[muskin]

Hi I hope its ok to ask this question on here.
My car isn't actually a hot rod but an old vw.

I had to cut out the old metal under the rear window of the 73 super beetle due to water damage from the factory sunroof. I replaced the metal from a donor car and welded it in pretty good for a newbie. I have one problem with the welds though. I noticed small pin holes in the welds, I have gone back over some of the pin holes and got most if not all the holes out now. What I'm wondering now is what I should put over these welds once i have gotten then grounded down smooth. I was wondering if I should just shoot the repair with epoxy primer and then go over the area with some evercoat z-grip filler. Or if i should use one of these products [USC DURAGLAS,Tiger Hair,Kitty Hair, or Everglass.] then epoxy over it.

Thanks Barry

[OneMoreTime]

What I would do is get the affected area clean and dry and shoot the epoxy primer then do a thin coat of filler as needed....The pinholes are what we call porosity in the welds..Just takes a lot of practice to get good clean welds..As long as it is soundly welded and all the holes are treated should be just fine..

Sam

[35WINDOW]

OneMoreTime,

I think you are right on, however, I have had tiny holes in my Mig and Tig welds in the past (as I "spot" Weld sheet metal). As I read his post I wondered if that was what muskin meant. I don't know what everyone else does, but if I have that problem I carefully re-weld and grind, and will sometimes take a flashlight (turn off the lights) behind the panel to make sure that no light shines through. I thought that was the correct way (for that problem)-maybe I"m anal?

[37ford4dr]

why not go back and fill the hole in with the mig welder? sometimes the flux core wire will give holes are you using flux core wire?...in this area you could use a fiberglass body filler since it will never absorb any moisture and fill the hole and then do the final sanding

[OneMoreTime]

Originally Posted by 35WINDOW

OneMoreTime,

I think you are right on, however, I have had tiny holes in my Mig and Tig welds in the past (as I "spot" Weld sheet metal). As I read his post I wondered if that was what muskin meant. I don't know what everyone else does, but if I have that problem I carefully re-weld and grind, and will sometimes take a flashlight (turn off the lights) behind the panel to make sure that no light shines through. I thought that was the correct way (for that problem)-maybe I"m anal?

That is the "correct way" however if all that is left to "fix" is some tiny pin holes the epoxy and fill wrks fine..Sometimes it is just time to move on and get it done..Your call on it as it is your car and your work..if one has holes those need to be filled but tiny porosities can be taken care of as I suggest..

Sam

[muskin]

35WINDOW yep you are correct its a donor piece that I welded in with gas. I'm going back over it also. What I have been doing is using a shop light, I stick it as far behind the weld as I can get it and it shows where the pin holes are.

[1931 steve]

Not to hijack the thread, but. I consider myself a OK welder but I get pin holes in just about every weld I do. Is there something I can change to eliminate this?

Steve

[oldred]

Steve, I assume you are using a mig? First thing is make sure both sides of both parts are CLEAN this means no paint, rust (especially rust), oil or dirt the exception here is weld through coating and some primers are ok. Then make sure there is no draft that can affect the weld, it only takes a tiny breeze to contaminate the shielding gas. A little note here about that, it is a very common mis-belief that turning up the gas flow will correct the draft problem but in reality it seldom helps since the shielding gas does not "blow away" as commonly believed, at least not unless the draft is really strong, but it becomes contaminated with atmospheric air causing porosity. Make sure the nozzle fits snug and is clean with the wire contact tip about flush with the end of the nozzle, I prefer it to stick past the nozzle about 1/16". If the nozzle is loose on the gun it can cause air to enter from the back due to the venturi effect and this can cause porosity also. This seems to be a little known phenomenon but I have seen it turn out to be the mystery problem several times.

[1931 steve]

Oldred, thanks for the tips. I will apply them the next time I weld something. It may also be my welder, I have one of the old flux core wire feed welders. I will be buying a new one (MIG or maybe TIG) before I start working on the 31. Thanks again for the tips.

Steve

[redsdad]

One thing that I have come to the conclusion on while working on my 41 is that when people say, "They don't put steel in cars like they used to!", it is better that they don't. I am not a great welder, but I can be welding along great and then all of a sudden, bam, it is like I forgot how to pull the trigger. The manufacturing manager from my plant, who is an expert welder, welded the front spring mounts on the frame and he agrees. The steel is just not consistent in these old cars. So, Steve. Go careful and don't beat yourself up if it seems like you go from genius to stupid in a matter of seconds.

[oldred]

Steve, Since you are using flux core instead of MIG the draft and tip/nozzle will not mean much HOWEVER the part about keeping the weld area clean is still extremely important.

[MARTINSR]

All I can say is move up to gas. That one change will make more of a difference than you can imagine.

Brian

[1931 steve]

I know, I know . I'm looking at the Lincoln Power Mig 215 or the Lincoln Precision Tig 185 about $200.00 difference in price. I think the Mig is what I need for most of my welding jobs here at the shop, mostly exhaust and mild steal but the Tig has the cool factor. I can assume that the Tig would do everything I need also, just at a slower welding pace. I will have some welding to do on the 31 Ford when I start. Some body panels and frame mods. What do you guys think would be the best welder for this type of work?

Steve

[oldred]

IMO the MIG is best for all around. Try and find some of the JW Harris twenty gauge MIG wire for body work, this stuff is unbelievable on body panels

www.jwharris.com/images/twentygauge.pdf

[1931 steve]

Oldred, is the JW Harris twenty gauge MIG wire you talk about for the new welder that I may buy or is it for the welder I have now? Can I weld aluminum with a Mig? I have a few parts that need to be modified such as a radiator that needs mounting pins welded onto it. Could I use a Mig to do this type work?

Thanks you and everyone else for your knowledge and help.

Steve