MR2 Roadster Owners Club

The Workshop => Maintenance, Problems & Troubleshooting => Topic started by: jvanzyl on November 20, 2022, 20:42

Title: Welding.. body with questions
Post by: jvanzyl on November 20, 2022, 20:42
So, I'm going to attempt a very minor patch weld.

Couple of questions for those in the know:

1- I'm assuming it's prudent to disconnect the battery and likely the ecu prior, anything wise to disconnect?

2- Grounding.. any suggestions on where or how?

3- is this a stupid thing to do? Should I just enlarge the hole and stick a rubber drain bung in it and can it quits?

4- what do people use to spray onto their welds to stop rust etc? Normal etch primer?

(https://i.ibb.co/YBSqQCH/F903-F69-F-A91-E-443-E-ABF4-0-E4-DC1-B20-B9-C.jpg) (https://ibb.co/YBSqQCH)

(https://i.ibb.co/bJ8Fpnt/69-FBACB8-AC94-4733-8-CE0-C60-A54-F77-E3-B.jpg) (https://ibb.co/bJ8Fpnt)
Title: Re: Welding.. body with questions
Post by: Carolyn on November 20, 2022, 20:57
Yes, do disconnect the battery.  The ECU should be fine, but if it worries you, disconnect it.

You can use the negative battery lead as an earth.

The drill out and bung it ain't a bad call either.

Etch primer and paint (both sides0 will  be fine

You got this one, John!
Title: Re: Welding.. body with questions
Post by: jvanzyl on November 20, 2022, 21:57
Quote from: Carolyn on November 20, 2022, 20:57Yes, do disconnect the battery.  The ECU should be fine, but if it worries you, disconnect it.

You can use the negative battery lead as an earth.

The drill out and bung it ain't a bad call either.

Etch primer and paint (both sides0 will  be fine

You got this one, John!


Thanks @Carolyn !  Your advice and confidence is very much appreciated!
Title: Re: Welding.. body with questions
Post by: shnazzle on November 20, 2022, 22:02
If it were me she'd be telling me to step away from the car before I kill someone :) 
Title: Re: Welding.. body with questions
Post by: jvanzyl on November 20, 2022, 22:58
Quote from: Anon on November 20, 2022, 22:31Drill it with a stepper bit till its metal. Paint up the edge.

Bond in a gromet bung with sikaflex/tiger seal etc.

That would be my call every day of the week.

It's not structural.... I'm sure if you go poking about you'll find worse elsewhere.

This idea is most likely the simplest... just out of interest, do you have any links to said grommets?

I do think my existing step drill bits don't go as wide as the grommets that are already in the car..

Update- just been searching and there are quite a few out there.. hopefully I'll find something decent.
Title: Re: Welding.. body with questions
Post by: McMr2 on November 21, 2022, 09:16
Quote from: jvanzyl on November 20, 2022, 20:42So, I'm going to attempt a very minor patch weld.

Couple of questions for those in the know:

1- I'm assuming it's prudent to disconnect the battery and likely the ecu prior, anything wise to disconnect?

2- Grounding.. any suggestions on where or how?

3- is this a stupid thing to do? Should I just enlarge the hole and stick a rubber drain bung in it and can it quits?

4- what do people use to spray onto their welds to stop rust etc? Normal etch primer?

(https://i.ibb.co/YBSqQCH/F903-F69-F-A91-E-443-E-ABF4-0-E4-DC1-B20-B9-C.jpg) (https://ibb.co/YBSqQCH)

(https://i.ibb.co/bJ8Fpnt/69-FBACB8-AC94-4733-8-CE0-C60-A54-F77-E3-B.jpg) (https://ibb.co/bJ8Fpnt)


I can't work out where on the car this is, but in any event I'd be making sure the fuel tank is well shielded.
Title: Re: Welding.. body with questions
Post by: jvanzyl on November 21, 2022, 09:57
Quote from: McMr2 on November 21, 2022, 09:16I can't work out where on the car this is, but in any event I'd be making sure the fuel tank is well shielded.

Ah- it's right underneath back drivers bum.
Title: Re: Welding.. body with questions
Post by: Joesson on November 21, 2022, 10:38
@jvanzyl
Quote from: Anon on November 20, 2022, 22:31Drill it with a stepper bit till its metal. Paint up the edge.

Bond in a gromet bung with sikaflex/tiger seal etc.

That would be my call every day of the week.

It's not structural.... I'm sure if you go poking about you'll find worse elsewhere.

@jvanzyl
I would also suggest that a welder has considerable potential for making things worse.
Not much to go wrong with a stepper bit and a grommet and I'm sure you have other things to occupy your time.
Title: Re: Welding.. body with questions
Post by: shnazzle on November 21, 2022, 10:38
Stick of chewing gum, wait for flavour to disappear, stick it in. Sorted.
Title: Re: Welding.. body with questions
Post by: tricky1138 on November 21, 2022, 10:43
Quote from: shnazzle on November 21, 2022, 10:38Stick of chewing gum, wait for flavour to disappear, stick it in. Sorted.

My mate was repairing his old Spitfire and found his seatbelt held in with roofing felt and tar!  :o
Title: Re: Welding.. body with questions
Post by: J88TEO on November 21, 2022, 13:49
ah...the old bodger at work!
Mate of mine filled up his Midget sill with newspaper and fibreglass over it! Then rattlecanned it and sold it to an unsuspecting young lady!
Title: Re: Welding.. body with questions
Post by: Dev on November 21, 2022, 14:56
In regards to welding on the car I did a few spot welds when I was making my own exhaust before I brought it over to my bench and noticed that my after market radio and gauges was flickering even though I disconnected the battery. The internet told me that it should not be a problem and it wasn't as the behavior went away but when I seen that happen I knew there is a potential for damaging any one of the modules or tiny circuits. 

 I had to redo the exhaust work later on which required welding on the car so I bought a device that hooks up to the battery that absorbs the surges. I am sure something like this is available in your market. This is just for future reference since it was brought up.
   
https://www.amazon.com/Dent-Fix-DF-601-Surge-Protector/dp/B002XMS0KU/ref=sr_1_4?crid=2BWQ04POPZ9I8&keywords=surge+protector+for+welding+on+cars&qid=1669042201&sprefix=welding+surge+protector%2Caps%2C61&sr=8-4&ufe=app_do%3Aamzn1.fos.08f69ac3-fd3d-4b88-bca2-8997e41410bb
Title: Re: Welding.. body with questions
Post by: jvanzyl on November 21, 2022, 19:50
Quote from: Dev on November 21, 2022, 14:56In regards to welding on the car I did a few spot welds when I was making my own exhaust before I brought it over to my bench and noticed that my after market radio and gauges was flickering even though I disconnected the battery. The internet told me that it should not be a problem and it wasn't as the behavior went away but when I seen that happen I knew there is a potential for damaging any one of the modules or tiny circuits. 

 I had to redo the exhaust work later on which required welding on the car so I bought a device that hooks up to the battery that absorbs the surges. I am sure something like this is available in your market. This is just for future reference since it was brought up.
   
https://www.amazon.com/Dent-Fix-DF-601-Surge-Protector/dp/B002XMS0KU/ref=sr_1_4?crid=2BWQ04POPZ9I8&keywords=surge+protector+for+welding+on+cars&qid=1669042201&sprefix=welding+surge+protector%2Caps%2C61&sr=8-4&ufe=app_do%3Aamzn1.fos.08f69ac3-fd3d-4b88-bca2-8997e41410bb

Interesting! Never heard of one of those.. thank you