If you use it on an open surface it will fail, taking any thing applied over it off with it.USE epoxy prime, let it dry then grind only the weld sites within 1/2 inch of the weld. Then apply the weld thru to the weld site only. Some of you guys giving advise might want to read up on products before you recommend them.
If I was to wait to blast the frame until after the boxing plates are on, would POR15 be another option to use on the inside, then grind 1/2" on the edge where the weld would be & use a weldable primer? I just want to get more of my ch***is mocked up first before I go to blasting but I need my plates on before I can go too much further.
I've often thought about his problem too. A couple of possibilities come to mind. In the aircraft industry tubular steel structures had small holes drilled and boiled linseed oil was poured inside and the sructure was rotated, tilted etc. to ensure the insides were well coated with the linseed oil, then it was drained and the small hole closed. This would work easiest if you had access to a ch***is rotisserie of course, but could be done with the help of a few buddies. Another option would be to take it to a rustproofing facility where they can insert a wand into a fairly small access hole(s) and the spray nozzle will coat the inside with the sealer of choice. his process doesn't require the tilt/rotate action as much, if at all, as the first method. Ray
Not a rust proofing suggestion, but if I ever build up another car from the frame up, and that ain't too likely at 73&1/2, there's one thing I didn't do on the current build that I would do for sure. And that's at strategic places front and rear, weld/braze 3/8" stainless bolts with threads out and head against frame. Tape them up before painting, and when you start your wiring, you'll have places to get good, solid electrical grounds. I think yall are wrong on POR15, I've found it to be a great paint system if you follow ALL the instructions on degreasing, etching, and using their self etching primer first, then the base coat, then the topcoat. Dave
I have to disagree. If I went the rout as described in my last post, epoxy would NOT be a better option. Clean blasted metal, of course epoxy would be the way to go.
Have you thought about doing speed hole in the boxing plates. It will give you access to paint and other things. Plus save weight but keeps the strength
That probably would've been the way to go. I've already got the boxing plates made and I'm not really set up to cut those so I'll have to find another way. Kind of kicking myself now for not ordering them with.
Why would you have to have the plates on? You have the chance to do it right right now. Why trap years of rust and **** in your frame and then fix it with a band-aid product?
i, myself, don't understand weld through primer. it makes no sense that your able to weld through something and have a good weld or have a good weld and retain a primer. always sounded like a sales ploy to me. that said i'd weld the frame up leaving enough holes to get primer and paint in there. i have pushed paint into enclosed hard to reach areas with an air gun with 3/16" brake line attached just spray the paint in as far as you can then blow it around with the air until it drips out of everywhere.
Weld it up and use sprayable wax like we use after putting on a door skin at the shop they sell it at any auto body supply u hafts buy the gun and it comes with a long flexable hose to stick in the holes and it has a 360 degree head that sprays kinda like a shower head but all the way around it or if u know anybody at a body shop maybe u can barrow it one nite when your done weldin it that way all u hafta do is buy the wax! Good luck it works great!
I want the plates on before I do the motor mounts and ladder bar crossmember. While some may call POR 15 a "band-aid" product, I do believe that most products, when used properly in the right situation, work. I'm not pushing for the POR 15 method, I was just wondering if anyone has gone that route before.
I sandblasted and vari-primed my frame before starting my 34 project. I plan to take my boxing plates to bare metal and vari-priming them before installing them. I'll grind the edges to be welded before welding and re-variprime the outsides...variprime the insides where I can reach through holes in the boxing plates. Plan is to tape all the holes in the rails, pour all my left-over epoxy paint into the top and flop the frame until all the area inside is covered...pour the excess out. I plan to weld a few bolts to the boxing plates for grounding points also...always makes things neater.
I'm on my lunch break, so I'll have time to explain. Weld thru primer is very mis-understood and often used incorrectly. It's a high zink material (about 17%) I'm now using a copper based product from U phol that I like much better than zink. When applied to bare metal mating flanges at the weld site several things happen. It conducts so you can weld thru it with a mig. It melts and pulls away from the weld, then as the weld cools it wicks back into the weld. Any time you put dissimilar metals together you get galvanic corrosion. In the case of zink or copper this corrosion seals the surface rather than flaking away like steel does. This protects the steel from corrosion. This product has been in use in collision work for years. most OEM car makers require it when the original zink has been removed from parts to be welded together. Some prohibit it's use, along with removing any of the factory zink impregnated into modern automotive steel. Our old cars are just mild steel with no zink coatings. So if you want the best protection from at your welds use it. As for the use of por 15, some like it, I don't. My PPG rep has told me if I use Por 15 don't even call him if I have a product failure. That carries a ton of weight for me. I don't build any cars without going to bare metal. I consider every build a restoration. I do use some conversion coatings, but only in areas I can't get to any other way.
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