frame stiffener ?s

This topic has been beaten time and again, which is why im going to ask this stuff. Im sure over time theres a few things you all would/wouldnt do again or can clarify.

Im leaning toward ruffstuff center stiffeners, 2nd choice iro

Prep:

remove all undercoating and Only remove paint to bare metal where welding, Yes?
I dont understand why everyone removes all of the factory primed metal. Sure some will burn away, but isn't this worth leaving where your not welding?, its far superior to rattle can.
I plan on torching/scrapping the undercoat off, then use goo gone pro power to remove remaining residue. Then just sand weld areas to bare metal.

Weld through primer, use or dont use?(upol copper)
all my research shows this burns off anyway so maybe better rust preventive coating should be used for the inside of the stiffener?

install/design:

ruff/iro both have that lip for the floor board. Was this designed to be welded on or just seam sealed around as a support?

welding the flex/split areas of the stiffeners, I see many folks weld this solid. Is this best practice or does that make a worse stress area compared to the rosette areas?


This is my DD so ide like to do the best job I can with these, thank you for your help.

I've done 3 set of stiffiners on 3 different XJ's. 2 were just center and one set full front to rear. Still own all 3 XJ's and the are holding up fine. I've used Ruff Stuff and TNT mids, and IRO's full set. All are about the same work to install.

I stripped off the undercoating with a heat gun, then hit it with acetone, flapped disked just the areas that I welded. Did not use weld through primer, but I did seam seal it all around, just leaving some of the holes open on the bottom. However, I'm not wheeling in wet areas usually.

You can weld the upper lip, but I did not on any of mine. I didn't want to remove the carpet, plus it's not exactly a tight fit up there. Plus more undercoating to remove. Didn't see an advantage, just seam sealed it really well.

Welded the splits solid. Wasn't an issue. Afterwards, primed them and hit it with 3M professional grade undercoating.

By far the worst part is the prep. Welding is not exactly easy either. Unless you have a lift, it's a bit of work, but worth it IMO.

Why not leave the undercoating intact on the frame except adjacent to welds? also the weld thru paint is important to have. Id put the weld thru primer only where needed near welds on the stiffener, and paint the rest of the inside with a good epoxy paint I think, then weld it.

post welding, what to do about the voids between the frame and stiffener? perhaps automotive cavity wax?

them is my random thoughts, what say you all?

i would think the undercoating would melt/drip. its typically similar to asphalt. cavity wax is definitely being used after the fact, as well as RP-342.

epoxy paint isnt a bad thought for it to bite and stay, its very durable, though its probably not the best thing to burn up, mask aside haha.

the only real reason for grinding that i have read is for removing the galvanized coating/ getting a bare metal surface to weld to. though i see so many examples of folks sanding the whole frame rail to bare bones, this seems to be a waste of work and efficiency.

johnnycatt63 good to know youve done this as im thinking. make sense to me.

does anyone know how many tubes of seam sealer the center stiffeners usually require?

4x4JeePmaNthINg said:

i would think the undercoating would melt/drip. its typically similar to asphalt. cavity wax is definitely being used after the fact, as well as RP-342.

epoxy paint isnt a bad thought for it to bite and stay, its very durable, though its probably not the best thing to burn up, mask aside haha.

the only real reason for grinding that i have read is for removing the galvanized coating/ getting a bare metal surface to weld to. though i see so many examples of folks sanding the whole frame rail to bare bones, this seems to be a waste of work and efficiency.

johnnycatt63 good to know youve done this as im thinking. make sense to me.

does anyone know how many tubes of seam sealer the center stiffeners usually require?

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I use a different product than most for seam sealer. It's a construction grade adhesive/sealant called Vulkem 116. Polyurethane and tough as nails.

Been using it for years in construction, stays flexible and lasts forever. I started using it in automotive applications because of it's ease to work with and it's bonding capabilities. You can put it on with a standard caulking gun and apply it as heavy or light as you want, it's non sagging. It also bonds metal together with incredible strength. Even my brother, who has years of experience as a auto and aircraft painter, says it's the best seam sealer he's ever used. YMMV.

It has a little bit of a texture to it, so when you apply undercoating, it blends in real well. I found it to be superior to any other automotive seam sealer on the market.

A couple of tubes will be more than enough. You can get it on-line, or maybe through some local retailers in your area. I buy it at Dixieline Lumber, but I think they're only in So Cal.

well i cant argue with the price !!!

