The Stovebolt Site Forums The Shop Area Paint and Body Shop weld clean-up

I'm doing some panel replacement. I'm tacking in the panels with multiple tack welds. What is a good way to knock down the welds. I'm using a 50 grit sand disc which works prety well. Wondering if there is a better way. Thinking about the use of a die grinder to run over the high spots. May I have some advice please. Thanx.

grinder works fine...... Be careful not to grind too much off. If you get your welder set just right, your need for grinding will be reduced.

3M makes a weld grinding wheel,it is made like a 3" cutoff wheel but much thicker, does a real good job for me,,brian

Be careful of heat build up when grinding. You don't want to warp your panel.

Thanks for the advice. Sounds like with a little more tweeking on weld settings and some finesse with the grinder I'll be fine. Thanks again for the insight.

I take it you are using a mig welder with shielding gas. If so you might want to try a wire called "Easygrind". It is made specifically for body work and grinds much easier than standard mig welding wire. It is a little pricey, around $40.00 for a 11# spool, but well worth the price if you are replacing very many panels. One place to find it is weldingsupply.com Part # for .023 is 130tf43, and for .030 is 130tf44. The wire is made by spoolarc.
John

For grinding down welds on body panels I like a 'flapper wheel' more than anything else. Its a wheel with sandpaper layered around it and probably has a proper name I don't know.

I got a 4 pack at Harbor Freight but couldn't find a picture on their webpage.

I will just make a quick not if you are new to welding sheet metal. Or anyone reading this.

I have seen over and over again people without welding experience grinding welds to make things look better. What they dont realize is that the weld's bead is the part that is holding it together. Grind the bead off and there is no strength.

I have seen people finish projects paint and then they fall apart.

I am not saying you are doing that, just warning you to leave enough weld to hold eveything together.

Consider a spot welder. You can ge them at harbor freight for about $100. It will give you a better weld without grinding.

It only works in areas you can reach, but a great tool.

Just remember to leave some weld. Grinding them flat looks great, untill it comes apart.

I hate to disagree but I would like to give another side of your post Buzz.

If you have properly welded with full penetration there is no reason what so ever that you can't grind the weld all the way down flush. If it fails after one ground the weld down, it was not welded properly, PERIOD, end of story.

I mean, let's go to the metal masters. They will make a fender out of many pieces, butt welded together and metal finish them with no filler what so ever. If you want to see this in action, I HIGHLY recommend getting the video/dvd "Making the Model A fender". http://www.fournierenterprises.com/cart/product.php?productid=16252&cat=2&page=2

Amazing stuff I don't expect to be able to do anything like this any time soon, but amazing to watch. Split the cost among some friends and have a movie night.

And I don't mean one needs to be a "Metal master" to do it, not in the least. If one is not penatrating one needs to learn how to weld properly. The bead should NEVER be expected to "hold" it together. The WHOLE POINT of welding is joining the metal making ONE piece. If one is relying on the bead, one has mearly "glued" it with some filler rod.

On the spot welder, I use a $20,000 Squeeze Type Resistance Spot Welder (STRSW) at work and I have to say, it barely reproduces an OEM type spot weld under PERFECT conditions and settings. That $100 welder from HF is just not going to get it done. I have tried a few of these economy spot welders, they DON'T work. I have not tried this one, it may be the anomaly.

Now, I totally agree in that grinding the welds down flush by someone not comfortable with their welding, and having done destructive tests to see how well they are penatrating is probably a bad idea.

A butt weld on a panel being "bondoed" might as well be left semi ground, being you are covering it with filler anyway.

However, one REALLY should be doing test welds, and destroying them to see if they are welding properly.

Brian