Fabrication - Rivet Nuts, tools or, blind rivets and sheet metal usage

Moderator - Please move this post if necessary. The fabrication forum appeared to be devoted to more sophisticated issues than my question.

I see the cost of the tools for setting riv nuts have reduced in cost but I have no clue which of these tools/brands is worth the investment. I am trying to extend the life of a vehicle whose floor pans have decayed. One of my primary thoughts to extend its lifespan is to cover up the affected areas with galvanized sheet metal. The unibody structural rail channels, the shape, and spacing permit me to do this. I am uncertain if I should secure the galvanized sheet metal using rivet nuts or rivets.

Please respond with your recommendation regarding rivet nut tools and rivet nuts. Note, I must also purchase a pneumatic rivet gun if this is determined to be the preferred method for securing the galvanized sheet metal.

R Van Camp said:

Moderator - Please move this post if necessary. The fabrication forum appeared to be devoted to more sophisticated issues than my question.

I see the cost of the tools for setting riv nuts have reduced in cost but I have no clue which of these tools/brands is worth the investment. I am trying to extend the life of a vehicle whose floor pans have decayed. One of my primary thoughts to extend its lifespan is to cover up the affected areas with galvanized sheet metal. The unibody structural rail channels, the shape, and spacing permit me to do this. I am uncertain if I should secure the galvanized sheet metal using rivet nuts or rivets.

Please respond with your recommendation regarding rivet nut tools and rivet nuts. Note, I must also purchase a pneumatic rivet gun if this is determined to be the preferred method for securing the galvanized sheet metal.

Click to expand...

Welding works better.

back in the old days I did a few daily drivers that had the front floor pans rust out. I later figured out the problem was rubber backer floor mats that trapped moisture laden with road salt from evaporating.

Pop rivets and some kind of sealer/caulking compound inside, and undercoating underneath. I had best results with asphalt based undercoating.

I even helped a friend with one in an old Triumph using an old steel cookie sheet he scrounged somewhere.

Rivnuts are used where something needs to be removable. I've used the to repair stripped out trim attachments such as plastic air dams. The holes strip because the excess screw length get badly rusted over the years. I usually replace the screws with stainless so the same thing won't happen to the rivnuts years from now.

Buy a Marson HP-2 hand riveter and use 1/8" or slightly larger rivets. It's only a floor pan, not a structural frame.

Scottl said:

Buy a Marson HP-2 hand riveter and use 1/8" or slightly larger rivets. It's only a floor pan, not a structural frame.

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If it includes any anchoring points for the seat or seat belts, it needs to be treated as a structural part. That means thick enough sheet, and using a backing washer on a sufficient number of of 3/16" rivets if riveting from inside the car.

JMO, of course...

Milland said:

If it includes any anchoring points for the seat or seat belts, it needs to be treated as a structural part. That means thick enough sheet, and using a backing washer on a sufficient number of of 3/16" rivets if riveting from inside the car.

JMO, of course...

Click to expand...

He said floor pans rather than floor and in my experience such rot seldom occurs past the are covered by the floor mats. Usually the seat area is slightly higher and water doesn't collect there. In my area it's very common with older cars after years of people getting in with snow covered boots contaminated by the salt they put on the roads. In my personal cars it mostly happened on the passenger side because I do usually do a "Dorothy" and click my heels together to dislodge snow before swinging my legs in.

PS: It hasn't happened in years because I use a needle in a Dremel to make tiny holes in the back of rubber backed carpet mats so water can evaporate.

digger doug said:

Welding works better.

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Yes....Welding..even if it's only a series of small welds. You can get a cheapo MIG welder from under $200. that will run on 110 volt if you don't already have welding equipment. Get your patch in place and use sheet metal screws to fit and hold it in place. Use button welds in the screw holds as you remove them.

Plenty of youtube vids covering patching floors. Only caution is welding galvanized.

Buy a Marson HP-2 hand riveter and use 1/8" or slightly larger rivets.

Click to expand...

Just be sure the rivets are steel, not the commonly available aluminum.
Stainless is also available, but at that level of "caring" you would probably want to do a better job and weld.

Buy a Marson HP-2 hand riveter

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There are times you will always need the hand tool, or disdain hauling out hoses to set a couple rivets somewhere.
However, HF will sell you the small size pneumatic gun for the same price or less (Depending your source for Marston)

3/16" Air Hydraulic Riveter

I've bought most of my good hand pullers at flea markets, for $5 - $15 each.
I have the larger size HF pneumatic - pulled some 450 - 500 #10-24 & 1/4-20 *riv-nuts last month..... Nothing wrong with that tool.

*not to confuse anyone about riv-nuts - the HF tool is only a rivet puller. But i got the larger size

1/4 in. Air Hydraulic Riveter

since it will pull heavier shanks (has a spare over-size collet).
Then using 4140 PH i made a pulling stud, & a nose piece for each size riv-nut. Depending on your application or preference, the 1/4" & larger size has to be an extension. If you want to support the riv-nut in the hole with the same full-size untreaded portion that will keep it from collapsing. Most don't collapse anyway, but building the tools as such a simple lathe job i included the shank.

