The AM Forum

I recently scored an 1/8" thick steel rack panel for a project. It has several 1/4" drilled holes that need to be filled. The panel needs refinishing...simple spray painting job. Any ideas out there for a decent filler? Obviously, I don't need a huge amount. Epoxy? Bondo?

I like JB Weld products for things like that.  If you use some tape on the back side to keep it from running through, you can easily sand out both sides to restore the panel to almost-new.  They have a plethora of different tubes of goop, and I haven't yet found one that I didn't like.  They are mostly epoxies and stronger and less brittle than Bondo.  Some you can even drill and tap.  I usually had one or two in my tool kit when I was overseas. 

I use a countersink a bit on both sides, it makes an hourglass-shaped chamfer so the filler won't easily push out.

Bondo works best for me that way, making sure to use a hard block to sand with so as not to dish the filler.

73DG

I have two ways that I’ve used in the past. The most durable way is to first tap the hole I got a brass screw that was not threaded all the way. Iused brass because it is soft and easy to sand down. I screwed it in as tight as possible. I used a thin hacksaw blade, placed a “very thin” metal shim between the blade and the panel and cut it flush (on both sides of the panel). Using some very fine emery paper I sanded it flush, and repainted the panel. If you use fine emery paper, the scratches are invisible after painting.

Tried body filler, but it actually fell out after about a year. I used some epoxy and affixed a small square of window screen on the back of the panel. That provided some additional surface for the body filler to adhere to.

I do it another way, I use bondo, place a piece of duct tape on the BACK SIDE of the hole. Then mix the body putty as instructed, and apply a small amount, but cover the hole.  wait for it to dry, usually 20-30 minutes is plenty of time, sand it with 100 grit, then re apply another dab of Bondo, This time More than cover the hole.  When that has dried very well, sand with 100, the 300 then 600 and primer it.

If you have a way to rough the hole up it does help with both bondo and jb weld adhesion.

 I asked a friend who does metal type resto.  He said a welder.

Show off.


--Shane
KD6VXI

Hi,

Has anyone tried tapping the hole before filling? It seems like the threads would give the filler something to grab onto so it doesn't fall out.

Bob

The proper way is to countersink both sides of the hole in the panel, then buck a countersunk rivit into the hole. The buck tail is then microshaved flush to the surface.

I checked out the JB Weld products. Looks like the way to go. Will countersink the holes first.

They make a "steel" filled epoxy.
It's slow set.

Hard as a rock. :D

Should be "good enough".

WBear: that's what I used. I'll give it another day to cure but so far, I've used a file to get started with the finishing. Works! Thanks!