markz Wrote:That's a bit further from a solid edge than I anticipated. There is some risk of warping. I would use a heat sink compound such as this one (this is the one I use - its reusable - just keep it wet)
http://www.eastwood.com/ew-anti-heat-compound-1-qt.html
This is a newer style I have not used before:
http://www.eastwood.com/coldshield-thermal-paste.html
To weld it, I would go down one heat setting than what is called for. Need to keep an eye on it - may need to go to rated heat.
Trick is to just zap it. Zap an edge, let it cool for a second, then zap right next to it using the first ball as a heat sink. Keep going around - you can fill about 2/3 of the hole and then finish it up - very small circular motion. If you are concerned about burning through then go all the way around the hole before you finish it - the welded part is much more difficult to burn through. It is pretty amazing how big a hole you can bridge with the mig. Certainly when you have about 1/8 inch hole left just finish it off. If you do it correctly after grinding all you will need is primer. Grind with a 36 grit sanding disk, although 24 grit can also be used. I use a 5 inch disc. Use 0.025 wire - thicker wire (0.030) can be used but its not as good or easy.
Practice..........
Thanks for your time Mark, I have 030 wire in machine now a friend has some 025 I can get a hold of.
Andy,
If you haven't finished yet try a piece of copper backing on the backside of the hole, the mig wire will not stick to it and it makes for a faster and more solid weld. I took a magnet and attached a piece or 1/8" flat copper to it and it works real good.
I am going to bring it down to the shop this weekend and give it a go thanks for the tip CD it all really helps allot to get these ideas.
cd45harris Wrote:Andy,
If you haven't finished yet try a piece of copper backing on the backside of the hole, the mig wire will not stick to it and it makes for a faster and more solid weld. I took a magnet and attached a piece or 1/8" flat copper to it and it works real good.
That's true. Watch out cause a magnet can/will distort the weld if too close. Also the copper gets VERY HOT! They sell special spoons for this purpose but I make mine out of copper 1/2 or 3/4 tubing.
I used all methods above and all worked great. The small 1/4 trim holes on pillar I used the uni-spotter just because I wanted to experiment, it was quick and easy but will not work on the bigger trim holes at bottom of rear window about 5/16 due to head on studs is too small. Maybe they make bigger ones I don't know.
So on the 5/16 I used some Hot Blocker spray gel and mig with copper held on with magnet on back side, this all worked well also. Took more time to smooth back out but all went well.
Then went back on back side and under coated each weld.
Thanks for the ideas and input I learned something new .
67r/t4speeder Wrote:I used all methods above and all worked great. The small 1/4 trim holes on pillar I used the uni-spotter just because I wanted to experiment, it was quick and easy but will not work on the bigger trim holes at bottom of rear window about 5/16 due to head on studs is too small. Maybe they make bigger ones I don't know.
So on the 5/16 I used some Hot Blocker spray gel and mig with copper held on with magnet on back side, this all worked well also. Took more time to smooth back out but all went well.
Then went back on back side and under coated each weld.
Thanks for the ideas and input I learned something new .
Sorry Andy, but.........
Worthless Without Pi
Richard