Alternatives to Rivnuts?

[Space Cadet]

I've got a firewall cover over my wheel-well that contains a swirl-pot and auxiliary pump & regulator etc, I need to be able to relatively easily remove the cover so using bolts and nuts from underneath the boot floor is not really viable. The cover was originally held down with self-tapping screws but these would just undo after a couple of weeks, so we've tried some rivnuts which in theory did the job as I could just undo a few Allen-screws from the top, but two of the rivnuts lost their purchase on the boot floor and were just spinning around (I have been able to remove them). What other alternatives are there to rivnuts where the 'nut' would be held more securely? Thanks.

 

[Cup_Phil]

Better rivnuts LOL

The better ones have grooves in them to stop them spinning

 

[Budgie]

Weld a standard nut to the underside?

 

[Gorms]

Could you rivet (solid rivets) some anchor nuts on the back? Or as already said weld some nuts?

 

[Space Cadet]

Ok, thanks, didn't know there were different types of rivnuts. They're M6 so will drill them all out and put M8's in which will have a larger circumference and hopefully therefore more purchase, will get grooved nuts this time. I did think about welding some nuts to the underside but sod's-law I've just finished up cleaning and painting the boot area with some truck bed-liner paint (looks really good and hard-wearing by the way) and I think the heat from the weld would probably fcuk up the paint. TBH some new larger, grooved, rivnuts would be easier, might think about putting a spot of liquid-metal around the rivnut once done just to give it a bit more strength.

 

[Cup_Phil]

Did they spin when you were removing the bolt?

Problem with stuff going through the boot floor is the bottom of the bolt corrodes with road water/salt and then when you go to undo them they're seized in
When you put the bolts in try putting a blob of grease or copper grease over the bolts to stop them corroding in

 

[Space Cadet]

The nuts span when I was tightening the bolt, must've gone in at a slight angle or got a spot of something in the threads. The car has only done 24k and the bottom of the floor and boot is literally spotless and I've never even had to clean it, must've just been used in the dry. One job soon though is to spray some waxoil rust proofing over a few places where I've put some steel harness eye-bolt plates and drilled through the floor to fix various things so will coat the rivnuts then.

 

[MG cup]

Use splined steel or stainless rivnut's and make sure the threads don't protrude through the rivnut, grease them and you won't have a problem if there being undone regularly. The ultimate is to have stainless rivnut's and fixings.