If you are not familiar with the collet set up in a pneumatic pullet, take some time to study it. The nose-piece to collet face distance has to be set such that the collet opens adequately, but does not use up overmuch travel. If a stem or pull stud won't enter the nose piece, don't jam it in. Or it will be extremely if not impossible to remove. & DAMHIKT. Remove the large nose piece and adjust the collet distance.

My HF gun will pull Marston ribbed riv-nuts, #10-24 on about 45psi, and 1/4-20 on about 50 - 60 psi.
Could probably even do less, but don't need to check every fastener. Sometimes on thicker assemblies it takes a little more pressure, thin ones not so much.

Marston does make pneumatic/hydraulic rivnut spinner-pullers if you do this all day every day.
I chose not to ask the price.

smt

I have had to do this job on a Datsun 240Z that I swear you could hear it rust on a quiet night. I went the pop rivet route and it worked quite well. If you are going to do this with pop rivets then I strongly suggest you buy a set of Cleco fasteners. Anyone who does anything with springy sheet metal and pop rivets needs to get a set of these. They are just amazing for holding everything in alignment while you install rivets. Just remove the fasteners one at a time and install rivet. Couldn't be easier. I didn't know they existed until a friend of mine who retired from a body shop gave me a set of them. I included a link below. Worth every penny for using pop rivets in sheet metal.


Amazon.com: 25 Pc. 1/8" Cleco Fasteners with Cleco Pliers : Industrial & Scientific

Fit the new panel up and drill the holes. Apply a generous coating of epoxy to the floor, then place and fasten the panel. The result will be solid and waterproof.

stephen thomas said:

Then using 4140 PH i made a pulling stud, & a nose piece for each size riv-nut.

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Stephen,

Would you mind showing some pictures of your pulling stud and nose piece?

I am slowly transforming a Ford Transit Cargo into a campervan and will have to become intimately acquainted with rivnuts in the near future. I have been looking for a simple solution and it sounds like that might be it.

Thanks,

Jacques

get an Astro tools drill adapter for riv nuts!

no704 said:

get an Astro tools drill adapter for riv nuts!

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Thanks a lot No704!

I looked it up, watched a few videos and I am sold. I ordered one.

That seems like how a rivnut tools should work. The idea of screwing and unscrewing each one by hand just for the installation just seemed primitive to me.

Thanks again for the tip!

Jacques

R Van Camp said:

I am uncertain if I should secure the galvanized sheet metal using rivet nuts or rivets.

Please respond with your recommendation regarding rivet nut tools and rivet nuts. Note, I must also purchase a pneumatic rivet gun if this is determined to be the preferred method for securing the galvanized sheet metal.

Click to expand...

I am certain of this... Removing a stainless steel rivet is a difficult task if it starts spinning in the hole. If you use stainless then be sure they are there to stay.

Head over to YouTube and search for MUSTIE1. This guy is a mechanic in New England up by the Canadian border that has a youtube site of repairing otherwise junk. He has a number of videos on doing exactly what you want to do, including restoring frame members. He uses welding and has tricks on MIG welding thin sheet metal. His solution to the undercoat is not the traditional asphalt undercoat but rather a mixture of chain oil lube and solvent.

undercoating with bar and chain oil, - YouTube Undercoating with bar and chain oil.
Metal Fabrication For Beginners. - YouTube Replacing rotted out floor in a VW.

Mustie1 - YouTube

Have fun

Tom

One time when I was a kid, my dad handed me the torch and told me to crawl in and weld the car floor, since I could fit way better than him. "See that tube? That's the fuel line. Don't weld that."

get an Astro tools drill adapter for riv nuts!

Click to expand...

Might fit someplaces a pneumatic/hydraulic won't. But the gun is so fast i'm sticking with it.

Would you mind showing some pictures of your pulling stud and nose piece?

Click to expand...

Sorry, we were traveling and then i was out of the shop for other reasons.

Someone on Homebuilt Airplanes asked about it. I posted pix there with short description.
Easier to post bigger pix there than on this site anymore.

(FWIW, my HF large size gun cost less than the Astro drill adaptor)

Scroll down to my/Aviacs post #65, Click on fingernails to enlarge.

Replicating a Hawker spun rivet joint | Page 4 | Homebuilt Aircraft & Kit Plane Forum

Nose pieces shown to illustrate how the backside opens the collets. Collet system has to be adjusted to open against the nose piece, but not too far or it reduces the travel. On these guns, don't jam a stud in if the nose won't open, becomes really devious to get it back out, so the chrome nose can come off, to further adjust the collet position.

The step-pilot drills were made so top and back sheets can be fastened together (Clecos, screws, clamps, whatever) and the screw holes drilled through both pieces. Then the top sheet is removed, and the step drill used in the hole in the back sheet to drill the rivnut dia hole.

smt

For auto sheet metal patching I use 1/2" (or 3/8") #8 Type A hex washer head self-tapping screws. Drive them with a socket in a drill or screw gun. No pre-drilling needed. Slop roofing tar around the hole so it seals the joint and adds structural stability, too,and cover everyting with it when done.

First car I had was a 1962 Peugeot 403, rusted-out unibody. I welded it all back together using oxyacetylene torch and 20 ga galvanized steel, then drove it for ten more years.

But welding IME predisposes the heated area to rust...Hollow sections you cannot re-coat inside, but moisture gets in and rusts it out again from inside.