Rear Subframe Paint Stripping

[XCRN]

I am in the process of prepping my rear subframe for powdercoatimg amd going through the painful task of stripping that current coating. The current coating seems rather tough. I am worried it is the same finish as the small diagonal crossbrace that is a real thick finish as it turns out.

I am reaching out to the community to see what you have done to remove the finish on it. I tried aircraft stripper and it really does not seem to work, and right now I am using an angle grinder with a wire brush and it kind of removes it. I am thinking about sand blasting but my portable one is a Harbor Freight special and the one we have at work is too small of a cabinet by 6” in width.

I called one place and they said potentially it will be $150 to strip and powdercoat which is almost worth not having to deal with it, but if I am able to do it my self, it would be about $20 in powder.

[5mall5nail5]

Was going to powder coat mine and then realized its a super high quality baked on enamel that is impossible to remove, as you've found. Not worth it IMHO.

[moroza]

Sandblasting is about the only reasonable way to strip it, what with all those nooks and crannies. Keep in mind that there may be rust lurking in inaccessible areas, like inside the main tube. If it's already rusty, you're doomed. If it's not, leave it alone, as the original finish is quite durable. Either way, not worth the trouble IMO.

I've sandblasted with cheap Harbor Freight equipment that barely lasted through the project (most of a truck frame). Cheap, effective, makes a hell of a mess. Don't use regular sand unless you're in the middle of nowhere and have proper respiratory protection (look up Silicosis). Mine took 500lb of red garnet that cost about $80, much of which was wasted because of equipment issues and other inefficiencies. As for DIY powdercoating, you have an oven big enough to fit a subframe?

[XCRN]

Sandblasting is about the only reasonable way to strip it, what with all those nooks and crannies. Keep in mind that there may be rust lurking in inaccessible areas, like inside the main tube. If it's already rusty, you're doomed. If it's not, leave it alone, as the original finish is quite durable. Either way, not worth the trouble IMO.

I've sandblasted with cheap Harbor Freight equipment that barely lasted through the project (most of a truck frame). Cheap, effective, makes a hell of a mess. Don't use regular sand unless you're in the middle of nowhere and have proper respiratory protection (look up Silicosis). Mine took 500lb of red garnet that cost about $80, much of which was wasted because of equipment issues and other inefficiencies. As for DIY powdercoating, you have an oven big enough to fit a subframe?

There is some surface rust here and there but nothing major. Worst of it is on the welds. My thought on this is I already got through some of the finish so at this point might as well try and complete it. But I do have access to 20’ x 20’ oven at work that is kept at 450 degrees so powdercoating it will not be a huge problem. Just need to weld up a custom rack from some scrap lying around and I will be good on that front.

If I was to continue I might just make a box enclosure to extend the cabinet at work to fit the subframe in. My compressor does not quite have the PSI and CFM that the shop air has. I would even consider acid dipping this since there are a few places around here that offer that service.

[CoyotE46]

On my E46 (different setup I know) I had mine media blasted and then powder coated with an anti rust coating and then a normal powder coat. Turned out great!

Before:
https://lh3.googleusercontent.com/oPpPlfzbdRlBPM-z9KeXpZ-KsslE1gMxAji_MZMkOmKIYSfpwaTFFHc7t_3c27Om8J1s9ogTy jP82gL973J8mgJGos8jxaqkm2VyXqyL37L0YwmsLZeMsay2qWr aMAEyn5GDT_ze2GZ1rRKJyVHVprXi2UxC3PggzE5h3eY7nyQCe 4CxO3EcTb_I3FyBSlExtEEjgkE8x9v-PClY_mf2FF1OrQ6I2jww_tGry3ynMsQW0OmjHtHr_kxUJNSndS ZcG7qHsBM9pnhQgF9OMnibUORZiQolbBQs3UeUw9O9Lbni6P7D UvDxEiZo6VTJqQ0vGxoZUQRMEfRvmmprf8DGk3bxnG0VlB-SG5UZTHhXux-T-3X16yZWNTN1oobbzW9s1rye2NAhKXt_cCOa_xOJPylyHYY1nR_ YxN3Ef2jfcr5mqn04v9QIxF9NjC2T20GAQ1UjgOZ2ml7bUyQoe INj5f5QEgJODUK8Mn1AhURQwPKfyXToSVduz6pJ0Q11n9n5jIo AshrMqJAXPMHJurgwo9t53F3zNe9fPokh2Lf1kIGedKFW-SWPOvVlb4YzNwlL-NR8GJriHvLteaB0BqB0ksPAcRA-qvR5Czpg8B2lXiitEQMx5YnEaNyB65kyoQglxJaYOfSie9y0HG Qp6_Znazce7A=w1324-h994-no

