Butt welding 5/8" plate to make a griddle?

[challenger]

I have a Blackwood grill/griddle. It's Chinese garbage and the griddle is very thin material. I have some 5/8" X 8" plate that I'm going to butt weld together to give me a 15" square griddle plate. My question is how much do I need to grind from the edges of the weld area. Obviously half way would be ideal but can I get away with just 1/4" or so since the edges fit tightly together?
Thanks

[sarge41]

Challenger: Are you talking about 1/4" from each side? To keep it somewhat flat, you will need to weld from each side.
Sarge41

[BCRider]

I'd clean up a single piece and try it first. 5/8 plate is really thick and heavy. I suspect that it'll take a lot of time to heat up and it won't be able to alter temperature very fast with all that "heat mass". I'm rather thinking that you'll find it's too thick.

Consider that even the heavier cast iron fry pans are only around 3/16 thick as an example.

Hey, if I'm wrong and the 5/8 turns out to do a great job then great. But either way it won't take much time to clean up and try a single piece first.

[danlb]

My understanding is that the bevel is to provide more filler to base contact area. You might look at it as 1/4 inch bevel simulating 3/8 inches of penetration. That's assuming that your welder can penetrate 1/8 or more reliably.

When I did a similar project with a 90 amp flux core welder I beveled both sides and was able to complete it with a single pass on each side.

[Willy]

What Dan said.
A good bevel on each side for maximum penetration, alternating passes from bottom side to top side in order to control distortion. The big factor of course as Dan eluded to is what type and process you have available. A big DC stick machine will of course be more capable and forgiving than a small mig machine insofar a penetration is concerned. Preheat may also help to control penetration and distortion.

Also I don't believe 5/8" plate is going to be too thick since most commercial griddles range in thickness from 1/2" all the way to 1". The thinner griddle tops are usually used for fast food/breakfast kitchens as they do allow for quicker response times. Amazing to see 1" plate gas fired griddles, definitely high end stuff and expensive., but oh so nice to work with.
The 5/8" plate should definitely be leagues above most of the consumer grade griddles. Keeping it flat is key to a happy user experience.

Edited due to grammar errors.

[Tungsten dipper]

Just be careful the weld doesn't pull and you lose your flatness.

[Baz]

Would it be worth heating up the plate beforehand anyway to see if it has some built in stress it wants to let go.

[challenger]

Would it be worth heating up the plate beforehand anyway to see if it has some built in stress it wants to let go.

Meh, maybe but the plate is mild steel and not CI. It's also been laying around my shop for over 10 years and if it all goes to hell I don't really care. At least I have a project that keeps me out of the house and may possibly make the wife happy for a nano or two😁

[Captain K]

Why would you need a continuous full penetration weld on a griddle? That’s just asking for distortion. Grind a small bevel an inch on each end and couple spots in between in both sides. 4 one inch welds on each side should hold up pancakes I would think. I suppose a small bead all the way across to hold anything runny on top would probably be fine after the other welds are done

[JRouche]

Obviously half way would be ideal but can I get away with just 1/4" or so since the edges fit tightly together?
Thanks

%/8", that will make a nice cooktop. I think a 1/4" bevel should be fine. Yer not stacking any cars on it are you? JR

[bborr01]

I'd probably grind about a 1/8" bevel on both sides and then then alternate welding one side then the other as needed to control warping.

[nickel-city-fab]

Meh, maybe but the plate is mild steel and not CI. It's also been laying around my shop for over 10 years and if it all goes to hell I don't really care. At least I have a project that keeps me out of the house and may possibly make the wife happy for a nano or two😁

Would like to add, that preheating with a large propane torch can make the welding go much easier on the heavy stuff like this. My rule of the thumb is to bevel down to leave a nose as thick as the filler material -- on 5/8 would prefer 1/8" 7018 rod at around 130 amperes. With plenty of tacks and braces say every 4 inches until you have a solid root on both sides. So that would mean a 1/2" bevel, leaving a 1/8" "land" or "nose" on the plate, being the usual industry recommendation for 100% penetration.

Its gonna take a while to heat up that plate with anything less than a bag of charcoal and a leaf blower. But that might be a good way to normalize it and lessen the chance of warping, if you do the job while its good-n-hot.

[metalmagpie]

Just be careful the weld doesn't pull and you lose your flatness.

But if it does, before you scrap it, consider flame straightening. You'd have nothing to lose at that point.

Personally, I'd go find a piece of flat 1/4" plate that isn't all pitted. Or, flycut your plate on both sides. That would clean up the weld bead as well.

For your initial seasoning, use peanut oil and rock salt. Keep scrubbing the salt in copious amounts of hot oil until the steel blackens. Do one part at a time.

And, if you decide to spend your way through this project, go visit https://www.mojoegriddle.com. They have a great product.

metalmagpie
who has built a bunch of cookers

[darryl]

Is steel plate really a good material to use? I suppose it will get seasoned much like a cast iron pan, but in the meantime it may give off a taste-? Just asking.

[reggie_obe]

Is steel plate really a good material to use? I suppose it will get seasoned much like a cast iron pan, but in the meantime it may give off a taste-? Just asking.

Would it be very different than food served from a cast iron skillet? My only concern would be minute additives in the rod.