
Subframe Welding
#1
Posted 29 July 2010 - 08:18 PM
Can anyone tell me the best places to weld it to give it more strength or seal it up or should I just weld up all the seams I can reach? Also what is the best way to protect the inside the of the subframe where I cant get a spray can or brush to? Can i somehow inject waxoyl or some other product in there?
Any advice would be really appreciated. Cheers.
#2
Posted 29 July 2010 - 08:58 PM
I would suggest getting the subbie either chemically stripped or media blasted after you have welded it up. Once its cleaned/blasted some serious priming and painting then you can use waxoyl in all the nooks and crannies.
Seeing as its going to be used on a trailer then maybe consider getting it powder coated. You have plenty of options.

#3
Posted 30 July 2010 - 07:30 AM
Is there any reason I can't weld up all the holes to seal up the front end (the box section part) of the frame then slosh some type of sealer around inside it? Also if parts of the inside have been sandblasted can I apply waxoyl directly to it as I cant get a brush or spray can to it.
Edited by Brams96, 30 July 2010 - 07:32 AM.
#4
Posted 30 July 2010 - 09:47 AM
#5
Posted 30 July 2010 - 09:50 AM
#6
Posted 30 July 2010 - 10:44 AM
The blue circles - Do I really need holes there?
The purple circles - Add strengthening triangles here top and bottom?
Also along the green circles (& a couple of other seams) the two bits of metal have started to seperate a bit (2-3mm) from rust I think. Should I chop these back and weld fresh metal in there? Are there any legal implications about cutting metal out of a subframe and replacing it?
Attached Files
Edited by Brams96, 30 July 2010 - 10:44 AM.
#7
Posted 30 July 2010 - 11:05 AM
You can buy aerosol cans of waxoyl that will be fine for the subframe, if you have more to do then as mk3cortina said then buy the bigger compressed air system.
Again as its only for a trailer you dont need to add the triangular gussets but if you want to practise then give it a go. The areas that are boxed wont be fully blasted so pump with waxoyl then turn it upside down and apply again to ensure full coverage.
Any welding that is done to a subframe that is fitted to a car must be of a good/high standard due to MOT regulations, as a trailer is not mot'd then it can be more relaxed but bear in mind that it will be carrying a load so it still needs to be good.
If you do weld up all the holes and there is rust already forming inside then waxoyl will limit it but it will eventually come through.
Edited by sonikk4, 30 July 2010 - 11:06 AM.
#8
Posted 30 July 2010 - 11:55 AM
What if I seal the box section all bar 1 hole with, lets say blue-tak, then put loads of rust killer/converter and flipped it around to cover everywhere. Then I could remove the blue-tak let it dry and then do the Waxoyl sealing?
Or I could cut back one side of the seam that is splitting, deal with any rust inside and then seal the whole thing before welding a new section in to replace the chopped out bit. I could then seal inside the final section with waxoyl and fit a rubber bung to stop water ingress?
Sound like a fesable plan??
#9
Posted 30 July 2010 - 12:16 PM
#10
Posted 30 July 2010 - 02:04 PM

#11
Posted 30 July 2010 - 04:00 PM
I need to look my rear subframe more closely. With it fitted to car is it possible to fill with waxoyl still?
#12
Posted 30 July 2010 - 08:35 PM
#13
Posted 31 July 2010 - 05:46 AM




And finally a seam I have welded up and sprayed, it still needs tidying up a bit though I just ran out of time that day:

(In Pic 2) Should I use a 1mm disc to cut along the seam open it up a bit, clean it all up then seam weld it all back together? Or should I just cut the top section out, clean and reweld new metal in?
#14
Posted 01 August 2010 - 07:59 AM

I ground it back and rust killed it before applying some zinc primer and have almost finished welding on the repair patch. It is galvanised so should be better in the future.


I did get the 'extra' holes filled in and finished though:

#15
Posted 01 August 2010 - 08:47 AM
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