i am looking to fill some holes about 3/8", irregular shaped, in 1/4" thick
steel plates. Anyone have any suggestions for filling in these divots?
They are deflection plates at the firing range for the local PD. There is a
4x4 angle iron riser, 3/8" thick, bottom of the "v" facing the shooter. The
angle iron holds two 8x18, 1/4" thick, plates angled away from the shooter at
45 degrees to each side. The plates and riser will deflect typical pistol
rounds, but not rifle rounds. Rifle rounds haven't penetrated, but do create
pits. I'd like to see if there is a way to fill in the pits without having to
replace the entire plate or riser.
Any help would be appreciated.
Yes, they can be filled. I wouldn't recommend it, tho. Most likely
easier, faster, safer, and cheaper to replace the plates.
I will presume you are talking about a mild, commodity steeel such as
A36. If it is a specialty steel, my concerns would be increased.
I have several reasons: (opinions may, and likely will, vary)
The plates take quite a beating, and will be worked where they are
imacted. The embrittles the steel. Whee weld metal is applied, this
will be annealed, but elsewhere it won't. As the steel is becomes more
brittle, is is more likely to fail. This may not be by cracking
visibly or outright breaking, but by spalling shards off. Not likely
to hurt anyone, but could lead to failure at an inopportune time.
Where they plates have been hit, there is likely a lot of
contamination (lead, which causes a lot of trouble when welded),
copper, and other jacketing materials as well. They will be embedded
in they surface of th metal whee there are flaws, as well as by the
impact energy (lots of force, and lots of heat. The contamanants will
alloy at the surface) Thourough prep by grinding will remove take
care of this, but how much is your time worth? A sheet (4X10) of 1/4"
A36 costs about 2 or 3 hours for me at my best local supplier.
Even experinced welders have trouble controlling distortion when
doing this type of repair. If the plates become distorted or puckered,
will they be acceptable? This really is a serious concern, as a small
area can apply tremendous force to bend the plate as the weld cools.
Now, if oyu deide to repair the sheets, one method (easiest) would be
to pad the areas and grind smooth. Generally, a pad is done by running
stringer beads across the area, each bead overlapping the previous one
by half of its width. If one layer isn't enough, another can be layed
on top. Preheat is useful for controlling distortion.
If the pits ae small enough, they can be rosetted. This requires more
skill, but uses less weld metal and is faster.
Padding is fastest with MIG or fluxcore, but requires a fairly high
skill level to get solid metal (Iv'e watched a lot of 'good' welders
lay crummy pads with MIG, even when they can run great groove welds.)
I would not use MIG or fluxcore for rosetting -- too easy to leave
pores or trap slag with fluxcore, leaving a place for failure to
I don't know if I would want a filler with high impact strength or
not- Might help with longevity.
Thanks for the input.
I ended up talking to a local welder, and he was able to fill in the dings on
the riser post, and we made a new plate from A36. That was his suggestion, I
gave him no input such as yours. Took it to the range and gave it a pounding,
performed just like the original plate.