Interesting thought about using the Vulkem. I have also used it for years in construction, but never thought about applying it to an automotive application. I can see it working well.

I will note that there are some issues with it curing in the presence of fresh latex paint. I believe it is a bit of alcohol that is added to water based paint to prevent it from freezing, but that will react with the Vulkem such that it will not cure properly. I doubt Vulkem would have issues with solvent based undercoatings and the like, but as the world goes water based more and more it might be a detail to pay attention to.

Anak said:

Interesting thought about using the Vulkem. I have also used it for years in construction, but never thought about applying it to an automotive application. I can see it working well.

I will note that there are some issues with it curing in the presence of fresh latex paint. I believe it is a bit of alcohol that is added to water based paint to prevent it from freezing, but that will react with the Vulkem such that it will not cure properly. I doubt Vulkem would have issues with solvent based undercoatings and the like, but as the world goes water based more and more it might be a detail to pay attention to.

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Yeah, I've ran into that issue with paint, too. It can check the paint a bit if you paint it too soon. You have to let it almost fully cure before latex paint. After that, I've hit it with latex no problem. I usually let it dry a couple of days or more before I hit it with any type of paint. Comes out really nice. Regardless of the type of paint you're using, if you're brushing it on, you have to let it dry, otherwise the bristles will kind of smear the Vulkem.

You can hit it sooner with oil based paints, like rattle cans, but I almost always let it dry no matter what. I used rattle can primer and 3M undercoating on all my jeeps and it's held up fine, but I let it dry a few days before paint.

A roofing company that I use for jobs, always uses Vulkem around the pipe flashings and other areas, and then they rattle can it right away. They never seem to have issuses with checking, but it's on a roof, so sometimes hard to tell.

the zinc plating on the body is fairly thin, it can be welded too I think. Zinc is really a great corrosion stopper. It would be a shame to remove it.

What brand did you go with?

I liked the TnT stiffeners on my ZJ... A ton of work to be sure. I jumped on a group buy for the TnT stiffeners is why I went that route

Stiffiners are all about the same. I've used TnT, IRO, and Ruffstuff. All are equally good. If I had to give a preference, it would be in this order:

1. IRO
2. Ruffstuff
3. TnT

Any reason why in that order?

ShoeterMcgav said:

Any reason why in that order?

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The IRO stiffiners were a full set front to rear, the others were just mid frame ones.

The IRO set fit well, plus I like their products and customer service. Everything fit nicely and was a well made product. I got them on sale for Black Friday.

RuffStuff is a good company, as well. I like them and their products, too. The mid frame stiffiners fit well and are well made. I don't know about their front or rear stiffiners, so that's why I rated IRO's higher. You can't go wrong with RuffStuff.

Basically, you're splitting hairs between RuffStuff and IRO. I have more experience with IRO and have purchased many of their products.

TnT, on the other hand, the mids fit well, but I don't think they have that upper lip. I could be wrong, I don't remember. I bought their long arm kit along with the stiffiners.
And here's the rub, I just didn't like TnT that much. The long arm kit, while well made, wasn't as well thought out as it could have been. the instructions were not very good, and some of the small components were not well made. I was just more aggravated doing business with TnT, that's all. They messed up the order, (it happens) and their customer service and website isn't that good.
Granted, this was 2013, things may have changed, or it just may have been circumstance. Personally, I just would not rather buy from TnT. Not a knock on them, I just prefer to spend my money elsewhere.

i like the ruffstuff design better, but the price and shipping on top of that is far more than the IRO.

IRO in the mail.

Front and rears included?

Getting the full set is hard to argue... I only had the stiffeners for the middle section on the Z, used sections of plate for the front

naw, havent decided on fronts. I dont like that ruff doesnt wrap under, but ide like any choice to fully run parallel to the ground. Iro do, hooligan do, but only the rear halfs have that wrap. I might mismatch down the road, fish plate sections together and add plate to the under portions of the frame. 3/16 throughout would be sweet to.

For what it's worth, I did a pretty detailed write up, including things like weld through primer, welding technique, and eventually POR-15, seam sealer and undercoating...

Starts in post 327
https://www.naxja.org/forum/showpost.php?p=246396713&postcount=327

But you'll probably want to jump over to the build thread. As the full effort on stiffeners winds down by post 378 as there are a couple of detours for ZJ brakes and few things in the midst of that.