kitty hair filler got wet?

[blazer2007]

Did a little rust repair and put some kitty hair or dynoglass filler over the welds and after it cured and got all sanded down nice and a couple days later had it outside and it get wet from the sprinkler while I was gone. Take it all off ?

[MP&C]

What drives the need to use Kitty Hair over top of welds?

Not to step on toes or assume what you have done, but in the past I have seen guys that had deficiencies in the welds that they had pin holes they wanted to fill in, so they used kitty hair.

One guy didn't have good weld penetration so he always added kitty hair over his welds (if you can call them that) in an attempt to give strength to a panel that was doomed for weld failure. Here are samples of his work:







And then would ask me how I could grind welds down flat without fear of the panel coming apart.



Your vehicle, your repair, do what you want. (disclaimer)

But adding Band-Aids to substandard work does not eliminate the risk of failure. Leaving weld prouds on top of a panel because there was no penetration risks ghost lines in paint just as much as a flange seam, it leaves excessive metal there that reacts differently than single thickness. If it is a weld issue, fix the weld. If it is a weld penetration issue, turn up the heat, planish the welds, grind both sides flat. We're trying to duplicate the panel that existed before, if that was single thickness metal, duplicate it to the best of your ability. Welds like shown above have no business being left as is and band-aided with kitty hair. I always suggest someone practice on scraps the same thickness to get your welder dialed in, and that picture is a textbook case of why. Sorry for jumping on a soapbox here, but there should be no reason to add kitty hair to a weld.



This forum is all about helping someone to do their bodywork on the own, and doing it correctly. Many people have shown pictures of welds and have been coached by myself and many others on here in order to better improve results. If that is needed, please let us help out by critiquing welds for you. If it is not the case, I apologize for stepping out of line.

[Foot Stomper]

Originally Posted by blazer2007

Did a little rust repair and put some kitty hair or dynoglass filler over the welds and after it cured and got all sanded down nice and a couple days later had it outside and it get wet from the sprinkler while I was gone. Take it all off ?

Yes, take it all off and do not use it on your project. Fibreglass reinforced fillers have no place in a vehicle restoration.