Epoxy and powercoating - coating inside of rails

[focusedontheprize]

So the frame is off to the sandblaster this weekend. I have my epoxy primer arriving on Friday so I will be all ready to cover it as soon as I get it home from the blaster.

My plan is to spray the complete frame with epoxy, complete my metal work where I need to (i.e. fill holes, weld in the IFS and 4 link, new crossmembers etc.) and then re-coat it with epoxy to seal everything. I want to make sure the frame is sealed so I do not have to worry about flash/surface rust.

Here is my dilemma:

I wanted to sandblast the frame so I am starting with something fresh. I wanted to also make sure I had a coating inside the frame rails so eventually when I box the frame - the inside of the boxing is protected. I also was debating on having the outside of the frame powdercoated (if I could).

The issue I am mainly running into is if I epoxy the frame then I probably cannot get the frame powder coated because I have heard they go into the oven after blasting to push the oils out of the frame and this would then burn the epoxy primer off inside correct?

Anyone who has experience with this will be a huge help. Thanks.

[mongocanfly]

Nothing against a good powder coat job but I would just use a good quality paint and skip the powder on a frame..unless your building a show truck..if you've got powder and want to change anything where you have to drill, grind, or weld then you've messed up a nice powder job...with paint you can just touch up and go...and yes a powdercoat oven gets extremely hot during curing.. (hot enough to burn rubber) so about any kind of paint will get burned...

[joedoh]

definitely what mongo is saying, powdercoat AFTER everything is done and run and welded on the frame. otherwise a good paint job looks as nice and is more forgiving when you want to add something or touch up.

you cant have any paint on the metal at all when you powdercoat. it has to be completely bare to attract the dry powder and get the powdercoat to bond correctly in the oven.

[Foot Stomper]

Here's what epoxy primer does; it prevents rust from creeping under it and spreading if the epoxy coating is damaged by a deep scratch, stone chip or other damage. https://forum.ih8mud.com/threads/how...-doing.515427/

Here's what powder coat does; it makes a very hard (and brittle) coating that allows rust to creep under it and spread when chipped, scratched or otherwise damaged. Almost impossible to paint over it to repair these areas once powder coated. Very easy to paint over these areas if they've been epoxy primed and then painted.

If you plan on driving your truck, plan on having stone chips, scratches and other damages (even a floor jack will damage coatings) so pick your poison.

If you are building a no start, no drive, only push into trailer queen, then you have options.

Same goes for rims, grills and bumpers.

Powder coat has it's place and purpose, just know why and where it suits your build the best.

Note: SPI, PPG, BASF, DuPont, Sikkens, ICI, Matrix, Lusid, SW, HOK, even Spray Max and all other epoxies are all the same...no difference in corrosion prevention between any of them... there's no "best" powder coat or epoxy primer... just like there's no "best" beer or vacation destination agreed by all... don't get caught up in brands or "what's best" BS.

[focusedontheprize]

Thanks Foot Stomper. I actually am aware of the differences between them, I guess I should be clarify my question a little better.


To the people who have boxed their frames - what was your process? Did you apply any sealer inside the rails and then box it and finish the frame?

[Foot Stomper]

I haven't boxed a frame but am experienced in coatings. Would you like my reccomendation?

[Flysocal]

I didn't fill the holes on the frame but I did box it. I think some of the original character is cool since I'm not trying to turn the original frame into something it's not. The original holes allowed the powder coater to spray inside the frame through the larger holes. Can't say how good the coverage is but I'm sure it won't rust from the inside out.

[mr48chev]

Somewhere I saw an article showing an extended nozzle setup to spray the inside of boxed or semi boxe frames.

Here is some discussion of it on a Mudder site https://forum.ih8mud.com/threads/pai...e-rail.135695/

Another thread on the subject https://www.jalopyjournal.com/forum/...frames.180080/

[hogfarm]

I boxed the frame on my 58 and then painted it,I would use por to paint,even thou I did not,discovered it to late. but I did use KBS cavity coat with the wands ot do inside frame

[MIKESAD50]

As Hogfarm suggest maybe one of the cavity waxes that they sell for shooting into frame rails, pillars etc for protection, I'm sure somewhat limited but better than nothing. Never used them.
If the frame hasn't rusted away yet then any protection, paint or powder coat will protect it for many many years ahead.
Paint will be better for touch up now and down the road.
Progress is go well keep up the work, gonna be nice.

[focusedontheprize]

Thanks everyone. I spoke to the powdercoater too and he recommend if I really want to go with a primer inside the rails - to just do the whole chassis and go down that route.

[HO455]

When you box your frame the welds will burn off whatever coating you use and you will have unprotected metal inside and out. The outside is an easy fix if you haven't powder coated it. If the inside rust is a problem you can recoat the inside with an undercoating sprayer that has a flexible wand like My48Chevy said. There are several products you can use to prevent rust. From organic products like Fluid Film to rust convertors to coatings like POR-15. I went the POR-15 route on my Burban to protect the voids in the body. Organic products like Fluid Film are much easier to clean up and may the best bet on something already restored. I have used it extensively at work on ocean going tugboats. It works well but must be reapplied from time to time. (At least on the boats it does, but that is a much harsher environment). They are less toxic too. If your interested I posted some more info on my process that I used in my WMB thread below.