During:
https://lh3.googleusercontent.com/CuSwovbdksbPQv0u4iAN-6DlpNGHemYZ39A_me4yoViv6x9PuUQEn_ckO_v3ra5ZycdRwEI XgYtZrKlQkIwp-C9kU7RSK8m0mDsWplTTrjLvVKWUJsKnVrEITLshn_B2w20cqbM 5JypxFdGyF7Hc5uDDTGEdsKNV97u_MnFwuc_tR-peX815YYVYnnNXpt-QGXez89ZkHbVnm3jBTyc0_n869iILOZRhjeRfxGmRGYFZdQb0Y QhdltGFNtemudLHRbcYznlSCWzM6V98X2gnTfbFlfX34T05262 FgfPTtForLAPkDrJ4smgJALiFC_5DR3PruIWMvqVlcMIdLREzV Lk4CHz7k38IN7H5ZGCZd-BGyL7NQTs3wp9putLK7iNEUjcSZTi5pw8Cs1CEdjOPx_txEzXj SPXpsb3QccQB0NrHZDoDlUzdxDKuTiDAAK56qE7mfT-cKJTPdiKSF5AcNEP2XIy_tX85nIW_qFt90B3Qb1tShlVCcrJbU NO4zlsTiVLiLwvzcMhaqz7H9Ek8GTYqVBrsX5PE6sWLIh-vknvOZbJZ6mvKClQHPGAZQ1t4gjB18uweF_WQBmG6N5xzE4LwW Fj5V3kKplyghVvGK7U1CjabCWP5vtKOtVDAt-rJV_KFR8BDcvKvrzV_7da6Nvvxhg=w745-h993-no
After:

https://lh3.googleusercontent.com/DHl1oWY_F6eEfCGfuaI8a4brvdnRHojGErW3stZHkT6kZZEN1g eU_ntjq-l0yCVOsZ3LARa5sBgjn6IRGsxWLt86rDPSrGJplZQOtex_P8OE ln6r4YTyGJT2BEPP-Yxi1rZTU5bkwv2LRuUK-bPhnX-eCx-2V4DB81TzhV57rQtecNw-tZzccjnED5VOCsRMDdh9StMN5yafmxelSkpM-jty1LDh8zB2GamSXukxjxIoHVxNtv8UCzeD_zQNm0JbXDrIVZT qGff9nIRQYrh92x3N0GSidDOaOa6TRmHNHdQm8VnV9N0NNm50s JKX2kOy6_wsL0xLiS2xU2a7tdQvGYLkhU6ubcH6M7b0BNt3Eef Z_3R9eR_iNa8zkvA7jXaHf28Rji8iCBOKF92GRc-q-TZSXGZ49uVrhWCtIvYEN84ymi1u5ek0Y0AI7aK6ImgQthL0Und ini-Q_Z1q65EDwaprEkHVwV0hJ0Wk1hz9jTEno75ClatnqtPkLFkO_ hEJKbxu_VA07iaxXuxKs0GoFBG3VcQg6kcOWGjqXh_btqYqPvc G9qP_CBVHWU_DFWg3Zr-WSx1TcHJUlX5PqePH21d_UExAtNwZypxbWuHpf7BcyH2Bq2nZ8 DOV7F5OGYsF-C-xey2QHohx0hWSm_A4GWkNqg=w1324-h994-no

[ross1]

Let the powder coater farm it out for blasting. Worth the $ spent and they will be responsible for the complete job.

[XCRN]

I just sand blasted the front subframe and that was easy! I wonder if it is the same coating as the rear. But the more I look at it the more I think just have someone else do it, especially if it is only $150.

[moroza]

If there are places nearby that'll acid-dip, perhaps there's a hot-tank galvanization facility as well? Done correctly, such that the inside gets treated as well, the two processes together are as good as it gets for anti-corrosion coating, and you can powdercoat over that. Then for extra overkill, paint the outside, pump the inside full of grease or oil, stick a sacrificial anode on it somewhere, and the sun will turn into a red giant before that subframe rusts. I got quotes of ~$900 to hot-dip a truck frame in California, would expect a subframe to be comparable to the $150 for powdercoating.

[katit2]

and you can powdercoat over that. Then for extra overkill, paint the outside, pump the inside full of grease or oil, stick a sacrificial anode on it somewhere, and the sun will turn into a red giant before that subframe rusts.

I picture year 2050, junk yard, pile of rust with a subframe in a middle :)

[m60power]

If there are places nearby that'll acid-dip, perhaps there's a hot-tank galvanization facility as well? Done correctly, such that the inside gets treated as well, the two processes together are as good as it gets for anti-corrosion coating, and you can powdercoat over that. Then for extra overkill, paint the outside, pump the inside full of grease or oil, stick a sacrificial anode on it somewhere, and the sun will turn into a red giant before that subframe rusts. I got quotes of ~$900 to hot-dip a truck frame in California, would expect a subframe to be comparable to the $150 for powdercoating.

Hahaha this is great. That would be funny to bolt some marine Zincs to it, the thing would last for years even at the bottom of the ocean.

[XCRN]

Hahaha this is great. That would be funny to bolt some marine Zincs to it, the thing would last for years even at the bottom of the ocean.

This is for my 95 which is getting a twin turbo LS so if it can survive slamming straight into a tree it will last forever!