tub prep: sandblasting, primers and patching

[malcolmzilla]

Hey folks, I need some advice, I did a search but didn't get the answers I was looking for...

I have a 68 bronco tub that I will eventually be putting on my 77 chassis, not too rusty but has some issues and bad PO handiwork. It's mounted on my homebrew rotisserie. Due to lack of funds and time, I didn't get around to this as quickly as I'd hoped. Anyhow, now I’d like to get the tub stripped to prep the surface to repair and expose all possible issues for repair, as well as get a coat of good primer on the base surface.

I am concerned about getting it done by sandblasting, mostly worried about the rockers and rear quarters warping, but a guy in my local 4x4 club told me he had no problems with warping on his (flat) Jeep Commando rear quarters as long as he angled the gun at 45 degrees (and stayed a ways back and didn't create a lot of heat I imagine...).

There is some minor rust in the seam on the rear quarters that needs to be cleaned up (blasted?) a bit, as well as the whole backside/inside of the quarter panel. Or should I save this for the wire wheel? So far sandblasting seems the most economical and labour saving option.

At the same time, I’d like to get it primered to prevent any surface rust, it's not overly humid here but preferably right after it's been stripped as the patches/repairs will take some time, what sort of primer should be used? I read that zinc based epoxy primers are the best, but can you remove it for welding/patching easily? POR, same deal and what about the color coats on top, will they stick?? Or use a weld through? Or fog the whole thing with rattle cans?

This isn’t going to be a concours restoration; rather the focus is good corrosion prevention so I can drive it around town and to the trailhead in winter (lots of salt). Final top coat will be a $300 Maaco job (or less, whatever easily retouched up for bush pinstriping), and then some form of spray in liner inside, and rubberized undercoating underneath.

So the order is blast, primer, patch, re-primer, seam sealer, topcoat?

Any advice is much appreciated thanks!


Edit: Also, where can I get that "Speedway" mini sandblast gun, 2badrotties, anyone? I had no luck on my ebay search...?:?

 

[2badrotties]

If you sandblast the tub, a good coat of epoxy primer would be good. PPG's DP is pretty good stuff if you mix it with the 401 cayalyst. PPG says you can do your body work right over the DP and the filler will stick better than it would to bare steel. You will have to use a clean and strip wheel on spots you need to weld but it is a pretty good corosion protection. Don't use etching primer AND the DP, use one or the other. As for the POR15. You can't do body work over it. You can't weld through it. You can't even paint over it unless you use their tie-coat primer over the POR15. Every company has a good product but here in the Northeast PPG pretty much is the product of choice.

That small sandblaster is a " speedblaster " it is not made by speedway. Try your search again for just sandblaster or speedblaster. Try this

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=22660&item=2392639253&rd=1

 

[malcolmzilla]

Wow, that is fast, thanks!;D

Hmm - the DP Epoxy Primer 50 isn't available in Canada, is that a big deal (the 40, etc, are...)? Also some of the metal prep products, but the instructions say that bare rust free metal (like just blasted?) is an acceptable surface prep.

 

[2badrotties]

Most people use DP40 ( greygreen ). I used 74 ( red ) but they are all the same. If that freshly blasted tub doesn't get dirty, greasy fingerprints all over it you should be fine. I washed mine with metal conditioner before I primed it. It leaves a phosphate coating on the steel just like the metalready that POR15 has. Good luck with it.

 

[trailpsycho]

WHy not use Rust Bullet? You can paint over it and I have heard (Monkey Biz) that you can weld through it as well. There is also a Mass Buy on it right now. If you have any questions, PM Rust Bullet, he is the president of the company. So far, I have heard only good things about it. I already have mine, but have not used it yet. OThers here have and can give you some good advice. It might be a bit more corrosion resistant than just a primer. It is also easy to patch and repair.

 

[69Sport]

I don't mean to hi-jack your post but, 2bad why did you say not to use the self etching primer. I have a guy that is going to media blast my tub and shoot it with self etching primer to seal it. It may be awhile before I can do the body work and paint it. Is this the wrong way to go. Thanks 69sport

 

[2badrotties]

What I said is " don't use self etching primer AND DP epoxy primer " Use one or the other. PPG says NO to self etching primer under the DP. They say to clean with metal conditioner and then use the DP or just use self etching primer.

 

[69Sport]

Thanks for the reply 2bad, 69sport